SE PA/Mt. Holly severe threats..

[NaoPos]

...NEW ENGLAND INTO THE LOWER GREAT LAKES AND MID-ATLANTIC

...NEW ENGLAND INTO THE LOWER GREAT LAKES AND MID-ATLANTIC

STATES...

AN EXPANSIVE PRE-FRONTAL BAND OF TSTMS IS ONGOING AS OF 12Z FROM

SWRN ONTARIO/LAKE ERIE SWWD INTO NRN KY...LIKELY FORCED BY THE

LEADING EDGE OF STRONGER HEIGHT FALLS ASSOCIATED WITH UPPER SYSTEM

MOVING THROUGH THE GREAT LAKES. BASED ON SATELLITE

IMAGERY...DOWNSTREAM AIR MASS ACROSS NY/PA SHOULD EXPERIENCE STRONG

DAYTIME HEATING. WHEN COUPLED WITH DEWPOINTS IN THE 60S AND

MIDLEVEL LAPSE RATES OF AROUND 7 C/KM...ENVIRONMENT WILL BECOME

MODERATE-STRONGLY UNSTABLE WITH MLCAPE VALUES INCREASING TO

2000-3000 J/KG. THIS DESTABILIZATION ALONG WITH THE EWD PROGRESSION

OF UPPER TROUGH WILL SUPPORT A MARKED INCREASE IN STORM VIGOR AND

COVERAGE BY EARLY AFTERNOON ALONG COLD FRONT AND/OR LEADING EDGE OF

COLD POOL ASSOCIATED WITH THE ONGOING STORMS.

THE STRONGEST MID- AND HIGH-LEVEL WIND FIELD ASSOCIATED WITH THE

TROUGH IS FORECAST TO LAG THE WARM SECTOR TO THE W...LIMITING

DEEP-LAYER SHEAR MAGNITUDES TO GENERALLY 30-40 KT. EXPECT THE

STRONG INSTABILITY TO COMPENSATE WITH ENVIRONMENT BECOMING

SUPPORTIVE OF MULTIPLE ORGANIZED STORM MODES...INCLUDING BOWING LINE

SEGMENTS AND SUPERCELLS WITH THE POTENTIAL FOR CORRIDORS OF WIND

DAMAGE AND SWATHS OF LARGE HAIL. THE GREATEST RISK FOR A TORNADO OR

TWO WILL EXIST ALONG WARM FRONT OVER NEW ENGLAND WHERE LOW-LEVEL

SHEAR WILL BE ENHANCED.

THE SEVERE WEATHER THREAT WILL SPREAD EWD TOWARD THE MID-ATLANTIC

COAST AND WRN NEW ENGLAND BY LATE AFTERNOON INTO THIS EVENING BEFORE

GRADUALLY DIMINISHING LATER TONIGHT WITH THE STABILIZATION OF THE

BOUNDARY LAYER.

As you can see, a good portion N&W of Philly is in the 30% risk for wind and hail...(hail outline was same as wind risk for the most part.)

I think for the Philly metro, we'll be more of a nocturnal threat (9p-2a). It takes away from the best thermodynamics, but I believe we should have enough leftover instability to have a chance of something severe.

Feel free to post & discuss.

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[NaoPos]

Hrrr snapshot for 19z

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[dryslotted]

Hrrr snapshot for 19z

Sent from my iPad HD

Looks like jerz gets in on the action at around 8:30 per the 12z run of the HRRR model. Hopefully, we can get the shield generator down in time (sorry ROTJ was on a lot this weekend )...

[stormspotterlive]

Storms for today are a definite go wild card is how fast the front moves through if it is slower some tropical moisture from beryl could come up enhancing the flash flooding threat some models like the spc wrf do in fact do that and the 12z Nam is not that far off from doing it but does not quite do it. Any how the threat of severe weather is looking pretty good for this evening and tonight.

Here is that spc wrf run for anyone who is interested in seeing it.

