DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 230056
SWODY1
SPC AC 230054

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0754 PM CDT MON SEP 22 2008

VALID 230100Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NRN PLAINS AND
CNTRL HIGH PLAINS...

...NRN PLAINS/CNTRL HIGH PLAINS...
THE LATEST WATER VAPOR IMAGERY SHOWS AN UPPER-LEVEL TROUGH OVER THE
CNTRL ROCKIES WITH SOUTHWEST FLOW IN PLACE ACROSS THE NRN PLAINS.
THIS FEATURE WILL CONTINUE MOVING QUICKLY NEWD WITH LIFT AHEAD OF
THE SYSTEM SUPPORTING THE DEVELOPMENT OF NUMEROUS THUNDERSTORMS OVER
THE NEXT FEW HOURS. THUNDERSTORMS WILL INCREASE IN COVERAGE ALONG A
COLD FRONT ORIENTED FROM WRN ND EXTENDING SWD ACROSS WRN SD INTO WRN
NEB. OTHER STORMS WILL DEVELOP AHEAD OF THE BOUNDARY IN WCNTRL
NEB...CNTRL SD AND ECNTRL ND. MODEL FORECASTS GREATLY INCREASE
CONVECTIVE COVERAGE EARLY THIS EVENING...ORGANIZING AN MCS AS THE
FRONT MOVES EWD AND THE LOW-LEVEL JET STRENGTHENS.

THE RUC CURRENTLY ANALYZES A LARGE AREA OF MODERATE INSTABILITY
AHEAD OF THE BOUNDARY ACROSS MOST OF NEB AND SD WHERE MLCAPE VALUES
RANGE FROM 1000 TO 2000 J/KG. THIS THERMODYNAMIC ENVIRONMENT COUPLED
WITH STRONG VERTICAL SHEAR PROFILES ASSOCIATED WITH A 50 TO 60 KT
MID-LEVEL JET WILL SUPPORT ISOLATED SUPERCELL DEVELOPMENT EARLY THIS
EVENING. THE LATEST 00Z SOUNDING FROM NORTH PLATTE NEB HAS AN
850-500 MB LAPSE RATE AROUND 8.5 C/KM. THIS IS ASSOCIATED WITH A
PLUME OF VERY STEEP MID-LEVEL LAPSE RATES EXTENDING NWD ACROSS WRN
NEB INTO SW SD WHERE THE LARGE HAIL THREAT SHOULD BE THE GREATEST
THIS EVENING. IN ADDITION...THE HAIL THREAT SHOULD GRADUALLY
INCREASE EWD AND NWD AS A CONVECTIVE LINE ORGANIZES OVER THE NEXT
FEW HOURS. ACCORDING TO THE RUC...LOW-LEVEL LAPSE RATES ARE ALSO
STEEP AND THE LOW-LEVEL JET IS FORECAST TO GRADUALLY STRENGTHEN THIS
EVENING WHICH ALSO SHOULD AID A POTENTIAL FOR WIND DAMAGE. HAIL AND
WIND DAMAGE WILL ALSO BE POSSIBLE FURTHER NORTH ACROSS ERN ND WHERE
LOW-LEVEL MOISTURE CONTENT IS SLIGHTLY GREATER. THE SEVERE THREAT
SHOULD DECREASE LATE THIS EVENING AS THE STORMS BECOME ELEVATED IN
NATURE.

..BROYLES.. 09/23/2008

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