SWODY2
SPC AC 050531
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1231 AM CDT WED OCT 05 2011
VALID 061200Z - 071200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM WRN SD TO THE TX
PANHANDLE...
...SYNOPSIS...
HIGHLY AMPLIFIED UPPER-LEVEL TROUGH OVER THE WRN CONUS WILL BECOME
ELONGATED AS A VORTICITY MAXIMUM /CURRENTLY APPROACHING THE NRN CA
COAST/ REACHES THE FOUR CORNERS BY THU MORNING AND THEN EJECTS NEWD
TOWARDS THE NRN PLAINS THROUGH EARLY FRI...WHILE A SECONDARY IMPULSE
MOVES ACROSS CA INTO THE SOUTHWEST. AT THE SURFACE...PRIMARY CYCLONE
SHOULD BECOME CENTERED INVOF THE NEB/CO/WY BORDER AREA ON THU
AFTERNOON AND THEN DEVELOP NWD ACROSS THE NRN HIGH PLAINS IN THE
EVENING/OVERNIGHT. AN ATTENDANT DRYLINE WILL MIX EWD ACROSS PARTS OF
THE CNTRL/SRN HIGH PLAINS BEFORE RETREATING WWD DURING THE EARLY
EVENING. THE NRN PORTION OF THE DRYLINE WILL BE OVERTAKEN BY A
PACIFIC COLD FRONT AND SURGE EWD ACROSS THE CNTRL HIGH PLAINS
OVERNIGHT.
...NRN PLAINS TO SRN HIGH PLAINS...
DOWNSTREAM OF THE WRN CONUS TROUGH...KINEMATIC FIELDS WILL
STRENGTHEN ACROSS THE HIGH PLAINS...RESULTING IN INCREASING
LOW-LEVEL MOISTURE BEING ADVECTED NWD AND STRONG DEEP-LAYER SHEAR
DEVELOPING BY THU AFTERNOON/EVENING. DESPITE THE INFLUX OF GREATER
MOISTURE...THE PRESENCE OF LOW-LEVEL RIDGING ENCOMPASSING MUCH OF
THE SRN/ERN CONUS IN PRECEDING DAYS WILL RESTRICT THE AMPLITUDE AND
LONGITUDINAL EXTENT OF A MODIFIED WRN GULF AIR MASS. WITH SURFACE
DEW POINTS EXPECTED TO ONLY REACH INTO THE UPPER 40S AND 50S BY
07/00Z...THIS SHOULD REMAIN A LIMITING FACTOR TO A MORE ROBUST
SEVERE THREAT.
NEVERTHELESS...A LARGE SWATH OF 500 MB S/SWLYS AOA 50 KT WILL
OVERSPREAD THE REGION BY LATE AFTERNOON AND LOW-LEVEL HODOGRAPHS
WILL ENLARGE DURING THE EVENING AS THE LLJ STRENGTHENS TO AOA 50 KT
ACROSS MUCH OF THE PLAINS. THIS WILL RESULT IN RATHER FAVORABLE
SUPERCELL WIND PROFILES DEVELOPING ALONG THE DRYLINE.
FORCING SHOULD REMAIN WEAK OVER MOST OF THE CNTRL/SRN HIGH PLAINS AS
PRIMARY SHORT WAVE TROUGH EJECTS N/NEWD TOWARDS THE NRN PLAINS...AND
MID-LEVEL LAPSE RATES WILL BE WEAKER WITH SRN EXTENT.
HOWEVER...CONVERGENCE AND HEATING ALONG THE DRYLINE SHOULD BE
SUFFICIENT FOR ISOLATED SUPERCELL TSTMS WITH ALL MODES OF SEVERE
WEATHER POSSIBLE.
IN THE NRN PLAINS...LARGE-SCALE FORCING WILL INCREASE DURING THE
LATE AFTERNOON AND EVENING...AND WITH STEEPER MID-LEVEL LAPSE
RATES...WILL LIKELY COMPENSATE TO SOME EXTENT FOR MARGINAL BOUNDARY
LAYER MOISTURE AND WEAKER EFFECTIVE SHEAR RELATIVE TO FARTHER S.
SCATTERED TSTMS APPEAR PROBABLE TO FORM AND SHOULD CONSIST OF A FEW
SUPERCELLS WITH PRIMARY THREATS OF SEVERE HAIL/WIND AND PERHAPS A
TORNADO OR TWO.
..GRAMS/KERR.. 10/05/2011
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