Sunday, April 15, 2007

DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 150719
SWODY3
SPC AC 150718

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0218 AM CDT SUN APR 15 2007

VALID 171200Z - 181200Z

..NO SVR TSTM AREAS FORECAST...

..SYNOPSIS...
UPPER LOW/TROUGH INITIALLY OVER THE S CENTRAL CONUS IS FORECAST TO
MOVE EWD INTO THE LOWER MS VALLEY REGION DURING THE SECOND HALF OF
THE PERIOD. MEANWHILE...A SECOND TROUGH IS FORECAST TO MOVE ONSHORE
ACROSS THE PAC NW ACCOMPANIED BY A PRONOUNCED SURFACE COLD FRONT.
SEVERE THREAT SHOULD REMAIN LOW THROUGH THE PERIOD...THOUGH A FEW
VIGOUROUS STORMS COULD DEVELOP INVOF EITHER/BOTH OF THE
AFOREMENTIONED UPPER FEATURES.

..TX...
COLD AIR AT H5 /-18 TO -22 C/ IS FORECAST TO SPREAD ACROSS WRN AND
INTO CENTRAL TX THROUGH LATE AFTERNOON/EARLY EVENING...AS UPPER LOW
MOVES ACROSS THIS AREA. THE GFS IS ABOUT 6 HOURS FASTER WITH THIS
FEATURE...DEPICTING THE CENTER OF CIRCULATION NEAR GGG /LONGVIEW TX/
AT 18/00Z...WHILE THE NAM AT THIS TIME INDICATES THE CENTER CLOSER
TO ABI /ABILENE TX/.

IN ANY CASE...THE COLD AIR ALOFT ABOVE A MOISTENING BOUNDARY LAYER
SHOULD RESULT IN MARGINAL DESTABILIZATION. WHILE DEEP-LAYER SHEAR
SHOULD REMAIN RELATIVELY WEAK ACROSS MUCH OF THE REGION DUE TO
PROXIMITY OF THE UPPER CIRCULATION CENTER...A FEW
STRONGER/LOW-TOPPED STORMS CAPABLE OF PRODUCING MARGINAL HAIL MAY
EVOLVE DURING THE AFTERNOON. WILL NOT INTRODUCE SEVERE PROBABILITY
ACROSS THIS REGION ATTM...BUT LOW PROBABILITIES MAY BECOME NECESSARY
IN LATER OUTLOOKS.

..THE NWRN CONUS...
AS STRONG COLD FRONT MOVES ACROSS THIS REGION DURING THE
DAY...MARGINAL WARM-SECTOR DESTABILIZATION IS EXPECTED DUE TO COLD
AIR ALOFT DESPITE DRY BOUNDARY LAYER. BOTH THE NAM AND NAMKF RUNS
SUGGEST SUFFICIENT INSTABILITY ACROSS PARTS OF WRN MT/ID/NRN NV FOR
A FEW STRONGER/HIGH-BASED STORMS. STRONG DEEP-LAYER SHEAR COULD
FURTHER ENHANCE ANY SUSTAINED UPDRAFT. GIVEN DEEP/DRY BOUNDARY
LAYER...AN OUTSIDE CHANCE FOR A LOCALLY STRONG WIND GUST COULD NOT
BE RULED OUT. HOWEVER...LOW CONFIDENCE IN THIS EVOLUTION PRECLUDES
THE INTRODUCTION OF SEVERE PROBABILITIES THIS FORECAST.

.GOSS.. 04/15/2007

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