[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 211755
SWOMCD
SPC MCD 211754
TNZ000-NCZ000-KYZ000-GAZ000-ALZ000-MSZ000-MOZ000-ARZ000-211930-

MESOSCALE DISCUSSION 1735
NWS STORM PREDICTION CENTER NORMAN OK
1254 PM CDT SAT AUG 21 2010

AREAS AFFECTED...MUCH OF TN...ERN AR...AND NRN MS/AL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 211754Z - 211930Z

THREAT FOR MAINLY DAMAGING WIND GUSTS/DOWNBURSTS IS EXPECTED TO
INCREASE ACROSS MUCH OF TN...ERN AR...AND NRN MS/AL DURING THE
AFTERNOON. AREA IS BEING MONITORED FOR A WW.

SHORTWAVE TROUGH EXTENDS SWWD OUT OF THE GREAT LAKES REGION INTO THE
MID MS VALLEY REGION...WITH LARGE SCALE ASCENT AND COOLING MID-LEVEL
TEMPERATURES SPREADING EWD AHEAD OF THIS FEATURE ACROSS THE TN
VALLEY. AT THE SURFACE...SOMEWHAT DIFUSE COLD FRONT EXTENDS SWWD OUT
OF IND INTO SRN MO AND ERN OK...WITH SUBTLE CONFLUENT ZONE LOCATED
AHEAD OF THE FRONT OVER CNTRL AR...AND A REMNANT OUTFLOW BOUNDARY
EXTENDING S-SWWD OUT OF ERN KY INTO MIDDLE TN. THUNDERSTORMS HAVE
RECENTLY DEVELOPED ALONG THE TN PORTION OF THE OUTFLOW
BOUNDARY...AND HAVE SHOWN SIGNS OF INTENSIFICATION AS TEMPERATURES
WARM INTO THE LOW 90S F. CONTINUED BOUNDARY LAYER HEATING COMBINED
WITH SURFACE DEWPOINTS IN THE MID 70S F IS CONTRIBUTING TOWARD THE
DEVELOPMENT OF MLCAPE VALUES IN EXCESS OF 2000 J/KG. THIS
INSTABILITY COMBINED WITH GENERALLY WEAK VERTICAL WIND SHEAR
PROFILES OBSERVED ACROSS THE REGION WILL SUPPORT STRONG MULTICELL
AND PULSE TYPE THUNDERSTORMS ALONG THE OUTFLOW BOUNDARY AND
PRE-FRONTAL WIND SHIFT. STRONG SURFACE HEATING/STEEPENING LOW-LEVEL
LAPSE RATES...HIGH PWAT AIR MASS...AND VERY UNSTABLE ENVIRONMENT
WILL LEAD TO A THREAT FOR DAMAGING WIND GUSTS/DOWNBURSTS WITH THE
STRONGER UPDRAFT CORES.

..GARNER.. 08/21/2010

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

ATTN...WFO...GSP...MRX...JKL...FFC...LMK...OHX...BMX...HUN...
PAH...MEG...LZK...

LAT...LON   34858450 33938827 34259319 35229293 36448888 36758434
            35948353 34858450


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