Severe Thunderstorm Warning 116, NWS Lincoln, IL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
842 PM CDT MON JUL 5 2004

.DISCUSSION...LATEST SURFACE ANALYSIS HAD LOW PRESSURE CENTERED OVER
EASTERN IOWA...WITH A COLD FRONT EXTENDING SOUTHWEST INTO THE
CENTRAL PLAINS. A PRE FRONTAL TROF EXTENDED SOUTH FROM THE LOW INTO
SOUTH CENTRAL MISSOURI. ALOFT...AN UPPER LOW WAS OVER IOWA AND
MINNESOTA...WITH AN IMPULSE EXTENDING SOUTH INTO MISSOURI.

SURFACE AND UPPER LOW WILL TRACK NORTHEAST OVERNIGHT...BRINGING THE
ASSOCIATED TROFS INTO ILLINOIS. THIS WILL CONTINUE THE CHANCE FOR
SHOWERS/STORMS OVERNIGHT...THOUGH THE LOSS OF DIURNAL HEATING SHOULD
KEEP THE COVERAGE MINIMAL AND DECREASE THE SEVERE THREAT.

GOING FORECAST IS IN PRETTY GOOD SHAPE AND ONLY MINOR TWEAKS TO
GRIDS/ZONES ARE NEEDED.

&&

.PREV DISCUSSION...MAIN FORECAST CONCERNS OVER THE SHORT TERM
INCLUDE THE SEVERE THREAT ALONG WARM FRONTAL BOUNDARY DRAPED OVER
CNTRL IL  THIS EVENING AND THEN TIMING OF COLD FRONT ACRS FCST AREA
WED AND PRECIP CHANCES ASSOCIATED WITH IT. ETA AGAIN THE MODEL OF
CHOICE THIS FCST PERIOD AS IT HAS HANDLED BNDRY AND CONVECTIVE
TRENDS VERY WELL OVER THE PAST SVL DAYS. FURTHER DOWN THE
ROAD...UPPER LEVEL RIDGING FCST TO BUILD OVER THE ERN CONUS
RESULTING IN A RETURN TO WARM AND HUMID CONDITIONS FOR THE SECOND
HALF OF THE WORK WEEK.

SHORT TERM...TONIGHT THROUGH THURSDAY...
NRN END OF BOW ECHO SYSTEM THAT PUSHED ACRS SRN IL HAS SHIFTED EAST
OF AREA EARLY THIS AFTERNOON. 18Z ILX SOUNDING SHOWING ATMOSPHERE HAS
BEEN AFFECTED BY CONVECTIVE SYSTEM BUT SHOULDNT TAKE TOO LONG TO
RECOVER AS VSBL SHOWING QUITE A BIT OF SUNSHINE TO OUR WEST WITH
TEMPS PUSHING WELL INTO THE 80S. VIGOROUS SHORTWAVE DEPICTED ON
WATER VAPOR LOOP ACRS WRN IA WITH CONVECTION FIRING ALONG AND NORTH
OF THE SFC WAVE AND BNDRY ACRS IOWA. MODELS SUGGEST ADDL DVLPMT
LATER THIS AFTN ALONG THE BNDRY WITH SHORT TERM MODELS INDICATING
THE POTENTIAL FOR A FEW STORMS TO ROTATE. PROFILES SHOWING 55 KNOTS
AT 500 MB AT LATHROP MISSOURI WITH SPEED MAX PROGGED TO PUSH INTO
WEST CNTRL IL LATE IN THE AFTN AND EVENING TO INTERACT WITH SYNOPTIC
SCALE BNDRY AS WELL AS ANY MESOSCALE BNDRYS LEFT OVER FROM THE
CONVECTION LATE THIS MRNG. WILL HAVE THE HIGHEST POPS ACRS THE NORTH
CLOSER TO SYNOPTIC SCALE BNDRY WITH PROGRESSIVELY LOWER POPS ACRS
THE FAR SOUTH. BASED ON THE ETAS TIMING OF THE COLD FRONT...PRECIP
CHANCES APPEAR TO BE HIGHEST INTO EARLY AFTN WITH A SHIFT IN
CONVECTION TO THE EAST AND SOUTH AS THE FRONT PUSHES ACRS THE FCST
AREA. LINGERING CHANCES OF SHOWERS AND THUNDERSTORMS TUESDAY NIGHT
WITH COOLER AND DRIER AIR FILTERING IN DURING THE DAY ON WEDNESDAY
INTO EARLY THURSDAY.

