Mar 28, 2007 1300 UTC Day 1 Convective Outlook
Updated: Wed Mar 28 14:36:11 UTC 2007
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting ...widespread severe thunderstorms expected over the western half of the southern and central plains this afternoon and tonight....   Please read the latest public statement about this event.

Categorical Graphic
20070328 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20070328 1300 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20070328 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20070328 1300 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 281240
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0740 AM CDT WED MAR 28 2007
   
   VALID 281300Z - 291200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF NWRN TX...ERN TX
   PANHANDLE...WRN OK...WRN/CENTRAL KS...SWRN/CENTRAL NEB...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE TX BIG BEND/SWRN TX
   NWD ACROSS MUCH OF THE SRN AND CENTRAL PLAINS INTO SD AND FAR ERN
   WY...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CENTRAL APPALACHIANS
   INTO PART OF THE CAROLINAS...
   
   ...WIDESPREAD SEVERE THUNDERSTORMS INCLUDING DAMAGING WINDS...VERY
   LARGE HAIL AND POSSIBLY STRONG TORNADOES WILL DEVELOP OVER THE
   WESTERN HALF OF THE CENTRAL AND SOUTHERN PLAINS LATER TODAY AND
   TONIGHT...
   
   ...CENTRAL/SRN PLAINS...
   STRONG UPPER LOW WILL SHIFT INTO THE CENTRAL ROCKIES AND THEN REMAIN
   STATIONARY OVERNIGHT.  AS THIS OCCURS...SURFACE DRY LINE WILL BECOME
   WELL ESTABLISHED OVER THE HIGH PLAINS AND LIKELY EXTEND FROM A LOW
   OVER FAR NERN CO SWD JUST EAST OF THE KS/CO BORDER INTO THE CENTRAL
   TX PANHANDLE AND FAR SWRN TX BY EARLY THIS EVENING.  THOUGH SMALL
   SCALE DETAILS ARE DIFFERENT...OPERATIONAL MODELS ALONG WITH SREF AND
   HIGH-RESOLUTION WRFS ARE ALL IN AGREEMENT IN WIDESPREAD THUNDERSTORM
   DEVELOPMENT OVER WRN PARTS OF THIS REGION LATER TODAY AND
   TONIGHT...WITH HIGH LIKELIHOOD OF SEVERE WEATHER/SUPERCELLS. 
   IMPRESSIVE EML EVIDENT ON MORNING SOUNDINGS SUGGEST AIR MASS WILL
   BECOME VERY UNSTABLE OVER WRN HALF OF THE SRN PLAINS BY LATER
   TODAY...WITH MODERATE INSTABILITY DEVELOPING NWD INTO WRN NEB. 
   MLCAPE IN EXCESS OF 2000 J/KG IS FORECAST BY NEARLY ALL MODELS JUST
   EAST OF DRY LINE INTO WRN KS...WITH AXIS OF NEARLY 1000 J/KG MLCAPE
   NOSING NNWWD TOWARDS NWRN NEB.  LOW AND DEEP LAYER SHEAR WILL BE
   SIGNIFICANT ALONG THE WRN PLAINS DESPITE STRONGEST MID LEVEL JET
   EXTENDING NNEWD BEHIND THE DRY LINE OVER ERN CO.  AS IS NORMALLY THE
   CASE...COMPLEXITIES REMAIN REGARDING EXACT LOCATION AND TIMING OF
   INITIATION AND IN OVERALL MODE OF STORM-SCALE ORGANIZATION.  CAPPING
   EVIDENT ON MORNING SOUNDINGS WILL AID IN NNWWD LOW LEVEL MOISTURE
   RETURN AND RETARD DEEP CONVECTIVE DEVELOPMENT FOR MUCH OF THE
   DAY...ESPECIALLY WITH LOW CLOUDS AND STRATUS THROUGH THE MORNING. 
   OVERNIGHT NAM AND GFS WERE BOTH SEVERAL DEGREES TOO COOL AT H85 AND
   FAIL TO ACCURATELY DEPICT CAP AT AMA ACCORDING TO THE 12Z SOUNDING. 
   HOWEVER...BOTH DID WELL AT DDC AND NAM-KF WAS ACCURATE AT AMA AND
   DDC.  
   
