ZCZC SPCSWOMCD ALL
ACUS11 KWNS 251942 
SPC MCD 251942 
VAZ000-NCZ000-252115-

MESOSCALE DISCUSSION 1173
NWS STORM PREDICTION CENTER NORMAN OK
0242 PM CDT THU JUN 25 2015

AREAS AFFECTED...CNTRL/ERN VIRGINIA...EXTREME NRN NC

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 251942Z - 252115Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...ISOLATED SUPERCELLS ARE POSSIBLE THIS AFTERNOON WITH A
THREAT OF LARGE HAIL...DAMAGING WIND...AND POSSIBLY A TORNADO OR
TWO. THE THREAT WILL TRANSITION TO AN ENHANCED WIND THREAT THIS
EVENING AS STORMS INCREASE IN COVERAGE.

DISCUSSION...STORM INITIATION HAS RECENTLY OCCURRED ACROSS SERN VA
NEAR A WARM-FRONTAL BOUNDARY. RICH MOISTURE AND STRONG HEATING HAS
CONTRIBUTED TO THE DEVELOPMENT OF MODERATE INSTABILITY...WITH MLCAPE
OF 1500-2000 J/KG IN PLACE ALONG AND SOUTH OF THE BOUNDARY PER
RECENT MESOANALYSIS. EFFECTIVE SHEAR OF 30-40 KTS WILL SUPPORT THE
POTENTIAL FOR SUPERCELL DEVELOPMENT WITH THE INITIAL ACTIVITY...WITH
AN ATTENDANT THREAT FOR LARGE HAIL AND DAMAGING WIND. WHILE
LOW-LEVEL FLOW IS NOT PARTICULARLY STRONG...VEERING LOW-LEVEL WIND
PROFILES AND THE POTENTIAL FOR FAVORABLE BOUNDARY INTERACTION WILL
ALSO RESULT IN A THREAT FOR A TORNADO OR TWO WITH ANY SUPERCELLS
THAT CAN BE MAINTAINED. 

FURTHER WEST...CU HAS BEEN INCREASING ALONG A LEE TROUGH AS
LARGE-SCALE ASCENT INCREASES AHEAD OF A CONVECTIVELY-ENHANCED VORT
MAX CURRENTLY OVER ERN OH. ISOLATED SUPERCELLS WILL ALSO BE POSSIBLE
THIS AFTERNOON IF DEEP CONVECTION CAN INITIATE IN THIS AREA...WITH A
PRIMARY THREAT OF LARGE HAIL AND DAMAGING WIND. 

TSTM COVERAGE IS EXPECTED TO INCREASE THIS EVENING AS STRONGER
ASCENT OVERSPREADS THE AREA...WITH POTENTIAL UPSCALE GROWTH AND A
TRANSITION TO AN ENHANCED DAMAGING WIND THREAT. WW ISSUANCE IS
POSSIBLE BEFORE 21Z IF CURRENT ACTIVITY CONTINUES TO INCREASE IN
COVERAGE...WITH WW ISSUANCE BECOMING LIKELY BY THIS EVENING IN
RESPONSE TO THE INCREASING WIND DAMAGE THREAT.

..DEAN/DIAL.. 06/25/2015

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

ATTN...WFO...AKQ...LWX...RAH...RNK...

LAT...LON   36637606 36407694 36207935 36668012 37137991 38177873
            38237795 38077724 37787657 36637606 

NNNN