SPC May 13, 2013 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0226 AM CDT MON MAY 13 2013

VALID 151200Z - 161200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MINOR AMPLIFICATION OF THE UPPER PATTERN IS FORECAST OVER THE U.S.
WEDNESDAY/DAY 3...AS WEAK PHASING BETWEEN THE ERN CANADA SHORT-WAVE
TROUGH AND THE SECOND CROSSING THE S CENTRAL STATES IS
EXPECTED...WHILE FARTHER W AN ERN PACIFIC TROUGH APPROACHES THE W
COAST.

AT THE SURFACE...AN INCREASINGLY E-W COLD FRONT IS FORECAST TO LIE
ACROSS THE MIDWEST/OH VALLEY REGION AND WWD INTO KS THROUGH THE
PERIOD -- PROVIDING A FOCUS FOR AFTERNOON SHOWER AND THUNDERSTORM
DEVELOPMENT.

...PARTS OF ERN OH/PA/NRN WV/MD/NRN VA...
AS THE SURFACE COLD FRONT BECOMES INCREASINGLY W-E ORIENTED ACROSS
THE OH VALLEY REGION...EXPECT AFTERNOON SHOWERS AND THUNDERSTORMS TO
DEVELOP ALONG THE BOUNDARY FROM THE MID-ATLANTIC REGION WWD.
HOWEVER...IT APPEARS ATTM THAT MODEL DEPICTIONS OF BOUNDARY-LAYER
MOISTURE IS OVERDONE -- WITH MID 60S DEWPOINTS EVOLVING WITHIN THE
MODELS DAY 2 /TUESDAY/ INVOF THE MID MS/LOWER OH VALLEYS AND THEN
SPREADING EWD ACROSS THE OH VALLEY WEDNESDAY.  AS A RESULT...THE
ACTUAL DEGREE OF DESTABILIZATION INVOF THE FRONT SHOULD REMAIN MUCH
LOWER THAN FORECAST -- THUS LIMITING SEVERE POTENTIAL.  STILL...WITH
MODERATELY-STRONG FLOW ALOFT ACROSS THE REGION...WILL INTRODUCE 5%
SEVERE PROBABILITIES ATTM TO INDICATE POTENTIAL FOR ISOLATED
HAIL/DAMAGING WINDS DURING THE AFTERNOON/EVENING ACROSS THIS REGION.


...NRN AND CENTRAL TX AND VICINITY...
SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP OVER THE SRN PLAINS
REGION AS A RELATIVELY WEAK UPPER TROUGH SHIFTS ACROSS THE AREA.
WITH DAYTIME HEATING COMBINING WITH MODEST MID-LEVEL
COOLING...MODERATE AFTERNOON DESTABILIZATION IS EXPECTED.
HOWEVER...WITH FLOW ALOFT PROGGED TO REMAIN RELATIVELY WEAK...STORMS
SHOULD REMAIN RELATIVELY DISORGANIZED -- SUPPORTIVE OF ONLY LOW /5%/
SEVERE PROBABILITY FORECAST ATTM.  THREAT SHOULD REMAIN LARGELY
DIURNAL IN NATURE...DIMINISHING AFTER SUNSET.

..GOSS.. 05/13/2013

via SPC Forecast Products http://www.spc.noaa.gov/products/outlook/day3otlk_0730.html