Friday, September 4, 2009

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 041619
SWODY1
SPC AC 041616

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1116 AM CDT FRI SEP 04 2009

VALID 041630Z - 051200Z

...NO SVR TSTM AREAS FORECAST...

...SRN PLAINS...
WEAK DEEP-LAYER CYCLONIC VORTEX/SHORT WAVE TROUGH ROTATING AROUND
LARGER SCALE TROUGH CENTERED ACROSS THE MIDWEST HAS PRODUCED 20-30M
500MB HEIGHT FALLS ACROSS THE PLAINS LAST 12H. THIS FEATURE HAS
SEVERAL WEAKLY CONFLUENT SFC TROUGHS/OUTFLOW BOUNDARIES ASSOCIATED
WITH IT FROM KS INTO NRN TX THIS MORNING. LIFT ACCOMPANYING THESE
FEATURES WILL COMBINE WITH POCKETS OF STRONGER DIURNAL
DESTABILIZATION AND RESULT IN SCATTERED TSTM DEVELOPMENT THROUGH
THIS FORECAST PERIOD.

CYCLONIC MID LEVEL FLOW AOB 30KT ACCOMPANYING THE SHORT WAVE
TROUGH...AND POTENTIAL FOR GREATEST SURFACE HEATING ACROSS THE
OZARKS...SUGGEST THAT SOME INCREASE IN MARGINALLY ORGANIZED
MULTICELL STORM CLUSTERS IN THIS AREA THROUGH LATE AFTERNOON.
GENERALLY WEAK SHEAR AND MARGINAL LAPSE RATES SUGGEST THAT THESE
STORMS WILL ONLY A LOW PROBABILITY OF PRODUCING SEVERE HAIL/WIND.

FARTHER S ACROSS WEST TX...DIFFERENTIAL HEATING BOUNDARY WAS
PERSISTING FROM SOUTH PLAINS ESEWD ACROSS THE CAPROCK. IT IS
POSSIBLE THAT ANOTHER BAND OF MORE VIGOROUS CONVECTION COULD DEVELOP
ALONG AND SOUTH OF THIS ZONE GIVEN SUPPORTIVE BACKGROUND ASCENT ON
THE SWRN FLANK OF THE SHORT WAVE TROUGH. MOIST LOW LEVEL ESELY FLOW
TOPPED BY WEAK WLY FLOW ALOFT MAY CONTRIBUTE TO POCKETS OF GREATER
EFFECTIVE SHEAR AND SOME POTENTIAL FOR A FEW BETTER ORGANIZED
STORMS. A COUPLE OF THESE CELLS COULD PRODUCE SEVERE HAIL OR
DAMAGING OUTFLOW GUSTS BUT OVERALL FOCUS/POTENTIAL AND DURATION OF
THIS THREAT DOES NOT APPEAR TO WARRANT HIGHER PROBABILITIES AT THIS
TIME.

...SOUTHWEST/GREAT BASIN...
STORMS WILL AGAIN DEVELOP ACROSS THESE LARGER REGIONS TODAY DRIVEN
PRIMARILY BY HEATING AND TERRAIN. DRY ADIABATIC SUB-CLOUD LAPSE
RATES...AND PERHAPS MORE PERSISTENT ACTIVITY AHEAD OF WEST COAST
SHORT WAVE TROUGH DEVELOPING INLAND TOWARD THE LOWER CO RIVER
VALLEY...MIGHT SUPPORT A FEW ISOLATED DOWNBURST WIND EVENTS.

..CARBIN/GRAMS.. 09/04/2009

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