Wednesday, June 16, 2010

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 161726
SWODY2
SPC AC 161725

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1225 PM CDT WED JUN 16 2010

VALID 171200Z - 181200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE NRN PLNS AND
THE UPR MS AND LWR MO VLYS...

...SYNOPSIS...
STRONG SHORTWAVE TROUGH NOW ROTATING AROUND BASE OF ORE UPR LOW
EXPECTED TO CONTINUE E ACROSS THE NRN GRT BASIN TODAY...BEFORE
TURNING NE INTO CNTRL WY EARLY THU. THE TROUGH SHOULD ACCELERATE
NEWD LATER THU AND REACH CNTRL ND BY EVE. THE SYSTEM IS THEN
FORECAST TO EVOLVE INTO A CLOSED LOW THAT SHOULD CONTINUE MORE
SLOWLY NE INTO SRN MB EARLY FRI.

STRONG SFC LOW ACCOMPANYING THE GRT BASIN TROUGH EXPECTED TO BE OVER
NE MT AT THE START OF THE PERIOD. THE LOW SHOULD MOVE SLOWLY ENE
INTO SRN MB BY 12Z FRI AS TRAILING FRONTAL SYSTEM SWEEPS RAPIDLY NE
INTO THE UPR MS VLY...BUT ONLY SLOWLY E/ESE ACROSS THE CNTRL
PLNS/LWR MO VLY.

...NRN PLNS INTO THE UPR MS AND LWR MO VLYS...
SEVERAL AREAS OF ELEVATED TSTMS LIKELY WILL BE ONGOING AT 12Z THU
OVER ND AND NRN/ERN SD...IN ZONE OF STRONG WAA/MOISTURE INFLOW ON
NERN FRINGE OF EML. MORE SCTD ACTIVITY MAY EXTEND SE INTO THE LWR
MO VLY. A FEW OF THE STORMS...ESPECIALLY IN THE DAKOTAS... COULD
PRODUCE DMGG WIND AND HAIL. THE STORMS SHOULD MOVE/DEVELOP MAINLY
NE THROUGH THE REMAINDER OF THE MORNING/EARLY AFTN...AND GRADUALLY
WEAKEN.

IN THE WAKE OF THE MORNING STORMS...MID LVL DRYING SHOULD ALLOW FOR
SUBSTANTIAL BOUNDARY LAYER RECOVERY ALONG AND E OF COLD FRONT/DRY
LINE FROM THE ERN DAKOTAS S/SE INTO WRN MN...ERN NEB...AND MUCH OF
IA. COMBINATION OF STRONG SFC HEATING AND CONTINUED MOISTURE INFLOW
BENEATH EML SHOULD BOOST SBCAPE TO NEAR 2000 J/KG IN ERN ND/NW
MN...AND TO AOA 3000 J/KG IN ERN NEB/IA.

STRONG DPVA ASSOCIATED WITH EJECTING UPR TROUGH WILL OVERSPREAD THE
MN/ERN DAKOTAS PART OF WARM SECTOR BY MID-AFTN. SOMEWHAT WEAKER
ASCENT LIKELY WILL GLANCE AREAS FARTHER S ACROSS ERN NEB AND IA.
COUPLED WITH FAVORABLY-TIMED LOW-LVL DESTABILIZATION/ WEAKENING
CIN...SETUP SHOULD SUPPORT RAPID...POTENTIALLY INTENSE ...TSTM
DEVELOPMENT IN AN ARC ALONG COLD FRONT/DRY LINE FROM FAR ERN ND/WRN
MN SWD. WITH TIME...STORMS ALSO SHOULD BUILD S INTO ERN NEB AND
NRN/WRN IA.

LOW-LVL LINEAR FORCING WILL BE STRONG OVER ERN ND AND MUCH OF MN.
BUT STRENGTH OF WIND FIELD /50-60 KT FLOW AT 700 MB/...AND THE FACT
THAT DEEP SHEAR VECTORS LIKELY WILL REMAIN PERPENDICULAR TO THE
LOW-LVL FORCING...SUGGEST THAT A FEW DISCRETE SUPERCELLS MAY
OCCUR...IN ADDITION TO BROKEN LINE SEGMENTS WITH EMBEDDED
SUPERCELLS. THESE STORMS COULD YIELD A FEW TORNADOES...IN ADDITION
TO LARGE HAIL/AND BOWING SEGMENTS WITH HIGH WIND. AS THE MESOSCALE
FORCING MECHANISMS FOR ASCENT BECOME MORE APPARENT...PARTS OF THE
FORECAST AREA MAY REQUIRE UPGRADE TO MODERATE RISK IN LATER
OUTLOOKS.

A BAND OR TWO OF GRADUALLY WEAKENING STORMS SHOULD CONTINUE NEWD
ALONG/AHEAD OF COLD FRONT INTO NRN/ERN MN...NRN/WRN WI AND UPR MI
THU NIGHT/EARLY FRI. AT THE SAME TIME...CONTINUED LOW LVL MOISTURE
INFLOW AND NOCTURNAL STRENGTHENING/VEERING OF SWLY LLJ SUGGEST
LIKELIHOOD FOR BACKBUILDING/REGENERATIVE STORMS OVER WRN MN/IA AND
ERN NEB. THESE MAY POSE A CONTINUED THREAT FOR ISOLD SVR WIND AND
HAIL...IN ADDITION TO HEAVY RAIN...THROUGH EARLY FRI.

..CORFIDI.. 06/16/2010

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