SWODY2
SPC AC 071727
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1227 PM CDT SAT MAY 07 2011
VALID 081200Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS MUCH OF NEB/SD INTO SWRN
MN/NWRN IA...
...THERE IS A SLGT RISK OF SVR TSTMS WRN OK/N CNTRL TX...
...SYNOPSIS...
A HIGHLY AMPLIFIED UPPER TROUGH WILL DEVELOP ALONG THE WEST
COAST...WITH SEVERAL SUBTLE SHORT WAVES EJECTING ENEWD IN ADVANCE OF
THE SYSTEM. FARTHER EAST...A STRONG UPPER JET WILL QUICKLY PROGRESS
THROUGH THE MID ATLANTIC...ALLOWING A NEW ENGLAND LOW TO SHIFT
OFFSHORE. AT THE SURFACE...A FRONTAL BOUNDARY WILL SETTLE OVER THE
SOUTHEAST...WITH THE WRN EXTENT OF THE FRONT IN THE MID/UPPER MS
VALLEY LIFTING NWD TO SD/SRN IA/NRN MO BY AFTERNOON. MEANWHILE...A
DRYLINE CIRCULATION WILL DEVELOP THROUGH THE CNTRL/SRN HIGH PLAINS.
...CNTRL/NRN PLAINS TO THE MID-MS VLY...
VERY WEAK HEIGHT RISES AND STRONG CONVECTIVE INHIBITION WILL LIKELY
LIMIT INITIAL DEVELOPMENT...GIVEN THAT THE MAIN UPPER TROUGH WILL
REMAIN WELL TO THE WEST. HOWEVER...AN INCREASING LOW LEVEL JET
THROUGH THE CNTRL/NRN HIGH PLAINS WILL RESULT IN A RAPID NWD
TRANSPORT OF MOISTURE...RESULTING IN MID 50S TO MID 60S DEW POINTS
AS FAR N AS SD...EAST OF A DRYLINE CIRCULATION. MEANWHILE...A WARM
FRONT WILL LIFT NWD...BECOMING ORIENTED W-E ACROSS CNTRL SD.
FAVORABLE CONVERGENCE ALONG THE AFOREMENTIONED BOUNDARIES IN CONCERT
WITH MOISTENING/HEATING MAY BE SUFFICIENT FOR AN INCREASE IN
CONVECTIVE COVERAGE BY LATE AFTERNOON/EVENING AS CAPPING BEGINS TO
ERODE...AND AS UPPER WINDS BECOME INCREASINGLY /ALBEIT WEAKLY/
DIFFLUENT ALOFT. THE APPROACH OF A SUBTLE MID LEVEL WAVE MAY ACT TO
INITIATE CONVECTIVE DEVELOPMENT AS WELL. GIVEN STEEP MID LEVEL LAPSE
RATES NEAR 8-8.5 C/KM...VERY UNSTABLE CONDITIONS...AND STRENGTHENING
WIND PROFILES WITH HEIGHT...SUPERCELLULAR STORMS CAPABLE OF LARGE
HAIL WILL BE POSSIBLE. SHOULD MORE SURFACE BASED CONVECTION BECOME
EVIDENT...FAVORABLE BACKING OF SURFACE WINDS NEAR THE AFOREMENTIONED
WARM FRONT...AND STRENGTH OF LOW LEVEL JET EAST OF THE DRYLINE
SUGGEST A FEW TORNADOES MAY BE POSSIBLE. OVERNIGHT...MODEL CONSENSUS
SUGGESTS ACTIVITY WILL CONGEAL EWD...WITH SOME REDEVELOPMENT OF
ELEVATED STORMS CAPABLE OF LARGE HAIL ALSO POSSIBLE NORTH OF THE
WARM FRONT...PRIMARILY ACROSS NRN IA/SRN MN AS THE LOW LEVEL JET
BECOMES FOCUSED FARTHER E.
FARTHER EAST ACROSS THE MID MS VALLEY...WILL MAINTAIN LOW
PROBABILITIES FOR SEVERE NEAR THE NWD PROGRESSING WARM FRONT.
HOWEVER...LARGE SCALE SUBSIDENCE/UPPER RIDGING WOULD SUGGEST
UNFAVORABLE CONDITIONS FOR DEVELOPMENT...DESPITE THE PRESENCE OF A
NWD LIFTING WARM FRONT...AND AVAILABLE INSTABILITY.
...SRN PLAINS...
A CONDITIONAL THREAT OF SUPERCELLS CAPABLE OF VERY LARGE HAIL WILL
EXIST. STRONG CONVECTIVE INHIBITION WILL GENERALLY LIMIT DEVELOPMENT
THROUGH MUCH OF THE AFTERNOON/EVENING. HOWEVER...HEATING/MIXING WEST
OF THE DRYLINE CHARACTERIZED BY HOT TEMPERATURES IN THE MID 90S TO
NEAR 100 F SUGGEST THE POSSIBILITY THAT THE CAP MAY ERODE IN A
NARROW CORRIDOR ACROSS WRN/CNTRL OK SWD INTO TX AS A WEAK UPPER
TROUGH/SUBTLE VORT MAX APPROACH THE AREA. GIVEN VERY STEEP MID LEVEL
LAPSE RATES IN EXCESS OF 8.5 C/KM...AND DEEP LAYER SHEAR VECTORS
ORIENTED PERPENDICULAR TO THE DRYLINE...A FEW HIGH-BASED SUPERCELLS
MAY DEVELOP. ALTHOUGH A TORNADO CANNOT BE RULED OUT...HIGH-BASED
NATURE SUGGESTS LOW PROBABILITIES OF THIS OCCURRING.
...SERN STATES...
FAVORABLE WSWLY LOW LEVEL FLOW WILL TRANSPORT GREATER MOISTURE
ENEWD...WITH LOWER 60S DEW POINTS EXPECTED ACROSS THE SOUTHEAST. AS
AN UPPER TROUGH SHIFTS OFFSHORE...A LINGERING FRONTAL BOUNDARY WILL
BE THE PRIMARY FOCUS FOR AFTERNOON DEVELOPMENT. THE MAINTENANCE OF
STEEPER MID-LEVEL LAPSE RATES IN WNWLY FLOW ALOFT COULD YIELD A FEW
MULTICELLULAR CLUSTERS CAPABLE OF DMGG WINDS/HAIL. AS MORE FOCUSED
AREAS BECOME APPARENT...AN UPGRADE TO SLIGHT RISK MAY BE POSSIBLE IN
SUBSEQUENT OUTLOOKS.
..HURLBUT/GUYER.. 05/07/2011
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