Sunday Thunder Threat

The heat will gradually be on this weekend, with 90 degree weather hitting the region on Saturday and perhaps lingering for as many as five days into the middle of next week.   Sunday originally looked like the hottest day of the stretch, with an outside chance of 95 degrees as soon as yesterday's computer guidance, in advance of a cool front that is poised to slide on through the region with a thunder threat.   The timing of the front looked originally to be late afternoon and early evening with thunderstorms popping up along and with the weak frontal boundary. Some hints are showing up that the timing could end up being a bit earlier on Sunday.

Most computer guidance from this afternoon is suggesting either a midday or afternoon thunder threat...some of which could be severe. It doesn't look like an all day event and thunderstorms could fire on a line (frontal boundary) and slide southeast.  Whether the storms fire at 12, 2, or 5 is always an exercise in "to be determinedness" but the odds of some thunder on Sunday are pretty good.

Regarding the weekend as a whole, it will be very warm as temperatures will be in the 90 degree range or the low 90's for the weekend.   Not the hottest on record (no 100 degree weather in sight) but it's still a "typical" summertime weekend around the Delaware Valley, with Sunday the one day with a thunder threat.

Dropping The Snowless Winter of Our (Dis)content

Tomorrow marks the "official" release of the newest average temperatures for Philadelphia from the good folks at NOAA and the National Weather Service. This new data incorporates the 2000's while discarding the 1970's from the mix as average temperatures are calculated on a 30 year basis locally. One of the things you will notice with average daily highs and lows is that they are smoothed out over the course of the year since the average high and low on a given day can change by a couple of degrees. The data smoothing process takes out that "jumpy" nature so the average high doesn't go from say, 80 on June 4th to 84 on June 5th back to 81 on June 6th. Drat that dreaded quality control process...just kidding!

Some of the data, specifically monthly averages, can already be used since it is based on raw data and is generally not subject to smoothing. There are a few trends, some not surprising in the grand scheme of things.

1) The average temperature in Philadelphia on an annual basis has increased by a half degree, from 55.3 to 55.8.   The 1970's did feature several years of coolish temperatures (averages in the 53 or low 54 degree range) which are below the historical 1872-2010 average of 54.8.   Discarding those years will naturally account for some temperature hike...as will the warm stretch in the 2000's.   No single month saw their average temperature drop although December's average looks to remain steady at 37.4.   All other months saw the needle move higher by at least 0.3 degrees, with February, April, and June gaining 0.9 degrees on average.

2) Winter snowfall average has increased from 20.2" to 21.8" -- the 1971-1980 time frame that's being dropped averaged 21.8" while the 00's averaged 26.8" so the increase in snows in this decade -- thank you three winters of 30"+ and December 2010 for the increase.  While the late 70's were relatively snowy, the early parts of the decade were not and the snowless winter of 72-73 is no longer factored in the average snowfall...the snow starved should rejoice knowing the measuring stick of average is a full 1.6" higher.

3) Rainfall averages dropped about a half inch for the year -- winter averages trended a bit more dry while the rest of the year didn't see much major change in the rainfall department.   July is still the wettest month locally, February the driest.  October and November flipped spots as the 'dry' month in the Fall season.

In 2001, the average temperatures were bumped by a full degree as the 1960's were discarded.  This decade's average climb was a half degree.   I'll post more info this weekend about the temperature changes on a daily basis but figured I'd throw the first parcels of data out there for consumption.

July 1st, 2011 Forecast

This stretch of weather has been pretty much picture perfect by summer standards -- modest humidity, tolerable temperatures, with not many folks hatin' on the weather!   We have one more good day before things warm up for the 4th of July weekend...and yes, the 90's will return for a few days, perhaps as many as five in a row.   That heat stretch doesn't look terrible considering the highs will probably just nudge 90 on most of the five and perhaps could come up short next Tuesday and/or Wednesday.   I'm getting ahead of myself though -- we'll talk more about the upcoming warmth later on tonight.

The weather for tonight and tomorrow looks great -- lows tonight between 58 and 65 locally with light winds and mostly clear skies, highs on Friday in the mid 80's with mostly sunny skies and low humidity.  The Shore should reach the low 80's since the wind is primarily offshore.

Weekend Sneak Peek:   The warm up will bring 90's for the 4th of July weekend, with a trough/weak cool front sliding down from Canada with a decent thunder threat on Sunday afternoon and evening.  There could be a pop up storm on Saturday afternoon but odds are favoring most of us staying dry.   Sunday's storms could be strong if not severe -- we'll update those chances as we go through the weekend.  The 4th looks dry for now with lowering humidity but temperatures should approach or hit 90 in most spots on Monday as well.

Low humidity airmass...

Our region gets to enjoy a nice break from the heat and humidity over the next couple of days. Dewpoints will be in the 50s today and tomorrow (even some 40s dps in some spots this afternoon), meaning humidity levels will be very low. Combine that with full sun and highs in the upper 80s and lower 90s, and the result is a couple of nice summer days.

The heat and humidity will build back in over the upcoming holiday weekend with highs well into the 90s Saturday and surging toward the upper 90s in many spots Sunday.

Afternoon storm chances return Sunday and extend through much of next week. If your fireworks display of choice is Saturday night, odds are you will be dry. However, some of the region's displays Monday evening will have to dodge some scattered storms.

Arlene...

Tropical Storm Arlene made landfall near Cabo Rojo, Mexico this morning as a 65mph tropical storm. I believe if the system had another 6-12 hours over water, it would have become a hurricane.

The big problem from Arlene will be flooding and mudslides in Mexico.

Arlene Heads Towards Mexico

The season's first tropical system is churning towards the Mexican coastline and is setting itself up as a prolific rain maker for Eastern Mexico.   Arlene is a 50 mph tropical storm as of this early evening and is slowly organizing as it moves west.  It will probably make landfall on Thursday morning near Tampico, perhaps as a strong tropical storm in best case.   Some of the hurricane guidance out there is suggesting a potential minimal hurricane but there is not much difference between 65 or 75 mph in wind in a minimal area near the storm's center.

