Tornado Watch Expected For NW Alabama Soon

MESOSCALE DISCUSSION 0409
NWS STORM PREDICTION CENTER NORMAN OK
0858 AM CDT MON APR 11 2011

AREAS AFFECTED…WRN AND CENTRAL KY….WRN AND MIDDLE TN…NRN
MS…AND SERN AR

CONCERNING…SEVERE POTENTIAL…TORNADO WATCH LIKELY

VALID 111358Z – 111500Z

A TORNADO WATCH WILL LIKELY BE NEEDED THIS MORNING ACROSS
WRN/CENTRAL KY SWWD THROUGH WRN-MIDDLE TN TO NRN MS/SERN AR.

AT 1340Z…REGIONAL RADAR IMAGERY/LIGHTNING DATA SHOWED TSTMS
EXTENDING FROM FAR SWRN KY SWWD TO THE ARKLATEX REGION. A
LONG-LIVED MCV ATTENDANT TO AN OVERNIGHT/EARLY MORNING CONVECTIVE
COMPLEX WAS SUPPORTING THE NERN EXTENT OF ACTIVITY…CURRENTLY
MOVING INTO FAR WRN TN/FAR SWRN KY. 40-50 KT SWLY LLJ PARALLEL TO
AND LOCATED JUST AHEAD OF THIS ACTIVITY COMBINED WITH LOW LEVEL
DIRECTIONAL SHEAR /0-1 KM SRH 400 M2 PER S2/ AS NOTED ON AREA
WSR-88D VWPS ARE FAVORABLE FOR TORNADOES ALONG WITH DAMAGING WINDS.
OBJECTIVE ANALYSES INDICATED AIR MASS IMMEDIATELY DOWNSTREAM IS
MARGINALLY UNSTABLE AND LIKELY PRECLUDING A GREATER COVERAGE OF
STRONGER TO SEVERE STORMS AT THIS TIME. HOWEVER…12Z LIT SOUNDING
IS LIKELY MOST REPRESENTATIVE OF THE ENVIRONMENT INVOF THE ONGOING
TSTMS…WHICH GIVEN THE THERMODYNAMICS AND KINEMATICS SUPPORTS BOTH
A TORNADO AND DAMAGING WIND THREAT GIVEN ALMOST NON-EXISTENT
INHIBITION.

SWLY LOW LEVEL WINDS ADVECTING 60S SURFACE DEWPOINTS NEWD IN ADVANCE
OF A COMPOSITE OUTFLOW BOUNDARY…WHICH EXTENDED FROM SRN OH TO FAR
WRN KY INTO ERN AR…COMBINED WITH DIABATIC HEATING FILTERED THROUGH
HIGHER CLOUDS WILL AID IN DOWNSTREAM DESTABILIZATION. THIS COMBINED
WITH STRONGER HEIGHT FALLS SPREADING INTO THE MID SOUTH AND TN/OH
VALLEYS AND STRONG WIND FIELDS SUGGESTS A TORNADO WATCH WILL BE
NEEDED THIS MORNING.

..PETERS.. 04/11/2011

Tags: severe storms

Category: Severe Weather