Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 030432
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1132 PM CDT THU JUL 2 2015

.UPDATE...
ISSUED AT 850 PM CDT THU JUL 2 2015

8PM SURFACE ANALYSIS INDICATES A STATIONARY FRONT SOUTH OF OUR
FORECAST AREA EARLY THIS EVENING FROM EXTREME SOUTHERN MISSOURI
EAST THRU WESTERN KENTUCKY. AN AREA OF LOW PRESSURE ON THE
BOUNDARY IS FORECAST TO EDGE EAST ACROSS KENTUCKY OVERNIGHT WITH
THE BEST THREAT FOR CONVECTION ALONG AND SOUTH OF THE FRONTAL
BOUNDARY. HOWEVER...A FEW OF THE SHORT TERM MODELS SUGGEST SOME
SHOWERS WRAPPING NORTH AND NORTHWEST BACK INTO PARTS OF EASTERN IL
LATER TONIGHT INTO FRIDAY MORNING. THESE SAME MODELS HAD SHOWERS
ALREADY DEVELOPING OVER PARTS OF INDIANA INTO EXTREME EASTERN IL
BY THIS TIME BUT REALITY PAINTS A DIFFERENT PICTURE WITH NO PRECIP
EXCEPT FOR A BAND OF WEAKENING LIGHT SHOWERS APPROACHING EXTREME
WESTERN IL.

ILX 00Z SOUNDING SHOWING THE ATMOSPHERE HAS DRIED OUT A BIT COMPARED
TO THE 12Z SOUNDING. ILX HI-RES OBJECTIVE ANALYSIS SHOWING MEAGER
ELEVATED CAPES OVER FAR SOUTHEAST IL WITH THE MOST UNSTABLE CAPES
OF LESS THAN 500 J/KG CONFINED TO EXTREME SE IL WITH THE AXIS OF
HIGHER THETA-E AIR POSITIONED CLOSER TO THE FRONTAL BOUNDARY...WELL
SOUTH OF OUR AREA. OUR CURRENT ZFP HAS A GOOD HANDLE ON THE SITUATION
FOR THE REST OF THIS EVENING AND THE OVERNIGHT HOURS WITH THE LOW
CHANCE POPS CONFINED TO FAR EASTERN AND SOUTHEAST IL. NO ZFP UPDATE
NEEDED AT THIS TIME.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 245 PM CDT THU JUL 2 2015

MID AFTERNOON SURFACE MAP SHOWS WEAK HIGH PRESSURE OF 1020 MB OVER
WI/MI...WHILE A QUASI-STATIONARY FRONTAL BOUNDARY WAS OVER SOUTHERN
MO AND EXTREME SOUTHERN IL/IN AND CONNECTED TO WEAK 1010 MB LOW
PRESSURE OVER NE OK. CENTRAL AND SOUTHEAST IL WILL STAY ON THE COOL
SIDE OF THIS FRONT AS WEAK LOW PRESSURE MOVES ENE ALONG THE BOUNDARY
REACHING IN/KY BORDER BY FRIDAY MORNING. NE WINDS OF 5 TO 10 MPH
PREVAILING TONIGHT OVER CENTRAL/SE IL AND LIGHTEST WINDS IN
SOUTHEAST IL CLOSER TO THE BOUNDARY. ISOLATED SHOWERS OVER FAR
SOUTHEAST IL AT MID AFTERNOON WHILE SCATTERED THUNDERSTORMS WERE
SOUTH OF I-64 CLOSER TO FRONTAL BOUNDARY. ANOTHER AREA OF SHOWERS
AND A FEW THUNDERSTORMS WAS OVER SW IA...NW MO AND EASTERN
NEBRASKA/KS AND TRACKING ESE. THIS CONVECTION ASSOCIATED WITH A
SHORT WAVE NEAR NE/IA BORDER AND PROJECTED TO TRACK SE INTO
CENTRAL/SOUTHERN IL BY 12Z/FRI. MODELS GENERALLY SHOW QPF OVER
SOUTHEAST IL TONIGHT WHERE LINGERED CHANCES OF SHOWERS AND ISOLATED
THUNDERSTORMS. KEPT SLIGHT CHANCES OF SHOWERS AND POSSIBLE
THUNDERSTORM FURTHER NORTH UP TO NEAR I-72 LATE THIS AFTERNOON AND
EARLY EVENING UNTIL SUNSET WITH CHANCES CONFINED TO AREAS ALONG AND
SE OF I-70 AFTER DARK/9 PM. HRRR NOW SHOWING SOME QPF INTO AREAS SW
OF SPRINGFIELD AFTER 06Z/1 AM FROM APPROACHING SHORT WAVE SO MAY
NEED SLIGHT CHANCES OF SHOWERS AND THUNDERSTORMS SW COUNTIES
OVERNIGHT. LOWS OVERNIGHT TO RANGE FROM MID 50S NORTH OF PEORIA TO
MID 60S IN SOUTHEAST IL FROM I-70 SE.