The big issue regardless of intensity will be the rainfall over a large portion of Eastern and Northeastern Mexico over the next 48-72 hours.   The Euro computer model, see below, is suggesting more than a foot of rain for parts of the Sierra Madre Mountains in Mexico through Saturday and the GFS is in similar agreement about precipitation potential for areas south of the border   The storm will weaken markedly in wind strength quickly after landfall but will rain itself out over the higher terrain of Mexico, meaning mudslides and flooding are likely.   Deep South Texas might be lucky to get an inch or two of rain from this, all of it sorely needed as they are in a major drought.  

More:  National Hurricane Center

June 30th, 2011 Forecast

As far as late June goes, a day with modest humidity levels and plenty of sunshine provides a great reason to celebrate.  Temperatures tomorrow should get into the mid 80's for nearly everyone with plenty of sunshine and dew point levels in the 50's.    It will be a nice respite from humidity (that's coming back this weekend) and continue our relatively dearth of 90 degree days as we have only topped 90 degrees once since June 10th.   That respite should come to an end as we work into the 4th of July weekend as low and mid 90 degree weather oozes into the region and hangs around for much, or all of the holiday weekend.  Until then, enjoy the next couple of days as the weather is about as ideal as it can be in late June locally.

Tonight will feature mostly clear skies and lows from the upper 50's in the burbs to mid 60's downtown, with the region generally in the mid 80's (80ish at the Shore) with west-northwest winds at 10 mph.

Coming Later:   An update on the season's first tropical system (Arlene) in the Gulf of Mexico.

Drier, quieter weather...

What an afternoon and evening of rain and storms! Many spots picked up over 1-2" of rain, and some localized locations picked up over 4 and even 5"....obviously flash flooding was problem from some areas. There was also some wind damage to contend with.



However, a cold front continues to ease southward, and behind that front, drier air is working in. For the I-85 corridor up into the foothills and mountains, it should be a dry day with highs in the upper 80s to near 90. Look for similar highs tomorrow with lots of sun.

Enjoy the break from the heat and humidity...it will really surge back in here for the Fourth of July weekend.

Arlene...

Tropical Storm Arlene formed yesterday in the Bay of Campeche, but as I discussed previously, the biggest problem with this one will be inland flooding for Mexico.

Depressed Dew Points in Vegas

Folks in the US Southwest jest about the 'dry heat' factor when temperatures are over 100 degrees during June and July. When dew point values are low, evaporation is sufficient enough to allow temperatures to feel a few degrees cooler than the actual air temperature. In Las Vegas Monday, the dew point-temperature differential was the largest it had been on record for them....129 degrees (see the last line of the photo below).

The temperature was 107 late Monday afternoon in Vegas while the dew point was a thirst-inducing -22.    Even in the most arctic of airmasses locally our dew point levels will rarely get below -15 in the dead of winter...a -22 dew point is even rare for the high desert in the heat of summer.    The culprit?   My guess is that gusty winds that downsloped off of mountains to Las Vegas' south and southwest yesterday played a role in the huge dew point-temp differential, allowing the air to dry out further and warm up more.

With the dew point factored in, the heat index in Vegas yesterday afternoon was in the mid to upper 90's at the height of the dew point drop.   Hardly comfortable but certainly better than 107!  

Some (Not Much) Thunder Lurking Around

It's warm and humid out this afternoon -- thankfully, not as warm as advertised as the midday showers/storms from this morning's discussion slipped through and were able to provide enough cloud cover to prevent a run at 90 degrees.   Still, though, it feels rather warm around town as temperatures plus dew points make it feel like 85-92 depending on location.   A few thunderstorms are around in Central Pennsylvania late this afternoon, slowly trudging east, and some activity can't be ruled out locally in a few hours.   I don't expect widespread thunder thanks to this morning's activity and more widespread activity down in Virginia stealing the juice from the atmosphere.

With that said, an isolated thunderstorm in spots can't be ruled out this evening...and any storm that moves through could bring localized downpours and perhaps some gusty winds.   Odds are favoring a mainly dry Phils' game...just be forewarned that a rogue storm could cross the region during the game.

More:   Current Weather Page

June 29th, 2011 Forecast

Tonight: Scattered evening storms. Some of these storms could be strong with damaging wind, downpours, and hail. After midnight, skies should become mostly clear. Lows will drop between 63 and 70 degrees. Southwest winds will shift from the northwest overnight at 5 to 10 mph. The chance of rain is about 60 percent. The sunset tonight is at 8:34 PM.

Wednesday: Mostly sunny, breezy, and less humid. Winds will occasionally gust around 25 mph. The high will be near 86 degrees in Philadelphia. Northwest winds in the morning will shift from the west, sustained at 10 to 15 mph. West winds will knock out the sea breeze and the Shore Points will climb into the lower and mid-80s.

Thursday: Sunny skies with low humidity. High around 84 degrees.

Friday: Very warm with bright sunshine. High around 88 degrees.

Wednesday Planner

7 AM 70 degrees, Mostly Sunny

Noon 82 degrees, Breezy

5 PM High near 86 degrees, Less Humid

Sunrise 5:35 AM

Sunset 8:33 PM

Off & On Thunder Threat Today

The muggies are back today -- it won't be oppressively hot out today but humidity levels will be high enough today to bring a summery feel to the region.   Along with more humidity is a risk for thunderstorms throughout the day.  Radar is already picking them up out to the west -- showers and storms in Maryland and Southwest Pennsylvania are slowly working east this morning and we'll see some of that activity around here in a few hours if they hold together.

After whatever amounts from this morning's activity moves through, off and on sun will greet us through the day, further destabilizing the atmosphere and allowing for more thunderstorm development this afternoon.   While (as of this morning) there is no declared risk of severe weather from the Storm Prediction Center, this airmass yields the potential of a few storms reaching severe criteria later on today in Pennsylvania.   The threat of localized heavier downpours exists as well and may ultimately be the bigger threat, not damaging winds (although those can't be ruled out).   Thunderstorm development looks to be scattered in nature (see below), with the focal point generally starting in Central Pennsylvania and then working east or east-northeast.   Models are uncertain about how widespread the thunder threat is and exact timing, with the NAM a bit later compared to the GFS on firing stuff up.   Odds, however, favor late afternoon through late evening (5-11 PM) locally for storms to move through, which means the Phils' game could have some delays if the timing is "right."