   STRONGEST ASCENT AND MODEST HEATING SHOULD SUPPORT INITIAL
   DEVELOPMENT INTO WRN NEB AND NWRN KS BY LATE THIS AFTERNOON ALONG
   NOSE OF 90+ KT H5 JET.  MODELS SUGGESTING RAPID THUNDERSTORM
   DEVELOPMENT WITHIN BROAD AREA OF UPPER DIFFLUENCE JUST EAST OF THE
   DRY LINE INTO WRN KS AND THE TX PANHANDLE/WRN TX BETWEEN 21-00Z AS
   CAP WEAKENS.  HOW LONG ACTIVITY REMAINS IN THE FORM OF DISCRETE
   SUPERCELLS REMAINS HARD TO SAY ATTM...AS ACTIVITY WILL LIKELY EVOLVE
   INTO LINEAR STRUCTURES AS IT EVOLVES ENEWD THROUGH THE EVENING. 
   HOWEVER...VERY STEEP LAPSE RATES AND SHEAR WILL ENHANCE THE
   POTENTIAL FOR SIGNIFICANT/DAMAGING HAIL AND STRONG TORNADOES INTO
   THE EARLY-MID EVENING WITH DISCRETE STORMS.  WIND DAMAGE THREAT
   SHOULD ALSO INCREASE AS LINEAR ORGANIZATION BECOME MORE PREDOMINANT
   THIS EVENING.  LACK OF EWD PROGRESSION WITH OVERALL SYSTEM AND
   NARROW INSTABILITY AXIS...SUGGEST STORMS SHOULD WEAKEN AS THEY MOVE
   ACROSS CENTRAL SD/NE/KS/OK LATER THIS EVENING.
   
   NAM AND GFS ARE ALSO INDICATING SECONDARY LOBE OF ENERGY ROTATING
   AROUND LARGE UPPER LOW AND INTO THE NERN NM/SERN CO LATE TONIGHT. 
   THIS SHOULD SUPPORT DEVELOPMENT OF ANOTHER MCS...POSSIBLY
   SEVERE...OVER WRN TX INTO WRN OK/SWRN KS OVERNIGHT.  
   
   ...CENTRAL APPALACHIANS INTO NC...
   COLD FRONT NOW EXTENDING FROM SERN VA INTO CENTRAL KY WILL SAG SSWWD
   AS A BACK-DOOR FRONT INTO NC AND EXTEND ROUGHLY E-W FROM ERN NC INTO
   SWRN VA BY LATE THIS AFTERNOON.  THIS WILL OCCUR UNDER EJECTING
   SHORTWAVE TROUGH AND ASSOCIATED 35-45 KT MID LEVEL JET NOW OVER
   KY/TN WHICH WILL MOVE EWD ACROSS THIS REGION TODAY.  NAM-KF
   SOUNDINGS NEAR AND JUST NORTH OF THE FRONT INDICATE EFFECTIVE BULK
   SHEAR WILL SUPPORT SUPERCELLS AND ORGANIZED CLUSTERS AS AIR MASS
   BECOMES MARGINALLY TO MODERATELY UNSTABLE.  LARGE HAIL WILL LIKELY
   BE PRIMARY SEVERE HAZARD WITH THESE STORMS AS THEY DEVELOP ESEWD
   INTO THE EVENING...THOUGH ISOLATED DAMAGING WINDS AND POSSIBLY A
   TORNADO OR TWO CAN ALSO BE EXPECTED.
   
   ..EVANS/LEVIT.. 03/28/2007
   
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