SPC AC 060600
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT TUE APR 06 2010
VALID 061200Z - 071200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM OK TO THE MIDWEST/UPPER
GREAT LAKES VICINITY...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NORTHEAST STATES...
...SYNOPSIS...
A PROGRESSIVE LARGE SCALE REGIME...WITH SPLIT UPPER FLOW ALONG THE
NORTH AMERICAN ROCKIES...WILL EXIST THROUGH THE PERIOD. A
STRENGTHENING SOUTHWESTERLY BELT OF MID/UPPER FLOW...AHEAD OF A
NEUTRAL TO POSITIVE TILT UPPER TROUGH SPREADING EASTWARD FROM THE
ROCKIES TO THE PLAINS...WILL CONTRIBUTE TO A BROAD SPATIAL EXTENT OF
SEVERE POTENTIAL COINCIDENT WITH A MODERATELY MOIST WARM SECTOR
ACROSS THE PLAINS/MIDWEST TO NORTHEAST STATES.
...OK/LOWER MO VALLEY TO MIDWEST/UPPER GREAT LAKES..
ONGOING EARLY DAY STRONG/SEVERE TSTMS WITH MAINLY HAIL POTENTIAL
SEEM LIKELY TO BE ONGOING ACROSS IA/SURROUNDING AREAS TO THE LAKE MI
VICINITY ON THE EDGE OF A STRONG ELEVATED MIXED LAYER. ISOLATED
DAMAGING WIND POTENTIAL CANNOT BE RULED IF ORGANIZED
QUASI-LINEAR/BOWING SYSTEMS PERSIST DURING THE MORNING.
OTHERWISE...THE NORTHWARD PROGRESSION OF THE WARM FRONT ACROSS THE
MIDWEST/UPPER GREAT LAKES VICINITY MAY BE IMPEDED/CONVECTIVELY
REINFORCED BY THE EARLY DAY SHOWERS/TSTMS...BUT OTHERWISE WILL
CONTINUE TO RETREAT A BIT NORTHWARD FROM NORTHERN IL/NORTHERN
INDIANA INTO FAR SOUTHERN WI AND LOWER MI. LOWER 60S F SURFACE
DEWPOINTS WILL BE COMMON ACROSS THE MAJORITY OF THE WARM
SECTOR...WITH THE POSSIBILITY OF WEAKLY CAPPED 1000-2000 J/KG MLCAPE
/ESPECIALLY FROM SOUTHERN IA TO OK/ BY MID/LATE AFTERNOON.
AS THE PARENT UPPER TROUGH CROSSES THE PLAINS AND MID/UPPER FLOW
STRENGTHENS/BACKS...A COLD FRONT SHOULD GRADUALLY OVERTAKE THE
OTHERWISE QUASI-STATIONARY SW-NE ORIENTED FRONT ACROSS THE LOWER MO
RIVER VALLEY. THIS SHOULD LEAD TO SURFACE BASED TSTM DEVELOPMENT
DURING THE AFTERNOON...INITIALLY FROM PORTIONS OF IA TO W/NW MO AND
EASTERN KS. QUASI-DISCRETE SUPERCELLS CAPABLE OF LARGE HAIL/SOME
TORNADOES WILL BE POSSIBLE EARLY IN MODAL EVOLUTIONS THROUGH LATE
AFTERNOON/EARLY EVENING...BUT DEEP LAYER SHEAR LARGELY PARALLEL TO
THE COLD FRONT IMPLIES AN EVENING EVOLUTION TO LINE SEGMENTS WITH
SOME INCREASE IN DAMAGING WIND POTENTIAL.
FARTHER SOUTH FROM SOUTHEAST KS INTO OK...TIMING OF CONVECTIVE
INITIATION AND/OR PROSPECTS FOR NEAR-PEAK HEATING TSTM DEVELOPMENT
IS MORE UNCERTAIN WITH SOUTHWARD EXTENT ACROSS THE DRYLINE.
HOWEVER...AT LEAST A CONDITIONAL-TYPE SEVERE RISK WILL INITIALLY
EXIST GIVEN A RELATIVELY MOIST/WEAKLY CAPPED AND POTENTIALLY
MODERATELY UNSTABLE BOUNDARY LAYER. WITH MID LEVEL FLOW SOMEWHAT
MORE NORMAL TO THE DRYLINE /AS COMPARED TO LOCATIONS FARTHER
NORTHEAST/...QUASI-DISCRETE SUPERCELLS CAPABLE OF LARGE
HAIL/TORNADOES ARE POSSIBLE. TSTM DEVELOPMENT/COVERAGE INCLUDING
SEVERE WILL BE BECOME MORE PROBABLE/GREATER BY EARLY/MID EVENING AS
THE COLD FRONT GRADUALLY OVERTAKES THE DRYLINE ACROSS SOUTHEAST KS
AND OK.
...NORTHEAST STATES...
RELATIVELY COMPLEX SCENARIO ACROSS THE NORTHEAST STATES TODAY
INCLUDING SOUTHERN NY/NORTHERN PA...AND PERHAPS NORTHERN NJ INTO
PORTIONS OF SOUTHERN NEW ENGLAND. EARLY DAY UPSTREAM STORMS /SOME
POSSIBLY STRONG/ MAY SPREAD INTO THE REGION THIS MORNING ON THE NOSE
OF A STRONG WSW LOW LEVEL JET/ELEVATED MOISTURE TRANSPORT REGIME.
ALTHOUGH AN INITIALLY DRY/RELATIVELY STABLE AIRMASS WILL EXIST
ACROSS THE REGION...THE NORTHWARD PROGRESSION OF A WARM
FRONT/ATTENDANT 50S F SURFACE DEWPOINTS AND A WARMING BOUNDARY LAYER
MAY CONTRIBUTE TO A DAYTIME UPSWING AND/OR RENEWED STRONG/SEVERE
DEVELOPMENT ALONG THE SURFACE FRONTAL ZONE. IN ALL...SEVERE
HAIL/DAMAGING WINDS WILL BE THE PRIMARY CONCERNS.
...TX...
INITIALLY WELL SOUTH OF THE UPPER JET AXIS...IT SEEMS PROBABLE THAT
CAPPING WILL LARGELY LIMIT TSTM DEVELOPMENT UNTIL TONIGHT ACROSS
MUCH OF NORTH CENTRAL/NORTHEAST TX TO CENTRAL TX/TX BIG BEND.
GREATEST CONFIDENCE IN ISOLATED TO SCATTERED TSTM DEVELOPMENT /AND
ASSOCIATED SEVERE THREAT/ WILL EXIST THIS EVENING AND ESPECIALLY
OVERNIGHT...AS GRADUAL HEIGHT FALLS OCCUR AND THE COLD FRONT
GRADUALLY OVERTAKES THE DRYLINE/ASSOCIATED MOIST SECTOR. ALTHOUGH A
CATEGORICAL SLIGHT RISK DOES NOT APPEAR TO BE
WARRANTED...STRENGTHENING FLOW ALOFT COUPLED WITH MODERATE
INSTABILITY IMPLIES SEVERE HAIL/PERHAPS DAMAGING WINDS WILL BE
POSSIBLE WITH THE STRONGEST STORMS.
..GUYER.. 04/06/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
|