More:   Current Weather Page

Scattered storms...

First of all, I wanted to mention that I will be participating in the Media Mayhem bus race out at Charlotte Motor Speedway this evening. I will be taking on some of the other media personalities from around the region. Gates open at 4:30pm, and some other racing action begins at 5pm. I believe our race is right at 8pm.

It should be a great time, and hopefully Conklin, Panovich, Justus, myself, and all can put on a good show. Come on out!

Here is the press release for the event.

Today's forecast features good chance of scattered storms, especially this afternoon and this evening. It will not rain all day, and I can't even say everybody will see rain, but I do expect a good number of showers and storms. Highs will be in the low to maybe mid 90s in spots.



Drier air will work in tomorrow behind a weak cold front, and that should limit any storm chances tomorrow to areas close to I-95 over to the coast. Everybody in the region should be dry Thursday and Friday.

The heat and humidity will return of the Fourth of July weekend with some mid 90s back for much of the Piedmont.

Tropics...

Monitoring an area of disturbed weather in the southern Gulf of Mexico...it might become our first classified tropical system of the season, but it looks as if it will head into Mexico. Flooding will likely be the biggest problem with this.

Potential for First Gulf Tropical System This Week

Some potential good news for parts of drought-stricken South Texas.  A tropical wave has been slowly oozing northwest through the Yucatan and has emerged into the southern parts of the Gulf of Mexico today, with computer modeling from the GFS and EURO both showing that this system has the potential to organize into a tropical system this week before it makes landfall along the Mexican coastline.   The Euro is the slightly stronger and farther north of the two computer models compared to the GFS but both are consistent in keeping the storm a tropical storm to the coast.

These early season systems are typically weaker in nature (there are notable exceptions like Audrey back in the 1950's) but there isn't much to suggest that this system becomes anything more than a tropical storm in the next couple of days...if that.   Guidance is generally pointing at a landfall a good distance to the south, which will send most of the heavy rainfall into Mexico.  However, the Euro suggests an inch of rain is possible for Brownsville and Padre Island, with potentially some rainfall as far north as Corpus Christi.  Granted, it's not getting to the areas that need it just as bad but considering the state of the drought in Texas any rain in any location is helpful at this point for those folks down there.

I would not be surprised if we have a tropical depression in the Gulf of Mexico by tomorrow evening, with perhaps a tropical storm on Wednesday afternoon or evening in time for landfall Wednesday night/early Thursday morning.   Intensification to a hurricane out of this system seems very unlikely at this point.

June 28th, 2011 Forecast

An advancing cool front will cross the region tomorrow evening while a warm front tied to the front lifts northward this evening and overnight.   The two of them will tandem together to bring thunder threats to the region -- first from the warm front tonight and then from the advancing cool front on Tuesday.   With the latter, localized downpours are possible in locations throughout the region with afternoon thunderstorm development.

Tonight, however, brings a few thunderstorms to the region with the warm front lifting northeast.  Odds are favoring the storms generally across New Jersey and Delaware this evening and overnight as the warm front lifts northeast but a few could sneak into Pennsylvania as well.   Temperatures tonight drop into the mid and upper 60's in many locations.    On Tuesday, the advancing cool front will trigger scattered afternoon and evening thunderstorms that could bring heavy downpours in spots...if not some localized severe weather in others.    Highs on Tuesday will range from around 80 at the Shore to 85-90 inland, with upper 80's expected around Philadelphia.

Week Ahead:   After tomorrow's thunder, a trio of nice days are likely as temperatures hang in the mid and upper 80's with modest humidity levels.  Thunder chances return for the 4th of July weekend in advance of a cool front.  Ahead of the cool front, a couple of 90 degree days can't be ruled out on Saturday and Sunday.   We'll continue to update the 4th of July forecast as we approach the holiday weekend.

Potential For Strong Storms Tomorrow

With a frontal boundary working east tomorrow into our region, warmth and humidity will provide the spark necessary for thunderstorm development during the afternoon and evening hours. Questions linger regarding how much rain is possible but there is some potential for heavy rain around the region as these storms develop tomorrow and march east.

Modeling is indecisive about the exact location of heavy rainfall -- the NAM (see below) places the heaviest and strongest thunderstorm activity to our north while the GFS places it to our south. The Euro doesn't give any one spot overly heavy rainfall but plants a general swath of half inch rains from tomorrow's thunderstorms. Predicting exactly where summertime thunder drops heavy rain is a low confidence prediction more often than not but noting that more computer models than not are showing the threat for heavy rainfall tomorrow afternoon and evening is worth bringing up.   Some spots could see an inch plus of rain -- if it is Philly or south, the rain will be quite welcome as things locally have been a bit dry of late.

We could see thunderstorms locally as early as later tonight as a warm front associated with this system lifts northeast up the coast. Thunder could break out this afternoon to our south in Virginia and lift northeast slowly this evening along the coast or across New Jersey.    However, the main burst of activity should be later tomorrow with the front crossing the region.

Some of tomorrow's storms could potentially go severe, especially north/west of the city.   Odds don't favor a widespread outbreak of severe as dynamics with the front aren't all that great but with a humid atmosphere and temperatures in the mid and upper 80's the potential does exist for some stronger thunderstorms in the afternoon hours.

Back to storm chances...

After a nice break from the humidity over the weekend (especially Saturday), we are back into the warm, muggy conditions today. The result will be scattered showers and storms, especially this afternoon and evening. Some storms could be severe, and the biggest threat today will be from damaging winds.

A cold front will approach tomorrow, and I anticipate a pretty good coverage of showers and storms by tomorrow afternoon.

That cold front is the leading edge of another push of drier air that will settle into the region by Wednesday. For much of the Piedmont, Wednesday through Saturday are looking dry with warm to hot afternoons and fairly pleasant overnight conditions. A few PM storms look to return for Sunday and the Fourth.

