It's Been Rather Dry Just West Of Us

Despite last night's half inch of rain at the Airport, many areas to the city's north and west missed out on thunderstorm activity and continue to sit in the midst of what is becoming a pretty significant dry spell in South Central through Western Pennsylvania.   Most of last night's heavy thunderstorm activity hit South Jersey, which could also use the rain but has been a bit luckier in the rainfall department this summer than those of us to the northwest of I-95.    Most places locally are running not just weekly deficits in the rainfall bucket...but are now approaching three to four month rainfall deficits.

Just in the last 60 days parts of Chester, Berks, and Lancaster County are running rainfall deficits of over four and a half inches.  Those deficits are also occurring down in Sussex County in Delaware, with deficits as high as six inches to the north of Pittsburgh in Western Pennsylvania.   The region itself needs about an inch of rain per week, give or take, to simply maintain "average" rainfall.   While average typically doesn't happen and rainfall in the summer can easily fall into the feast or famine department, with little separating the two, the lack of rain in parts of our area is starting become a bit of a crop issue.

While we're not technically in a drought in the region, we are entering a pretty prolonged dry spell in parts of the area which is starting to show up in drought reports, particularly for Western Pennsylvania and also Delaware as of last week's drought report.   The newest drought report will come out tomorrow morning, likely expanding some of the abnormally dry zones in Pennsylvania and probably introducing some abnormally dry conditions to parts of our area.  Even in Philadelphia, which has been hit with some significant thunderstorm events since June 1st (June 16th, July 8th, and last night to name three), the Airport's observation site is running over one and a third inches below typical rainfall.

If you're doing a dance to bring on chillier weather, please throw in a rain dance for the region...we could use it!

July 21st, 2011 Forecast

The hothouse of the last few days will become a full fledged sauna over the next three days, with a run at 100 degrees on Friday...perhaps even Saturday...in the Delaware Valley.   The temperature alone is hot but with dewpoints that are poised to be in the 70's more often than not through Saturday we could see heat index values that could reach or perhaps exceed 110 in the worst of the heat on Friday.

Despite the presence of an isolated storm or two in parts of the region this afternoon and evening, most of the region is setting up for a warm, muggy night with low temperatures in the 70's across the whole of the region.   Light winds will add little relief to the mugginess.   Sunshine should dominate on Thursday, with only a few pop up clouds around in the afternoon.   High temperatures should range from 94-98 inland, 83-86 at the immediate Shore thanks to the presence of a south-southwest wind...once you get a couple of miles inland temperatures will be just as hot as we expect to get in Philly.

Eventually the heat will ease -- we promise!   Friday does look to be the worst of the days although Saturday could be just as nasty as heat index values could reach 110 in the worst of conditions.   Thunderstorm chances should increase through the weekend as a weak frontal boundary tries to slip south late Friday into Saturday, holding over the region until a more potent cool front moves through on Monday with a more widespread thunder chance.

Heat and humidity getting oppressive...

Heat and humidity will be our big weather stories through the weekend. Highs today will reach at least the mid 90s in many spots with upper 90s to near 100 degree readings across the region as a whole tomorrow into the weekend. Heat index values today will exceed 100 in many spots with heat indices making a run at 105 or so tomorrow on through the weekend.

A few PM storms are possible today, and then the overall chance of rain in any one spots looks to diminish for tomorrow and Friday before increasing again this weekend.

Stay cool!

Tropics...

Bret continues to behave as expected and is headed out to sea.

The Canadian and European models are trying to sniff out a possible East Coast tropical system later next week....see today's video for the graphics on that.

Excessive Heat Watches & Warnings Up

The prospect of the worst of the season's longest heat wave is coming upon us for late this week, with Excessive Heat Watches and Warnings out for much of the region due to the nasty combination of heat and humidity that is poised to worsen over the latter half of the week.   Excessive Heat Warnings are out for the Delaware Valley for now through at least Thursday, likely extending to Saturday given current trends, with watches out in Central Pennsylvania and in the New York Metro area for later this week.

We all know it's going to be hot, with computer guidance suggesting 100 is certainly within possibility for Friday and upper 90's sandwiching around that for both Thursday and Saturday.   The heat itself is bad enough and on Friday and Saturday, potentially record breaking.  However, the humidity will be the worse impact as dew point values in the lower 70's could yield heat index values upwards of 110 in some parts of town.   The heat/humidity combination is arguably much, much more potent and to be frank, it doesn't matter if anyone is forecasting 100 or not...the heat index will be higher and frankly makes the weather that much worse.

Thursday's records are rather tough to hit but Friday could pose a potential record breaking day, especially in Atlantic City and perhaps Philadelphia.  Saturday's record could be tied in many locations.   Even if we don't break a record, Friday will likely be the season's hottest day in terms of both temperatures and heat index.

Scattered Storms Bringing Some Relief

Apologies for the delay in getting something out there on this afternoon's thunderstorms.    After a scorching high of 96 degrees, some relief hit parts of the region this afternoon as thunderstorms developed...initially across Delaware and then slowly building farther north and west as the afternoon turned into evening.   While not everyone was stormed upon today (my backyard is in a proverbial dust bowl it seems of late), others are under flood advisories after picking up a couple of inches of rain per doppler estimates.

There are no severe thunderstorm warnings out as of 8 PM in the immediate area (there is one until 9 for Southern Chester County and Cecil County in Maryland) -- but there are some heavy thunderstorms still to the south of the city and in the city proper -- all of which are moving slowly southeast.   We should see activity fizzle out in the next couple of hours, leaving a partly to mostly cloudy sky with some patchy fog possible through the region in the overnight hours.

More:   Current Weather Page

Union Gamecast

Everton is in the midst of warming up for the Premier League season (which seemed like it just ended a few weeks ago...some "offseason" for the footballers!) while the Union are taking the week to play a couple of "friendlies" (also known as exhibition games for the non soccer crowd) against a couple of European teams.   Wednesday's match will be at PPL Park and will be played in a proverbial hothouse -- temperatures in the 80's for the match with partly cloudy skies.   There *could* be a storm that pops up in the afternoon tomorrow but odds are leaning against any storms at the match as of this evening.

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Union Gamecasts will be updated throughout the course of the season (or at least whenever possible), featuring the forecast for the game at kickoff and in the 90th minute.

July 20th, 2011 Forecast

Tonight: There is a 20 percent chance of an isolated thunderstorm this evening and overnight. Otherwise, expect a stuffy and muggy night under partly cloudy skies. Lows will only drop into the lower to mid-70s overnight. Winds will be light out of the east-southeast. The sunset tonight is at 8:26 PM.

Wednesday: Hot sun and humid. The high will be near 94 degrees in Philadelphia, but the humidity will make it feel like 96 to 101 degrees. The record high of 99 degrees, set back in 1930, will be safe. Southeast winds will shift from the south at 5 to 10 mph.

Thursday: Very hot sun and humid. The high will be around 98 degrees with a heat index between 105 and 110 degrees. This record high of 103 degrees, set back in 1930, should be safe as well.

Friday: Blazing hot sun and humid. The high will easily break 100 degrees, and I am forecasting a high around 102 degrees for the city of Philadelphia. Once again it will feel like 105 to 110 degrees with the humidity. This record high of 100 degrees, set back in 1957, will be broken.

Wednesday Planner

7 AM 78 degrees, Humid

Noon 90 degrees, Hot Sun

5 PM High near 94 degrees, Feels Like 96 to 101

Sunrise 5:49 AM

Sunset 8:25 PM