DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 200058
SWODY1
SPC AC 200055

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0755 PM CDT SAT SEP 19 2009

VALID 200100Z - 201200Z

...NO SVR TSTM AREAS FORECAST...

...NRN ROCKIES/HIGH PLAINS...
A MID/UPPER LEVEL TROUGH...CURRENTLY MOVING EWD THROUGH THE PACIFIC
NW PER WATER VAPOR IMAGERY...WILL UNDERGO SOME AMPLIFICATION TONIGHT
AS IT PROGRESSES EWD TOWARD THE NRN ROCKIES. AN ATTENDANT COLD
FRONT IS EXPECTED TO MOVE ACROSS MT THIS FORECAST PERIOD...REACHING
THE FAR WRN DAKOTAS BORDER BY 12Z SUNDAY. TSTMS WILL BE POSSIBLE...
GENERALLY ALONG AND IN THE POST-FRONTAL ENVIRONMENT OF THE COLD
FRONT. ALTHOUGH A CORRIDOR OF WEAK INSTABILITY WILL PRECEDE THE
FRONT...STRONGER DEEP LAYER SHEAR IS EXPECTED TO BE WEST OF THE
FRONT. THIS WILL LIKELY PRECLUDE THE THREAT FOR SEVERE WEATHER.

...PARTS OF TN/LOWER OH VALLEYS...
MODELS SUGGEST SHOWERS/EMBEDDED TSTMS SHOULD BECOME MORE LIKELY
LATER THIS EVENING/OVERNIGHT FROM NRN MS/AL INTO LOWER OH VALLEY AS
LOW LEVEL WAA INCREASES SOME ALONG STRENGTHENING SLY LLJ /30-35 KT/
ACROSS THIS REGION. WEAK INSTABILITY/LAPSE RATES AND WEAK SHEAR
WILL PRECLUDE A SEVERE WEATHER THREAT.

...CENTRAL/SRN GA...
COLD POOL ENHANCED LINE OF TSTMS EXTENDING FROM WEST CENTRAL INTO
SWRN GA EARLY THIS EVENING MAY PERSIST FOR THE NEXT HOUR OR SO.
HOWEVER...THIS ACTIVITY IS MOVING INTO A MORE STABLE AIR MASS PER
OBJECTIVE ANALYSES AND GIVEN THE OVERALL LOSS OF DAYTIME HEATING.
HEAVY RAINFALL RATES WILL BE THE PRIMARY THREAT THIS EVENING SINCE
WEAK LAPSE RATES/INSTABILITY AND WEAK SHEAR WILL PRECLUDE A SEVERE
WEATHER THREAT.

...ELSEWHERE...
THE LOSS OF DAYTIME HEATING WILL STABILIZE THE BOUNDARY LAYER AND
PRECLUDE THE DEVELOPMENT OF ADDITIONAL TSTMS...WITH ANY LINGERING
ACTIVITY EXPECTED TO WEAKEN DURING THE NEXT HOUR OR TWO.

..PETERS.. 09/20/2009

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.