[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 071217
SWODY1
SPC AC 071216

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0716 AM CDT FRI APR 07 2006

VALID 071300Z - 081200Z

...THERE IS A HIGH RISK OF SVR TSTMS TODAY ACROSS PARTS OF NORTHERN
MS...NORTHERN AL...AND SOUTHERN TN...

...THERE IS A MDT RISK OF SVR TSTMS OVER MUCH OF THE LOWER/MIDDLE MS
VALLEY...TN 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
ACROSS PARTS OF THE LOWER/MID MS VALLEY AND TN VALLEY...

MORNING WATER VAPOR IMAGERY SHOWS LARGE...DEEP UPPER LOW OVER
NEB...WITH BAND OF VERY STRONG MID LEVEL WINDS EXTENDING AROUND BASE
OF LOW FROM TX/OK INTO AR/MO.  THIS SYSTEM IS FORECAST TO MOVE
SOUTHEASTWARD TODAY...WITH STRONGEST MID LEVEL WINDS SPREADING
ACROSS MUCH OF THE MID/LOWER MS VALLEY AND TN VALLEY. 
MEANWHILE...SURFACE LOW WILL DEVELOP SOUTHEASTWARD INTO SOUTHERN
MO/NORTHERN AR BY EVENING.  STRONG SOUTHERLY LOW LEVEL WINDS IN WARM
SECTOR OF LOW WILL TRANSPORT RICH MOISTURE NORTHWARD AND HELP TO
RAPIDLY DESTABILIZE THE AIR MASS BY EARLY AFTERNOON.

...LA/MS/TN/AL/GA...
PRESENT INDICATIONS ARE THAT ISOLATED THUNDERSTORMS WILL DEVELOP BY
EARLY AFTERNOON IN LOW LEVEL JET AXIS ACROSS PARTS OF LA/MS.  THESE
STORMS SHOULD MOVE RAPIDLY EAST-NORTHEASTWARD INTO NORTHERN AL AND
MIDDLE TN DURING THE AFTERNOON/EVENING.  MODEL FORECAST SOUNDINGS IN
THIS REGION INDICATE VERY FAVORABLE LOW LEVEL AND DEEP LAYER
VERTICAL SHEAR PROFILES FOR SUPERCELLS AND TORNADOES /EFFECTIVE
SHEAR OVER 50 KNOTS AND 3KM SRH VALUES OF 250-400 M2/S2/.  ASSUMING
MID 60S SURFACE DEWPOINTS BECOME WIDESPREAD IN THIS REGION AHEAD OF
CONVECTION...THERMODYNAMIC PARAMETERS ALSO APPEAR QUITE FAVORABLE
FOR A FEW STRONG/LONG-TRACK TORNADOES /MLCAPE OF 1500-2000
J/KG...MINIMAL CAP...AND LCL HEIGHTS GENERALLY BELOW 1KM/. 
WIDESPREAD LARGE HAIL WILL BE A THREAT ACROSS THIS REGION AS WELL. 
ACTIVITY MAY SPREAD AS FAR EAST AS NORTHWEST GA AND EASTERN TN BY
LATE EVENING WITH A CONTINUED THREAT OF TORNADOES AND DAMAGING
WINDS.

...MID MS/LOWER OH VALLEYS...
STRONG DAYTIME HEATING IS EXPECTED ACROSS PARTS OF SERN MO/ERN
AR/SRN IL/WRN KY THROUGH EARLY AFTERNOON.  THIS SHOULD YIELD VERY
STEEP LOW/MID LEVEL LAPSE RATES AND MLCAPE VALUES OVER 2000 J/KG. 
DEEP LAYER EFFECTIVE SHEAR OVER 60 KNOTS AND SUFFICIENT LOW LEVEL
SHEAR WILL PROMOTE SUPERCELL STORMS CAPABLE OF VERY LARGE HAIL AND
ISOLATED TORNADOES.  ACTIVITY WILL LIKELY SPREAD EASTWARD ACROSS
PARTS OF IND/KY/TN THROUGH THE AFTERNOON AND EVENING.

...IL/IND/OH/PA...
SURFACE FRONT IS FORECAST TO EXTEND FROM CENTRAL MO INTO NORTHERN
OH/NORTHWESTERN PA BY MID AFTERNOON.  STRONG HEATING IS EXPECTED
ALONG AND SOUTH OF FRONT RESULTING IN AT LEAST MODERATE INSTABILITY.
SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO FORM IN
THIS REGION AS CONVECTIVE TEMPERATURE IS REACHED AND JET STREAK
APPROACHES FROM THE WEST.  LARGE HAIL APPEARS TO BE THE MAIN
THREAT...ALTHOUGH DAMAGING WINDS WILL ALSO BE POSSIBLE THROUGH THE
AFTERNOON/EVENING AS CLUSTERS MERGE AND GROW UPSCALE.

..HART/CROSBIE.. 04/07/2006