SWODY1
SPC AC 021640
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1140 AM CDT SAT JUN 02 2007
VALID 021630Z - 031200Z
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON ACROSS PARTS OF
NEW ENGLAND AND NRN NY STATE...
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON FOR THE E COAST
OF FL...
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING ACROSS
THE UPPER MS VALLEY...
..THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON INTO TONIGHT
ACROSS THE SRN HIGH PLAINS...
..UPPER MS VALLEY THIS AFTERNOON...
THE VERTICALLY STACKED LOW OVER SW MN WILL DRIFT EWD TO WRN WI BY
LATE TONIGHT. REGIONAL 12Z SOUNDINGS SHOW RATHER POOR MID LEVEL
LAPSE RATES IN PROXIMITY TO THE MID LEVEL LOW...THOUGH MID LEVEL
TEMPERATURES ARE RATHER COOL /-15 C AT 500 MB/. E OF THE MID LEVEL
LOW AND IN ASSOCIATION WITH A LEAD SHORTWAVE TROUGH...A PERSISTENT
BAND OF THICK CLOUDS AND SOME RAINFALL EXTENDS FROM CENTRAL MO
ACROSS NW IL INTO WI. THE STRONGEST SURFACE HEATING WILL OCCUR W OF
THIS CLOUD BAND TODAY...IMMEDIATELY E OF THE STACKED LOW AND COOLER
MID LEVEL TEMPERATURES. THOUGH LOW-MID LEVEL VERTICAL SHEAR WILL BE
RELATIVELY WEAK IN PROXIMITY TO THE LOW...THE COOL MID LEVEL
TEMPERATURES COULD SUPPORT A FEW STORMS WITH LARGE HAIL THIS
AFTERNOON.
THE STRONGER DEEP LAYER VERTICAL SHEAR WILL COINCIDE WITH THE CLOUD
BAND...AND ONLY WEAK INSTABILITY. THERE WILL BE A NARROW CORRIDOR
ACROSS ERN WI WHERE SOMEWHAT GREATER INSTABILITY WILL COINCIDE WITH
THE STRONGER VERTICAL SHEAR...AND THIS IS WHERE THE THREAT FOR
SUPERCELLS WILL BE GREATEST...ALONG WITH THE POSSIBILITY OF A COUPLE
OF TORNADOES. FARTHER E...AFTERNOON TEMPERATURES IN THE 80S AND
BOUNDARY LAYER DEWPOINTS IN THE LOW-MID 60S WILL CONTRIBUTE TO
MLCAPE VALUES OF 1000-1500 J/KG. THIS AREA WILL BE E OF THE
STRONGER VERTICAL SHEAR AND THERE WILL BE NO OBVIOUS FOCUS FOR
THUNDERSTORM DEVELOPMENT...THUS ONLY ISOLATED HAIL/WIND ARE EXPECTED
WITH A FEW MULTICELL CLUSTERS.
..SE ATLANTIC COAST THROUGH TONIGHT...
THE REMNANTS OF TROPICAL STORM BARRY WILL MOVE NNEWD FROM N OF TAMPA
TO NEAR JAX BY THIS EVENING...AND THEN CONTINUE JUST OFF THE SE
ATLANTIC COAST OVERNIGHT. THE STRONGEST LOW-LEVEL SHEAR WILL BE
CONFINED TO THE AREA IMMEDIATELY E/NE OF THE SURFACE CENTER THROUGH
ABOUT 18-21Z...THEN THIS AREA OF STRONGER SHEAR WILL SHIFT OFFSHORE.
FARTHER S ALONG THE FL E COAST...LOW-LEVEL FLOW WILL GRADUALLY VEER
TO SWLY AND WEAKEN BY LATE AFTERNOON. THE THREAT FOR ISOLATED
SUPERCELLS WITH A TORNADO OR TWO AND A FEW DAMAGING GUSTS WILL SHIFT
SLOWLY EWD WITH THE PRIMARY CONFLUENCE BANDS S OF THE CIRCULATION
CENTER...AND THE SEVERE STORM THREAT SHOULD DIMINISH BY MID-LATE
AFTERNOON.
