SPC AC 120532
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 AM CDT SUN OCT 12 2008
VALID 121200Z - 131200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND SRN
HIGH PLAINS...
...SYNOPSIS...
MID AND UPPER-LEVEL LOW INITIALLY OVER THE GREAT BASIN WILL RAPIDLY
LIFT NEWD THROUGH THE NRN HIGH PLAINS IN CONCERT WITH ATTENDANT JET
STREAKS PROPAGATING DOWNSTREAM FROM MEAN TROUGH AXIS. THIS IN
CONJUNCTION WITH UPSTREAM RIDGE AMPLIFICATION FROM THE ERN PACIFIC
INTO WRN CANADA AND THE PACIFIC NW WILL RESULT IN AN INCREASINGLY
ELONGATED LARGE-SCALE TROUGH CONFIGURATION...ORIENTED IN NE-SW
FASHION FROM THE S-CNTRL CANADIAN PRAIRIES INTO THE LOWER CO
VALLEY.
IN THE LOW-LEVELS...A DEEPENING SURFACE LOW WILL DEVELOP NEWD
THROUGH THE ERN DAKOTAS AND UPPER MS VALLEY WITH TRAILING COLD FRONT
PUSHING SEWD THROUGH THE CNTRL PLAINS AND PORTIONS OF THE SRN HIGH
PLAINS. A SECONDARY COLD FRONT OF PACIFIC ORIGIN WILL SLOWLY PUSH
EWD FROM CNTRL INTO ERN NM.
...CNTRL/SRN HIGH PLAINS...
CURRENT GOES SOUNDER AND GPS IPW DATA INDICATE THAT AN INCREASINGLY
MOIST BOUNDARY LAYER IS RAPIDLY BEING ADVECTED NWD THROUGH THE HIGH
PLAINS ALONG STRENGTHENING NOCTURNAL LLJ. WHILE PRIMARY LLJ CORE
WILL MIGRATE NWD THROUGH THE MID MO VALLEY TODAY...SLY LOW-LEVEL
FLOW WILL MAINTAIN AN AXIS OF 55-65 F DEWPOINTS AHEAD OF SEWD-MOVING
COLD FRONT AND TO THE E OF PACIFIC FRONT. REMNANTS OF HURRICANE
NORBERT RAPIDLY LIFTING NEWD ACROSS THE REGION AND RESIDUAL
CLOUDS/PRECIPITATION ALONG LLJ AXIS ARE LIKELY TO INHIBIT DAYTIME
HEATING AND WEAKEN MIDLEVEL LAPSE RATES ACROSS SYSTEM WARM SECTOR.
THESE FACTORS WILL LIKELY LIMIT AFTERNOON MLCAPE TO LESS THAN 1000
J/KG DESPITE THE RELATIVELY MOIST BOUNDARY LAYER CONDITIONS.
SIMILAR TO SATURDAY...A BROADLY-CONFLUENT LOW-LEVEL FLOW REGIME
SHOULD SUPPORT AN INCREASE IN STORM COVERAGE AND INTENSITY BY
AFTERNOON AHEAD OF PACIFIC FRONT OVER ERN NM/WRN TX INTO SERN
CO/SWRN KS. FARTHER N...MORE FOCUSED...MESOSCALE ASCENT ALONG
SEWD-MOVING COLD FRONT WILL FOSTER ADDITIONAL STORM CLUSTERS OVER
NWRN KS INTO CNTRL NEB. CONVECTIVE MODE WILL LIKELY BE COMPLEX WITH
THE POTENTIAL FOR EMBEDDED SUPERCELL AND BOWING STRUCTURES GIVEN
45-55 KT OF EFFECTIVE BULK SHEAR. THE GREATEST THREAT FOR A TORNADO
OR TWO WILL BE WITH ANY MORE SUSTAINED SUPERCELLS THAT DEVELOP AHEAD
OF PACIFIC FRONT LATER THIS AFTERNOON INTO EVENING AS LOW-LEVEL
SHEAR STEADILY INCREASES. OTHERWISE...HAIL AND LOCALLY DAMAGING
WIND GUSTS WILL ACCOMPANY THE MOST INTENSE STORMS.
..MEAD/GRAMS.. 10/12/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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