DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 011233
SWODY1
SPC AC 011231

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0731 AM CDT MON OCT 01 2012

VALID 011300Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF AL...THE FL
PANHANDLE...WRN/CNTRL GA AND SERN TN...

...SYNOPSIS...
LARGE-SCALE UPPER HEIGHT PATTERN WILL BE CHARACTERIZED BY A
STATIONARY TROUGH OVER THE LOWER MS VALLEY...AND A SERIES OF
PROGRESSIVE NRN STREAM WAVES AFFECTING THE NRN ROCKIES...GREAT LAKES
REGION...AND NEW ENGLAND. GREATEST SVR WEATHER THREAT WILL BE
ASSOCIATED WITH THE SRN CONUS TROUGH. AS A 60 KT S-SWLY MIDLEVEL JET
SPREADS NWD ACROSS THE TN VALLEY...SURFACE LOW PRESSURE LOCATED OVER
CNTRL MS THIS MORNING WILL OCCLUDE AS IT LIFTS NWD INTO THE
MID-SOUTH REGION. MEANWHILE...SHOWERS AND THUNDERSTORMS OCCURRING
ALONG A N-S ORIENTED CONFLUENCE ZONE WILL EVENTUALLY BE OVERTAKEN BY
A COLD FRONT AS IT ADVANCES EWD TOWARD CNTRL GA AND NRN FL TONIGHT.
ADDITIONAL SHOWERS/STORMS MAY BE FORCED INVOF A WARM FRONT AS IT
LIFTS NWD ACROSS NRN AL/GA AND UPSTATE SC. ELSEWHERE...AN UPPER
IMPULSE WILL MOVE SWD ACROSS THE SRN PLAINS THIS AFTERNOON AND AID
IN ISOLATED/SCATTERED THUNDERSTORM DEVELOPMENT.

...FL PANHANDLE...AL...WRN/CNTRL GA...SERN TN...
A LOW-LEVEL PRE-FRONTAL CONFLUENCE ZONE IS FOCUSING SHOWER AND
THUNDERSTORM DEVELOPMENT THIS MORNING. THE THERMODYNAMIC ENVIRONMENT
IS VERY MOIST WITH SURFACE DEWPOINTS IN THE LOW 70S...BUT WEAK LAPSE
RATES ARE LIMITING SBCAPE VALUES TO 500-1000 J/KG. AREA VWP/S SHOW
THE PRESENCE OF A 40 KT SLY LLJ JUXTAPOSED WITH MIDLEVEL SWLYS NEAR
50 KT. THIS SHEAR PROFILE IS FAVORING ROTATING STORMS THAT WILL POSE
A THREAT FOR ISOLATED TORNADOES AND DAMAGING WIND GUSTS. THE TORNADO
THREAT MAY BE MAXIMIZED THIS MORNING NEAR A WARM FRONT LIFTING NWD
OVER CNTRL AL/GA...WHERE SURFACE WINDS ARE BACKED OUT OF THE
SE...AND LOW-LEVEL VERTICAL WIND SHEAR IS ENHANCED.

LATER THIS MORNING INTO THE AFTERNOON...WARM SECTOR CONVECTION MAY
STRENGTHEN SOMEWHAT AS MODEST DIABATIC HEATING BOOSTS TEMPERATURES
INTO THE MID/UPPER 70S. HOWEVER...LARGE-SCALE FORCING FOR ASCENT
WILL GENERALLY BE WEAK...WHICH WILL PRECLUDE A GREATER COVERAGE IN
STRONG/SVR THUNDERSTORMS. NEVERTHELESS...WIND PROFILES WILL REMAIN
FAVORABLE FOR ROTATING STORMS POSING A CONTINUED THREAT FOR A
TORNADO OR TWO AND ISOLATED DAMAGING WIND GUSTS. LATER TODAY...A
COLD FRONT WILL EVENTUALLY OVERTAKE THE CONFLUENCE ZONE...WHICH WILL
SHIFT THE SVR WEATHER THREAT INTO CNTRL GA AND THE ERN FL PANHANDLE
TONIGHT.

...SC...
A WARM FRONT WILL LIFT NWD ACROSS SC TODAY. THE 12Z CHS RAOB AND
MODEL FORECAST SOUNDINGS INDICATE DEWPOINTS NEAR 70F AND
TEMPERATURES IN THE LOW 80S WILL AID IN MLCAPE VALUES AROUND 1000
J/KG ALONG AND S OF THE FRONT. N OF THE FRONT...SURFACE WINDS WILL
BE BACKED OUT OF THE E...AND THEN RAPIDLY VEER TO S-SWLY ABOVE 1 KM
AGL. THERE MAY BE OVERLAP BETWEEN THE AREA OF STRONGER BUOYANCY AND
ENHANCED LOW-LEVEL SHEAR...SUCH THAT ISOLATED THUNDERSTORMS WILL
POSE A MARGINAL THREAT FOR A TORNADO OR DAMAGING WIND GUST.

...W TX...EDWARDS PLATEAU...
ISOLATED TO SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP OVER W
TX AND THE EDWARDS PLATEAU THIS AFTERNOON AS AN UPPER IMPULSE MOVES
SWD ACROSS THE SRN PLAINS. TEMPERATURES WARMING INTO THE 80S
COMBINED WITH 50S DEWPOINTS WILL FAVOR MLCAPE VALUES FROM 500-1000
J/KG AND STEEP LOW-LEVEL LAPSE RATES. THIS ENVIRONMENT MAY SUPPORT A
FEW STRONG STORMS POSING A THREAT FOR GUSTY WINDS AND SMALL HAIL.

..GARNER/THOMPSON.. 10/01/2012

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.