LOOP: http://www.emc.ncep.noaa.gov/mmb/mpyle/spcprod/00/nmmwrf.pcp_animate_1h.html

QPF TOTALS: compared to last nights 00z Nam http://www.emc.ncep.noaa.gov/mmb/mpyle/spcprod/00/eta_36h_total.gif

[stormspotterlive]

Tornado watch is coming for north central and northeast pa through ny and westeren new England

http://www.spc.noaa.gov/products/md/md0956.html

[NaoPos]

Tornado watch is coming for north central and northeast pa through ny and westeren new England

http://www.spc.noaa.gov/products/md/md0956.html

And a mod risk

[tombo82685]

Tornado watch is coming for north central and northeast pa through ny and westeren new England

http://www.spc.noaa..../md/md0956.html

that makes sense, some nice shear out there

[tombo82685]

as of noon, cape is ranging from 2000 to the south to 4000 up in the lehigh valley and pocs. LI is in the -5 to -7 range over the area. The best instability is up north, but the whole region has good instability, the shear though from lehigh valley south is pretty weak, while form the pocs north has decent shear.

area LI

[Riptide]

Another factor in this pretty decent setup is the remnants of Tropical Storm Beryl moving up and inducing some additional moisture and low-level dynamics. I really like this setup and think it's the best of the year in terms of severe wx.

[soadforecaster]

maybe ill actually get a see a nice thunderstorm today

[Boch23]

I'll say we get something because we have hockey practice tonight and the rink loses power at the drop of a hat when it comes to decent thunderstorms.

[Quakertown needs snow]

we shall see

[NaoPos]

http://forecast.weather.gov/showsigwx.php?warnzone=PAZ070&warncounty=PAC045&firewxzone=PAZ070&local_place1=Drexel+Hill+PA&product1=Flash+Flood+Watch

Won't touch on it too much, but a flash flood watch has been issued for SE PA and most of eastern PA.

[NeffsvilleWx]

Tagging along, it's downright oppressive right now. Definitely have enough heat and moisture for some good storms.

[NortheastPAWx]

Until 9pm -- STW 314 for most of E PA except extreme SE - Philly area out of it.

[Quakertown needs snow]

http://forecast.weat...ash Flood Watch

Won't touch on it too much, but a flash flood watch has been issued for SE PA and most of eastern PA.

i can see this an issue for around my area since ground is still saturated

[NaoPos]

SEL4

URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 314

NWS STORM PREDICTION CENTER NORMAN OK

105 PM EDT TUE MAY 29 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

CENTRAL AND SOUTHERN NEW YORK

CENTRAL AND EASTERN PENNSYLVANIA

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 105 PM UNTIL

900 PM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES SOUTHWEST OF

HARRISBURG PENNSYLVANIA TO 65 MILES NORTHEAST OF BINGHAMTON NEW

YORK. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 312...WW 313...

DISCUSSION...STRONG/SEVERE STORMS FROM WRN PA INTO WRN NY ARE

EXPECTED TO SPREAD EWD THIS AFTERNOON...WHILE NEW STORMS ARE LIKELY

TO DEVELOP FARTHER TO THE EAST WITHIN A VERY UNSTABLE AND WEAKLY

CAPPED ENVIRONMENT /MUCAPE TO 3000 J PER KG/. SWLY MID LEVEL WINDS

OF 30-35 KT ARE CONTRIBUTING TO SUFFICIENT VERTICAL SHEAR TO ENHANCE

STORM ORGANIZATION WITH MULTICELL AND ISOLATED SUPERCELL STRUCTURES

LIKELY. LARGE HAIL AND DAMAGING WIND GUSTS WILL BE POSSIBLE WITH

STRONGER CELLS AS ACTIVITY SPREADS EWD/NEWD INTO THE EARLY EVENING

HOURS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 24025.

...WEISS

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[johnc]

Some heavy rain in NE PA already.

yummy.

[Quakertown needs snow]

boom boom

[Riptide]

Thar she blows.

[NeffsvilleWx]

Stuffs popping in wv that is tracking towards the susquehanna valley

[Thunder Road]

Nice little tower popped up in NW Lebanon County in the last 2 frames on KCCX. I wonder if yet another line will form ahead of the "new" line that currently stretches from Williamsport to Cumberland.

[NaoPos]

MESOSCALE DISCUSSION 0959

NWS STORM PREDICTION CENTER NORMAN OK

0113 PM CDT TUE MAY 29 2012

AREAS AFFECTED...CNTRL/ERN PA...S CNTRL NY/SERN NY...SRN NEW ENGLAND

CONCERNING...SEVERE THUNDERSTORM WATCH 314...

VALID 291813Z - 291915Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 314

CONTINUES.

SUMMARY...SEVERAL ROUNDS OF SEVERE THUNDERSTORMS APPEAR LIKELY

ACROSS THE WW AREA. WITH NEW DEVELOPMENT NOW NOTED ACROSS THE

POCONOS AND CATSKILLS...AN ADDITIONAL WW WILL LIKELY BE NEEDED EAST

OF WW314.