Tropics...

As I mentioned last week, some modeling continues to show development over the southern Gulf of Mexico over the next couple of days. If anything does develop, the biggest threat would likely be from inland flooding over the mountainous terrain of Mexico.

Weather Rewind, June 19-25, 2011

Temperatures last week were warmer than average -- coming in at 3.7 degrees above normal.  No one day was excessively hot or cold, with Wednesday's 92 degree high the only day last week above 90 degrees as the overall weather profile for last week was pretty typical for summer...lots of 80's, scattered thunderstorms on several days, but no heat waves or cold snaps during the week.   The biggest weather story was probably the funnel cloud sightings at a couple of different times last week in New Jersey, along with some scattered storms that caused some damage in parts of the area on Wednesday afternoon.

The operative word with the storms of last week were "scattered" since not all of the region benefited from their rains.  In fact, Philadelphia picked up just 0.09" of rain last week and other areas to the south picked up nary a drop or two of rain through the course of the week.  Allentown, on the other hand, picked up over two inches of rain on Thursday from thunderstorm activity and Reading, just 30 miles away, picked up only four tenths of an inch for the entire week.

June 27th, 2011 Forecast

Tonight: A mix of clouds and stars. It will be comfortable for sleeping with lows dropping between 59 and 66 degrees. West-northwest winds will shift from the north overnight at 5 to 10 mph. The sunset tonight is at 8:33 PM.

Monday: Warm sun. Expect just a few clouds passing through from time to time. The high will be near 87 degrees in Philadelphia with lower 80s likely at the Shore. North winds in the morning will shift throughout the day, eventually becoming southwest at 5 to 15 mph by the late afternoon hours. The UV Index will be at an 8, which means you can burn in about 25 minutes.

Tuesday: Hazy sun, humid, and very warm. There is a 60 percent chance of thunderstorms popping up, especially in the afternoon. Some of these storms could be strong to severe. The high will be around 89 degrees.

Wednesday: Less humid with scattered clouds. Breezy with occasional wind gusts around 25 mph. The high will be near 85 degrees.

Monday Planner

7 AM 66 degrees, A Bit Cool to Start

Noon 82 degrees, Few Clouds

5 PM High near 87 degrees, Warm Sun

Sunrise 5:34 AM

Sunset 8:34 PM

Running Scared...

The Weather Channel has a new ad out poking fun at Jim Cantore's penchant of showing up where disaster has or is about to strike.  It's somewhat funny...of course in the winter most snow lovers want Jim Cantore in their backyard if there's a winter storm on the way so I doubt that people would be running away...unless it was to the ACME for bread and milk.

Link to video (via youtube)

Forecast for Sunday, June 26, 2011

Cumulus clouds early this evening will dissipate with the loss of daytime heating. Skies should become clear across the entire region. An area of high pressure to our north will control our weather for Sunday, providing dry weather conditions. Skies should be mostly sunny with perhaps a few afternoon cumulus clouds appearing. On Sunday Night, a few cirrus clouds could enter the picture, moving up from the south.

On Monday, the cold front responsible for pushing out the high humidity from late this week will return northward as a warm front. The front may take a great deal of time pushing through the forecast area and it may not be until Tuesday that it lifts through a good part of the area. Yet again, there are considerable differences as to the movement of the front. This placement has large implications on temperatures and possibility of severe weather. It sounds like a broken record.

For Tuesday, we will assume that Philadelphia enters the warm sector, and makes a run at 87-90 degrees. With a shortwave riding along the warm front, showers and thunderstorms are likely. Again, if a portion of our area lies immediately south of the boundary, some of these storms could once again become spinners. It is too early to nail down the exact location and it may end up that it is entirely north of our area. We will also have to keep a watchful eye as to how close the cold front gets as the warm front is lifting through. That could also provide added lift. I would much rather have the cold front swinging through when the warm front is well to our north to avoid spinning thunderstorms. Anyhow, the cold front is expected to move through on Tuesday Night, likely preceded by a pre-frontal line of thunderstorm development. Some of the modeling keeps the front in New Jersey and Delaware through Wednesday Morning.

There could be some locally heavy rain on Tuesday, perhaps leading to another flash flood threat, especially in the northern counties. I expect some locations to get another one to two inches of precipitation. Precipitable water values become fairly decent by Tuesday Morning.

From Wednesday Afternoon through Friday, conditions look warm…but not humid. I don’t see any opportunities for much in the way of measurable precipitation.

Heat Index 101

I rambled in a post here last July about the difference in using dew point versus using humidity in describing how humid it feels outside, with me trying to make a case that dew point is quantifiable as opposed to a relative measurement of atmospheric moisture.   Most folks wouldn't know that 78% humidity on a 60 degree morning isn't humid whereas they would know that a dew point of 53 on a 60 degree morning in summer is rather comfortable.

We're asking in a poll here if you feel heat or humidity is worse -- and so far the results aren't surprising as humidity wins handily.   Taking it to another level, I figured that I would help explain the tie between dew point (and humidity) and temperature when it is hot out.   Most know what a heat index is -- the "feels like" temperature that combines the impact of heat and humidity together.   Some call it the summer equivalent of wind chill although that's a bit of a malaprop and misnomer since heat index does not account for wind nor does it feel chilly on a hot and humid day.   Regardless, the heat index is really the tell tale sign of how it really feels outside.   The higher the dew point (or humidity level) at a constant temperature, the higher the heat index.

Heat index is a critical measurement used to determine excessive heat warnings and heat advisories locally.   Typically, 100 degree heat index values are the standard to issue heat warnings in the Delaware Valley but in the early parts of the summer the criteria is lower (96 before June 15th, 98 in the latter half of June).

