Generous Rains For Some...Others Could Use More

Yesterday's rains and thunderstorms put a dent into our muggies for a couple of days, coming with the price of localized flooding and damage to property and tree, but bringing some decent dents into the rainfall deficit that's been a part of our region for the past couple of months.  Rainfall totals varied a good deal based on location, with localized downpours bringing some folks two inches of rain while bringing others just a half inch 10 minutes down the road.   Philadelphia did pick up 1.48" of rain yesterday but that was hardly a representative total of the whole region as some spots picked up over two inches and others did not fare as well.   Regardless, most everyone saw at least some rain yesterday.  

Yesterday's thunderstorms were brought to you by a disturbance tracking along a stalled frontal boundary.   This weak low enhanced thunderstorms across our region while bringing additional fuel in along its path.   You can see the evolution of those storms in three separate radar screen shots (from wunderground.com) at 12:30, 2:30, and 4:30 PM.

Storms initially popped up and moved little, leading to highway flooding across South Jersey during the early and mid afternoon hours.   Thunderstorm coverage in the early afternoon was initially scattered and slowly spread out to become more widespread as the atmosphere "broke" from the heat cap that had been in place. Whether the expanding thunderstorm coverage looked like abstract art or The Blob (hat tip to the festival in Phoenixville this weekend) is up to the eye of the beholder but thunderstorms increased in coverage through the afternoon.

By 4:30, a bit of a squall line developed across New Jersey back into Delaware, with a secondary line back to the northwest over the Lehigh Valley through Lancaster.  This secondary line joined up with the Jersey line and the larger line of thunderstorms gradually pushed themselves east to the coast over the course of several hours.  

By 7 PM, the line (below) and the band of thunderstorms took up the width of New Jersey, taking another three hours or so to pull off the coast completely due to their relatively slow movement.   While rainfall totals were scattered around through the region, areas to the south and southeast of Philly did pick up more rain on the whole than areas north/west (in some cases more than two inches in parts of the Pinelands).

Yesterday's storms won't take away the warmth -- but they did take away the humidity as dew point values will be closer to 60 today than yesterday's lower and middle 70's.   While it will still be warm (approaching 90), the humidity will be tolerable.

Severe Weather Reports for 4/28/2011

Tornado Damage in York County from earlier this morning.


Tornado Damage in York County from earlier this morning.

The severe weather today in our area was plentiful in our region (although nothing like the severe devistation in the Gulf States). Several thunderstorms did prompt tornado warnings across North-Central and Northeastern New Jersey, portions of the Lehigh Valley, and in South-Central Pennsylvania. There were numerous severe thunderstorm warnings issued throughout New Jersey.

In York County (we have a few readers there), the State College National Weather Service Forecast Office has confirmed an EF1 tornado. It occurred at Roundtop Mountain Resort in Fortney Township, Pennsylvania. This touchdown occurred around 5:55 a.m. today. It was 100 yards in width. Details on the max wind speed and length are listed as "to be determined". An EF1 tornado produces wind speeds of 86 to 110 MPH.

In Hunterdon County (New Jersey), a funnel cloud was reported in Alexandria Township. In Morris County, a funnel cloud was reported in Chester Township. In Passaic County, an impressive three funnel clouds were spotted at one time in Wayne Township. There were trees and power lines knocked down in Hunterdon and Morris Counties, including in Alexandria Township. WNBC in New York is reporting possible tornado damage in Denville Township. Jersey Central Power and Light’s online outage map did show several thousand in that area without power at one point in these areas. Of course, we will keep you updated if there is a report of an actual tornado touchdown in this area.

Update: Anthony Gigi told NJ.Com the following:  "The reports that we are getting are more consistent with a severe thunderstorm rather than a tornado. We’re not seeing hundreds of trees down or roofs ripped off of homes."

Elsewhere, a tree fell down on a bus this morning in Berks County near South Heidelberg Township. In Mertztown large tree limbs were downed. In Jackson, Monroe County in Pennsylvania there was trees that were felled onto houses. Stroud Township also reported trees down. Wires were knocked down in Springfield Township in Bucks County. In Cumru Township in Berks County, trees were reported to be down. Hail was reported in Hunterdon County at White Horse Station which isn’t surprising to hear about when you have tornado characteristic thunderstorms. Trees and wires were taken down in Somerset County near North Plainfield Township.

More:   Storm Damage Reports (NWS)

Recapping Saturday's Soaker

Nearly two inches of rain in just two hours is never a good thing and for the Schuylkill Expressway last night the heavy rain and thunder that rocked through the region provided a muddy mess for those traveling east towards Center City.   Saturday's soaking ended up bringing 3.11" of rain to Philadelphia, breaking a 25 year old daily record of 2.43" by a good bit.  The region ended up with between one and three inches of rain, heaviest along I-95 and also along I-81 across Central into Northeastern Pennsylvania, with Mount Pocono picking up over three and a half inches of rain yesterday.

The storm started around midday with the first wave of steady rain but the worst of the storm occurred in two shots, first between 6 and 9 PM in Philadelphia that brought two inches of rain in just three hours' time, accompanied by occasional cracks of lightning and strong gusty winds from the southeast ahead of the frontal boundary.   This wave set up the mudslide along the Schuylkill, which occurred towards 9 PM last night.

Rain tracked from south-southwest to north-northeast along the front as it moved east.   This training of moisture helped exacerbate rainfall totals since there was a slower eastward component than a northward component, given the strong amount of moisture riding north along the front.   Low pressure tracking along the front aided in enhancing the rain in and around Philadelphia.

The last wave of rain and thunder came through around 11 PM with the front itself, once again flaring up with more rain and thunderstorms as it slipped east and adding another quarter to half an inch of rain as it hit the immediate area.

Saturday's heavy rains and strong southeast winds helped cause tidal flooding in Delaware Bay and along the Delaware River, with the Delaware River seeing the worst tidal flooding since November 1950.

So Much For Spring

From morning temperatures around 70 degrees in many parts of the Delaware Valley to sleet mixing in with rain during the early afternoon in the northern and western suburbs...a six hour swing of temperatures that was rather wild and an abrupt reminder that Spring doesn't arrive easily and permanently.   Temperatures in Philadelphia dropped about 20 degrees from 6 AM to Noon today, hitting the upper 40's before settling in the mid 40's late in the afternoon.  

Round one of the stormy weather today came in the predawn or dawn hours -- generally impacting Chester County with gusty winds that were as high as 65 mph before the first band of rain and wind weakened as it hit Philadelphia.   A second round of wind and rain developed around 8 AM across Central Pennsylvania and Maryland, marching east and crossing the Philadelphia area around 10 AM (see below).   This second line was the main front and meant business, dropping temperatures 15 degrees between 10 and 11 AM in Philadelphia and similar levels elsewhere.   In addition to gusty winds, a quick shot of heavy rain accompanied the frontal boundary passage as well.   Winds gusted to 56 mph in Philadelphia and 55 mph in Wilmington with the front as it crossed through.

Now that "calmer" weather has moved in, expect a return to more typical April temperatures tomorrow with highs generally in the 50's.  Unfortunately, calmer doesn't mean tons of sunshine...the coming days will feature a battle between southern warmth and northern chill as a frontal boundary lingers across the Mid Atlantic.