ETA MODEL CONTINUES TO SHOW A FAIRLY DECENT BAND OF FRONTOGENETIC
FORCING TO OUR WEST LATE WED NIGHT INTO THURSDAY RESULTING IN SOME
EARLY MORNING CONVECTION. THE GFS IS SHOWING SOME PRECIP AS WELL
WITH THE RETURN FLOW THURSDAY BUT NO WHERE NEAR THE ETAS SOLUTION.
FOR NOW...WL KEEP THU DRY BUT THIS WILL HAVE TO WATCHED IN LATER
FCSTS IF THE ETA CONTINUES FROM PREVIOUS RUNS TO DVLP WARM ADVECTION
PRECIP TO OUR WEST.

LONG TERM...FRIDAY THROUGH MONDAY...
UPPER LEVEL RIDGING FORECAST TO BUILD ACRS THE ERN U.S. DURING THE
SECOND HALF OF THE WORK WEEK...AS MODELS HAVE BEEN ADVERTISING FOR
SVL DAYS. A RETURN TO VERY WARM AND HUMID CONDITIONS WILL RESULT WITH
ONLY LOW PRECIP CHANCES...ESPECIALLY DURING THE WEEKEND AS MEDIUM
RANGE MODELS SUGGEST A WEAK FRONTAL SYSTEM WILL TRY TO SHIFT SOUTH
ACRS THE MIDWEST DURING THIS TIME FRAME.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
IL...NONE.

&&

BAK/SMITH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
1125 AM CDT MON JUL 5 2004

ILZ027>031-036>038-040>057-061>063-066>068-071>073-061100-
CASS-CHAMPAIGN-CHRISTIAN-CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-
DE WITT-DOUGLAS-EDGAR-EFFINGHAM-FULTON-JASPER-KNOX-LAWRENCE-LOGAN-
MACON-MARSHALL-MASON-MCLEAN-MENARD-MORGAN-MOULTRIE-PEORIA-PIATT-
RICHLAND-SANGAMON-SCHUYLER-SCOTT-SHELBY-STARK-TAZEWELL-VERMILION-
WOODFORD-
INCLUDING THE CITIES OF...BLOOMINGTON...CHAMPAIGN...DANVILLE...
DECATUR...EFFINGHAM...FLORA...GALESBURG...HAVANA...JACKSONVILLE...
LAWRENCEVILLE...LINCOLN...MATTOON...PEORIA...SHELBYVILLE...
SPRINGFIELD AND TAYLORVILLE
1125 AM CDT MON JUL 5 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND SOUTHEAST ILLINOIS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

TWO WEATHER SYSTEMS WILL MOVE ACROSS ILLINOIS THIS AFTERNOON AND
TONIGHT AND PROVIDE A THREAT FOR SEVERE THUNDERSTORMS. STORMS WILL
CONTINUE TO MOVE ACROSS THE SOUTHERN HALF OF ILLINOIS EARLY THIS
AFTERNOON WITH LARGE HAIL AND STRONG WINDS THE PRIMARY THREATS.

A SECOND DISTURBANCE OVER SOUTHEASTERN NEBRASKA WILL THEN MOVE INTO
THE AREA THIS EVENING. STRONG TO SEVERE THUNDERSTORMS WILL ALSO BE
POSSIBLE AS THIS SYSTEM APPROACHES...MAINLY BEFORE MIDNIGHT. ONCE
AGAIN...DAMAGING WINDS WILL BE THE PRIMARY THREAT...BUT AN ISOLATED
TORNADO WILL BE POSSIBLE AS WELL.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...

THERE IS A RISK FOR SEVERE THUNDERSTORMS LATE TUESDAY AFTERNOON AND
TUESDAY EVENING AS A COLD FRONT MOVES SOUTHEASTWARD ACROSS CENTRAL
ILLINOIS. THE PRIMARY SEVERE WEATHER THREAT WILL BE FOR DAMAGING
WINDS AND LARGE HAIL BETWEEN 3 PM AND 11 PM.

THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE SATURDAY NIGHT AND SUNDAY.

.SPOTTER ACTIVATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED DURING THE AFTERNOON AND EVENING
HOURS.

&&
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.

BYRD