Mar 23, 2009 1300 UTC Day 1 Convective Outlook
Updated: Mon Mar 23 12:58:11 UTC 2009
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting ...severe thunderstorms expected over parts of the central and southern plains....   Please read the latest public statement about this event.

Categorical Graphic
20090323 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20090323 1300 UTC Day 1 Tornado Probabilities Graphic
Torndao Legend Image
Probabilistic Damaging Wind Graphic
20090323 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20090323 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 231254
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0754 AM CDT MON MAR 23 2009
   
   VALID 231300Z - 241200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF CNTRL AND ERN KS
   AND NRN OK...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK AREA
   FROM N TX INTO MID MO AND MID MS VLYS...
   
   ...SYNOPSIS...
   POTENT /80 KT/ MID LVL JET STREAK NOW OVER NRN NM WILL REDEVELOP NE
   INTO THE LWR MO VLY BY THIS EVE AS ATTENDANT CLOSED LOW TRACKS FROM
   NE CO TO N CNTRL NEB.  AT THE SAME TIME...UPSTREAM VORT NOW IN NV
   SHOULD CONTINUE ESE TO NM THIS EVE...BEFORE TURNING NE ACROSS THE
   OK/TX PANHANDLES AND SW KS EARLY TUE.
   
   AT THE SFC...LOW NOW OVER SW NEB SHOULD MOVE SLOWLY NE INTO ERN SD
   BY 12Z TUE AND OCCLUDE...WHILE TRAILING PACIFIC COLD FRONT CONTINUES
   ESE AND OVERTAKES PRE-FRONTAL TROUGH/DRY LINE FROM N TO S ACROSS
   KS...OK AND N TX.  THE FRONT SHOULD EXTEND FROM CNTRL IA THROUGH WRN
   MO...S CNTRL OK...AND W CNTRL TX BY THE END OF THE PERIOD.  THE
   FRONT AND...TO A LESSER EXTENT...THE DRY LINE...WILL BE THE FOCUS
   FOR SVR TSTM DEVELOPMENT LATER TODAY THROUGH EARLY TUE.
   
   ...S CNTRL/ERN SD SWD INTO CNTRL/ERN NEB AND N CNTRL KS TODAY...
   SUBSTANTIAL /90-150 M/ HEIGHT FALLS WILL PROGRESS STEADILY ENE
   ACROSS KS/NEB AND SRN SD TODAY AS CO UPR LOW CONTINUES NEWD.  THE
   HEIGHT FALLS WILL BE ACCOMPANIED BY ASCENT IN EXIT REGION OF
   ASSOCIATED UPR JET STREAK...AND WITH LOW LVL UPLIFT ALONG PACIFIC
   COLD FRONT.
   
   ALTHOUGH BOUNDARY LAYER MOISTURE WILL REMAIN COMPARATIVELY LIMITED
   /SFC DEWPOINTS IN THE LOW 50S/...WITH 500 MB TEMPS AROUND MINUS 20
   C...EVEN MODEST SFC HEATING SHOULD BOOST SBCAPE TO AOA 500 J/KG. 
   COMBINATION OF DESTABILIZATION AND INCREASING ASCENT SHOULD SUPPORT
   TSTM DEVELOPMENT ALONG COLD FRONT/OCCLUSION LATER THIS MORNING
   THROUGH LATE THIS AFTN FROM S CNTRL SD ACROSS CNTRL NEB INTO N CNTRL
   KS.
   
   DEEP SHEAR WILL BE STRONG /40-50 KTS/ THROUGHOUT REGION...ALTHOUGH 
   WITH A SUBSTANTIAL COMPONENT ORIENTED PARALLEL TO FRONT IN SD AND
   NEB.  OVERALL SETUP SHOULD YIELD A FEW SUSTAINED STORMS WITH A
   THREAT FOR SVR HAIL/WIND.  ASSUMING THE PRESENCE OF SUSTAINED
   UPDRAFTS...BACKED LOW-LVL FLOW NE OF SFC LOW IN NRN NEB AND SRN SD
   ALSO MAY PROVE FAVORABLE FOR LOW LVL STORM ROTATION/ISOLD TORNADOES
   ...BEFORE FRONT AND DEEP ASCENT OUTRUN LOW LVL MOIST AXIS LATE IN
   THE DAY.
   
   ...CNTRL/ERN KS SSW INTO MUCH OF OK/NW TX LATE TODAY/TONIGHT...
   DEEP FORCING FOR ASCENT AND MID LVL COOLING WILL REMAIN WEAK FROM
   CNTRL KS SW ACROSS OK AND NW TX TODAY AS LEAD SPEED MAX/UPR VORT
   LIFT NE INTO NEB/SD.  COUPLED WITH RELATIVELY LIMITED BOUNDARY LAYER
   MOISTURE AND SUBSTANTIAL EML CAP ON S SIDE OF UPR JET...EXPECT
   LITTLE IF ANY TSTM DEVELOPMENT TIL LATE IN THE DAY OVER OK AND NW
   TX.  SCTD STORMS MAY...HOWEVER...CONTINUE TO DEVELOP SLOWLY SWD
   ALONG FRONT IN KS.
   
   BY EARLY EVE...ASCENT WITH UPSTREAM JET DISTURBANCE SHOULD BEGIN TO
   OVERSPREAD THE SRN PLNS AS COLD FRONT OVERTAKES PRE-FRONTAL
   TROUGH/DRY LINE.  COMBINATION OF STRENGTHENING ASCENT WITH SLOWLY
   INCREASING BOUNDARY LAYER MOISTURE /SFC DEWPOINTS IN THE UPR 50S TO
   NEAR 60 F/ MAY SUPPORT INCREASED STORM COVERAGE/STRENGTH ALONG THE
   FRONT IN KS...AND DEVELOPMENT OF OTHER STORMS SW ALONG FRONT OR DRY
   LINE INTO OK.
   
   50+ KT DEEP SHEAR OVER REGION WILL BE ORIENTED AT A CONSIDERABLE
   ANGLE TO THE FRONT.  GIVEN SUSTAINED UPDRAFTS...THIS SHOULD ALLOW
   FOR THE DEVELOPMENT OF ELONGATED SUPERCELL STRUCTURES WITH A GOOD
   THREAT FOR LARGE HAIL AND HIGH WIND.  IN ADDITION...35-40 KT 0-1 KM
   SHEAR WITH A SUBSTANTIAL DIRECTIONAL COMPONENT /ASSOCIATED WITH 60
   KT SSWLY LOW LVL JET/...SUGGESTS POTENTIAL FOR STRONG TORNADOES
   ...IF SUSTAINED SEMI-DISCRETE STORMS DO INDEED FORM.
   
   THE CONVECTION COULD REMAIN STRONG TO SVR THROUGH EARLY TUE AS
   ACTIVITY DEVELOPS BOTH SWD INTO N TX...AND MOVES E INTO WRN MO.  THE
   GREATEST SVR THREAT SHOULD...HOWEVER...OCCUR BEFORE 06Z.
   
   ..CORFIDI/SMITH.. 03/23/2009
   
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