DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1154 PM CST WED FEB 22 2012

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF THE OH/TN VALLEYS
AND DEEP SOUTH...

...SYNOPSIS...
INTENSE MID-LEVEL JET FROM THE PACIFIC NW TO THE CNTRL ROCKIES WILL
PROGRESS EWD ON THU...AIDING IN AMPLIFICATION OF A SHORT WAVE
IMPULSE CURRENTLY OVER THE NRN HIGH PLAINS. THIS FEATURE SHOULD
REACH THE LOWER/MID-MO VALLEY BY EVENING AND REMAIN
POSITIVELY-TILTED AS IT EJECTS ACROSS THE MIDWEST TOWARDS THE LOWER
GREAT LAKES THROUGH FRI MORNING. PRIMARY SURFACE CYCLONE IS EXPECTED
TO BE INVOF IL/IND BORDER BY 00Z...WITH A W/E-ORIENTED WARM FRONT
SHIFTING NWD ACROSS THE OH VALLEY. THIS LOW SHOULD TRACK TOWARDS LK
ERIE...WHILE AN ATTENDANT COLD FRONT SWEEPS E/SEWD ACROSS THE MS/TN
VALLEYS AND WRN GULF COAST IN THE EVENING...BEFORE REACHING THE
CNTRL/SRN APPALACHIANS AND CNTRL GULF COAST BY 12Z/FRI.

...OH/TN VALLEYS TO THE CNTRL GULF COAST...
IN THE WAKE OF THE SHORT WAVE IMPULSE CURRENTLY OVER THE CNTRL/SRN
APPALACHIANS...STRONG LOW/MID-LEVEL WLYS HAVE ENVELOPED THE RESIDUAL
WARM SECTOR FROM THE TN VALLEY TO THE CNTRL GULF COAST. ALTHOUGH
MODEST BACKING TO SWLY LOW-LEVEL FLOW IS EXPECTED AS THE N-CNTRL
CONUS SHORT WAVE TROUGH AMPLIFIES...THIS TYPE OF REGIME SHOULD SERVE
TO LIMIT THE VERTICAL EXTENT OF RICHER GULF MOISTURE BENEATH AN
EXPANDING EML.

EVENING MODEL GUIDANCE VARY MARKEDLY WITH THEIR HANDLING OF THE
MOISTURE RETURN TOWARDS THE LOWER OH VALLEY. THE NAM AND
WRF-NMM/ETA-BASED MEMBERS OF THE SREF ARE MORE AGGRESSIVE THAN THE
GFS/ECMWF AND WRF-ARW/RSM MEMBERS OF THE SREF...WHICH RESULTS IN
SUBSTANTIAL DIFFERENCES IN BUOYANCY PROFILES.
NEVERTHELESS...VIGOROUS LARGE-SCALE ASCENT COUPLED WITH DAYTIME
HEATING SHOULD YIELD TSTM INITIATION INVOF SURFACE CYCLONE NEAR THE
LOWER OH VALLEY BY LATE AFTERNOON. HERE...VERY STRONG DEEP-LAYER
SHEAR AND AT LEAST MEAGER INSTABILITY WOULD PROMOTE A RISK FOR
ORGANIZED TSTM CLUSTERS AND EMBEDDED SUPERCELLS. BUT GIVEN THE
UNCERTAINTY IN THE QUALITY OF THE BOUNDARY LAYER MOISTURE...WILL
REFRAIN FROM INTRODUCING HIGHER SEVERE PROBABILITIES ATTM.

WITH SRN EXTENT...CONFIDENCE LESSENS ON TSTM INITIATION AS STRONGER
LARGE-SCALE ASCENT LARGELY REMAINS N OF THE OH VALLEY. BUT
CONVERGENCE ALONG THE COLD FRONT ALONG WITH WEAK MID-LEVEL HEIGHT
FALLS MAY RESULT IN TSTMS FORMING SWD ACROSS THE TN VALLEY INTO THE
DEEP SOUTH DURING THE EVENING. EVEN WITH ONLY WEAK
INSTABILITY...DEEP-LAYER SHEAR WILL BE QUITE FAVORABLE FOR ISOLATED
SUPERCELLS WITH ALL SEVERE THREATS POSSIBLE.

TOWARDS THE CNTRL GULF COAST...GUIDANCE IS LARGELY CONSISTENT IN
MAINTAINING AN EML THROUGH MOST OF THE PERIOD. SOME POTENTIAL FOR
TSTM DEVELOPMENT SHOULD EXIST OVERNIGHT ALONG THE COLD FRONT. BUT
MODEST INSTABILITY AND VEERING/WEAKENING LOW-LEVEL WINDS SHOULD
RESULT IN A MORE MARGINAL SEVERE RISK RELATIVE TO FARTHER N.

..GRAMS/LEITMAN.. 02/23/2012

MESOSCALE DISCUSSION 0144
NWS STORM PREDICTION CENTER NORMAN OK
1125 PM CST WED FEB 22 2012

AREAS AFFECTED...CNTRL NC...SRN VA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 230525Z - 230700Z

AN ISOLATED SEVERE THREAT ONGOING WITH A CONVECTIVE LINE IN WCNTRL
NC WILL LIKELY CONTINUE FOR A FEW MORE HOURS. HOWEVER...THE THREAT
SHOULD REMAIN ISOLATED AND WW ISSUANCE DOES NOT APPEAR LIKELY ATTM.

A NEARLY CONTINUOUS LINE OF THUNDERSTORMS IS ONGOING JUST AHEAD A
WELL-DEFINED SHORTWAVE TROUGH MOVING THROUGH THE SRN APPALACHIAN
MTNS. REGIONAL WSR-88D VWPS AND FORECAST SOUNDINGS OVER CNTRL NC
THIS EVENING SHOW VERY STRONG DEEP LAYER SHEAR WITH 0-6 KM SHEAR
AROUND 70 KT. THIS ALONG WITH AN EWD STORM MOTION OF 40 TO 50 KT IS
CREATING A WIND DAMAGE THREAT ALONG THE LEADING EDGE OF THE LINE.
ALTHOUGH...A GUST OF 46 KT WAS RECORDED EARLIER AT
GREENSBORO...OBSERVATIONS OVER THE LAST HALF HOUR SUGGEST WINDS WITH
THE LINE HAVE RECENTLY BEEN BELOW 40 KT SUGGESTING THE WIND DAMAGE
THREAT IS MARGINAL. THE ORIENTATION OF THE WIND FIELD PARALLEL TO
THE LINE AND THE WEAK INSTABILITY COULD BE RESULTING IN THE MARGINAL
THREAT. FOR THIS REASON...A WATCH IS NOT EXPECTED DURING THE
OVERNIGHT PERIOD.

..BROYLES.. 02/23/2012

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

ATTN...WFO...AKQ...RAH...ILM...RNK...

LAT...LON   36547788 36217758 35727791 35517810 35167838 34827876
            34787923 34967967 35248004 35528009 36687857 36547788