MODERATE RISK of Severe Monday ... MO, TX, AR, LA
Posted: Sun Nov 16, 2003 5:21 pm
SPC has issued a moderate risk for severe Wx from Southern MO, all of AR, NE TX, and NW LA for Monday ... and the risk continues Tuesday (as a slight for the Southeast on Tuesday in which GSP has released a disturbing discussion regarding this) ...
...SRN AND CNTRL PLAINS/LOWER MS VALLEY...
SCATTERED CONVECTION WILL LIKELY BE ONGOING ACROSS MUCH OF THE SRN
PLAINS IN RESPONSE TO STRONG FORCING ASSOCIATED WITH AN APPROACHING
UPPER-LEVEL TROUGH. A COLD FRONT WILL ORGANIZE AND MOVE SWIFTLY EWD
ACROSS W TX BY AFTERNOON. CONVECTION SHOULD FOCUS ALONG A PREFRONTAL
TROUGH LOCATED ACROSS CNTRL TX EXTENDING NWD INTO CNTRL OK DURING
THE DAY. AS THE CONVECTIVE LINE MOVES EWD...IT WILL ENCOUNTER
INCREASING SFC MOISTURE WITH SFC DEWPOINTS IN THE MID 60S F ACROSS
NE TX AND SERN OK. ALTHOUGH SFC HEATING WILL BE LIMITED BY
WIDESPREAD CLOUD COVER...MLCAPE VALUES SHOULD REACH 500 TO 1000 J/KG
ACROSS THE ARKLATEX REGION. THE LINE SHOULD ORGANIZE AS IT MOVES EWD
INTO INCREASING INSTABILITY DURING THE EVENING HOURS. THE AMOUNT OF
INSTABILITY THAT MATERIALIZES WILL DETERMINE THE AMOUNT OF SEVERE
WEATHER COVERAGE. STRONG DEEP LAYER SHEAR WITH 0-6 KM SHEAR AROUND
50 KT WILL ENHANCE A WIND DAMAGE POTENTIAL ESPECIALLY WITH BOWING
SEGMENTS WITHIN THE LINE. IN ADDITION...STRONG 0-1 KM SHEAR AND LOW
LCL HEIGHTS WILL FAVOR AN ISOLATED TORNADO THREAT. THE GREATEST
TORNADO THREAT WILL EXIST WITH SHALLOW SUPERCELLS WITHIN BREAKS IN
THE LINE THAT FORM IN LOCALLY HIGHER AREAS OF INSTABILITY. A STRONG
TORNADO OR TWO MAY OCCUR IN THE AREA INCLUDING SRN MO...AR...NRN
LA...SERN OK AND ERN TX CONSIDERING THE FORECAST POSITION OF THE
LOW-LEVEL JET AND UPPER-TROUGH.
...UPPER MIDWEST AND OH VALLEY...
MOISTURE ADVECTION WILL INCREASE ACROSS THE UPPER MS VALLEY AS THE
UPPER-TROUGH SHIFTS EWD INTO THE PLAINS MONDAY. SFC DEWPOINTS SHOULD
INCREASE INTO THE 50S F ACROSS ERN NEB...IA AND IL BY AFTERNOON.
STRONG CONVERGENCE AHEAD OF A SFC LOW AND ASSOCIATED TROUGH SHOULD
AID CONVECTIVE DEVELOPMENT ACROSS NERN KS AND ERN NEB IN THE
AFTERNOON. AS LARGE-SCALE ASCENT INCREASES...CONVECTIVE COVERAGE
WILL EXPAND AND MOVE EWD ACROSS IA AND INTO WI AND IL DURING THE
EVENING. FORECAST SOUNDINGS INDICATE INSTABILITY WILL BE MINIMAL.
HOWEVER...LOW-LEVEL SHEAR WILL BE STRONG AND 0-6 KM SHEAR IS
FORECAST TO BE AROUND 50 KT. THIS SUGGESTS ISOLATED SEVERE STORMS
WILL BE POSSIBLE. STRONG UPPER-LEVEL FORCING ASSOCIATED WITH THE
UPPER-TROUGH WILL AID THE DEVELOPMENT OF A CONVECTIVE LINE DURING
THE EVENING WITH A POTENTIAL FOR WIND DAMAGE. THE GREATEST POTENTIAL
FOR WIND DAMAGE WILL EXIST WITH BOWING SEGMENTS WITHIN THE LINE
ACROSS SERN IA...NRN MO AND IL.
