[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 311640
SWODY1
SPC AC 311639

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1039 AM CST FRI MAR 31 2006

VALID 311630Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF THE GREAT
LAKES INTO THE MID SOUTH/NERN TX...

...OH VALLEY NWD INTO CENTRAL GREAT LAKES...
UPPER SYSTEM NOW LOCATED OVER THE UPPER/MID MS VALLEY WILL CONTINUE
TO EJECT NEWD ACROSS THE GREAT LAKES/OH VALLEY TODAY AND TONIGHT.
BAND OF 60+ KT WSWLY MID LEVEL WINDS WILL EXTEND ALONG SRN PERIPHERY
OF THIS TROUGH FROM THE LOWER MO VALLEY TO OH VALLEY/SRN GREAT LAKES
REGION.  A COLD FRONT TRAILED SSWWD FROM SURFACE LOW OVER NRN WI
THROUGH THE MID MS VALLEY INTO CENTRAL OK TO NW TX.  THIS BOUNDARY
WILL SPREAD EAST AND SOUTH TODAY ACROSS THE GREAT LAKES/OH VALLEY
REGION... REACHING NY AND THE CENTRAL APPALACHIANS SWWD TO THE TN
RIVER VALLEY BY 12Z SATURDAY.  A NARROW AXIS OF UPPER 50S SURFACE
DEWPOINTS HAD ADVECTED INTO ERN IL TO CENTRAL IND THIS MORNING WITH
50+ VALUES EXPECTED TO SPREAD INTO SRN LOWER MI AND THE UPPER OH
VALLEY BY LATE THIS AFTERNOON...WITH LOWER 60S DEWPOINTS INTO THE
LOWER OH VALLEY.

ONGOING THUNDERSTORMS FROM LOWER TN/LOWER OH VALLEYS WILL CONTINUE
TO SPREAD EWD WITHIN ZONE OF WEAK LOW-LEVEL WAA.  GENERALLY WEAK TO
MODEST MID-LEVEL LAPSE RATES SHOULD TEND TO LIMIT SEVERE DEVELOPMENT
WITH THIS ACTIVITY.

12Z MODELS CONTINUE TO SUGGEST GREATER THREAT FOR SEVERE STORMS
EXPECTED FROM PARTS OF SRN LOWER MI SWD ACROSS LOWER OH VALLEY
REGION...POTENTIALLY BY MID-LATE AFTERNOON AS THE COLD FRONT MOVES
INTO THIS REGION.  PLUME OF STEEP MID LEVEL LAPSE RATES /7+ C/KM/
WILL SPREAD EWD WITH UPPER TROUGH AND ATOP MOISTENING LOW-LEVEL
LEVELS AHEAD OF THE COLD FRONT.  THIS COMBINED WITH INSOLATION IN
WAKE OF MORNING CLOUDINESS/CONVECTION WILL LIKELY RESULT IN NARROW
AXIS OF INSTABILITY WITH MUCAPE VALUES UP TO 1000-1500 J/KG LATER
THIS AFTERNOON.

STRONG SHEAR VECTORS ORIENTED MORE NORMAL TO THE COLD FRONT WILL
SUPPORT BOTH ORGANIZED LINES/SUPERCELLS PRODUCING LARGE HAIL AND
DAMAGING WINDS.  LOW-LEVEL SHEAR VALUES REMAIN QUITE STRONG FOR A
TORNADO THREAT.  SEVERE THREAT IS EXPECTED TO SPREAD EWD ACROSS OH
AND TOWARDS THE UPPER OH RIVER VALLEY THROUGH THE MID/LATE EVENING.

...MID SOUTH INTO THE LOWER MS VALLEY AND PART OF SRN PLAINS...
THE SRN EXTENT OF THE COLD FRONT IS EXPECTED TO DRIFT SLOWLY SSEWD
TOWARD THE RED RIVER VALLEY AND AR...STALLING LATER TODAY.  SOMEWHAT
MORE UNCERTAINTY EXISTS FOR STORM COVERAGE FROM THE MID SOUTH SWD
GIVEN RISING HEIGHTS/WARMING MID LEVEL TEMPERATURES ACROSS THIS AREA
TODAY. HOWEVER...50+ WLY MID LEVEL WINDS LOCATED ALONG THE SRN
PERIPHERY OF THE UPPER/MID MS VALLEY STORM SYSTEM WILL PROVIDE
FAVORABLE DEEP LAYER SHEAR FOR ORGANIZED STORMS.  LOW-LEVELS WILL
CONTINUE TO MOISTEN TODAY WITH MID/UPPER 60S SURFACE DEWPOINTS AND
SURFACE HEATING CONTRIBUTING TO MODERATE INSTABILITY /MUCAPE
1500-2500 J/KG/ FROM NERN TX TO MS.

LATER TONIGHT...INCREASING SSWLY H85 FLOW SHOULD FOCUS ELEVATED
STORMS WITH THE THREAT OF LARGE HAIL INTO PORTIONS OF ERN OK/AR INTO
WRN TN/NWRN MS.  THIS ACTIVITY MAY BE SUPPORTED BY A WEAK SRN STREAM
MID-LEVEL SHORT WAVE TROUGH...NOW LOCATED ACROSS NWRN/WRN
MEXICO...APPROACHING THE SRN PLAINS LATE IN THE FORECAST PERIOD.

...NRN CA...
PRONOUNCED MID/UPPER LEVEL LOW NOW JUST OFF THE NRN CA/SWRN ORE
COAST WILL SHIFT SLOWLY ESEWD ACROSS NRN CA LATER TODAY AND TONIGHT.
AHEAD OF THIS FEATURE...WINDS ALOFT WILL BECOME QUITE STRONG WITH
50+ KT SSWLY H5 WINDS EXPECTED ACROSS THE NRN HALF OF CA.  AFTERNOON
HEATING WILL LIKELY BE SUFFICIENT FOR STEEP LOW/MID LEVEL LAPSE
RATES AND MARGINAL INSTABILITY BY 22Z. THUS... ENVIRONMENT WILL
BECOME FAVORABLE FOR MARGINALLY SEVERE HAIL WITH THE STRONGER CORES.

..PETERS/JEWELL.. 03/31/2006