DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 181300
SWODY1
SPC AC 181258

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0658 AM CST MON JAN 18 2010

VALID 181300Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF CA...

...SYNOPSIS...
THE FIRST IN AN EXTENDED SERIES OF STRONG SHORTWAVE IMPULSES IN FAST
ZONAL JET OVER THE CNTRL AND ERN PACIFIC WILL SWEEP E ACROSS CA AND
ORE LATER TODAY/TONIGHT AS UPSTREAM SYSTEM NOW NEAR 150W CONTINUES
ESE TO 130W. AT THE SFC...POTENT LOW ASSOCIATED WITH LEAD
IMPULSE...NOW NEAR 40N/132W...SHOULD ARC NE TO OFF THE ORE/WA CST BY
EARLY TUE...WITH FURTHER DEEPENING LIKELY. MAIN FRONTAL BAND WITH
THE LOW SHOULD MOVE ACROSS SW ORE...AND NRN/CNTRL CA THIS AFTN...AND
ACROSS THE REMAINDER OF ORE AND CA THIS EVE.

...CA...
CURRENT SATELLITE DATA SUGGEST THAT LEAD PACIFIC SHORTWAVE TROUGH IS
BEGINNING TO SPLIT...MORE OR LESS AS FCST BY THE ECMWF/GFS. SRN
MEMBER OF SPLIT WILL DRIVE ESE INTO CNTRL CA LATER TODAY... WHILE
NRN PART MOVES ENE INTO NRN CA/WRN ORE. WARM CONVEYOR/ FRONTAL RAIN
BAND WITH SRN MEMBER WILL OVERSPREAD NRN AND CNTRL CA THIS
AFTN...AND SRN CA BY EVE. ALTHOUGH THERMODYNAMIC PROFILES WILL BE
CLOSE TO MOIST ADIABATIC WITHIN THE BAND...COMBINATION OF STRONG UVV
AND FAIRLY RICH MOISTURE MAY SUPPORT EMBEDDED CONVECTION AND A FEW
TSTMS. GIVEN STRONG/VERTICALLY-VEERING WIND PROFILES...INTERMITTENT
ROTATING CELLS/LEWP STRUCTURES COULD EVOLVE...YIELDING A THREAT FOR
ISOLD STRONG WIND GUSTS AND/OR A BRIEF TORNADO.

IN THE WAKE OF THE FRONTAL BAND...POTENTIAL WILL EXIST FOR THE
DEVELOPMENT OF SCTD CONVECTION/STORMS AS UPR COLD POCKET /WITH
TEMPERATURES AOB MINUS 22C/ SWEEPS INLAND ACROSS CNTRL CA LATE IN
THE DAY. MID LVL COOLING/ASCENT ATOP BOUNDARY LAYER LEFT MOISTENED
BY EARLIER RAINS COULD SUPPORT STORMS WITH MARGINALLY SVR HAIL ALONG
THE CST...OVER THE CSTL RANGES...AND E ACROSS THE SACRAMENTO AND SAN
JOAQUIN VLYS INTO TONIGHT. WIND PROFILES WILL BE FAVORABLE FOR
STORM ROTATION IN AREAS WHERE INSTABILITY/ CONVERGENCE ARE
SUFFICIENT FOR UPDRAFT SUSTENANCE. THUS...A CONDITIONAL THREAT WILL
EXIST FOR STRONG/ISOLD SVR WIND GUSTS...AND PERHAPS A TORNADO OR
TWO...DESPITE ONSET OF NIGHTFALL.

..CORFIDI.. 01/18/2010

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