[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 172143
SWOMCD
SPC MCD 172142
KYZ000-OHZ000-TNZ000-172315-

MESOSCALE DISCUSSION 2175
NWS STORM PREDICTION CENTER NORMAN OK
0342 PM CST MON DEC 17 2012

AREAS AFFECTED...CNTRL KY/MIDDLE TN

CONCERNING...SEVERE THUNDERSTORM WATCH 683...

VALID 172142Z - 172315Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 683
CONTINUES.

SUMMARY...THE THREAT FOR SVR STORMS CONTINUES ACROSS PARTS OF WW
683...WITH THE GREATEST THREAT CONFINED TO PORTIONS OF MIDDLE TN IN
THE SHORT TERM.

DISCUSSION...RADAR LOOPS SUGGEST THAT CONVECTION HAS CONGEALED INTO
A WAVY SQUALL LINE...APPROXIMATELY LYING FROM COLUMBUS OH TO
LEXINGTON KY TO NASHVILLE TN TO THE AL/MS/TN BORDER. ACROSS CNTRL KY
AND NWD...MUCH OF THE LINE HAS OUTPACED MARGINAL WARM-SECTOR
BUOYANCY. DOWNSTREAM ANVIL SHADING OWING TO STRONG HIGH-LEVEL
STORM-RELATIVE FLOW IS FURTHER LIMITING BUOYANCY OF INFLOW AIR.
HOWEVER...WITH OVER 50 KT OF DEEP SHEAR EVIDENT PER JACKSON KY VWP
DATA...STRONG TO PERHAPS MARGINALLY SVR WIND GUSTS WILL REMAIN
POSSIBLE WITH THIS LINE OF STORMS ACROSS ERN KY.

FARTHER SOUTH ACROSS MIDDLE TN...CONVECTION HAS BEEN SLOWER TO GROW
UPSCALE. ANY REMNANT SEMI-DISCRETE CONVECTIVE ELEMENTS MAY STILL
POSE A THREAT FOR MARGINALLY SVR HAIL/WIND WITHIN THE NEXT HOUR OR
TWO AS INFLOW IS CHARACTERIZED BY COMPARATIVELY GREATER
INSTABILITY -- I.E. MLCAPE VALUES OF 400-800 J/KG.
THEREAFTER...STORM INTENSITY SHOULD LESSEN AS NOCTURNAL
COOLING/STABILIZATION COMMENCE.

DESPITE THE CONTINUED APPROACH OF ADDITIONAL FORCING FOR
ASCENT...STORM DEVELOPMENT BEHIND THE AFOREMENTIONED QLCS IS
UNLIKELY OWING TO EARLIER CONVECTIVE OVERTURNING AND THE ONSET OF
NOCTURNAL COOLING. AS SUCH...REMAINING VALID PORTIONS OF THE WW MAY
BE CLEARED BEHIND THE QLCS.

..COHEN.. 12/17/2012

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

ATTN...WFO...RLX...MRX...JKL...ILN...LMK...OHX...PAH...MEG...

LAT...LON   38738357 38448321 36548446 35878508 35618621 35668766
            35788822 36358811 36528780 36638744 36718705 36848658
            37198612 37478585 37718569 38128542 38568508 38728485
            38808446 38738357



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