Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 291752
SWOMCD
SPC MCD 291752
OHZ000-WVZ000-KYZ000-INZ000-292015-

MESOSCALE DISCUSSION 1228
NWS STORM PREDICTION CENTER NORMAN OK
1252 PM CDT MON JUN 29 2015

AREAS AFFECTED...PORTIONS OF SOUTHERN OHIO...WESTERN WEST
VIRGINIA...KENTUCKY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 291752Z - 292015Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THE AREA IS BEING MONITORED FOR AN INCREASING RISK OF
ISOLATED TO WIDELY SCATTERED SEVERE THUNDERSTORMS THIS
AFTERNOON...AND THE ISSUANCE OF A WW IS POSSIBLE.

DISCUSSION...VISIBLE SATELLITE AND MOSAIC RADAR LOOPS HIGHLIGHT
CONVECTION BEGINNING TO DEEPEN ALONG A BAROCLINIC TROUGH/CONFLUENCE
AXIS RUNNING APPROXIMATELY ALONG THE OHIO RIVER SW OF A SFC CYCLONE
NEAR CINCINNATI. THE AIR MASS SE OF THIS TROUGH CONTINUES TO
DESTABILIZE OWING TO DIABATIC SFC HEATING AMIDST DEWPOINTS IN THE
MIDDLE 60S. THIS IS SUPPORTING MLCAPE AROUND 1000-2000 J/KG ACROSS
SW AND CNTRL KENTUCKY NEWD TO A MULTI-WARM-FRONTAL ZONE ACROSS
ERN/NRN KY TO THE OHIO RIVER. WITH LITTLE IN THE WAY OF WARM-SECTOR
CAPPING...CONVECTION WILL CONTINUE TO DEEPEN ALONG THE TROUGH AND IN
THE OPEN WARM SECTOR ACROSS PARTS OF CNTRL/WRN KY. THE LOUISVILLE
VWP SAMPLES AROUND 20-35 KT OF FLOW IN THE 1-5-KM AGL LAYER...WHICH
WILL LIKELY FOSTER EWD-SPREADING MULTICELL CLUSTERS AND PERHAPS A
FEW SUSTAINED DISCRETE CELLS WITH LOCALLY DMGG WIND GUSTS AND
PERHAPS MARGINALLY SVR HAIL THIS AFTERNOON.

PRESENT INDICATIONS ARE THAT CONVECTIVE ACTIVITY WITH AN ASSOCIATED
SVR RISK WOULD THEN SPREAD INTO AND/OR DEVELOP ACROSS AREAS FARTHER
E/N INTO ERN/NRN KY...SRN OH...AND WRN WV WITH TIME -- ESPECIALLY
LATER IN THE AFTERNOON -- WHERE AIR-MASS RECOVERY IS ONGOING OR HAS
YET TO BEGIN IN THE WAKE OF EARLIER CLOUDS/PRECIP. AS THE
MULTI-WARM-FRONTAL ZONE BRANCHING SE/E OF THE SFC CYCLONE ADVANCES
NWD...AT LEAST MARGINALLY UNSTABLE AIR WILL SPREAD N OF THE OHIO
RIVER...WHILE NEAR-SFC WINDS REMAIN SOMEWHAT BACKED IN THE
SHELTERED/DESTABILIZING PBL. THIS WILL LOCALLY ENHANCE LOW-LEVEL SRH
AND YIELD SOME POTENTIAL FOR A WEAK/SHORT-DURATION TORNADO OR TWO --
ESPECIALLY IN SRN OHIO...NERN KY...AND FAR WRN WV. THIS IS
CONSISTENT WITH THE JACKSON KY VWP THAT PRESENTLY DEPICTS AROUND
150-175 M2/S2 OF 0-1-KM SRH.

HOWEVER...REGION-WIDE...MID-LEVEL LAPSE RATES ARE NOTABLY MORE POOR
IN ADVANCE OF THE VORT MAX -- PER 12Z ILN RAOB -- THAN THEY WERE IN
PREVIOUS DAYS. FURTHERMORE...WATER VAPOR LOOPS SUGGEST THAT THE
VORT-MAX PRECEDING LOBE OF ASCENT IS IN THE PROCESS OF ADVANCING
ENE/NE OF THE DESTABILIZING PBL. THESE FACTORS CAST CONSIDERABLE
DOUBT ON OVERALL CONVECTIVE VIGOR AND THE NEED FOR A WW.
REGARDLESS...VERTICAL SHEAR REMAINS SUFFICIENTLY STRONG AMIDST AREAS
OF DESTABILIZATION TO WARRANT CONSIDERATION OF POSSIBLE WW ISSUANCE
THROUGHOUT THE AFTERNOON.

..COHEN/HART.. 06/29/2015

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

ATTN...WFO...RLX...JKL...ILN...LMK...PAH...

LAT...LON   36868516 37338730 38258579 39268477 39668411 39738277
            39418172 38568169 37278318 36868516



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