OVERNIGHT...THE N/NW EDGE OF THE MOIST AND WEAKLY UNSTABLE WARM
SECTOR MAY APPROACH ERN NC. FOR THIS REASON...LOW TORNADO
PROBABILITIES WILL BE MAINTAINED FOR THE 06-12Z TIME PERIOD.
..SRN HIGH PLAINS TODAY INTO EARLY TONIGHT...
A WNWLY MID-UPPER FLOW REGIME WILL PERSIST OVER THE SRN HIGH PLAINS
BETWEEN THE NRN PLAINS MID LEVEL LOW...AND A SRN STREAM RIDGE OVER
THE SRN ROCKIES. AN MCV ASSOCIATED WITH OVERNIGHT CONVECTION IS
MOVING WELL TO THE E OVER NE TX...WHILE A WEAKER SPEED MAX IS
ALREADY MOVING ESEWD OVER SE CO AND THE OK/NRN TX PANHANDLES. AT
THE SURFACE...A WEAK COLD FRONT IS DRIFTING SWD ACROSS W TX AND SEWD
INTO CENTRAL OK.
CONVECTION DURING THE TWO PREVIOUS DAYS HAS REDUCED INSTABILITY
ACROSS MUCH OF N TX AND OK...WITH THE RICHER MOISTURE AND STRONGER
INSTABILITY CONFINED TO A CORRIDOR FROM NW LA/E TX WWD ACROSS
CENTRAL TX INTO W CENTRAL TX ALONG THE FRONT/REMNANT OUTFLOW
BOUNDARY. IF STORMS CAN FORM ALONG THE FRONT IN W TX...OR IN
ASSOCIATION WITH THE TERRAIN-INDUCED LOW NEAR FST...THEN SUPERCELLS
WITH LARGE HAIL AND A TORNADO OR TWO WILL BE POSSIBLE. CONVECTIVE
INHIBITION WILL BE WEAKER WELL N OF THE FRONT INTO THE TX PANHANDLE
AND E OF THE HIGHER TERRAIN IN NE NM. STORM DEVELOPMENT APPEARS
LIKELY NEAR THE RATON MESA AGAIN TODAY...AND MAY ALSO OCCUR FARTHER
E INTO THE PANHANDLE IN ASSOCIATION WITH THE WEAK MID-UPPER SPEED
MAX. SUPERCELLS WILL ALSO BE POSSIBLE THIS AREA...WITH LARGE HAIL
THE MAIN THREAT. THERE WILL BE SOME POSSIBILITY FOR CONVECTION TO
EVOLVE INTO A SMALL MCS BY THIS EVENING ACROSS NE NM OR NW
TX...THOUGH CONFIDENCE IN THIS SCENARIO IS RATHER LOW.
..NEW ENGLAND THIS AFTERNOON...
THE REGIME HAS CHANGED LITTLE SINCE YESTERDAY...WITH A BAROCLINIC
ZONE STALLED ACROSS NRN NEW ENGLAND...WITH A MODERATELY UNSTABLE
WARM SECTOR ALONG AND S OF THE BOUNDARY. SCATTERED THUNDERSTORMS
WILL LIKELY DEVELOP ALONG THE FRONT AND THE HIGHER TERRAIN THIS
AFTERNOON...NAMELY THE ADIRONDACKS. AFTERNOON MLCAPE VALUES NEAR
1500 J/KG AND MODEST DEEP LAYER SHEAR COULD SUPPORT A FEW ORGANIZED
MULTICELL CLUSTERS OR SUPERCELLS...WITH LARGE HAIL AND DAMAGING
WINDS THE MAIN THREATS.
.THOMPSON/GRAMS.. 06/02/2007
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