[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 061729
SWODY2
SPC AC 061728

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT SAT MAY 06 2006

VALID 071200Z - 081200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL GULF COAST TO
THE SC/GA COASTS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CNTRL AND
SRN HIGH PLAINS...

...SYNOPSIS...

PROGRESSIVE SPLIT FLOW PATTERN WILL CONTINUE THROUGH THE DAY TWO
PERIOD WITH SRN STREAM IMPULSE TRANSLATING EWD THROUGH THE TN VALLEY
AND CNTRL GULF COAST TO THE CNTRL/SRN ATLANTIC COAST. 
MEANWHILE...NRN BRANCH SHORT WAVE TROUGH WILL SHIFT EWD FROM THE NRN
AND CNTRL ROCKIES INTO THE HIGH PLAINS REGION SUNDAY AFTERNOON INTO
EVENING...WHILE SRN STREAM POSITIVE TILT TROUGH MORE SLOWLY MOVES
EWD THROUGH THE SRN ROCKIES INTO SRN HIGH PLAINS.

IN THE LOW-LEVELS...SEVERAL FRONTAL WAVES WILL DEVELOP EWD ALONG
BAROCLINIC ZONE FROM CNTRL MS/AL TO SRN SC...WITH PRIMARY SURFACE
LOW CONSOLIDATING OVER SC NEWD INTO THE GULF STREAM SUNDAY NIGHT. 
TO THE W...LEE TROUGH WILL INTENSIFY OVER THE HIGH PLAINS WITH
PACIFIC COLD FRONT EVENTUALLY OVERTAKING THIS FEATURE OVER THE WRN
DAKOTAS INTO NEB SUNDAY AFTERNOON INTO EVENING.

...CNTRL GULF COAST NEWD THROUGH CNTRL/SRN GA INTO SRN SC...

CLUSTERS OF TSTMS ARE EXPECTED TO BE ONGOING SUNDAY MORNING INVOF
FRONTAL ZONE OVER THE CNTRL AND ERN GULF STATES WITH REGION OF
LARGE-SCALE FORCING FOR ASCENT AHEAD OF SRN STREAM SHORT WAVE
TROUGH.  DESPITE RELATIVELY POOR LAPSE RATES...INFLUX OF A MOIST
LOW-LEVEL AIR MASS SHOULD MAINTAIN THIS CONVECTION EWD TOWARD THE
ATLANTIC COAST SUNDAY AFTERNOON INTO EVENING.  PRIMARY UNCERTAINTY
IS DEGREE OF INSTABILITY THAT WILL DEVELOP WITHIN THIS REGION OF
STRONGER SYNOPTIC-SCALE FORCING AHEAD OF MAIN SHORT WAVE TROUGH
GIVEN ANTICIPATED WIDESPREAD CLOUDS AND PRECIPITATION.

IT APPEARS BETTER POTENTIAL FOR AIR MASS DESTABILIZATION WILL OCCUR
ALONG SRN PERIPHERY OF CLOUD/PRECIPITATION SHIELD FROM ERN LA/SRN MS
INTO CNTRL/SRN PORTIONS OF AL AND GA WHERE LOCALLY STRONGER DIABATIC
HEATING COUPLED WITH DEWPOINTS IN THE 60S WILL CONTRIBUTE TO MLCAPES
OF 1000-1500 J/KG.  WHILE STRONGER FORCING MAY HAVE ALREADY SHIFTED
E OF THE SRN APPALACHIANS...SUSTAINED LOW-LEVEL CONVERGENCE ALONG
FRONT SHOULD BE SUFFICIENT TO SUPPORT ORGANIZED STORM DEVELOPMENT. 
LARGELY UNIDIRECTIONAL VERTICAL SHEAR OF 40-45 KTS SUGGESTS
POTENTIAL FOR BOWING SEGMENTS OR SPLITTING SUPERCELLS CAPABLE OF
LOCALLY DAMAGING WINDS...MARGINAL HAIL AND PERHAPS A COUPLE OF
TORNADOES.