..BROYLES.. 11/16/2003

...SRN AND CNTRL PLAINS/LOWER MS VALLEY...
SCATTERED CONVECTION WILL LIKELY BE ONGOING ACROSS MUCH OF THE SRN
PLAINS IN RESPONSE TO STRONG FORCING ASSOCIATED WITH AN APPROACHING
UPPER-LEVEL TROUGH. A COLD FRONT WILL ORGANIZE AND MOVE SWIFTLY EWD
ACROSS W TX BY AFTERNOON. CONVECTION SHOULD FOCUS ALONG A PREFRONTAL
TROUGH LOCATED ACROSS CNTRL TX EXTENDING NWD INTO CNTRL OK DURING
THE DAY. AS THE CONVECTIVE LINE MOVES EWD...IT WILL ENCOUNTER
INCREASING SFC MOISTURE WITH SFC DEWPOINTS IN THE MID 60S F ACROSS
NE TX AND SERN OK. ALTHOUGH SFC HEATING WILL BE LIMITED BY
WIDESPREAD CLOUD COVER...MLCAPE VALUES SHOULD REACH 500 TO 1000 J/KG
ACROSS THE ARKLATEX REGION. THE LINE SHOULD ORGANIZE AS IT MOVES EWD
INTO INCREASING INSTABILITY DURING THE EVENING HOURS. THE AMOUNT OF
INSTABILITY THAT MATERIALIZES WILL DETERMINE THE AMOUNT OF SEVERE
WEATHER COVERAGE. STRONG DEEP LAYER SHEAR WITH 0-6 KM SHEAR AROUND
50 KT WILL ENHANCE A WIND DAMAGE POTENTIAL ESPECIALLY WITH BOWING
SEGMENTS WITHIN THE LINE. IN ADDITION...STRONG 0-1 KM SHEAR AND LOW
LCL HEIGHTS WILL FAVOR AN ISOLATED TORNADO THREAT. THE GREATEST
TORNADO THREAT WILL EXIST WITH SHALLOW SUPERCELLS WITHIN BREAKS IN
THE LINE THAT FORM IN LOCALLY HIGHER AREAS OF INSTABILITY. A STRONG
TORNADO OR TWO MAY OCCUR IN THE AREA INCLUDING SRN MO...AR...NRN
LA...SERN OK AND ERN TX CONSIDERING THE FORECAST POSITION OF THE
LOW-LEVEL JET AND UPPER-TROUGH.
...UPPER MIDWEST AND OH VALLEY...
MOISTURE ADVECTION WILL INCREASE ACROSS THE UPPER MS VALLEY AS THE
UPPER-TROUGH SHIFTS EWD INTO THE PLAINS MONDAY. SFC DEWPOINTS SHOULD
INCREASE INTO THE 50S F ACROSS ERN NEB...IA AND IL BY AFTERNOON.
STRONG CONVERGENCE AHEAD OF A SFC LOW AND ASSOCIATED TROUGH SHOULD
AID CONVECTIVE DEVELOPMENT ACROSS NERN KS AND ERN NEB IN THE
AFTERNOON. AS LARGE-SCALE ASCENT INCREASES...CONVECTIVE COVERAGE
WILL EXPAND AND MOVE EWD ACROSS IA AND INTO WI AND IL DURING THE
EVENING. FORECAST SOUNDINGS INDICATE INSTABILITY WILL BE MINIMAL.
HOWEVER...LOW-LEVEL SHEAR WILL BE STRONG AND 0-6 KM SHEAR IS
FORECAST TO BE AROUND 50 KT. THIS SUGGESTS ISOLATED SEVERE STORMS
WILL BE POSSIBLE. STRONG UPPER-LEVEL FORCING ASSOCIATED WITH THE
UPPER-TROUGH WILL AID THE DEVELOPMENT OF A CONVECTIVE LINE DURING
THE EVENING WITH A POTENTIAL FOR WIND DAMAGE. THE GREATEST POTENTIAL
FOR WIND DAMAGE WILL EXIST WITH BOWING SEGMENTS WITHIN THE LINE
ACROSS SERN IA...NRN MO AND IL.
..BROYLES.. 11/16/2003