When we have a 90 degree day, we generally feel that it is very warm if not hot outside.   Just how hot it feels depends greatly on the dew point outside.   If we have a comfortable atmosphere with dew points in the 50's, the apparent temperature (heat index) is lower than the air temperature as evaporation off of our skin from sweat and regular ol' moisture transport around the body will cool us off somewhat, not accounting for any additional wind that may help keep us comfortable.  As dew points reach around 60, that evaporation benefit is negated and temperatures feel as warm as advertised.   It's hot but most everyone can deal with it feeling like 90 degrees out.   The higher the dew point gets, the higher the apparent temperature becomes on a hot day.   If the actual temperature is 90 and the dew point is 75, the heat index is 100 on that given day and we're all sweltering.

The heat index is a sliding scale, meaning the higher the dewpoint and/or higher the temperature, the progressively worse it will feel.   If we keep a constant 75 degree dew point but increase the temperature from 90 to 95, the heat index is now 107 (seven degrees worse).  Increasing the temperature to 100 with a dew point of 75 brings us an ungodly heat index of 114, whereas a dew point of 50 at 100 degrees yields a heat index of "just" 97.   At some point, even the "dry heat" folks will begin to complain when the air temperature gets too hot, despite a lack of atmospheric moisture.

June 25th and 26th, 2011 Forecast

Tonight: There is a 40 percent chance of scattered thunderstorms this evening. Some of these storms have the possibility of being strong to severe with damaging wind, downpours, and hail. Lows will drop between 61 and 68 degrees across the region. Winds will be out of the west-northwest at 5 to 10 mph. The sunset tonight is at 8:33 PM.

Saturday: Mix of sun and clouds. Dew points will be falling throughout the day, making it feel much more comfortable by the afternoon and especially the evening. A 20 percent chance of an isolated thunderstorm remains in the forecast. The high will be near 86 degrees in Philadelphia, with mid-80s also expected at the Shore. Winds will be out of the west at 5 to 15 mph with occasional gusts to 20 mph.

Sunday: Few clouds and nice ! The high will be around 82 degrees.

Monday: Warm sunshine with a high around 86 degrees.

Saturday Planner

7 AM 68 degrees, Mix of Sun & Clouds

Noon 81 degrees, Isolated Storm

5 PM High near 86 degrees, Less Humid

Sunrise 5:34 AM

Sunset 8:33 PM

Drier air moving in...

Scroll to the post below this one for the radar images of a rotating thunderstorm in eastern Tennessee last night.

Here's today's edition of the video...


A cold front is progressing through the region today, and that front will usher in some drier air for us for a couple of days. Highs today will be in the 89-92 degree range for much of the region. The best chance of any storms today will be roughly from I-95 over toward the coast.

We are setting up for some very nice Saturday weather. Look for low levels of humidity and lots of sun....and the chance of rain will be very low. Highs tomorrow in the Piedmont look to be in the upper 80s to around 90.

I will maintain a small chance of a few storms very late Sunday, but it's really looking like Monday is the day with good chance of showers and storms as a disturbance approaches from the west.

Tennessee Overnight...

A rotating thunderstorm possibly producing a tornado moved through eastern Tennessee overnight last night. Here is a reflectivity and velocity image I snapped when the possible tornado was just west of Knoxville...

New Video of Ocean County Funnel Cloud Surfaces

NBC 10 aired a new video earlier today of the funnel cloud which occured yesterday in Jackson Township which is located in Ocean County. The photo we posted earlier today from Channel 6's Action Cam caught was a view from Plumstead Township.

Perhaps what is most incredible about this video is that it shows that for a brief time there were two vortexes that formed out of the wall cloud.

NBC 10 obtained the video from Patrick Mackin.   The full video can found below, which is 5 minutes in length:

Forecast for Friday, June 24, 2011

As of 3:00 p.m., a few thunderstorms were developing across Monmouth and Ocean Counties into New York and Long Island & Atlantic. An area of showers around Baltimore and Delaware was moving into the southern and western sections of our region. As this area of showers moves into the area into this evening, some thunderstorms may evolve with heavy rainfall, frequent lightning, and possible severe weather. We remain under a slight risk for severe weather by the Storm Prediction Center. Overall…better forcing is on tap for Friday to produce more organized lift. Some cloud debris from the showers and thunderstorms that impacted the Poconos, Northern New Jersey, and New York could have been effective in reducing the coverage of pop-up thunderstorms. We will maintain a chance of thunderstorms and a chance that any storm could turn severe given the potential energy, moisture, and shear in place.

Otherwise: Another active day is expected on Friday. Friday could be quite busy with numerous strong to severe thunderstorms. Tomorrow we will have a true forcing mechanism in the form of a cold front. Damaging winds, large hail, and an isolated tornado are possible in any thunderstorm that turns severe. Tomorrow’s storms will rely on temperatures to excel for a few hours with some breaks through the clouds. Should some unforeseen circumstance reduce the sunshine, then we may have to evaluate the threat. Overall, I think even without much sunshine, some wet microbursts and hail may occur with the moisture in place. Dew points are about as high as we can achieve this time of the year with readings in the seventies. We are under a slight risk designation for severe thunderstorms for Friday in the Storm Prediction Center Day 2 outlook.

For Saturday, lingering energy could trigger a few isolated thunderstorms. High pressure and drier air move in Saturday Night and provide some relief for Sunday and Monday. Questions evolve around Tuesday and beyond with more warm frontal and cold frontal fights in store. For now, we will insert thunderstorm and shower chances by mid-week.

More Severe Thunderstorms Today Likely

This morning, we awake to some stunning photos and videos caught by WPVI-TV showing what appears to be a funnel cloud developing around New Eygpt in Ocean County during Wednesday Afternoon's thunderstorms which caused a lot of damage in Ocean County. Plumstead Township is the same area where a tornado was confirmed last year.

More severe thunderstorms are likely today.

Morning clouds with some breaks of sunshine will allow for strong surface heating to take place today. Pop-up thunderstorms will occur as early as late this morning and become more numerous this afternoon. Damaging winds and large hail are the primary threats. An isolated tornado cannot be ruled out.

We are under a slight risk of severe thunderstorms for today and on Friday. There is a 15% chance of severe weather occuring within 25 miles of a point.

Scattered showers and storms today...

