MESO: Mesoscale Discussion 1789

ACUS11 KWNS 281842
SWOMCD
SPC MCD 281842
WVZ000-OHZ000-VAZ000-KYZ000-281945-

MESOSCALE DISCUSSION 1789
NWS STORM PREDICTION CENTER NORMAN OK
0142 PM CDT WED AUG 28 2013

AREAS AFFECTED...PORTIONS OF S-CNTRL OH...CNTRL/SRN WV...FAR NERN KY

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 281842Z - 281945Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A THREAT FOR STRONG TO MARGINALLY SVR WIND GUSTS COULD
ACCOMPANY DEVELOPING TSTMS THIS AFTERNOON ACROSS PARTS OF S-CNTRL OH
INTO CNTRL/SRN WV AND FAR NERN KY. A WW IS NOT ANTICIPATED.

DISCUSSION...LATEST VISIBLE SATELLITE AND RADAR LOOPS SHOW ISOLATED
SHOWERS/TSTMS DEVELOPING WITHIN A THICKENING CU FIELD...ORIENTED
FROM S-CNTRL OH ESEWD INTO CNTRL WV. THIS LIKELY COINCIDES WITH AN
AXIS OF RELATIVELY RICHER MOISTURE /PW AOA 1.8 INCHES/ DOWNSTREAM
FROM A SUBTLE UPPER IMPULSE ENTERING NERN OH. SFC OBS SHOW NEARLY
UNIFORM WLY WINDS ACROSS THIS REGION...INDICATIVE OF MINIMAL SFC
CONVERGENCE INVOF THE THICKENING CLOUD BAND.

WIDESPREAD CLOUD COVER FROM EARLIER THIS MORNING IS BEGINNING TO
DISSIPATE...ALLOWING FOR POCKETS OF STRONGER HEATING AND INCREASING
INSTABILITY...WITH MLCAPE VALUES OF 1000-1500 J/KG COMMON. GLANCING
INFLUENCE OF THE UPSTREAM UPPER IMPULSE SHOULD CONTRIBUTE TO
GRADUALLY INCREASING TSTM COVERAGE ACROSS THE AREA. VEERING WIND
PROFILES WITH HEIGHT BENEATH MODERATELY STRONG MIDLEVEL FLOW IS
RESULTING IN EFFECTIVE SHEAR VALUES NEAR 30 KT...SUFFICIENT FOR
PERSISTENT MULTICELL CLUSTERS. AN ACCOMPANYING THREAT FOR A FEW
STRONG TO MARGINALLY SVR WIND GUSTS MAY EXIST...ESPECIALLY WITHIN
AREAS WHERE STRONGER HEATING HAS OCCURRED. HOWEVER...UNCERTAINTY
ABOUT THE MAGNITUDE AND COVERAGE OF THE THREAT WILL LIKELY PRECLUDE
WW ISSUANCE.

..ROGERS/THOMPSON.. 08/28/2013

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

ATTN...WFO...RNK...RLX...ILN...

LAT...LON 37648047 37298108 37348163 37928237 38368305 38978325
39368323 39518312 39528274 39378220 39258165 38978088
38908069 38358024 38018025 37648047

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