[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 021231
SWODY1
SPC AC 021229

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0729 AM CDT SUN APR 02 2006

VALID 021300Z - 031200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER CENTRAL/ERN MO...FAR SERN
IA...WRN/SRN IL...FAR WRN KY THIS AFTERNOON INTO THE EVENING...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
NERN TX/LOWER MS RIVER VALLEY INTO THE SRN GREAT LAKES...

...MO ACROSS MID MS/OH/TN RIVER VALLEYS...
COMPLEX FORECAST THIS MORNING AS LINEAR MCS CONTINUES TO LIFT NEWD
ACROSS THE MID MS RIVER VALLEY...WHICH WILL LIKELY HINDER
HEATING/NWD RETURN OF WARM FRONT INTO THE EARLY AFTERNOON. 
HOWEVER...SURFACE WINDS CONTINUE TO BACK TO SLY BEHIND THIS ACTIVITY
WITH STRONG PRESSURE FALLS DEVELOPING TOWARDS SERN IA EARLY THIS
MORNING.  THIS SHOULD ALLOW BOUNDARY LAYER MOISTURE TO RECOVER
TODAY...WITH LOWER TO MID 60F SURFACE DEW POINTS EXPECTED TO LIFT
ACROSS MUCH OF MO/LOWER OH RIVER VALLEY BY THE MID AFTERNOON.  MID
LEVEL LAPSE RATES WILL ALSO BE ABLE TO RELOAD RELATIVELY QUICKLY
UNDER VERY STRONG WLY FLOW ALOFT.  THOUGH THERE REMAIN SOME
QUESTIONS ABOUT AIR MASS QUALITY DUE TO MORNING STORMS...ESPECIALLY
REGARDING HIGHER SEVERE PROBABILITIES...OVERNIGHT MODELS CONTINUE TO
INDICATE FAVORABLE CONDITIONS FOR SEVERE THUNDERSTORMS/SUPERCELLS BY
21Z AT LEAST INTO CENTRAL MO.

AT THIS TIME...EXPECT AXIS OF MODERATE INSTABILITY WITH MLCAPE FROM
1000-2000 J/KG TO NOSE NEAR THE IA/MO BORDER DURING THE MID TO LATE
AFTERNOON.  AS A RESULT...DEEP ASCENT AND CONVERGENCE ALONG PRIMARY
SURFACE TROUGH SHOULD INCREASE SEVERE THUNDERSTORMS FROM WEST TO
EAST INTO WRN AND CENTRAL MO AND POSSIBLY SRN IA BETWEEN 18Z-21Z. 
GIVEN EXPECTED MLCAPE...FORECAST SOUNDINGS CONTINUE TO INDICATE A
VERY FAVORABLE SUPERCELL ENVIRONMENT WITH BRN SHEAR AROUND 60 M2/S2
AND SFC-1 KM SRH IN EXCESS OF 150 M2/S2.  THUS...A FEW LONGER-LIVED
SUPERCELLS AND BOW ECHOES WILL EVOLVE THROUGH THE LATE AFTERNOON. 
HAIL MAY BECOME QUITE LARGE WITH THIS ACTIVITY...WITH LOCAL HAIL
MODEL INDICATING 2+ INCH HAIL FROM MANY OF THE FORECAST SOUNDINGS. 
SHOULD HEATING/DESTABILIZATION OVERCOME CAP ALONG WARM
FRONT...ISOLATED SUPERCELLS MAY ALSO DEVELOP AHEAD OF THIS ACTIVITY
ACROSS PORTIONS OF SRN/CENTRAL IL AND WRN IND. TORNADOES WILL ALSO
REMAIN POSSIBLE AND WIND DAMAGE THREAT MAY BECOME ENHANCED AS STORMS
SHIFT QUICKLY EWD AT 40-50 KT AND CONSOLIDATE INTO SMALL BOW
ECHOES/LINES INTO THE EARLY EVENING.  DEPENDING ON WHERE WARM FRONT
SETS-UP...GREATER SEVERE THREAT WILL SPREAD INTO SRN/CENTRAL IL INTO
THE EARLY EVENING.  ACTIVITY SHOULD EVOLVE INTO ONE OR MORE MCSS AND
SPREAD EWD ACROSS THE OH/TN RIVER VALLEYS AND THE SRN GREAT LAKES
AFTER DARK.  LARGE HAIL AND DAMAGING WINDS WILL REMAIN
POSSIBLE...WITH AN ISOLATED TORNADO POSSIBLE GIVEN VERY STRONG SHEAR
SHOULD STORMS REMAIN ROOTED INTO THE BOUNDARY LAYER.

...MID SOUTH SWWD INTO NERN TX...
REGION WILL REMAIN REMOVED FROM STRONGEST LARGE SCALE ASCENT WHICH
IS EXPECTED TO SUPPORT MORE WIDESPREAD SEVERE THREAT ALONG AND NORTH
OF THE LOWER OH RIVER VALLEY TODAY.  HOWEVER...SURFACE CONVERGENCE
ALONG SURFACE TROUGH WILL SHIFT INTO WRN AR AND NRN TX BY 21Z...AND
SPREAD ESEWD THROUGH THE EARLY EVENING.  IN ADDITION...STRONG WLY
H85 WINDS WILL MAINTAIN LOW LEVEL WAA ATOP DESTABILIZING WARM SECTOR
AND MAY DEVELOP STORMS WELL AHEAD OF THE FRONT TODAY. 
WARM...EARLY-APRIL TEMPERATURES IN THE UPPER 70S/LOWER 80S WILL
WEAKEN CAP AND SUPPORT A LARGE AREA OF MODERATE TO STRONG
INSTABILITY GIVEN MID 60F SURFACE DEW POINTS ALREADY IN PLACE. 
SHEAR WILL ALSO REMAIN QUITE STRONG ACROSS THE REGION WITH EFFECTIVE
SHEAR NEAR 60 KT AND SFC-1 KM SRH IN EXCESS OF 200 M2/S2.  THIS
WOULD SUPPORT SUPERCELLS...AND TORNADOES ACROSS THE MID
SOUTH...SHOULD CAP BREAK AND VIGOROUS STORMS DEVELOP.

..EVANS.. 04/02/2006