Showers and storms that were over Alabama and Georgia during the pre-dawn hours will be working into the Piedmont later this morning and into this afternoon. Due to the early arrival of the showers and storms, temps in the I 85 corridor will be held down.....look for 80s for highs.

For tomorrow and Saturday, the coverage of showers and storms will be less....probably in the isolated category. Highs will be in the upper 80s and lower 90s for most.

It still looks like better storm chances will arrive again for Sunday and Monday.

See today's video for more on this, plus some tropical talk...

Fire & Flood

The news has been rather active of late with stories of wildfires in Southwest, floods in the Mississippi, Ohio, and Missouri River Valleys, not to mention the wild tornado season we experienced in April and May -- much of which can be blamed on the weakening La Nina that wreaked havoc across the US with record snows and rains in the North and Ohio Valley, while leaving little if any rain to spare for Texas and the Southwest.   Over the last couple of months or so, the most waterlogged parts of the country compared to "typical" have been in the High Plains of Montana and in a belt from the Ozarks through the Northeast.  Notice our region had been just slightly below average over that timeframe...and if you throw out the three inch soaker that pelted our region on April 16th we had been running between 50 and 75 percent of normal in the rainfall department through late last week and before our much needed rains that we picked up late last week and again last Sunday.

Taking that 60 day trend and extending it out to six months, you can see the excessive rains (and snows) to average across the High Plains, an area that had seen excessive snow and rain all winter (going back to November), with the conveyor belt of moisture in the Ohio Valley not as excessive (rains started in earnest there in February).   The dryness, however, of the South and Southwest has been persistent -- particularly in Texas as they have been drought stricken and suffering from exceptional drought conditions that have been going on since October.    La Nina is a major consideration in the precipitation patterns of the past winter as storm systems will gravitate towards a northern track and subtropical moisture from the Pacific is less of a factor, meaning that the South stays dry while the North generally is not...the reverse would be true with an El Nino (the South is wet, North is typically not).

Dangerous Rotating Thunderstorms Strike

Today’s warm front made considerable northward progress…and it was the model runs during the weekend which nailed this frontal placement….not the more recent model runs. Temperatures accelerated into the upper eighties and lower nineties with breaks in the clouds. Although we sided with the cooler guidance, as did the National Weather Service on Tuesday, we mentioned the possibility that temperatures could be several degrees warmer should this front nudge northward further than expected. As a result of the area entering into the warm sector, thunderstorms had plenty of instability and surface heating to feed on.

As is typically the case, areas just immediately south of the warm frontal boundary, when a wave of low pressure rides along it, is the prime spot for severe weather development, including the development of tornadoes. In past instances, the sweet spot for the tornado development was the Lehigh Valley into Northwestern New Jersey because these areas seem to classically fall just south of warm fronts that put on the brakes when energy rides along it. However, today the placement of the front was slightly different. The front was further to the south and thus it was areas from Bucks County to Warren County to Ocean County that saw areas of rotation.

A thunderstorm that did not prompt a tornado warning in Whiting, Ocean County is reported to have caused significant wind and structural damage. Unfortunately, one fatality was confirmed. Golf ball size hail also occurred in Whiting. Needless to say, Whiting saw a pretty impressive super cell. An additional thunderstorm prompted a tornado warning early this evening north of Lakewood. The local newspaper and law enforcement is reporting funnel cloud sightings. The Asbury Park Press has gone as far as to say that a tornado occurred in Jackson Township...but soon back tracked the report. We will wait for the National Weather Service to confirm any tornado damage and for potential pictures to surface (if there was anything).

Another thunderstorm around Warren County, which also prompted a tornado warning, caused significant tree damage according to the National Weather Service. Again, we will see if the National Weather Service performs damage assessments in these areas.

It is safe to say these were at least "rotating thunderstorms".

June 23rd, 2011 Forecast

With the first day of summer gone, it is all downhill from here, so to speak. The days will now continue to gradually get shorter until the winter solstice on December 22nd at 12:30 AM.

Tonight: Any thunderstorms that pop-up today will be scattered in nature through the evening hours. It will be stuffy and muggy overnight with lows dropping between 67 and 72 degrees. South winds in the evening will shift from the west-southwest at 5 to 10 mph. The chance of rain is about 60 percent. The sunset tonight is at 8:33 PM.

Thursday: Hazy and humid. Thunderstorms could pop-up at any time and some could be strong to severe with damaging wind, downpours, and hail. The high will be near 88 degrees in Philadelphia with lower to mid-80s expected at the Shore. Winds will be out of the southwest at 5 to 15 mph. The chance of rain is around 60 percent.

Friday: Hazy sun and very warm. Once again, thunderstorms could pop-up at any time during the day. The high will be around 89 degrees. The chance of rain is about 40 percent.

Saturday: Mix of sun and clouds with just a 30 percent chance of a thunderstorm passing through. Expect a high around 87 degrees.

Thursday Planner

7 AM 72 degrees, Hazy & Humid

Noon 84 degrees, Strong Storms

5 PM High near 88 degrees, Strong Storms

Sunrise 5:33 AM

Sunset 8:33 PM

More heat with scattered storms...

First, some select highs from yesterday around the region...

Charlotte: 96
Greensboro: 96
Rockingham: 100
Laurinburg: 101
Fayetteville: 101
Charleston: 102



It will be another hot day today with highs in the mid 90s for much of the Piedmont...and once again, some of the traditionally hotter spots could see upper 90s or even 100.

Like yesterday, we will likely see some scattered storms fire off this afternoon through this evening, and again, some storms will probably be severe in addition to being prolific lightning producers.

The heat still looks to subtly back down this weekend into early next week with some upper 80s creeping in for many highs.

Forecast for Tuesday, June 22, 2011

1:16 p.m. marked the official start of the calendar Summer. Enjoy the extended daylight for the next few days with some of the longest days of 2011 ahead before we begin to lose.

The main weather feature we will be following for the next 36 hours will be a slow moving warm frontal boundary that will meander through our forecast region. This is an extremely difficult forecast and the latest computer model guidance is not providing any cleat answers as to the progress of this front. The models are all over the place. This has major implications as to temperatures, dew points, and placement of precipitation.

