Apr 7, 2006 1630 UTC Day 1 Convective Outlook
Updated: Fri Apr 7 17:22:15 UTC 2006
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting an outbreak of severe thunderstorms today and tonight across portions of the United States. This is an extremely dangerous situation. Please read the latest public statement about this event.

Categorical Graphic
20060407 1630 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20060407 1630 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20060407 1630 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20060407 1630 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 071632
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1132 AM CDT FRI APR 07 2006
   
   VALID 071630Z - 081200Z
   
   ...THERE IS A HIGH RISK OF SVR TSTMS TODAY ACROSS PARTS OF NORTHERN
   MISSISSIPPI...NORTHERN ALABAMA AND WESTERN/MIDDLE TENNESSEE...
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER MUCH OF THE LOWER/MIDDLE MS
   VALLEY...TN VALLEY...LOWER OH VALLEY AND SOUTHERN APPALACHIANS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE REMAINDER OF THE OH
   VALLEY AND CENTRAL APPALACHIANS...
   
   ...OUTBREAK OF SEVERE THUNDERSTORMS AND TORNADOES EXPECTED TODAY
   INTO TONIGHT ACROSS PARTS OF THE LOWER/MID MS VALLEY AND OH/TN
   VALLEYS...
   
   ...SYNOPSIS...
   WATER VAPOR IMAGERY THIS MORNING INDICATED DEEP UPPER LOW OVER THE
   CENTRAL PLAINS HAD BEGUN TO MOVE TOWARD THE ESE....WITH THIS TREND
   EXPECTED TO CONTINUE TODAY AS LOW REACHES THE LOWER MS/TN VALLEYS BY
   12Z SATURDAY.  BAND OF VERY STRONG MID LEVEL WINDS WITHIN BASE OF
   LOW FROM TX/OK INTO LOWER OH VALLEY WILL CONTINUE TO SPREAD
   DOWNSTREAM ACROSS MUCH OF THE MID/LOWER MS VALLEY AND TN/OH VALLEYS.
   
   IN THE LOW LEVELS...SURFACE LOW LOCATED OVER NRN/NERN KS...WILL
   DEVELOP SOUTHEASTWARD INTO SRN MO/NRN AR BY EVENING.  MEANWHILE... A
   COLD FRONT...ASSOCIATED WITH A STRONG NRN STREAM UPPER TROUGH OVER
   ERN CANADA...CURRENTLY EXTENDED FROM SRN QUEBEC SWWD THROUGH SRN
   LOWER MI TO SRN IA.  THIS BOUNDARY WILL MOVE SSE ACROSS THE NERN
   STATES AND OH VALLEY REGION TODAY...AND SHOULD EXTEND FROM THE
   DELMARVA REGION TO THE TN VALLEY BY 12Z SATURDAY.  STRONG SLY LOW
   LEVEL WINDS IN WARM SECTOR OF LOW AND S OF COLD FRONT WILL TRANSPORT
   RICH MOISTURE NORTHWARD.
   
   ...LA/MS/TN/AL/GA INTO MID MS/OH VALLEYS...
   SEVERAL ROUNDS OF SEVERE STORMS APPEAR LIKELY ESPECIALLY ACROSS THE
   HIGH RISK AREA FROM NRN MS/AL INTO WRN/MIDDLE TN...WITH THREAT
   EXTENDING EWD INTO ERN TN/NRN GA BY THIS EVENING.  FORECAST
   SOUNDINGS CONTINUE TO INDICATE THERMODYNAMIC PARAMETERS QUITE
   FAVORABLE FOR A FEW STRONG/LONG-TRACK TORNADOES /MUCAPE OF 2000-3000
   J/KG AND LCL HEIGHTS GENERALLY BELOW 1KM/ ACROSS NRN MS/NRN AL AND
   WRN/MIDDLE TN.
   
