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April 11-12 Severe Obs/Disc


Ellinwood

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A wall of precip. to our west will be slowly pushing eastward today as a secondary low develops over the TN valley. Timing the line will be rather difficult as the secondary low slows the progression of the front, and the threat for severe storms could extend into early afternoon tomorrow in the far eastern parts of the region.

The main concern with this system will be damaging winds along and just ahead of the cold front. The northern end of the line, which has a more E-W tilt than the bottom part of the line, will drape itself across the northern parts of the region. The northern part of the line down to the change in the orientation of the line could be an enhanced tornado risk, though the risk is still on the low side. This area is expected to be in WV, SoPA, NoVA, and NoMD as we head into the late afternoon through the overnight hours. The main tornado threat should stay north and west of most of the region, but we'll see what happens.

Tentative chase area is SW PA or S-Cent. PA.

day1probotlk_20110411_1200_torn_prt.gif

day1probotlk_20110411_1200_wind_prt.gif

day1probotlk_20110411_1200_hail_prt.gif

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Not much change in the 1300z SPC OTLK besides making the 30% wind contours combined...

...NY/PA INTO CENTRAL APPALACHIANS.

MODEL GUIDANCE IS IN AGREEMENT THAT A RATHER POTENT ENVIRONMENT WILL

DEVELOP LATER TODAY AHEAD OF THE COLD FRONT FROM SOUTHERN NY AND

MUCH OF PA INTO WV/VA. STRONG DAYTIME HEATING AND DEWPOINTS IN THE

LOWER 60S WILL YIELD AFTERNOON MLCAPE VALUES OF AROUND 1000 J/KG.

RATHER STRONG DEEP LAYER EFFECTIVE SHEAR WILL ALSO BE PRESENT AS

80-100 KT MID LEVEL JET OVERSPREADS THE REGION. CURRENT INDICATIONS

ARE THAT SCATTERED THUNDERSTORMS WILL DEVELOP BY MID AFTERNOON OVER

PORTIONS OF NY/PA INTO THE CENTRAL APPALACHIANS AND SPREAD QUICKLY

EASTWARD. ONSHORE FLOW AND ASSOCIATED MORE STABLE AIR MASS WILL

LIMIT EASTWARD PROGRESSION OF STORMS TO THE COAST. HOWEVER...IT

APPEARS POSSIBLE THAT A RATHER CONCENTRATED AREA OF DAMAGING WINDS

AND ISOLATED TORNADOES MAY OCCUR TODAY OVER THIS REGION.

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Not expecting much unless the cap breaks and we get some scattered convection. The pre-frontal QLCS won't be here until late and by that time the coastal low will be developing and the region will take on stable oceanic eastern flow. Death sentence for any convection.

yeah this was a concern once we started seeing the idea of a cutoff. last night the nam was trying to keep some energy spitting out ahead of the digging trough.. not so much now. if the newer run is right then svr threat seems pretty minimal around here.

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yeah this was a concern once we started seeing the idea of a cutoff. last night the nam was trying to keep some energy spitting out ahead of the digging trough.. not so much now. if the newer run is right then svr threat seems pretty minimal around here.

I agree for the most part, with the outside chance of getting some elevated action as we hit the early morning hours.

Latest RUC actually showing a possible cap break mid/late afternoon in the northernmost areas... *raises an eyebrow*

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I agree for the most part, with the outside chance of getting some elevated action as we hit the early morning hours.

Latest RUC actually showing a possible cap break mid/late afternoon in the northernmost areas... *raises an eyebrow*

The RUC will probably fail. :(

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I agree for the most part, with the outside chance of getting some elevated action as we hit the early morning hours.

Latest RUC actually showing a possible cap break mid/late afternoon in the northernmost areas... *raises an eyebrow*

tomorrow could still be interesting with the 500 low coming in neg tilted especially if we can get some sun to get things bubbling. http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/images/nam_500_036m.gif

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A tornado watch is about to be issued up into central KY. Any chance of that threat extending further east later on today?

Full sun here, just about to soar past 80...dp 65. SW wind is mixing it up a little.

Drier conditions and higher cloud bases should lessen the impact, but there is a decent TOR risk in your area later today.

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Jason and I will be heading up towards Lancaster, PA today. We've got better instability, but higher cloud bases than further west. Good luck with the storms down here!

I live in Lancaster county...where are thinking about heading too?

The sun has been out all morning here, and our area always seems to do well with severe weather (if you're into that stuff)

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Tornado watch coming west -

MESOSCALE DISCUSSION 0412

NWS STORM PREDICTION CENTER NORMAN OK

1124 AM CDT MON APR 11 2011

AREAS AFFECTED...ERN KY...WV...AND PARTS OF SWRN PA

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 111624Z - 111700Z

A NEW TORNADO WATCH WILL BE NEEDED SOON FROM ERN KY...THROUGH MUCH

OF WV AND POSSIBLY INTO SWRN PA. DAMAGING WINDS SHOULD BE THE

PRIMARY THREAT...BUT LOW LEVEL SHEAR /EFFECTIVE SRH 100-200 M2 PER

S2/ IS SUFFICIENT FOR A TORNADO THREAT.

THE AIR MASS...ALTHOUGH ONLY MARGINALLY UNSTABLE AT THIS

TIME...ACROSS ERN KY...WV INTO SWRN PA WILL CONTINUE TO DESTABILIZE

GIVEN ADDITIONAL SURFACE HEATING COMBINED WITH SURFACE DEWPOINTS

AROUND 60 F. EFFECTIVE BULK SHEAR IS ALREADY SUPPORTIVE FOR

ORGANIZED STORMS WITH VALUES OF 40-60 KT. MEANWHILE... A FAST

MOVING /ENE AT 55 KT/ LINE OF CONVECTION OVER SRN KY IS ATTENDANT TO

A LONG-LIVED MCV...WITH THIS ACTIVITY LOCATED ALONG A WIND SHIFT

EXTENDING FROM SWRN TN TO FAR WRN WV AND FAR NWRN PA. GIVEN THE

FORWARD SPEED OF THE SRN KY CONVECTION AND FORCING FOR ASCENT AS

GREATER HEIGHT FALLS SPREAD EWD AHEAD OF THE TROUGH EXTENDING FROM

THE UPPER GREAT LAKES TO SRN PLAINS...TSTMS ARE EXPECTED TO DEVELOP

AND SPREAD ENEWD ACROSS ERN KY INTO WV AND MAY AFFECT SWRN PA.

HOWEVER... ONGOING CONVECTION OVER SWRN PA MAY TEND TO LIMIT

AFTERNOON DESTABILIZATION AND THE OVERALL NWD EXTENT OF SEVERE

WEATHER INTO THIS REGION.

..PETERS.. 04/11/2011

ATTN...WFO...CTP...LWX...RNK...PBZ...RLX...MRX...JKL...ILN...

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Makes me think what will happen for us if there is a TW coming out west of us for late this afternoon and evening.. probably getting my hopes up again :axe: Kenny, how were the 09z SREFs?

Held serve - still looked good but we all know how those don't like to verify

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Makes me think what will happen for us if there is a TW coming out west of us for late this afternoon and evening.. probably getting my hopes up again :axe: Kenny, how were the 09z SREFs?

problem is unless we get outflow storms there's not going to be much advancement eastward as the trough digs and a new low forms.

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