If the warm front remains right over our region…and cloud cover remains persistent…temperatures could be held in the lower eighties at best…and we would just see some scattered showers and thunderstorms with the main threat heavy rainfall. Extreme southwestern sections of the area would be the exception and the place to watch for thunderstorm’s reaching severe criteria.

If the warm front lifts through at least the southern two-thirds of the region…we would see some sunshine break through the clouds…temperatures spike into the middle and upper eighties with even a few 90 degree readings…and we would be in the favorable quadrant for severe thunderstorms if indeed a wave develops and portions of our region lie immediately south the front within the warm sector.

At this point…it does not appear that the warm front’s movement is so aggressive that the entire area enters the core of the warm sector and thunderstorms remain mainly to our north.

Since late this weekend, the Storm Prediction Center has kept us in a slight risk for severe thunderstorms. With the uncertainty, they have removed our region from the risk…but have kept “see text” probabilities. Depending on the cloudiness…they very well may need to bring back the risk designation for Wednesday as some downbursts and hail could develop in the strongest thunderstorms. Near the warm front can also be a favorable area for the development of rotation. Needless to say, we will be keeping an eye on any developments tomorrow as it will be a day of near-term decisions and now-casting.

On Thursday, the warm front should move to our north. This should allow the region to enter the core of the warm sector. The mostly cloudy skies should clear and the region should be partly sunny with a buildup of cumulus clouds as afternoon heating takes place. With an approaching cold front from the west and hot and humid conditions…thunderstorms…scattered in nature…will be a possibility. The best chance will likely be near the focus…so north and west of Philadelphia. The entire region has been placed under a slight risk designation of severe weather in the Day 3 Convective Outlook that issued by the Storm Prediction Center. Bay and sea breezes...if they can move inland...would help serve as a possible focus.

The cold front will swing through on Friday. Showers and thunderstorms will be likely as a result. Depending on the timing of the front and amount of destabilization ahead of the front…additional strong to severe thunderstorms would be possible. A lingering opportunity for thunderstorms could occur on Saturday…especially if any upper-level features pass through behind the front.

Sunday and Monday are the driest days of the next seven with high pressure in control and more northerly wind component lowering the humidity substantially….
Flash flooding is also a possible threat Wednesday and Thursday…maybe into Friday.

Summer arrives today...

Check out this AP photo (Dan Weaver) of the shelf cloud that rolled into Omaha, delaying the Florida/ Vandy game at the College World Series last night.



Summer officially arrives at 1:16pm EDT today, but in terms of the weather, it has been Summer for a while.

Yesterday featured some stifling heat in parts of the region. Check out some of the highs....

Wilmington: 101
Charleston: 102
Columbia: 101
Myrtle Beach: 97

Many locations in the Piedmont will be a little hotter today than yesterday with lots of mid 90s on the board this afternoon. Tomorrow's highs will be much the same.

While I expect a few afternoon storms to fire today and tomorrow, the chance of rain in any one locations is pretty small.

Later this week, a weak cold front will approach from the west, and that will subtly increase the daily storm chances. The heat will also back down a bit for the weekend with some upper 80s returning for highs.

Skirting The Horizon

Ever wanted to witness the longest day of the year, Alaskan style?   The video above was captured on youtube last June 21-22 at Midnight Alaskan time at Eagle Summit.   It's a rather crazy view of the sun skirting the northern horizon "overnight" on the longest day of the year...a view I had never seen before until a few minutes before I wrote up this post.

Certainly makes up for what happens six months from now, unless you're a vampire or totally into living in darkness.   Check out the shortest day of the year in time lapse mode and again, this is an equally crazy view of the southern horizon as the sun skirts it.   For those of us out there who suffer from a lack of daylight in the winter, this video might be the best way to "enjoy" the short Alaska day.

June 21st, 2011 Forecast

Tonight: Scattered clouds and comfortable. Lows will drop between 60 and 65 degrees which is normal for this time of year. Winds will be out of the southwest at 5 to 10 mph. The sunset tonight is at 8:33 PM.

Tuesday: Hazy sun, warm, and more humid. There is a 30 percent chance of an afternoon or evening thunderstorm. The high will be near 87 degrees in Philadelphia, and in the mid to upper 70s at the Shore. Winds will be out of the southwest at 5 to 15 mph. The summer solstice is at 1:16 PM, and we will have exactly 15 hours of daylight.

Wednesday: Hazy, hot, and humid with pop-up thunderstorms in the afternoon. The high will be around 90 degrees. The chance of rain is about 40 percent.

Thursday: Hazy sun and humid with scattered afternoon thunderstorms. The high will be near 88 degrees. The chance of rain is around 40 percent.

Tuesday Planner

7 AM 65 degrees, Hazy Sun

Noon 83 degrees, More Humid

5 PM High near 87 degrees, Warm, Storm Possible

Sunrise 5:33 AM

Sunset 8:33 PM

Hotter with fewer overall storms...

Highs should return to the 90s across the entire region the next few days as the overall coverage of storms will be less than what we had over the weekend. That's not to say the entire region will be dry....I am just not anticipating as many storms as what lit up the radar screen over the weekend.

Later this week another front will slowly approach the region, and at that point, the daily coverage of storms will likely increase again.

Severe weather will likely be a big problem in parts of the Plains states the next couple of days as a potent upper level system interacts with hot and unstable air.

Next week, as we end June and head into July, it looks like the core of the heat in the US will shift to the western part of the country for a while.

See the video for lots more on all of this...

Voyage vers Montréal et Cooperstown

It's time for my annual "week off" from Phillyweather.net.   This year, I'm travelling to two places I've never been, both of which are places I have waited far too long to visit.

Cooperstown is famous for being the childhood home of author of James Fenimore Cooper but is not the namesake of the town in Upstate New York.   It's also known for being a shrine to immortality in a particular sport.   One of my bucket list items is to visit all four major sports halls of fame in my life -- I will now have two of the four knocked out after Monday...still have to get to Toronto and Springfield, MA for hockey and hoops.

