SPC AC 200727
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0227 AM CDT MON MAY 20 2013
VALID 221200Z - 231200Z
...THERE IS A SLGT RISK OF SVR TSTMS LOWER GREAT LAKES/MID AND UPPER
OH VALLEY REGIONS...
...SYNOPSIS...
AS A LARGE UPPER LOW/TROUGH SETTLES SLOWLY SEWD INTO THE WRN
CONUS...A SECOND UPPER TROUGH EXITING THE CENTRAL U.S. WILL MOVE
SLOWLY EWD ACROSS THE MIDWEST/MID SOUTH REGIONS. AT THE SURFACE...A
STRONG COLD FRONT WILL CONTINUE TO MOVE SLOWLY ACROSS THE GREAT
BASIN AHEAD OF THE WRN UPPER TROUGH...WHILE A MUCH WEAKER COOL FRONT
CROSSES THE LOWER GREAT LAKES/OH VALLEY/MID SOUTH THROUGH THE
PERIOD.
...WRN PORTIONS OF NY/PA WWD ACROSS THE MID OH VALLEY...
WIDESPREAD PRECIPITATION AND CLOUD COVER FROM THE START OF THE
PERIOD ONWARD IS EXPECTED ACROSS THE SLIGHT RISK AREA...WHICH SHOULD
GREATLY HINDER DESTABILIZATION POTENTIAL ACROSS MOST AREAS.
STILL...WITH MODERATE FLOW /30 TO 45 KT/ THROUGH MOST OF THE LOWER
HALF OF THE TROPOSPHERE ACROSS THE OH VALLEY REGION AHEAD OF THE
WEAK/ADVANCING FRONT...SOME POTENTIAL FOR SEVERE WEATHER -- MAINLY
IN THE FORM OF LOCALLY DAMAGING WINDS -- APPEARS TO EXIST.
THUS...WILL INTRODUCE 15%/SLIGHT RISK ACROSS THE MID AND UPPER OH
VALLEY AND LOWER GREAT LAKES REGION TO COVER A POSSIBLE
AFTERNOON/EVENING RAMP-UP IN CONVECTIVE INTENSITY.
...SABINE AND LOWER MS RIVER VALLEYS AND VICINITY...
SLIGHTLY ENHANCED FLOW ALOFT ACCOMPANYING A VORT MAX FORECAST TO BE
CROSSING E TX EARLY IN THE PERIOD WILL SUPPORT MODEST SHEAR ACROSS
LA AND SURROUNDING AREAS. WHILE QUESTIONS REGARDING DEGREE OF
DESTABILIZATION EXIST DUE TO REMNANT CLOUDS/PRECIPITATION...THE
ENHANCED FLOW FIELD ALOFT MAY SUPPORT A FEW STRONGER CELLS AND THUS
LOW-PROBABILITY SEVERE POTENTIAL.
...TX...
WITH MODEST SHEAR AND AFTERNOON DESTABILIZATION FORECAST ACROSS
TX...SOME SEVERE POTENTIAL IS EVIDENT. HOWEVER...WITH
RIDGING/SUBSIDENCE FORECAST TO OVERSPREAD THE REGION FROM THE
W...CONVECTIVE DEVELOPMENT SHOULD REMAIN LIMITED/ISOLATED.
THUS...WILL CARRY ONLY LOW /5%/ SEVERE PROBABILITY ACROSS THE SRN
PLAINS.
..GOSS.. 05/20/2013
CLICK TO GET WUUS03 PTSDY3 PRODUCT
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z