Mesoscale Discussion 1376

Issued

Jul 3, 2012, 5:58 PM EDT (21:58 UTC)

Expired

Jul 3, 2012, 8:30 PM EDT

In force

3 hr

Issued by

the Storm Prediction Center

Chance of a watch

20%

The Pittsburgh radar (KPBZ), 144 km from the middle of the area, began a volume at 22:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

297 
ACUS11 KWNS 032159
SWOMCD
SPC MCD 032158
MDZ000-PAZ000-VAZ000-WVZ000-OHZ000-040030-

MESOSCALE DISCUSSION 1376
NWS STORM PREDICTION CENTER NORMAN OK
0458 PM CDT TUE JUL 03 2012

AREAS AFFECTED...CNTRL/SERN OH...MUCH OF WV...WRN VA...PARTS OF
WRN/CNTRL MD...S-CNTRL PA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 032158Z - 040030Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED MARGINALLY SVR THUNDERSTORMS WILL BE POSSIBLE
THROUGH EARLY EVENING ACROSS PARTS OF THE OH VALLEY TO THE MID
ATLANTIC. ANY SVR THREAT SHOULD REMAIN LARGELY
MARGINAL/BRIEF/SPORADIC...AND...AS SUCH...A WW IS NOT NEEDED.

DISCUSSION...SFC MESOANALYSIS PLACES AN ARCING...COMPOSITE OUTFLOW
BOUNDARY/DIFFERENTIAL HEATING ZONE OWING TO EARLIER CONVECTION AND
DEBRIS CLOUDINESS/SHOWERS EXTENDING FROM S-CNTRL UPSTATE NY THROUGH
CNTRL PA TO SOUTH OF MORGANTOWN WV AND FARTHER NW TO JUST EAST OF
COLUMBUS OH TO TOLEDO OH. A SFC MESOHIGH DRIVEN BY DIABATIC COOLING
PROCESSES IS LOCATED NW OF THIS BOUNDARY IN WRN PA. LOW-LEVEL ASCENT
ALONG THIS BOUNDARY AUGMENTED BY CROSS-BOUNDARY
DIFFERENTIAL-HEATING-INDUCED BAROCLINICITY CONTINUES TO SUPPORT
ISOLATED TO WIDELY SCATTERED CONVECTIVE INITIATION. WITH 10-15 KT OF
WLY TO NWLY FLOW BELOW 6 KM AGL PER REGIONAL VWP
DATA...EWD/SEWD-MOVING COLD POOLS WILL FOSTER ADDITIONAL CONVECTIVE
REGENERATION/PROPAGATION AMIDST 1000-2000 J/KG OF MLCAPE WITHIN A
ZONE OF ENHANCED SFC THETA-E SOUTH OF THE BOUNDARY.

THE AFOREMENTIONED DEGREE OF BUOYANCY WILL SUPPORT A THREAT FOR
VIGOROUS UPDRAFTS AND MARGINALLY SVR HAIL POSSIBLE WITH THE
STRONGEST CORES. AMPLE DCAPE -- IN EXCESS OF 800 J/KG IN MANY
INSTANCES AND IN EXCESS OF 1100 J/KG IN OHIO -- WILL SUPPORT A
MARGINALLY SVR WIND THREAT. WHILE A BROAD AREA OF ISOLATED STRONG TO
PERHAPS MARGINALLY SVR STORM THREAT WILL EXIST FROM THE BLUE RIDGE
WWD ACROSS WV...THE THREAT AREA NARROWS INTO CNTRL OH OWING TO A DRY
SLOT PER WATER VAPOR IMAGERY THAT EXTENDS FROM CNTRL IND INTO
W-CNTRL OH. THIS IS PROMOTING BOUNDARY-LAYER DRYING VIA VERTICAL
MIXING AND CAPE REDUCTION ACROSS W-CNTRL OH. WEAK DEEP SHEAR AND THE
EVENTUAL ONSET OF NOCTURNAL COOLING SHOULD KEEP ANY SVR THREAT BRIEF
IN DURATION AND SPARSE IN COVERAGE.

..COHEN/HART.. 07/03/2012

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

ATTN...WFO...AKQ...CTP...LWX...RNK...PBZ...RLX...CLE...ILN...

LAT...LON   40248298 40648273 40418197 39898118 39527999 39517911
            39757819 39987731 39317721 38167788 37517888 37498009
            37798123 38378218 39018265 39718291 40248298

Mesoscale Discussions in West Virginia, 2012Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in Ohio, 2012Every mesoscale discussion in 2012

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.