[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 041955
SWODY1
SPC AC 041953

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0253 PM CDT TUE APR 04 2006

VALID 042000Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL/SRN CA...

...SYNOPSIS...
HIGHLY AMPLIFIED UPPER AIR PATTERN WILL CONTINUE TO FEATURE DEEP
LOWS OVER ERN GREAT LAKES...AND MOVING INLAND CA COAST.  SFC FRONTAL
ZONE ASSOCIATED WITH NERN STATES LOW IS ANALYZED ACROSS N-CENTRAL
FL...WWD OVER NRN GULF OF MEXICO...TO S-CENTRAL TX.  THIS FRONT
SHOULD DECELERATE OVER CENTRAL FL THIS AFTERNOON/EVENING...WHILE
BECOMING MORE DIFFUSE AND RETURNING NWD ACROSS S-CENTRAL/SW TX. 
PACIFIC COLD FRONT IS EVIDENT IN VIS IMAGERY ATTM FROM AROUND
27N125W NEWD TO NEAR 32N121W...THEN NWD ACROSS COASTAL AREAS OF SAN
LUIS OBISPO COUNTY.  THIS FRONT SHOULD MOVE EWD ACROSS MOST OF
CENTRAL/SRN CA THIS AFTERNOON...AND INTO NV/AZ OVERNIGHT.

...CA...
SEVERE POTENTIAL IS EXPECTED TO INCREASE THROUGH LATE AFTERNOON OVER
PORTIONS SAN JOAQUIN/SRN SAC VALLEYS...ALONG/AHEAD OF SFC COLD
FRONT. BREAKS IN CLOUD COVER ARE ALLOWING DIABATIC HEATING TO
WEAKEN CINH FURTHER...COMBINING WITH COOLING TEMPS ALOFT TO STEEPEN
LOW-MIDDLE LEVEL LAPSE RATES.  THOUGH FLOW ALOFT REMAINS QUITE
MERIDIONAL...OROGRAPHICALLY FORCED BACKING OF SFC FLOW IN VALLEY
WILL ENHANCE DEEP-LAYER VERTICAL SHEAR.  THIS SUPPORTS MAINLY
LINEAR MODES WITH ENHANCED STORM-RELATIVE INFLOW AT SFC. 
EMBEDDED/LOW-TOPPED SUPERCELLS AND BOW ECHOES ARE POSSIBLE.  REF WW
149 AND RELATED MESOSCALE DISCUSSIONS FOR NOWCAST DETAILS.

SEVERE THREAT IS EXPECTED TO SHIFT SWD OVERNIGHT AS STRONG SHORTWAVE
TROUGH MOVES TROUGH BASE OF LARGER SYNOPTIC SYSTEM...GREATLY
ENHANCING GRADIENT FLOW ALOFT AND STRENGTHENING LOW-MIDDLE LEVEL
SHEAR PROFILES.  ALTHOUGH TIME OF DAY WILL NOT BE FAVORABLE INLAND
WITH RESPECT TO ABSOLUTE SFC HEATING...SFC-BASED BUOYANCY ACTUALLY
SHOULD INCREASE THIS EVENING AND MUCH OF TONIGHT OVER REGION
CONTAINING COASTAL SRN CA -- LA BASIN...SBA AREA AND CHANNEL
ISLANDS.  THIS SHOULD OCCUR AMIDST STRONG DIFFERENTIAL THERMAL
ADVECTION WITH HEIGHT...WHERE COOLING OCCURS AT A FASTER RATE ALOFT
THAN IN BOUNDARY LAYER.  FCST VERTICAL SHEAR PROFILES SUGGEST
LOW-TOPPED SUPERCELLS OR SMALL BOWS WITH HAIL...STRONG/DAMAGING WIND
AND SOME TORNADO POTENTIAL.

...CENTRAL FL...
AIRMASS CONTINUES TO DESTABILIZE ACROSS PORTIONS CENTRAL FL...WHERE
SFC HEATING ALREADY HAS BOOSTED MLCAPES INTO 1500-2000 J/KG RANGE. 
VIS IMAGERY SHOWS TCU OVER MUCH OF CENTRAL FL INVOF FRONTAL
ZONE...AND ALONG E COAST SEA BREEZE FRONT.  ALTHOUGH STRONGEST
MIDLEVEL FLOW WILL REMAIN N OF AREA...EFFECTIVE SHEARS 35-45 KT
INVOF FRONT AND SEA BREEZE BOUNDARY INDICATE POTENTIAL FOR SOME
TSTMS TO BECOME ORGANIZED WITH ISOLATED HAIL AND STRONG/DAMAGING
GUSTS POSSIBLE.  REF SPC MESOSCALE DISCUSSION 427 FOR MORE DETAILS
ON NEAR-TERM THREAT.  ACTIVITY SHOULD WEAKEN BY EARLY EVENING WITH
LOSS OF SFC HEATING.

...E-CENTRAL PLAINS...WRN OZARKS...
WIDELY SCATTERED TSTMS IN CLUSTERS ARE EXPECTED OVERNIGHT --
PRIMARILY AFTER 5/06Z...AS ELEVATED MOIST ADVECTION AND ISENTROPIC
ASCENT RESULT IN PARCELS REACHING LFC. EXPECT FAVORABLE SHEAR FOR
ORGANIZED ACTIVITY THROUGH DEPTH OF CONVECTIVE COLUMN...WITH
ELEVATED MUCAPES INCREASING TO AROUND 400-700 J/KG.  ISOLATED HAIL
NEAR SEVERE LEVELS MAY OCCUR FROM MOST VIGOROUS CELLS.

..EDWARDS.. 04/04/2006