[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 312005
SWODY1
SPC AC 312003

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0203 PM CST FRI MAR 31 2006

VALID 312000Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL GREAT LAKES INTO
THE MID SOUTH AND ARKLATEX...

...SRN GREAT LAKES INTO OH VALLEY...

STRONG DAYTIME HEATING COUPLED WITH DEWPOINTS LARGELY IN THE 50S
HAVE CONTRIBUTED TO DESTABILIZATION OF PRE-FRONTAL AIR MASS /SBCAPES
OF 500-1000 J/KG/ THIS AFTERNOON FROM SWRN LOWER MI SWWD THROUGH WRN
IND/ERN IL TO THE CONFLUENCE OF THE OH AND MS RIVERS.
SUSTAINED LOW-LEVEL CONVERGENCE ALONG FRONT COUPLED WITH ZONE OF
HEIGHT FALLS AHEAD OF MID/UPPER-LEVEL LOW NOW OVER WI WILL LEAD TO
AN INCREASE IN TSTM DEVELOPMENT THIS AFTERNOON INTO EVENING WITHIN
THIS INSTABILITY AXIS.

CURRENT VAD AND PROFILER DATA IN ADDITION TO RUC FORECAST SOUNDINGS
INDICATE RELATIVELY STRONG LOW AND DEEP-LAYER SHEAR WITH EFFECTIVE
BULK SHEAR OF 40-50 KTS AND 0-1 KM SRH OF 150-250 M2/S2.  GIVEN
ANTICIPATED FURTHER AIR MASS DESTABILIZATION AND THIS
SHEAR...ENVIRONMENT WILL BE SUPPORTIVE OF SUPERCELLS AND BOWING LINE
SEGMENTS CAPABLE OF LARGE HAIL...DAMAGING WINDS AND ISOLATED
TORNADOES.

ACTIVITY WILL CONTINUE EWD THROUGH THE OH VALLEY THIS
EVENING...PRIOR TO WEAKENING LATER TONIGHT AS AIR MASS SLOWLY
STABILIZES.

...MID SOUTH INTO ARKLATEX...

VISIBLE SATELLITE IMAGERY AND MESOANALYSIS INDICATE THAT WEAK COLD
FRONT EXTENDS FROM SERN MO THROUGH NRN AR INTO SERN OK.  MOIST
BOUNDARY-LAYER /DEWPOINTS IN THE LOW TO MID 60S/ CONDITIONS ALONG
WITH DIABATIC HEATING HAVE CONTRIBUTED TO A WEAKLY CAPPED AND
MODERATELY UNSTABLE /SBCAPES OF 1000-1500 J/KG/ AIR MASS OVER THE
WRN TN AND LOWER MS VALLEYS THIS AFTERNOON.  WATER VAPOR IMAGERY AND
SHORT TERM MODEL DIAGNOSTICS SUGGEST THAT LARGE-SCALE FORCING WILL
REMAIN QUITE WEAK --PERHAPS EVEN SUBSIDENT-- THROUGH THE REMAINDER
OF THE AFTERNOON INTO EVENING.

NONETHELESS...THE WEAK CAPPING AND FURTHER DESTABILIZATION SHOULD
LEAD TO AN INCREASE IN TSTM COVERAGE ACROSS FREE WARM SECTOR NWD TO
FRONTAL ZONE. PRESENCE OF 40-50 KT WSWLY MID-LEVEL WINDS ON SRN
PERIPHERY OF UPPER MIDWEST LOW IS RESULTING IN SUFFICIENT DEEP-LAYER
SHEAR TO SUPPORT A FEW ORGANIZED/ROTATING UPDRAFTS.  THE STRONGEST
STORMS WILL BE CAPABLE OF PRIMARILY DAMAGING WINDS AND LARGE HAIL
THROUGH LATE EVENING.  A BRIEF TORNADO IS POSSIBLE...GIVEN
MODERATELY STRONG LOW-LEVEL SHEAR /PER OKOLONA MS PROFILER/.

...RED RIVER VALLEY...

AS MENTIONED ABOVE...LARGE-SCALE SUBSIDENCE WILL LIKELY INHIBIT
DIURNAL TSTM DEVELOPMENT ALONG FRONT THROUGH THIS EVENING.  IT
APPEARS BETTER POTENTIAL FOR MAINLY ELEVATED TSTM DEVELOPMENT WILL
OCCUR LATE TONIGHT AS LOW-LEVEL WAA AND ISENTROPIC ASCENT INCREASE
ALONG AND N OF SURFACE FRONT.  STEEPENING MID-LEVEL LAPSE RATES
ABOVE THE NWD-RETURNING MOISTURE WILL CONTRIBUTE TO POCKETS OF
ELEVATED INSTABILITY WITH MUCAPES OF 1000-1500 J/KG.  VERTICAL SHEAR
IS EXPECTED TO REMAIN MARGINAL THROUGH THE BUOYANCY LAYER...WHICH
SHOULD LIMIT STORM ORGANIZATION.  HOWEVER...ISOLATED LARGE HAIL WILL
BE POSSIBLE WITH THE STRONGEST STORMS.

...NRN CA...

CURRENT VISIBLE SATELLITE DATA SHOW PRIMARY FRONTAL CLOUD BAND FROM
NWRN CA SWWD INTO THE ERN PACIFIC.  WITH ONSHORE MOVEMENT OF SURFACE
FRONT AND MID-LEVEL TROUGH...AIR MASS IS EXPECTED TO DESTABILIZE
OWING TO COOLING MID-LEVEL TEMPERATURES AND STEEPENING LOW TO
MID-LEVEL LAPSE RATES. TSTMS ARE EXPECTED TO BECOME INCREASINGLY
LIKELY LATER THIS AFTERNOON INTO EVENING WITH THE POTENTIAL FOR SOME
MARGINALLY SEVERE HAIL OWING TO THE STEEP LAPSE RATES AND COLD
THERMODYNAMIC PROFILES.

...CNTRL TX...

VISIBLE SATELLITE AND RUC OBJECTIVE FIELDS SUGGEST THAT AIR MASS IS
BECOMING MODERATELY UNSTABLE WITH A WEAKENING CAP ALONG A
LOOSELY-DEFINED PRE-FRONTAL TROUGH.  WATER VAPOR IMAGERY SUGGESTS
CONSIDERABLE MID-LEVEL RIDGING AND IMPLIED SUBSIDENCE ACROSS REGION.
 LATEST SHORT TERM MODEL GUIDANCE INDICATES SOME POTENTIAL FOR
DIURNAL STORM DEVELOPMENT LATER THIS AFTERNOON.  SHOULD STORMS
DEVELOP...THREAT WILL EXIST FOR ISOLATED LARGE HAIL OR DAMAGING
WINDS INTO THIS EVENING.

..MEAD.. 03/31/2006