SPC AC 241242
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0642 AM CST TUE NOV 24 2009
VALID 241300Z - 251200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
AN ACTIVE...PROGRESSIVE PATTERN WILL PREVAIL THIS PERIOD...WITH
LARGE SCALE RIDGE IN THE WEST AND LARGE SCALE TROUGH OVER THE MS/OH
VLYS. UPR LOW NOW OVER NE KS WILL CONTINUE ENE TO LK MI BY THE END
OF THE PERIOD. THE LOW SHOULD DEVOLVE INTO AN OPEN TROUGH AS POTENT
UPSTREAM SPEED MAX NOW OVER THE CANADIAN RCKYS ACCELERATES SE INTO
THE DAKOTAS. FARTHER S...SUBTROPICAL JET WILL REMAIN CONFINED TO
CNTRL MEXICO AND THE SRN GULF OF MEXICO. SATELLITE SHOWS A
DISTURBANCE ON THE NRN FRINGE OF THIS FLOW...ATTM OVER DEEP S TX.
THE DISTURBANCE SHOULD SHEAR E/NE INTO THE ERN GULF OF MEXICO BY 12Z
WED.
AT THE SFC...COLD FRONT ASSOCIATED WITH KS UPR LOW WILL CONTINUE
E/SE ACROSS THE MID/LWR MS AND LWR OH VLYS. ELSEWHERE...ERN PART OF
WEAK W/E BOUNDARY OVER THE CNTRL GULF OF MEXICO/S FL SHOULD RETURN
NWD TONIGHT/EARLY WED AS A WAVE FORMS OVER THE CNTRL GULF IN
RESPONSE TO S TX UPR IMPULSE.
...MID MS VLY...
MODERATE TO STRONG FORCING FOR ASCENT AND STEEPENING MID LVL LAPSE
RATES ASSOCIATED WITH KS UPR LOW/TROUGH WILL CONTINUE TO FOSTER
DEVELOPMENT OF SCTD CONVECTION/STORMS FROM NRN MO AND CNTRL/SRN IA
EWD INTO PARTS OF IL/FAR SRN WI. INITIAL ROUND OF STORMS NOW
DIMINISHING OVER IA/MO MAY BE FOLLOWED BY A NEW ROUND OF DEVELOPMENT
LATER THIS AFTN INTO TONIGHT OVER CNTRL/NRN IL AS VORT LOBE NOW OVER
CNTRL KS/NW OK ROTATES NEWD. SPARSE MOISTURE AND MODEST LOW LVL
WIND FIELDS SHOULD BAR ANY SVR THREAT.
...S TX...
DIURNAL HEATING OF MOISTURE-RICH...WEAKLY-CAPPED...AND MODERATELY
UNSTABLE /SBCAPE OF 1000-2000 J PER KG/ AIR MASS WILL SUPPORT
SCTD STORMS ALONG AND AHEAD OF AFOREMENTIONED COLD FRONT THIS AFTN.
WEAK SHEAR SHOULD PRECLUDE ANY ASSOCIATED SVR THREAT.
...CNTRL/S FL...
SCTD MAINLY DIURNAL STORMS EXPECTED TODAY INVOF WEAK W-E FRONT...
WHERE SBCAPE WILL APPROACH 1000-1500 J/KG. RELATIVELY WEAK LOW TO
MID LVL SHEAR AND MODEST LAPSE RATES SHOULD LIMIT ANY SUSTAINED SVR
THREAT TODAY. HOWEVER...ADDITIONAL STORMS MAY MOVE INTO/DEVELOP
ACROSS THE REGION LATE TONIGHT/EARLY WED AS WIND FIELD/WAA
STRENGTHEN AHEAD OF AFOREMENTIONED GULF UPR IMPULSE. ALTHOUGH A
SUBSTANTIAL AMPLIFICATION OF THE UPR IMPULSE IS NOT
EXPECTED...SATELLITE DATA SUGGEST THAT FEATURE MAY BE A BIT STRONGER
THAN INDICATED IN OBJECTIVE GUIDANCE. COUPLED WITH BACKED LOW-LVL
FLOW INVOF ASSOCIATED SFC WAVE...SETUP MAY YIELD A FEW DISCRETE OR
SEMI-DISCRETE STORMS. THESE COULD POSE A LOW CONDITIONAL THREAT FOR
AN ISOLD TORNADO EARLY WED.
..CORFIDI/JEWELL.. 11/24/2009
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
|
