[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 071634
SWODY1
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