Severe Thunderstorm Warning 276, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
135 PM CDT MON AUG 11 2003

SHORT TERM CONCERNS FOCUS ON PCPN CHANCES. IN THE EXTENDED...HIGH
TEMPS UNDER THE RIDGE ALOFT AND TIMING OF THE NEXT FRONT/PCPN
CHANCES OVER THE WEEKEND STILL APPEARS TO BE PROBLEMATIC.

MIDDAY SFC CHART SHOWING WEAK AND SOMEWHAT DIFFUSE FRONT/TROFF
LOCATED ACROSS CENTRAL IL. COOLER TEMPS (READINGS IN THE 60S)
HOWEVER LAG BEHIND AND MAINLY OVER WI. SAT PICS SHOWING UPPER LOW
OVER KY/OH WITH THINGS WRAPPING UP TO THE NW OVER THE OHIO VALLEY
AND THEN TO THE SW OVER WI/IL. NEW CONVECTION BREAKING OUT OVER N
IL...SCT SHRAS CONTINUE OVER THE NORTHERN AND NW PORTIONS OF THE
CWA...ALSO MOVING TO THE SW.

SENSIBLE WEATHER...SOME CONCERNS ON HOW TO HANDLE POPS TONIGHT AS IN
JUST EVENING WORDING VERSUS NO TIMING AND HOW HARD TO HIT THE POPS
AS WELL. THINK THE BULK OF THE PCPN WILL BE DURING THE EVENING HOURS
BUT HAVE SOME CONCERNS ABOUT SOME SCATTERED...EARLY AM SHOWERS AS
WELL. SKY COVER ALSO A PROBLEM TONIGHT AND TOMORROW (PARTLY VERSUS
MOSTLY CLOUDY) AND WILL MAKE FINAL DECISION CLOSER TO PRESS TIME.

KEPT CHC POPS IN FOR TOMORROW AFTERNOON AND EVENING AS UPPER LOW
STILL OVER THE OHIO VALLEY AND VORTS ROTATING AROUND IN THE FLOW
SHOULD BE ENUFF TO SPARK SOME CONVECTION. MAX TEMPS TOMORROW COULD
BE A LITTLE TRICKY WITH SKY COVER/PCPN AROUND. BASICALLY FOR THE
SAME REASONS...DECIDED TO GO AHEAD AND ADD SOME AFTERNOON POPS ON
WED...MAINLY CENTRAL-SE ZONES. LEFT POPS OUT FOR WED EVENING BUT MAY
HAVE TO ADD LATER. UPPER TROFF ON WED STILL OVER THE AREA WITH SOME
VORT AND WEAK SFC TROFF ACROSS S IN/IL ALSO.

AT THIS TIME THE GFS SEEMS OVERDONE WITH QPF ON THU CONSIDERING THE
AREA UNDER A 598 5H HIGH. AS THE UPPER LOW PULLS OUT TO THE NE AND
SW...THINKING THAT MOST OF THE PCPN SHOULD BE SOUTH OF OUR AREA ON
THU...THEREFORE LEFT POPS OUT FOR NOW BUT MAY HAVE TO ADD LOW CHC
POPS AT A LATER DATE IF THINGS PLAY OUT SLOWER.

MED RANGE MODELS BEGIN TO DIVERGE QUITE A BIT ON FRIDAY AND THRU THE
WEEKEND. GFS STILL FASTER THAN ECMWF AND SOME OF THE OTHER MODELS
WITH FRONT ON SUN/MON. PREV SHIFT REMOVED POPS SAT AND THIS LOOKS
GOOD. ON SUNDAY...GFS HAS THE AREA UNDER A W-NW FLOW WHILE THE ECMWF
LOOKS COMPLETELY DIFFERENT WITH THE SYNOPTIC SCALE FEATURES.
CONFIDENCE LOW THROUGH THIS PERIOD AND FEEL THAT A BLEND IS PROBABLY
BEST. I LEFT POPS IN ON SUNDAY FOR NOW AND KEPT MONDAY
DRY...ALTHOUGH WOULDNT BE SURPRISED IF LATER SHIFTS MAY HAVE TO
REMOVE SUN POPS AND PUSH THEM INTO THE MONDAY PERIOD.

MET MOS NUMBERS COOLER TOMORROW AND ESP ON WED THAN THE NGM/AVN
NUMBERS. WILL GO WITH A BLEND.

ISC GRIDS ALL SENT AND LOOK CLOSE. NOT SURPRISING...WE HAVE SOME
DIFFERENCES IN THE POP FIELDS...BUT NOTHING TOO SERIOUS. FURTHER
COORDINATION WELCOME.

.ILX...NONE.

HALL

ILZ027>031-036>038-040>057-061>063-066>068-071>073-121100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
1045 AM CDT MON AUG 11 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTHEAST ILLINOIS.

.DAY ONE...TODAY AND TONIGHT

A DISTURBANCE WILL MOVE ACROSS ILLINOIS AND ALLOW SCATTERED
THUNDERSTORMS TO CONTINUE INTO THE EVENING HOURS ACROSS CENTRAL AND
SOUTHEAST ILLINOIS. AN ISOLATED STRONG THUNDERSTORM IS POSSIBLE
WITH HAIL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

ANOTHER DISTURBANCE WILL MOVE THROUGH ILLINOIS ON TUESDAY...BRINGING
A CHANCE OF THUNDERSTORMS TO CENTRAL AND SOUTHEAST ILLINOIS. ANOTHER
SYSTEM WILL ARRIVE LATE IN THE WEEKEND...BRINGING A CHANCE OF
THUNDERSTORMS TO ILLINOIS ON SUNDAY. AT THIS TIME...WIDESPREAD
SEVERE STORMS ARE NOT EXPECTED EITHER DAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

&&
THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC
AND CLIMATE INFORMATION...IS AVAILABLE ON THE WEB AT:

HTTP://WWW.CRH.NOAA.GOV/ILX. THIS ADDRESS IS ALL
IN LOWER CASE.

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