   RAPID DESTABILIZATION IS UNDERWAY WITHIN WEAKLY CAPPED AIR MASS
   ACROSS THE LOWER/MID MS VALLEYS INTO LOWER OH VALLEY WITH SURFACE
   DEWPOINTS IN UPPER 50S/LOWER 60S EXPECTED TO SPREAD ACROSS MUCH OF
   THE OH VALLEY BY THIS AFTERNOON...AND MID 60S ACROSS MUCH OF THE
   MODERATE AND HIGH RISK AREAS.  ABUNDANT SURFACE HEATING WILL
   CONTINUE TO AID IN THIS DESTABILIZATION PROCESS FURTHER WEAKENING
   CAP AS INDICATED PER SPECIAL 14Z JAN SOUNDING. PLUME OF STEEP LAPSE
   RATES WILL SPREAD EWD INTO OH VALLEY AND EXISTING STEEP LAPSE RATES
   ACROSS REST OF WARM SECTOR WILL COMBINE WITH MOISTURE AND INSOLATION
   TO RESULT IN MUCAPE RANGING FROM 2000-3000 J/KG ACROSS THE MODERATE
   AND HIGH RISK AREAS BY THIS AFTERNOON.
   
   STRONG VEERING WIND PROFILES WITH HEIGHT /40-50 KT SSWLY LOW-LEVEL
   WINDS BENEATH 80 KT SWLY MID-LEVEL WINDS/ WILL PROVIDE A FAVORABLE
   ENVIRONMENT /EFFECTIVE SHEAR OVER 50 KT AND 0-3 KM SRH VALUES OF
   250-400 M2/S2/ FOR SUPERCELLS PRODUCING TORNADOES...VERY LARGE HAIL
   AND DAMAGING WINDS.  
   
   FARTHER N...AIR MASS WILL CONTINUE TO DESTABILIZE FROM IL/IND EWD
   ACROSS OH/PA IN ADVANCE OF THE COLD FRONT.  STRENGTHENING WIND
   FIELDS WILL RESULT IN FAVORABLE DEEP LAYER SHEAR FOR THUNDERSTORMS
   TO DEVELOP AS THE COLD FRONT MOVES SSEWD INTO THE MODERATELY
   UNSTABLE AIR MASS.  DEEP LAYER SHEAR VECTORS ORIENTED NEARLY
   PARALLEL TO THE FRONT SUGGEST ACTIVITY WILL PRIMARILY BE LINEAR...
   BUT SUPERCELLS WITH AN ATTENDANT TORNADO THREAT WILL BE POSSIBLE
   ESPECIALLY ACROSS SRN IL/IND INTO SRN OH WHERE LOW-LEVEL MOISTURE
   WILL BE GREATER.
   
   ...CENTRAL APPALACHIANS...
   SEVERE THREAT MAY DEVELOP AS FAR EAST AS THE CENTRAL APPALACHIANS AS
   AIR MASS DESTABILIZES IN THE WAKE OF MORNING SHOWERS/ THUNDERSTORMS.
    STRONG DEEP LAYER SHEAR WILL BE SUPPORTIVE OF ORGANIZED STORMS INTO
   PARTS OF SRN PA AND POTENTIALLY WRN MD/ERN WV AS MLCAPE VALUES REACH
   AROUND 1000 J/KG.  ADDITIONAL STRONG TO SEVERE STORMS THAT DEVELOP
   ACROSS THE OH/TN VALLEYS TODAY SHOULD APPROACH THE CENTRAL/SRN
   APPALACHIANS THIS EVENING...BUT EWD SEVERE THREAT WILL BE LIMITED BY
   DIMINISHING INSTABILITY OVERNIGHT.
   
   ...PARTS OF KS/OK/WRN MO/NWRN AR...
   COLD MID LEVEL TEMPERATURES WITH CENTRAL PLAINS LOW ATOP PROGGED
   WEAK LOW-LEVEL WARM AIR ADVECTION SHOULD RESULT IN DESTABILIZING THE
   AIR MASS ACROSS THIS REGION FOR A FEW THUNDERSTORMS THIS AFTERNOON. 
   WEAK INSTABILITY/SHEAR WILL TEND TO LIMIT THE SEVERE POTENTIAL...BUT
   A FEW OF THE STRONGER CORES MAY BE CAPABLE OF PRODUCING ISOLATED
   HAIL/STRONG WIND GUSTS.  THIS THREAT WILL DIMINISH THIS EVENING
   GIVEN THE ONSET OF STABILIZATION PER THE LOSS OF DAY TIME HEATING.
   
   ..PETERS/GRAMS.. 04/07/2006
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z