SPC AC 200054
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0654 PM CST TUE JAN 19 2010
VALID 200100Z - 201200Z
...NO SVR TSTM AREAS FORECAST...
...CNTRL CA...
AN UPPER-LEVEL TROUGH IS CURRENTLY ORIENTED NNW TO SSE PARALLELING
THE CA COAST EVIDENT ON WATER VAPOR IMAGERY. THUNDERSTORMS ARE
ONGOING JUST AHEAD OF THE TROUGH IN THE SACRAMENTO VALLEY WHERE
OBJECTIVE ANALYSIS SHOWS LOCALLY MAXIMIZED INSTABILITY WITH MUCAPE
OF 250 TO 500 J/KG. THIS ALONG WITH STEEP MID-LEVEL LAPSE RATES
AROUND 7.0 C/KM COMBINED WITH 45 KT OF 0-6 KM SHEAR EVIDENT ON THE
SACRAMENTO WSR-88D VWP SHOULD BE SUFFICIENT FOR A HAIL THREAT THIS
EVENING...SEE MCD 14.
...SE CA/SW AZ...
AN UPPER-LEVEL TROUGH WILL CONTINUE TO APPROACH THE CO RIVER VALLEY
THIS EVENING AS THE EXIT REGION OF A MID-LEVEL JET OVERSPREADS THE
REGION. INCREASING LARGE-SCALE ASCENT AHEAD OF THE TROUGH SHOULD
HELP CONVECTION TO INTENSIFY. CURRENT THINKING IS THAT A NARROW LINE
OF STORMS WILL DEVELOP AND MOVE INTO SW AZ THIS EVENING.
STRENGTHENING FLOW ASSOCIATED WITH A LOW-LEVEL JET STRENGTHENING AND
MOVING EWD INTO THE REGION FROM THE WEST MAY BE SUFFICIENT FOR A
MARGINAL THREAT FOR DAMAGING WIND GUSTS OVER THE NEXT 2 TO 3
HOURS...SEE MCD 15.
...SRN OZARKS/MID-MS VALLEY...
A SUBTLE UPPER-LEVEL TROUGH ON WATER VAPOR IMAGERY CURRENTLY OVER
NORTHWEST TX WILL MOVE QUICKLY ENEWD INTO THE OZARKS TONIGHT. AHEAD
OF THE TROUGH...MOISTURE ADVECTION WILL CONTINUE ACROSS THE OZARKS
AS A LOW-LEVEL JET STRENGTHENS. FORECAST SOUNDINGS IN AR AFTER 06Z
INCREASE MUCAPE VALUES INTO THE 500 TO 1000 J/KG RANGE BUT SHOW A
WARM LAYER AROUND 850 MB CONCENTRATING MOST OF THE CAPE ABOVE 750
MB. THIS SHOULD KEEP MOST OF THE CONVECTION ELEVATED. 500 MB TEMPS
OF -18 TO -20C AND STEEP MID-LEVEL LAPSE RATES SHOULD BE FAVORABLE
FOR HAIL WITH THE MORE INTENSE STORMS MAINLY IN THE 09Z TO 12Z
TIMEFRAME WHEN MODEL FORECASTS AGREE WITH INCREASING CONVECTIVE
COVERAGE.
..BROYLES.. 01/20/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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