.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 245 PM CDT THU JUL 2 2015

SOME WELCOME DRY WEATHER WILL BE FOUND ACROSS A GOOD PART OF THE
FORECAST AREA INTO THE HOLIDAY WEEKEND. HAVE KEPT SOME 15-25% POP`S
GOING SOUTH OF I-70 CLOSER TO THE FRONTAL BOUNDARY WHICH WILL BE
HANGING UP ACROSS THE OHIO AND TENNESSEE VALLEYS...BUT THESE WILL BE
LOWERING WITH TIME. TEMPERATURES WILL CLIMB A COUPLE DEGREES EACH
DAY...BUT THE NORTHEAST FLOW WILL KEEP DEW POINT VALUES RELATIVELY
COMFORTABLE FOR EARLY JULY.

MAIN CONCERN FOR THIS PART OF THE FORECAST IS WITH THE UPCOMING WORK
WEEK. UPPER LOW CURRENTLY ALONG THE SOUTHEAST ALASKA PANHANDLE WILL
BE DIGGING ACROSS THE CANADIAN ROCKIES THIS WEEKEND...WITH THE
ASSOCIATED TROUGH TRACKING ACROSS THE UPPER MISSISSIPPI VALLEY EARLY
NEXT WEEK. LONGER RANGE MODELS CONTINUE TO BRING THE ASSOCIATED
SURFACE FRONT INTO THE MIDWEST AND SOUTHERN PLAINS...WITH THE GFS
SLOWING DOWN A TAD WITH THIS FEATURE ON THE LATEST RUNS. HAVE
INCREASED POP`S INTO THE LIKELY RANGE ACROSS THE NORTHWEST HALF OF
THE CWA MONDAY NIGHT AND OVER MOST OF THE AREA FOR TUESDAY. GFS
SHOWING PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES MONDAY NIGHT
INTO WEDNESDAY...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL
FOR EARLY JULY...SO THERE ARE SOME CONCERNS FOR UNWANTED HEAVY RAIN
DURING THIS TIME FRAME.

THE FORECAST FOR MID WEEK STARTS TO BECOME MORE MURKY...AS THE ECMWF
AND GFS ARE SIGNIFICANTLY DIFFERENT WITH THE TIMING OF A WAVE OF LOW
PRESSURE RIDING NORTHEAST OUT OF OKLAHOMA ALONG THE BOUNDARY. THE
ECMWF IS SLOWER...WETTER AND FURTHER NORTH WITH THIS FEATURE. HAVE
KEPT RAIN CHANCES OVER MOST OF THE AREA FOR WEDNESDAY AND THURSDAY
AS A RESULT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1125 PM CDT THU JUL 2 2015

LOW PRESSURE PUSHING SLOWLY EAST ACROSS KENTUCKY WITH A EASTERLY
FLOW AROUND THE SURFACE WAVE SENDING LOW AND MID LEVEL MOISTURE
BACK TO THE WEST. WILL HAVE TO WATCH FOR THE POSSIBILITY FOR SOME
LOW VFR TO MVFR CIGS EDGING BACK INTO CMI AND DEC OVER THE NEXT
SEVERAL HOURS WITH THE MAIN CONCERN BEING HOW FAR WEST WILL THE
MOISTURE PUSH OVERNIGHT. STILL THINKING MOST AREAS WILL SEE CIGS
LOWER TO BETWEEN 2000-3000 FEET OVERNIGHT WITH PIA THE LAST TO SEE
THE CHANGE IN THEIR CIG. A FEW SHOWERS WERE TRYING TO DEVELOP OVER
WEST CENTRAL INDIANA AND WERE EDGING WEST OVER THE PAST HALF HOUR
TO HOUR. COVERAGE IS STILL VERY LIMITED BUT WILL KEEP AN EYE ON IT
TO SEE IF WE WANT TO COVER IT WITH AT LEAST VCSH AT CMI AND DEC
LATE TONIGHT. FORECAST SOUNDINGS CONTINUE WITH THE PREVIOUS TREND
OF CIGS LIFTING BY MID TO LATE MORNING FRIDAY WITH VFR CONDITIONS
EXPECTED THEREAFTER. SURFACE WINDS WILL CONTINUE FROM AND EAST TO
NORTHEAST DIRECTION THRU THE PERIOD WITH SPEEDS IN THE 8 TO 13 KT
RANGE.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...SMITH
SHORT TERM...07
LONG TERM...GEELHART
AVIATION...SMITH



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