DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 041645
SWODY2
SPC AC 041644

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1144 AM CDT MON JUN 04 2012

VALID 051200Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF CNTRL MT...

...THERE IS A SLGT RISK OF SVR TSTMS FOR PORTIONS OF SRN GA/SERN
AL/NRN FL...

...SYNOPSIS...

AN OMEGA-BLOCKING PATTERN WILL PERSIST THROUGH THE DAY TWO
PERIOD...FEATURING A HIGH-AMPLITUDE RIDGE OVER THE GREAT PLAINS
WHICH WILL BE BRACKETED BY TROUGHS OVER THE INTERMOUNTAIN WEST AND
ERN THIRD OF THE NATION. WITHIN THIS BROADER-SCALE PATTERN...AN
INTENSE VORTICITY MAXIMUM AND ASSOCIATED 60-70 KT MIDLEVEL JET
STREAK INITIALLY OVER THE SIERRA NEVADAS INTO GREAT BASIN WILL
PROGRESS NEWD INTO THE NRN HIGH PLAINS WITH A CORRIDOR OF 50-100
M/12-HR HEIGHT FALLS AT 500 MB FORECAST ALONG SYSTEM TRACK.
ELSEWHERE...A SERIES OF LOW-AMPLITUDE PERTURBATIONS WILL EXIST ALONG
CYCLONIC SIDE OF 40-50 KT MIDLEVEL JET CORE SETTLING SWD THROUGH THE
TN VALLEY AND SERN STATES.

AT THE SURFACE...LEE CYCLOGENESIS WILL OCCUR TUESDAY OVER CNTRL MT
IN RESPONSE TO LOWERING MIDLEVEL HEIGHTS/DCVA PRECEDING THE GREAT
BASIN SYSTEM MENTIONED ABOVE. AT THE SAME TIME...A STRENGTHENING
PACIFIC FRONT WILL ADVANCE EWD THROUGH THE NRN INTERMOUNTAIN
REGION...EVENTUALLY LINKING WITH THE SURFACE LOW OVER THE NRN HIGH
PLAINS TUESDAY NIGHT. THE SRN EXTENSION OF THE PACIFIC FRONT WILL
MAKE STEADY SEWD PROGRESS INTO THE CNTRL ROCKIES AND LOWER CO
VALLEY. FARTHER E...A COLD FRONT INITIALLY FROM THE LOWER SAVANNAH
RIVER VALLEY WWD THROUGH THE LOWER MS VALLEY INTO SRN PLAINS WILL
MOVE SWD/SWWD ACROSS THE GULF COAST STATES.

...NRN HIGH PLAINS...

LOW-LEVEL MASS RESPONSE TO APPROACHING VORTICITY MAXIMUM --MANIFEST
AS A 30-40 KT SSELY LLJ AND SURFACE LEE CYCLOGENESIS-- WILL MAINTAIN
A MOIST UPSLOPE FLOW COMPONENT BENEATH STEEPENING MIDLEVEL LAPSE
RATE PLUME PRECEDING UPPER SYSTEM. LATEST MODEL GUIDANCE INDICATES
THAT DEEPER PBL MIXING WILL RESULT IN A DECREASE IN LOW-LEVEL
MOISTURE THROUGH THE AFTERNOON OVER S-CNTRL MT...WITH THE STRONGEST
DESTABILIZATION /I.E. MLCAPE OF 1500-2500 J PER KG/ FORECAST FROM
THE WRN DAKOTAS/FAR ERN MT NWWD INTO N-CNTRL MT.

MULTI-MODEL CONSENSUS IS SUGGESTIVE THAT THE HIGHEST LIKELIHOOD FOR
STORM INITIATION AND SUSTENANCE WILL BE LATE TUESDAY AFTERNOON INTO
EVENING WITHIN IMMEDIATE POST-FRONTAL ENVIRONMENT W/NW OF SURFACE
LOW WHERE THE CAP WILL BE THE WEAKEST. HERE...THE WRN EXTENSION OF
LOW-LEVEL INSTABILITY AXIS WILL COINCIDE WITH MODERATELY STRONG
DEEP-LAYER SHEAR WITH THE POTENTIAL FOR ORGANIZED STORM MODES
--INCLUDING SUPERCELLS-- WITH A RISK FOR DAMAGING WINDS AND LARGE
HAIL.

...SERN U.S...

CONVECTIVE EVOLUTION AND RESULTANT SEVERE THREAT WILL BE MODULATED
TO SOME DEGREE BY ANTECEDENT TSTM ACTIVITY DURING THE DAY ONE
PERIOD. STILL...IT APPEARS THAT DIURNALLY ENHANCED STORM
DEVELOPMENT WILL BE FAVORED ALONG COLD FRONT AND PRE-EXISTING
CONVECTIVE OUTFLOW BOUNDARIES SAGGING SWD. THE MOST INTENSE STORMS
MAY BE FOCUSED ACROSS PARTS OF GA INTO NRN FL WHERE DEEP-LAYER SHEAR
AND FORCING FOR ASCENT WILL BE ENHANCED BY A VORTICITY MAXIMUM
PROGRESSING SEWD THROUGH THE SRN APPALACHIANS. GIVEN THE PRESENCE
OF A MOIST...MODERATELY UNSTABLE WARM SECTOR /I.E. MLCAPE OF
1500-3000 J PER KG/...SETUP WILL FAVOR ORGANIZED STORM CLUSTERS WITH
A RISK FOR DAMAGING WINDS AND HAIL.

...LOWER MS VALLEY INTO SRN PLAINS...

SCATTERED TSTMS APPEAR LIKELY ALONG COLD FRONT TUESDAY
AFTERNOON/EVENING WITHIN A MODERATELY UNSTABLE BUT GENERALLY WEAKLY
SHEARED ENVIRONMENT. WHILE ISOLATED OCCURRENCES OF DAMAGING WINDS
AND HAIL WILL BE POSSIBLE...WEAK SHEAR AND FORCING FOR ASCENT WILL
PRECLUDE A MORE ORGANIZED SEVERE WEATHER THREAT.

...CNTRL HIGH PLAINS...

ISOLATED-WIDELY SCATTERED TSTMS WILL BE POSSIBLE TUESDAY
AFTERNOON/EVENING ALONG LEE TROUGH WITHIN A STEEP LAPSE RATE
ENVIRONMENT. MARGINAL BOUNDARY LAYER MOISTURE CONTENT /AND
RESULTANT INSTABILITY/ AND WEAK VERTICAL SHEAR WILL LIMIT UPDRAFT
STRENGTH/LONGEVITY. STILL...A FEW MARGINALLY SEVERE STORMS WILL BE
POSSIBLE WITH A RISK FOR GUSTY WINDS AND SOME HAIL.

..MEAD.. 06/04/2012

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