DISCUSSION...SEVERAL LINES OF PRE-FRONTAL CONVECTION FORMED THIS

MORNING IN RESPONSE TO FORCING FOR ASCENT ATTENDANT TO AN

APPROACHING UPPER TROUGH. A LEADING SURGING OUTFLOW HAS BEEN NOTED

ON 18Z VISIBLE IMAGERY...AND WILL LIKELY INITIATE NEW SEVERE

CONVECTION IN ADVANCE OF THE PRIMARY LINE OF CONVECTION. THIS NEW

CONVECTIVE DEVELOPMENT WILL LIKELY OVERTAKE THE ONGOING ACTIVITY

ALONG THE ALLEGHENIES. GIVEN AMPLE SURFACE-BASED DESTABILIZATION AND

INCREASING HEIGHT FALLS...THE ACTIVITY WILL LIKELY CONTINUE TO

PRODUCE DMGG WINDS AND HAIL. DMGG WINDS ARE ESPECIALLY POSSIBLE

ACROSS CNTRL NY...WHERE LOW-LEVEL SHEAR REMAINS STRONGER THAN TO THE

S.

FARTHER E...A FEW STRONGER CELLS HAVE BEEN NOTED ALONG THE POCONOS

AND CATSKILLS. ALTHOUGH MORE VIGOROUS AND WIDESPREAD ACTIVITY MAY BE

SOMEWHAT DELAYED UNTIL HEIGHTS FALL MORE RAPIDLY...SBCAPE NEAR

2000-2500 J/KG PER MESOANALYSIS AND MODEST EFFECTIVE SHEAR OF 30 KTS

OVER SERN NY MAY SUPPORT A FEW SEVERE STORMS IN THE MEANTIME. WITH

THE NEW ACTIVITY AND AN INCREASE IN CONVECTION FROM THE W...A NEW WW

EAST OF WW314 MAY BE NEEDED.

..HURLBUT.. 05/29/2012

ATTN...WFO...OKX...ALY...PHI...BGM...CTP...LWX...

LAT...LON 39687878 41807754 43047577 42637469 42187449 41977339

41827305 41347339 40847406 40097480 39757529 39687878

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[dryslotted]

the image would likely be too big to post here, but man, the radar presentation for the whole eastern third of the country is just awesome to behold...

http://radar.weather.gov/ridge/Conus/full_loop.php

[stormspotterlive]

Keep a very close eye on the disturbance in eastern Kentucky riding along the front some moisture from beryl is getting worked in. with this disturbance being stronger then modeled I think the flash flood watches the nws has issued will really come in handy over night if we get into training segments with this behind the main line of severe wx some could see locally high amounts of 3-4 inches going to be a long evening and night of watching this.

[Riptide]

the image would likely be too big to post here, but man, the radar presentation for the whole eastern third of the country is just awesome to behold...

http://radar.weather...s/full_loop.php

So far this year has been amazing; perhaps not in the local area but in a historical sense. The march heatwave was amazing and now two tropical cyclones in May.

[dryslotted]

Keep a very close eye on the disturbance in eastern Kentucky riding along the front some moisture from beryl is getting worked in. with this disturbance being stronger then modeled I think the flash flood watches the nws has issued will really come in handy over night if we get into training segments with this behind the main line of severe wx some could see locally high amounts of 3-4 inches going to be a long evening and night of watching this.

I think tombo used the "squeeze play" reference earlier today. it's a fitting description, and is becoming really evident on radar as we've gone through the day...

[tombo82685]

still think what i said earlier holds true. Around the phl area we will get t storms but the svr aspect will be limited, and nothing like further west. Timing of the front was the achillies heel, though should be a good light show tonight. I think the potential hvy rains tonight is the bigger factor. Areas from lns-rdg west have a better shot of good svr weather as the front will be there faster with better instability to work with.

[phlwx]

still think what i said earlier holds true. Around the phl area we will get t storms but the svr aspect will be limited, and nothing like further west. Timing of the front was the achillies heel, though should be a good light show tonight. I think the potential hvy rains tonight is the bigger factor. Areas from lns-rdg west have a better shot of good svr weather as the front will be there faster with better instability to work with.

I'd nudge that to ABE-PTW-MQS and west but yeah, I pretty much agree with what you say.

I do think a ST watch gets issued til 10 or 11 for Philly, TTN, NYC, DC, and BWI as a precaution.

[iceman56]

Latest point & click for here now mentioning just a chance of a TS tonight with no mention of high winds & hail

that was in there earlier.

Had my 2nd 90+ day of the season with 90.3 today and 89.9 yesterday.

HI made it to 96 this afternoon, back down to 91 now.