Wednesday, November 5, 2008

DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 051301
SWODY1
SPC AC 051258

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0658 AM CST WED NOV 05 2008

VALID 051300Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SRN/CNTRL PLNS INTO
THE OZARKS AND LWR MO VLY...

...SYNOPSIS...
POTENT...NEGATIVE TILT SHORTWAVE TROUGH NOW CROSSING THE FOUR
CORNERS WILL CONTINUE E INTO THE HIGH PLNS THIS EVENING BEFORE
EVOLVING INTO A CLOSED LOW OVER SE SD/NE NEB EARLY THURSDAY.
ASSOCIATED 90 KT MID LVL JET STREAK NOW ENTERING NRN AZ SHOULD REACH
THE TX PANHANDLE BY LATE TODAY...AND REDEVLOP NNE ACROSS ERN KS/WRN
MO TONIGHT/EARLY THURSDAY.

AT THE SFC...ELONGATED LOW ATTM EXTENDING FROM NW KS TO THE ERN
DAKOTAS SHOULD CONSOLIDATE INTO A DEEPENING...NEARLY STATIONARY
CENTER OVER ERN SD THIS EVE. TRAILING COLD FRONT SHOULD
SUBSEQUENTLY ACCELERATE E/SEWD...REACHING THE LWR MO VLY...THE
OZARKS...AND THE SRN PLNS BY THE END OF THE PERIOD.

...SRN/CNTRL PLNS INTO OZARKS...
SYSTEM NOW DEEPENING OFF THE NC CST WILL CONTINUE TO LIMIT W/E
BREADTH OF LOW LVL MOISTURE RETURN ACROSS ERN PARTS OF THE SRN
PLNS/LWR MS VLY. BUT LATEST GPS AND SATELLITE-DERIVED PW DATA DO
SHOW AXIS OF MODERATE MOISTURE /PW AOA 1 INCH/ NOW WELL ESTABLISHED
FROM CNTRL/E TX NNE INTO THE ERN HALF OF KS. AT THE SAME TIME...SFC
DATA SHOW 60 DEG F ISODROSOTHERM NOW NOSING N TO NEAR ADM. LOW LVL
MOISTURE SHOULD CONTINUE TO SPREAD N INTO ERN KS/FAR WRN MO
TODAY/EARLY TONIGHT ALONG 50 KT SSWLY LLJ.

LARGE SCALE ASCENT SHOULD GRADUALLY INCREASE TODAY FROM N TX NWD
INTO ERN SD AS FOUR CORNERS TROUGH CONTINUES EWD. A MORE
SUBSTANTIAL INCREASE IN ASCENT SHOULD...HOWEVER...OCCUR THIS EVE
FROM CNTRL/ERN OK NNE INTO ERN KS/ERN NEB/NW MO AS EXIT REGION OF
120 KT HIGH LVL JET STREAK APPROACHES REGION.

COMBINATION OF INCREASING UVV AND FAVORABLY-TIMED SFC HEATING SHOULD
SUPPORT TSTM DEVELOPMENT BY MID TO LATE AFTN ALONG COLD FRONT FROM
SE SD/ERN NEB SWD INTO N CNTRL OK. GIVEN STRENGTH OF WIND FIELD AND
STEEP MID LVL LAPSE RATES WITH EML...THESE SHOULD QUICKLY BECOME
SUPERCELLS AND POSE A THREAT FOR SVR WIND...SOME HAIL...AND POSSIBLY
A COUPLE TORNADOES. ADDITIONAL STORMS MAY ALSO FORM AHEAD OF COLD
FRONT IN OK AND SRN/ERN KS...WHERE W/E EXTENT OF RETURNING MOISTURE
WILL BE GREATEST...AND WHERE AN AXIS OF LOW LVL CONFLUENCE LIKELY
WILL EXIST INVOF PREFRONTAL TROUGH/WEAK DRY LINE.

THE COLD FRONTAL STORMS SHOULD EVOLVE INTO A BROKEN QLCS THIS EVE AS
ACCLERATION OF FRONT AND INCREASING HEIGHT FALLS FAVOR EVOLUTION TO
DOMINANT LINEAR MODE. STRENGTH OF WIND FIELD
SUGGESTS...HOWEVER...THAT THE STORMS WILL HAVE THE POTENTIAL TO
PRODUCE ISOLD TORNADOES IN ADDITION TO DMGG WINDS AS THE LINE
CONTINUES E INTO MO LATER TONIGHT. FARTHER SE...POTENTIAL WILL
EXIST FOR A MORE EXTENDED PERIOD OF SEMI-DISCRETE STORMS INVOF
CONFLUENCE AXIS IN OK/FAR SRN KS. GIVEN STRENGTH OF WIND FIELD AND
SUBSTANTIAL DEGREE OF LOW LVL SPEED/DIRECTIONAL SHEAR...SETUP COULD
YIELD A STRONG TORNADO OR TWO THROUGH MID TO LATE EVE.

THE SVR THREAT SHOULD DIMINSH LATER TONIGHT/EARLY THURSDAY OVER
PARTS OF MO...NW AR...AND ERN OK AS AREA OF ASCENT OUT-RUNS AXIS OF
RETURNING MOISTURE.

...NRN PLAINS/MID-MO VALLEY...
ELEVATED TSTMS SHOULD PERSIST THROUGH MUCH OF THE PERIOD IN ZONE OF
SUSTAINED WAA N OF CONSOLIDATING SFC LOW IN ERN SD. THESE STORMS
COULD YIELD A FEW SPOTS OF HAIL FROM NRN SD INTO PARTS OF ND/MN.
SFC-BASED STORMS MAY FORM FOR A FEW HOURS THIS AFTN/EVE CLOSER TO
SFC LOW AND COLD FRONT IN ERN SD/ERN NEB AND NW IA. THESE WILL MOVE
QUICKLY NNEWD. WHILE A LIMITED SVR THREAT WILL EXIST WITH THIS
ACTIVITY...WEAK INSTABILITY SHOULD ALLOW ACTIVITY TO WEAKEN BY MID
EVE.

..CORFIDI/PETERS.. 11/05/2008

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

No comments: