Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KILX 060408
AFDILX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1108 PM CDT SUN JUL 5 2015

.UPDATE...
ISSUED AT 852 PM CDT SUN JUL 5 2015

HIGH PRESSURE CONTINUES TO DOMINATE THE WEATHER OVER OUR AREA THIS
EVENING AND SHOULD KEEP THE WEATHER QUIET AROUND HERE THRU MOST OF
THE DAY ON MONDAY. STILL MAY SEE SOME PATCHY FOG/HAZE LATE TONIGHT
BUT WHATEVER DOES FORM SHOULD QUICKLY DISSIPATE BY 7 OR 8 AM.
BASED ON 850 TEMP FORECASTS TOMORROW AFTERNOON AND A GUSTY SOUTH
WIND...WE SHOULD SEE AFTERNOON TEMPERATURES WARM SOME 3 TO 6
DEGREES FROM WHAT WE HAD TODAY...RESULTING IN HIGHS IN THE
86 TO 90 DEGREE RANGE ACCOMPANIED BY DEW POINTS IN THE LOW TO
MID 70S. THAT PUSHES THE HEAT INDEX INTO THE MID TO UPPER 90S
TOMORROW AFTERNOON.

A WEAK FRONTAL BOUNDARY LOCATED OVER PARTS OF SOUTHERN MISSOURI
COMBINED WITH AN UPPER LEVEL WAVE TO PRODUCE SOME SCATTERED STORMS
LATE THIS AFTERNOON WHICH SINCE HAVE DECREASED IN AREAL COVERAGE
EARLY THIS EVENING. ALTHOUGH THIS FRONTAL BOUNDARY IS EXPECTED TO
WASH OUT LATER TONIGHT...THERE MAY BE JUST ENOUGH CONVERGENCE
ALONG IT TOMORROW AFTERNOON TO COMBINE WITH MODERATE INSTABILITY
TO PRODUCE SOME WIDELY SCATTERED STORMS. HOWEVER...A LARGER BAND
OF SHOWERS AND STORMS WILL FORM ALONG A COLD FRONT LATE TOMORROW
AFTERNOON OVER CENTRAL IOWA AND THEN TRACK EAST INTO WESTERN IL BY
TOMORROW EVENING BRINGING A BETTER THREAT FOR MORE WIDESPREAD
SHOWER AND THUNDERSTORM ACTIVITY OVER THE FORECAST AREA MONDAY
NIGHT INTO TUESDAY MORNING.

CURRENT FORECAST IN GOOD SHAPE THIS EVENING...SO OTHER THAN THE
USUAL TWEAKS TO THE EARLY EVENING TEMPERATURES...NO OTHER CHANGES
WERE NEEDED THAT WOULD WARRANT A ZFP UPDATE.

&&

.SHORT TERM...(TONIGHT)
ISSUED AT 302 PM CDT SUN JUL 5 2015

WEAK HIGH PRESSURE WILL CONTINUE TO DRIFT AWAY FROM THE AREA TONIGHT
AS OUR NEXT FRONTAL SYSTEM...CURRENTLY OVER THE WESTERN DAKOTAS...
TRACKS EAST INTO THE MIDWEST LATE MONDAY. THE EXTENSIVE CUMULUS
FIELD SHOULD DISSIPATE QUICKLY LATE THIS AFTERNOON/EARLY THIS
EVENING LEAVING A MOSTLY CLEAR SKY OVERNIGHT. THAT COMBINED WITH A
LIGHT WIND AND ABUNDANT LOW LEVEL MOISTURE SHOULD LEAD TO SOME
PATCHY GROUND FOG ACROSS THE EAST AND SOUTHEAST LATE TONIGHT
ALTHOUGH FORECAST SOUNDINGS ARE NOT AS AGGRESSIVE WITH THE SHALLOW
MOISTURE JUST OFF THE SURFACE AS THEY HAVE BEEN OVER THE PAST FEW
NIGHTS...PROBABLY DUE TO SOME DECENT MIXING OCCURRING THIS AFTERNOON.

.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 302 PM CDT SUN JUL 5 2015

COLD FRONT SLATED TO PRESS SE ACROSS IA DURING THE DAY MONDAY AND
BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE IL RIVER VALLEY
BY LATE MONDAY AFTERNOON. COLD FRONT THEN SPREADS SE ACROSS NW IL
MONDAY EVENING AND REACHING NEAR I-55 BY 12Z/7 AM TUE LIKELY
SPREADING SHOWERS AND THUNDERSTORMS SE INTO CENTRAL IL MONDAY NIGHT.
THE WABASH RIVER VALLEY AND AREAS NEAR THE INDIANA BORDER MAY STAY
DRY MOST OF MONDAY NIGHT. SPC HAS MARGINAL RISK OF SEVERE STORMS NW
OF I-55 LATE MONDAY AFTERNOON AND MON EVENING WITH SLIGHT RISK OF
SEVERE FROM GALESBURG NW. VERY UNSTABLE AIRMASS WITH CAPES PEAKING
BY LATE MON AFTERNOON FROM 2-4K J/KG THOUGH WEAKER BULK SHEAR OF 15-
25 KTS. MAIN SEVERE WX THREAT WILL BE DAMAGING WIND GUSTS. ALSO
HEAVY RAIN THREAT MONDAY NIGHT INTO TUE WITH PRECIPITABLE WATER
VALUES NEAR OR JUST ABOVE 2 INCHES.

COLD FRONT PUSHES INTO SE IL TUE AFTERNOON SHIFTING LIKELY CHANCES
OF SHOWERS AND THUNDERSTORMS INTO AREAS SOUTH OF I-72. SPC HAS
MARGINAL RISK OF SEVERE SE OF I-70 TUE AFTERNOON FOR THUNDERSTORMS
WITH GUSTY WINDS ALONG WITH HEAVY RAINS. VERY WARM HIGHS IN UPPER
80S TO NEAR 90F MON WITH HUMID DEWPOINTS IN THE LOWER 70S BY MON
AFTERNOON GIVING HEAT INDICES PEAKING MON AFTERNOON IN MID TO UPPER
90S. COOLER HIGHS TUE IN MID TO UPPER 70S CENTRAL IL AND LOWER 80S
SE OF I-70.

FRONTAL BOUNDARY TO TEMPORARILY STALL IN SOUTHERN IL JUST SOUTH OF
CWA TUE NIGHT WITH SURFACE WAVE RIDGING ALONG THE BOUNDARY AND
BRINGING QPF BACK NORTH INTO SOUTHERN HALF OF CWA TUE NIGHT AND
ACROSS AREA WED AND WED NIGHT ALONG WITH CHANCES OF HEAVY RAINS
AGAIN.

12Z MEDIUM AND EXTENDED RANGE FORECAST MODELS SHOW UPPER LEVEL RIDGE
OVER THE SOUTHEAST STATES DURING MIDWEEK THAT GRADUALLY RETROGRADES
WESTWARD INTO THE HIGH PLAINS BY EARLY NEXT WEEK. THIS DEVELOPS AN
UPPER LEVEL TROF OVER THE THE GREAT LAKES AND BRING SHORT WAVE
DISTURBANCES SE INTO IL THAT INTERACTS WITH SEASONABLY WARM/HUMID
TROPICAL AIRMASS (DEWPOINTS IN UPPER 60S/LOWER 70S) TO BRING DAILY
CHANCES OF SHOWERS AND THUNDERSTORMS FROM THU THROUGH SUNDAY OF NEXT
WEEKEND AS A FRONTAL BOUNDARY MEANDERS ACROSS THE REGION. HEAVY
RAINS WILL BE POSSIBLE IN TROPICAL AIRMASS IN PLACE OVER CENTRAL/SE
IL. HIGHS IN THE UPPER 70S AND LOWER 80S THU CLIMB INTO THE LOW TO
MID 80S FRI AND MID TO UPPER 80S NEXT WEEKEND. LOWS WILL BE CLOSE TO
DEWPOINTS IN THE MID 60S TO LOWER 70S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CDT SUN JUL 5 2015

WILL HAVE THE POTENTIAL FOR A BRIEF PERIOD OF MVFR VSBYS IN FOG/HZ
IN THE 09Z-12Z TIME FRAME OVERNIGHT...OTHERWISE...VFR CONDITIONS
ARE EXPECTED THRU THIS FORECAST PERIOD. AFTER THAT...THE THREAT
FOR SCATTERED SHOWERS AND THUNDERSTORMS WILL INCREASE FROM WEST TO
EAST MONDAY NIGHT ALONG A COLD FRONT. COVERAGE STILL IN QUESTION
WITH SEVERAL CONVECTIVE ALLOWING MODELS SUGGESTING SOME ISOLATED
STORMS DEVELOPING AFTER 20Z OVER PARTS OF CENTRAL ILLINOIS WELL
AHEAD OF THE MAIN CLUSTER OF STORMS ALONG THE COLD FRONT TO OUR
WEST. AT THIS POINT WILL CONTINUE WITH VCTS AFTR 20Z AT PIA AND
SPI AND HOLD OFF AT THE OTHER SITES FOR NOW. WE WILL SEE SOME
SCATTERED CUMULUS DEVELOP AGAIN LATE TOMORROW MORNING INTO THE
AFTERNOON HOURS WITH BASES OF 3000-4000 FEET. SURFACE WINDS WILL
BE FROM A LIGHT SOUTHEAST DIRECTION TONIGHT AND THEN PICK UP IN
SPEED FROM THE SOUTH ON MONDAY WITH SPEEDS IN THE 10 TO 15 KT
RANGE BY AFTERNOON WITH GUSTS AROUND 20 KTS AT TIMES...ESPECIALLY
DURING THE AFTERNOON. SOUTH WINDS OF 10 TO 15 KTS ARE EXPECTED
TOMORROW EVENING.

&&

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

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.