CONDITIONAL SLIGHT RISK HAS BEEN EXTENDED EWD TO THE SC COAST GIVEN
POTENTIAL FOR SOME DESTABILIZATION NEAR DEEPENING SURFACE LOW WHERE
SHEAR PROFILES WILL BE SUPPORTIVE OF SUPERCELLS CAPABLE OF A COUPLE
TORNADOES AND DAMAGING WINDS.

...SWRN NEB SWD TO THE TX PNHDL...

DESPITE STRENGTHENING SLY LOW-LEVEL FLOW AHEAD OF INTENSIFYING LEE
TROUGH...BOUNDARY-LAYER MOISTURE WILL REMAIN LIMITED WITH DEWPOINTS
IN THE MID 40S TO LOWER 50S.  HOWEVER...STEEPENING LOW TO MID-LEVEL
LAPSE RATES WILL LARGELY CONTRIBUTE TO AIR MASS DESTABILIZATION
SUNDAY AFTERNOON WITH MLCAPES APPROACHING 1000 J/KG.  INCREASED
LARGE-SCALE FORCING ASSOCIATED WITH APPROACHING SHORT WAVE TROUGH
COUPLED WITH DAYTIME HEATING AND CONVERGENCE ALONG LEE TROUGH WILL
SUPPORT TSTM DEVELOPMENT BY LATE AFTERNOON FROM WRN NEB SWD THROUGH
ERN CO/WRN KS INTO NERN NM AND THE TX PNHDL.

INSPECTION OF FORECAST SOUNDINGS SUGGESTS THAT REGION DELINEATED BY
HIGHER SEVERE PROBABILITIES AND CATEGORICAL SLIGHT RISK WILL HAVE AT
LEAST MODEST DEEP-LAYER VERTICAL SHEAR /25-35 KTS/ WHICH WILL
SUPPORT A FEW ORGANIZED SEVERE STORMS CAPABLE OF SEVERE HAIL AND
DAMAGING WINDS.  EVOLUTION INTO CLUSTERS OR AN MCS MAY OCCUR SUNDAY
NIGHT OVER CNTRL KS INTO THE ERN TX PNHDL/WRN OK...THOUGH WEAKENING
INSTABILITY WITH THE ONSET OF NOCTURNAL COOLING SHOULD PRECLUDE A
MORE ORGANIZED SEVERE THREAT FARTHER TO THE E.

...WRN/SWRN TX...

BELT OF RELATIVELY STRONG MID AND HIGH-LEVEL FLOW WILL BE MAINTAINED
ACROSS REGION IN ASSOCIATION WITH MORE ACTIVE SRN BRANCH OF
WESTERLIES.  PRIMARY UNCERTAINTY IS INITIATION OF DEEP CONVECTION
OWING TO STRONGER CAP AND APPARENT LATER ARRIVAL OF NEXT UPSTREAM
IMPULSE.  SHOULD STORMS DEVELOP AND BECOME SUSTAINED ALONG LEE
TROUGH OR WRN EXTENSION OF REMNANT STATIONARY BOUNDARY...THE
MODERATELY STRONG DEEP-LAYER SHEAR AND MODEST INSTABILITY WOULD
SUPPORT A THREAT OF ORGANIZED/ROTATING UPDRAFTS CAPABLE OF LARGE
HAIL AND LOCALLY STRONG WINDS. AN UPGRADE TO SLIGHT RISK MAY BECOME
NECESSARY IN LATER OUTLOOKS.

...DAKOTAS...

TSTMS ARE EXPECTED TO DEVELOP BY MID TO LATE AFTERNOON ALONG LEE
TROUGH OR PACIFIC COLD FRONT WITHIN STEEP LAPSE RATES ENVIRONMENT
CHARACTERIZED BY MLCAPES OF 500-1000 J/KG.  A FEW OF THE STORMS WILL
BE CAPABLE OF MARGINALLY SEVERE WIND/HAIL...BUT RELATIVELY WEAK
VERTICAL SHEAR SHOULD PRECLUDE A MORE ORGANIZED SEVERE THREAT.

..MEAD.. 05/06/2006