[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 210752
SWOMCD
SPC MCD 210752
GAZ000-ALZ000-TNZ000-MSZ000-ARZ000-210945-

MESOSCALE DISCUSSION 0037
NWS STORM PREDICTION CENTER NORMAN OK
0152 AM CST SAT JAN 21 2012

AREAS AFFECTED...PORTIONS NRN MS...NRN/CENTRAL AL...W-CENTRAL/NWRN
GA...MAINLY MIDDLE TN.

CONCERNING...TORNADO WATCH 2...

VALID 210752Z - 210945Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 2 CONTINUES.

WW MAY BE CLEARED BEHIND SFC COLD FRONT...OTHERWISE CONTINUE VALID
PORTIONS WW.

FRONT WAS ANALYZED AT 07Z FROM SFC LOW BETWEEN BNA-BWG...EXTENDING
SWWD HARDEMAN COUNTY TN AND COAHOMA COUNTY MS.  FRONT WILL CONTINUE
MOVING SEWD ACROSS WW AREA...ACCOMPANIED BY QUASI-LINEAR BAND OF
TSTMS...AND PRECEDED BY BANDS OF WARM-SECTOR CONVECTION MOVING FROM
MID-ERN TN.  SLOW-MOVING WARM FRONT WAS DRAWN FROM LOW SSEWD ACROSS
JACKSON COUNTY AL THEN BECOMING QUASISTATIONARY SEWD OVER ATL METRO
AREA.  CONVECTION INTERACTING WITH LATTER FRONTAL ZONE...ESPECIALLY
IF RELATIVELY DISCRETE...MAY EXPERIENCE TEMPORARY INTENSIFICATION OF
STORM-SCALE ROTATION BEFORE BECOMING ELEVATED ATOP STRONGLY STABLE
LAYER TO ITS NE.  OTHERWISE...WARM-SECTOR ALSO WILL REMAIN FAVORABLE
WITH ENLARGED HODOGRAPHS...EFFECTIVE SRH IN 300-500 J/KG RANGE.
WARM-SECTOR INFLOW PARCELS OVER WW AREA ARE EFFECTIVELY
SFC-BASED...MLCAPE INCREASING FROM AROUND 300 J/KG ALONG WARM FRONT
TO AROUND 1000 J/KG NERN MS.

FARTHER SE ACROSS ERN AL AND WRN GA...SCATTERED TO WIDELY SCATTERED
SHALLOW CONVECTION AND SHOWERS ARE EVIDENT.  FCST SOUNDINGS SUGGEST
MUCAPE REMAINING 100-300 J/KG FOR NEXT FEW HOURS...WITH INFLOW
PARCELS ROOTED ABOVE BOUNDARY LAYER AMIDST 40-45 KT LLJ EVIDENT IN
VWP.  NEWD/45-50 KT MOTION OF THIS CONVECTION ALSO IS CONSISTENT
WITH MEAN WIND COMPUTED SANS BOUNDARY-LAYER INVOLVEMENT...FURTHER
INDICATING THIS ACTIVITY IS ROOTED ABOVE SFC.  BUOYANCY DECREASES
BOTH IN MAGNITUDE AND DEPTH...RELATED TO DECREASING LOW-MIDDLE LEVEL
LAPSE RATES.  MLCINH AND MUCINH ALSO WILL CONTINUE TO INCREASE WITH
EWD EXTENT FROM AL OVER GA.  THIS ACTIVITY IS ON SERN FRINGE OF
FAVORABLE EFFECTIVE SRH AND MRGL BUT INCREASING DEEP-LAYER SHEAR.
PRIND SVR THREAT IS NONZERO BUT TOO MRGL TO WARRANT ADDITIONAL WW
THROUGH AT LEAST 10Z...WHEN POTENTIAL ASSOCIATED DIRECTLY WITH WW
MAY SHIFT EWD/SEWD SOMEWHAT.

..EDWARDS.. 01/21/2012

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

ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MEG...JAN...LZK...

LAT...LON   34249073 35218890 36468641 36068566 34878586 34178549
            33678366 33268441 32378591 32288686 33088788 33238895
            33279075 33909103 34249073



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