My other visit will be to Montreal and that's why the title of this entry was in French.   Never been, have always wanted to go despite a total of lack of fluency in French, and will now to get to enjoy Canada's second largest city for a few days.    Needless to say, the weather will not be entirely dissimilar in either location to what it is here in the summer, just a few degrees cooler each day on average and in Montreal, delivered in Celsius and not Fahrenheit...I should be able to handle that.   Street signs in French, however, may be a bit more "fun" to comprehend should I stumble across them but I have my nord, sud, ouest, and est figured out...as well as bonjour and merci in case I need it.   While Montreal has great cuisine my stomach may not ultimately take on their noted poutine (despite some of my friends recommending me go "all in" and try it)...I'll probably stick to bagels and any other Montreal cuisine that is a bit less grating on the heart.

Even though I'm away, the site won't be lacking for activity while I'm gone.   Doug and Brian will provide daily forecasts while I am away this week, plus I have three posts in the queue over the coming days, with one that I think many of you will really enjoy coming up on Tuesday...I may "tweet" on occasion depending on my time and availability but I tend to spend my week of vacation "unplugged" from the technological world when possible.

I'll see you all when I return!

Weather Rewind, June 12-18, 2011

Last week's temperatures were nearly where they were supposed to be for the first time in several weeks.   Temperatures averaged four tenths of a degree above where they should be, thanks in large part to  a couple of days with high temperatures in the 70's, which balanced out the 87 we picked up yesterday in Philadelphia.   The relatively 'rare' normal week of temperatures was welcome after getting pummeled with upper 90's the week prior.

We had some showers on Sunday, more showers on Tuesday thanks to upper level energy, and a stronger complex of storms developed and moved through in the late night hours on Thursday night.   Those overnight storms brought nearly an inch and a half of rain to Philadelphia, with one inch totals in spots to the east and south of the city.   Those rains were needed and beneficial; however, we still have a bit of a rainfall deficit locally over the past month (see below) as rainfall over the past 30 days is below average despite a surplus of nearly a half inch of rainfall month-to-date in Philadelphia so far this June.

June 20th, 2011 Forecast

 A weak front essentially provided a block on advancing showers and storms last night and today.  While rain is still somewhat needed in spots, the block is providing for a pretty nice Father's Day.   That weak frontal boundary will fizzle out as a push of heat advances up the East Coast for midweek.   In that transition back to heat, scattered thunderstorms will hang with us tomorrow night and Tuesday before lifting north of the city (this is still not a complete lock) for Wednesday.

Tonight will feature comfortable sleeping weather with light winds, mostly clear skies, and temperatures in the 50's in the coolest burbs and in the 60's in the city.   Monday features mostly sunny skies, perhaps trending a touch cloudier in the afternoon as thunderstorms may advance towards the region.   Those storms could pass through parts or all of the region Monday night.   Highs tomorrow will be in the mid 80's inland, mid/upper 70's at the Shore as winds nudge to the south.

Week Ahead:   Tuesday features some passing thunderstorms, perhaps lingering from Monday night's activity.   Wednesday and Thursday will be very warm, with Wednesday the hotter of the two as temperatures crack 90 in many spots.   Thursday will feature the passage of a cool front that slows down as it slides through, with lingering thunder possible into Friday before the front gets out of here for the weekend.   As of now, next weekend looks quite good.  

Revisiting the First Half of June

The first half of June has been a hot one -- averaging 4.3 degrees above where we "should" be through Wednesday, a monthly average temperature of 74.3 over that time frame to an average of just over 70 degrees in the first half of the month.    We blitzed past the 90 degree mark four times so far, including a scorching 99 on June 9th, preceded the day prior by an equally oppressive 97 on the 8th.  Believe it or not, the first half of the month also featured four days of below average temperatures although those departures were rather modest, unlike the blitzing of heat we dealt with earlier this month.

In terms of precipitation, the first half of the month an inch of rain (not including the rains from Thursday night/early Friday morning), which was about an inch below average for the month's first half.   Thanks to those heavy rains and thunderstorms on Thursday night we are running with a surplus in the rainfall department locally.

Forecast for Sunday, June 19, 2011

A cold front will swing through the region this evening. While there is a slight chance of showers and thunderstorms with the passage of the front, the main focus along the front will be with waves of low pressure riding along it. At this point, it appears that all three of these waves of energy will be passing south of our region and affect primarily Baltimore, Washington, Georgetown, and Salisbury with the most widespread activity. South of the Atlantic City Expressway, you may be close enough to the energy for a pop-up thunderstorm. I feel the northern counties will be too far away from the focus mechanism for thunderstorm initiation and may actually be well into the drier atmospheric conditions behind the front by Sunday Afternoon.

This front will return as a warm front, most likely an active warm front, Monday Night into Tuesday. Periods of showers and thunderstorms will accompany the front. If the region enters the warm sector and remains just south of the warm front…some strong to severe thunderstorms would become a possibility in addition to efficient rainfall producers on Tuesday. The guidance is diverging and painting various solutions as to the location of the warm front. If the warm front manages to lift well north of the region, then the chances of thunderstorms could be for less than six hours with the passage of the front and will not be more than isolated during the day on Tuesday.

Wednesday, if not Tuesday, we will likely see the warm front lift far enough north… so that the forecast area is entrenched into the warm sector. This means uncomfortable, warm, and humid conditions are likely. If full sunshine occurs on Wednesday and Thursday, we could see even hot weather conditions with high temperatures in the nineties.

There are some models indicating that the warm front has difficultly budging northward the entire week, but lifting it just far enough northward to keep us in the favorable quadrant for frequent thunderstorms and severe weather episodes. For now, I will side with the solution of keeping the frequent thunderstorm development to the north of Philadelphia as has been the trend for the past few months. I will include some pop-up thunderstorms, especially for the northwestern counties, as we have seen some of the past similar situations result in nasty thunderstorms between Reading, Lancaster, and Mount Pocono.

A cold front is expected to swing through our area on Friday. This will likely bring another chance for showers and thunderstorms and this chance could be more inclusive of the entire region.