Friday, December 7, 2012

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 070543
SWODY1
SPC AC 070541

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1141 PM CST THU DEC 06 2012

VALID 071200Z - 081200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A BROAD CYCLONIC FLOW REGIME WILL CHARACTERIZE THE SYNOPTIC PATTERN
FRIDAY. SEVERAL EMBEDDED LOW-AMPLITUDE PERTURBATIONS WILL ADVANCE
THROUGH THIS REGIME INCLUDING A POSITIVE TILT SHORTWAVE TROUGH
LOCATED OVER SRN CA AND NRN BAJA AREA. THIS FEATURE WILL CONTINUE
EWD...REACHING THE SRN PLAINS AND LOWER MS VALLEY FRIDAY NIGHT. NRN
PORTIONS OF A COLD FRONT THAT STRETCHES FROM THE UPPER MS VALLEY
SWWD INTO THE SRN PLAINS WILL CONTINUE THROUGH THE GREAT LAKES IN
ASSOCIATION WITH A PROGRESSIVE NRN STREAM TROUGH. TRAILING PORTIONS
OF THIS BOUNDARY WILL LIKELY STALL OVER THE SRN PLAINS.

...NERN TX THROUGH LOWER MS...TN AND OH VALLEYS...

MODIFIED CP AIR WILL ADVECT NEWD THROUGH PRE-FRONTAL WARM SECTOR
ALONG A 20-30 KT SWLY LLJ WITH DEWPOINTS RANGING FROM THE MID 60S
OVER SERN TX TO LOW 50S OVER SRN PORTIONS OF THE TN AND OH VALLEY
FRIDAY EVENING. PLUME OF STEEPER LAPSE RATES WILL ADVECT EWD ABOVE
THE MODEST MOIST AXIS CONTRIBUTING TO MARGINAL INSTABILITY. MUCAPE
WILL LIKELY RANGE FROM BELOW 500 J/KG OVER TN AND KY TO 500-1000
J/KG FARTHER SW ACROSS ERN TX...WHERE RICHER MOISTURE WILL RESIDE
BUT WHERE ATMOSPHERE WILL LIKELY BE MORE CAPPED. SHORTWAVE TROUGH
OVER THE SWRN U.S. IS EXPECTED TO SHEAR EWD AND WEAKEN AS IT MOVES
INTO THE SRN PLAINS AND LOWER MS VALLEY FRIDAY NIGHT. HOWEVER...AT
LEAST MODEST FORCING FOR ASCENT WILL EXIST IN CONVEYOR BELT
DOWNSTREAM FROM THIS FEATURE AND CONTRIBUTE TO POTENTIAL FOR A FEW
ELEVATED SHOWERS AND THUNDERSTORMS...ESPECIALLY FROM PARTS OF THE
LOWER MS VALLEY INTO WRN PARTS OF THE TN VALLEY WHERE THE CAP SHOULD
BE WEAKER.

..DIAL.. 12/07/2012

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