[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 300704
SWOMCD
SPC MCD 300703
TNZ000-MSZ000-KYZ000-MOZ000-ARZ000-LAZ000-300800-

MESOSCALE DISCUSSION 2166
NWS STORM PREDICTION CENTER NORMAN OK
0203 AM CDT FRI OCT 30 2009

AREAS AFFECTED...NERN LA/ERN AR/WRN MS INTO WRN TN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 300703Z - 300800Z

PERIODIC INCREASES IN TSTM ACTIVITY ARE POSSIBLE OVERNIGHT INTO THE
EARLY MORNING ACROSS NERN LA TO WRN TN...WITH AN ISOLATED THREAT FOR
STRONG WIND GUSTS AND/OR A BRIEF TORNADO.  GIVEN WEAK
INSTABILITY...OVERALL SEVERE WEATHER THREAT DOES NOT WARRANT A WATCH
AT THIS TIME...BUT TRENDS WILL CONTINUE TO BE MONITORED.

REGIONAL RADARS SHOWED CORRIDOR OF SHOWERS WITH EMBEDDED TSTMS
EXTENDING FROM E TX/WRN-NRN LA INTO SERN MO/WRN IL.  RADAR AND
LIGHTNING DATA INDICATED THE STRONGEST TSTMS WERE LOCATED ALONG THE
LEADING EDGE OF THIS EXTENSIVE AREA OF ACTIVITY...WITH SOME STORM
ORGANIZATION OVER NERN LA/SERN AR AND ALSO ACROSS FAR ERN AR.  THESE
STORMS AREA LOCATED AHEAD OF A COLD FRONT ADVANCING EWD INTO THE
LOWER MS VALLEY OVERNIGHT AND ARE LIKELY UNDER THE INFLUENCE OF A
ZONE OF LOW LEVEL CONVERGENCE...GIVEN 850 MB SSWLY WINDS OVER SE TX
TO AR AND AT THE SAME LEVEL...SSELY WINDS OVER MS TO SERN LA.

THUS...GIVEN THE PRESENCE OF A VERY MOIST AIR MASS /SURFACE
DEWPOINTS 70+ F/ EXTENDING INTO THE MID-SOUTH...LOW LEVEL
CONVERGENCE BENEATH WEAK HEIGHT FALLS SPREADING EWD AHEAD OF PLAINS
UPPER TROUGH WILL SUPPORT ADDITIONAL TSTMS INTO THE EARLY MORNING.
STRONG SSWLY MID LEVEL WINDS COMBINED WITH THE AFOREMENTIONED LOW
LEVEL FLOW WILL MAINTAIN EFFECTIVE BULK SHEAR 40-50 KT.  ALTHOUGH
INSTABILITY IS WEAK...THE STRONG DEEP LAYER SHEAR WILL SUPPORT
PERIODIC STORMS/CLUSTERS TO BECOME ORGANIZED WITH AN ISOLATED THREAT
FOR MAINLY STRONGER WIND GUSTS...GIVEN 40-50 KT WINDS JUST OFF THE
SURFACE IN THE LOWER MS VALLEY.  OBJECTIVE ANALYSIS AND AREA WSR-88D
VWPS INDICATED VERY STRONG LOW LEVEL SHEAR ACROSS THE LOWER MS
VALLEY WITH SFC-1 KM VALUES EXCEEDING 40 KT AND EFFECTIVE SRH
RANGING FROM 300-600 M2/S2.  THIS LOW LEVEL SHEAR COMBINED WITH THE
LACK OF SURFACE BASED INHIBITION WITHIN A VERY MOIST BOUNDARY LAYER
IS SUPPORTIVE OF A TORNADO THREAT...THOUGH ISOLATED DUE TO THE
OVERALL WEAK INSTABILITY.

..PETERS.. 10/30/2009

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

ATTN...WFO...PAH...MEG...JAN...LZK...SHV...

LAT...LON   31899233 33089183 34429095 35299061 36578984 36528895
            35928872 33818950 32069039 31449124 31559212 31899233

This weather bulletin was brought to you by:
www.nashvilleweather.net