SPC AC 200104
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0804 PM CDT TUE JUN 19 2007
VALID 200100Z - 201200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL AND SRN HIGH
PLAINS INTO OK/WRN N TX...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE
NORTHEAST...
...CENTRAL AND SRN HIGH PLAINS INTO OK/WRN N TX...
THUNDERSTORMS CONTINUE TO INCREASE IN COVERAGE IN SEVERAL CLUSTERS
FROM SWRN AND S CENTRAL KS SWD INTO OK...THE TX PANHANDLE/TX SOUTH
PLAINS...AND ADJACENT ERN NM. INSTABILITY IS EXTREME ACROSS THIS
REGION...WITH WIDESPREAD 5000 TO 6000 J/KG MIXED-LAYER CAPE AS A
RESULT OF WIDESPREAD MID-UPPER 70S DEWPOINTS AND VERY STEEP LAPSE
RATES. WITH LOW-LEVEL JET FORECAST TO VEER TO SLY AND INCREASE TO
35 KT THROUGH THE EVENING WHILE MID-LEVEL WINDS VEER TO A MORE NLY
DIRECTION...EXPECT STORMS TO CONTINUE TO INCREASE -- AND EVENTUALLY
CLUSTER INTO A LARGE SWD-MOVING MCS. SOME POTENTIAL APPEARS TO
EXIST THAT A LARGE COLD POOL COULD EVOLVE...WITH AN EXTENSIVE
CONVECTIVE OUTFLOW BOUNDARY SPREADING SWD ACROSS TX OVERNIGHT. IF
THIS WILL OCCUR...AND HOW FAR S THE BOUNDARY AND ASSOCIATED
CONVECTIVE REDEVELOPMENT COULD SPREAD REMAINS UNCERTAIN ATTM. THUS
HAVE EXPANDED THE SLIGHT RISK SWD INTO CENTRAL TX/THE TRANSPECOS
REGION.
OTHERWISE...DEGREE OF INSTABILITY AND SHEAR WILL CONTINUE TO SUPPORT
SUPERCELLS...WITH VERY LARGE HAIL...LOCALLY-DAMAGING WINDS...AND
ISOLATED TORNADOES POSSIBLE. SHOULD AFOREMENTIONED/LARGE STORM
COMPLEX DEVELOP/PROPAGATE SWD...THREAT FOR MORE WIDESPREAD DAMAGING
WINDS WOULD INCREASE.
...PARTS OF THE NORTHEAST...
THUNDERSTORMS CONTINUE JUST AHEAD OF COLD FRONT...AND IN A SEPARATE
NNE-SSW LINE FROM WRN NEW ENGLAND SSWWD TO ERN PA.
OVERALL...THUNDERSTORMS HAVE BEGUN TO SHOW A DECREASE IN INTENSITY
OVER THE PAST HOUR OR SO. HOWEVER...WITH AMPLE INSTABILITY FROM ERN
PA SWD INTO VA...A CONTINUED THREAT FOR LOCALLY-DAMAGING WINDS WILL
LIKELY CONTINUE FOR ANOTHER 2-3 HOURS BEFORE STORMS WEAKEN BELOW
SEVERE LEVELS.
..GOSS.. 06/20/2007
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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