Friday, April 16, 2010

MESO: Mesoscale Discussion 0319

ACUS11 KWNS 162034
SWOMCD
SPC MCD 162034
PAZ000-MDZ000-VAZ000-WVZ000-OHZ000-KYZ000-INZ000-162200-

MESOSCALE DISCUSSION 0319
NWS STORM PREDICTION CENTER NORMAN OK
0334 PM CDT FRI APR 16 2010

AREAS AFFECTED...PORTIONS WRN/CENTRAL PA...OH...NRN WV...SRN
INDIANA...NWRN MD...EXTREME N-CENTRAL/NERN KY.

CONCERNING...SEVERE THUNDERSTORM WATCH 71...

VALID 162034Z - 162200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 71
CONTINUES.

CLUSTERS OF TSTMS HAVE BECOME BETTER ORGANIZED WITH DAMAGING WIND
FROM PORTIONS ERN OH INTO WRN PA...AND WILL MOVE EWD INTO FAVORABLY
UNSTABLE AIR MASS ACROSS PORTIONS SRN/CENTRAL PA AND PERHAPS NRN WV.

GROUND TRUTH DURING PAST HOUR INCLUDES MEASURED 62 KT GUST AT HLG IN
WV...AND 57 KT AT AGC IN WRN PA. ASSOCIATED COLD POOL SHOULD HELP
TO MAINTAIN ASCENT INTO THIS ACTIVITY AS IT MOVES EWD THROUGH AIR
MASS CHARACTERIZED BY MRGL BUT SUFFICIENT BUOYANCY FOR SFC-BASED
UPDRAFTS...I.E. MLCAPE 250-500 J/KG BASED OM MODIFIED RAOBS AND RUC
SOUNDINGS. OTHER BANDS OR CLUSTERS OF TSTMS MAY BECOME SVR AS
CONVECTION NOW ACROSS SERN INDIANA...S-CENTRAL/SWRN OH AND EXTREME
NRN KY BECOMES BETTER-ORGANIZED AS THEY MOVE INTO PATCHES OF
RELATIVELY MAXIMIZED BUOYANCY WHERE PREVIOUS CONVECTION HAS NOT
SIGNIFICANTLY STABILIZED BOUNDARY LAYER. INCREASING MIDLEVEL HEIGHT
GRADIENTS WITH TIME -- AS TROUGH ALOFT APCHS FROM NRN ONT AND UPPER
GREAT LAKES -- WILL HELP TO MAINTAIN LOW-MIDDLE LEVEL SPEED SHEAR
AND POTENTIAL FOR DOWNWARD MOMENTUM TRANSFER. MAIN THREAT WILL
CONTINUE TO BE DAMAGING WIND FOR NEXT COUPLE HOURS...AS MLCINH AWAY
FROM OUTFLOWS REMAINS MINIMIZED BY DIURNAL HEATING. MEANWHILE...SFC
MESOANALYSIS INDICATES COLD FRONT CONTINUING TO MOVE SEWD ACROSS
NERN THROUGH CENTRAL OH...AND S-CENTRAL INDIANA. RELATED
CAA/STABILIZATION WILL REMOVE SVR CONVECTIVE WIND THREAT...AND WW
MAY CONTINUE TO BE CLEARED FROM NW-SE ACCORDINGLY.

SVR POTENTIAL WILL BECOME PROGRESSIVELY LESS W OF WW...WHERE CAPE
WILL REMAIN STRONGER BUT SHEAR MUCH WEAKER...AND E TO SE OF WW WHERE
AIR MASS BECOMES SUBSTANTIALLY MORE STABLE WITH PROXIMITY TO
DELAWARE RIVER VALLEY AND OVER CHESAPEAKE BAY.

.EDWARDS.. 04/16/2010

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PHI...BGM...CTP...LWX...PBZ...RLX...CLE...JKL...
ILN...LMK...IND...

LAT...LON 39278678 39928414 40858270 41627889 41727706 41477640
40987605 40507614 40187635 39387679 39227728 39327828
38658039 38368339 38378479 38528650 39278678

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