737
FXUS63 KILX 121056
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
556 AM CDT SUN JUL 12 2026
KEY MESSAGES
- AN ISOLATED SHOWER OR THUNDERSTORM IS POSSIBLE IN FAR
SOUTHEAST IL THIS AFTERNOON, MAINLY OVER LAWRENCE COUNTY.
- AFTER MORE SEASONABLE TEMPERATURES AND HUMIDITY LEVELS EARLY
THIS WEEK, EXPECT VERY WARM AND MORE HUMID CONDITIONS TO
RETURN TO CENTRAL AND SOUTHEAST IL DURING MID TO LATE WEEK.
LREF HAS A 40-60% CHANCE OF HEAT INDICES REACHING AROUND 100
DEGREES OR HIGHER OVER THE IL RIVER VALLEY TUE AFTERNOON, AND
OVER MUCH OF CENTRAL IL WEDNESDAY AFTERNOON WITH HIGHS IN THE
LOWER 90S. HEAT INDICES IN THE UPPER 90S TO AROUND 100 LOOK
LIKELY DURING THE AFTERNOON AND EARLY EVENING HOURS FROM
THURSDAY THROUGH SATURDAY.
DISCUSSION
ISSUED AT 300 AM CDT SUN JUL 12 2026
SHORT TERM (TODAY THROUGH MONDAY NIGHT):
THE 08Z/3 AM SURFACE MAP SHOWS WEAK 1015 MB LOW PRESSURE OVER
WESTERN TIP OF KY NEAR THE IL BORDER WITH FRONTAL BOUNDARY NEAR
THE MO/AR BORDER INTO SOUTHERN KY. MEANWHILE A WEAK 1021-1023
MB HIGH PRESSURE RIDGE WAS OVER CENTRAL PARTS OF WI AND LOWER
MI AND EXTENDING INTO THE SOUTHEAST ONTARIO PROVINCE. NE WINDS
UNDER 10 MPH OVER CENTRAL/SE IL. NEARLY CLEAR SKIES OVER CWA
WITH SOME PATCHY LIGHT FOG/HAZE IN EASTERN IL. ALOFT A WEAK 586
DECAMETER 500 MB LOW NEAR THE OHIO/KY BORDER WAS EMBEDDED IN AN
UPPER LEVEL TROF FROM NEW BRUNSWICK CANADA SW ACROSS THE OHIO
RIVER VALLEY AND INTO THE MID MS RIVER VALLEY. OUT WEST AN
EXPANSIVE 500 MB HIGH PRESSURE RIDGE WITH 595-599 DECAMETER
HEIGHTS WAS OVER THE ROCKIES AND NOSING INTO THE NORTHERN
PLAINS.
SOME PATCHY SHALLOW GROUND FOG IN EASTERN IL TO LIFT BY MID
MORNING. LATEST CAMS SHOWS WEAK SURFACE LOW PRESSURE MOVING SE
INTO SOUTH CENTRAL KY AND NORTH CENTRAL TN LATER TODAY, WHILE
HIGH PRESSURE RIDGE SLOWLY SETTLES DOWN INTO THE SOUTHERN GREAT
LAKES REGION. THE UPPER LEVEL TROF PIVOTS SE INTO THE TN RIVER
VALLEY. BRUNT OF IT CONVECTION AND DEEPER MOISTURE WILL BE
SOUTHEAST OF CWA TODAY. WE JUST HAVE A SLIGHT CHANCE OF SHOWERS
AND POSSIBLE THUNDERSTORMS OVER LAWRENCE COUNTY THIS AFTERNOON.
SCATTERED CUMULUS CLOUDS TO DEVELOP IN SOUTHEAST IL LATER THIS
MORNING AND AFTERNOON GIVING PARTLY TO MOSTLY SUNNY SKIES, WHILE
JUST FEW CUMULUS CLOUDS OVER CENTRAL IL WHERE SUNNY TO MOSTLY
SUNNY SKIES EXPECTED. NE WINDS 8-15 MPH AND GUSTS TO AROUND 20
MPH EAST OF THE IL RIVER. HIGHS IN THE LOW TO MID 80S, WARMEST
FROM THE IL RIVER NW. DEWPOINTS IN THE 60S OVER CENTRAL IL AND
LOWER 70S IN SOUTHEAST IL. FAIR TONIGHT WITH LOWS IN THE LOW TO
MID 60S.
HIGH PRESSURE RIDGE GETS CLOSER TO CENTRAL IL ON MONDAY AS
FRONTAL BOUNDARY PUSHES DOWN INTO THE NORTHERN GULF COAST
STATES. A FAIR AMOUNT OF SUNSHINE EXPECTED MONDAY WITH FEW
CUMULUS CLOUDS MON AFTERNOON OVER THE WABASH RIVER VALLEY. THE
500 MB RIDGE BUILDS INTO THE UPPER MS RIVER VALLEY AND WESTERN
GREAT LAKES ON MONDAY WITH A 600 DECAMETER 500 MB HIGH OVER
SOUTHERN MN BY SUNSET MONDAY. THIS WILL START OUR WARM UP AS IT
BUILDS CLOSER TO CENTRAL IL WITH HIGHS IN THE MID TO UPPER 80S
MONDAY, WARMEST OVER THE IL RIVER VALLEY. HEAT INDICES MONDAY
AFTERNOON AROUND 90F IN EASTERN IL AND 90-95F WEST OF I-57,
HIGHEST OVER THE IL RIVER VALLEY.
LONG TERM (TUESDAY THROUGH SUNDAY):
THE STRONG AND LARGE MID/UPPER LEVEL HIGH PRESSURE RIDGE WILL
CONTINUE TO DOMINATE THE MIDWEST AND NOSING INTO THE OHIO RIVER
VALLEY MUCH OF THIS WEEK. THE WEAK UPPER LEVEL LOW OVER THE
SOUTHERN TN RIVER VALLEY TUE DRIFTS WESTWARD INTO AR ON WED.
CONVECTION CHANCES SHOULD STAY SOUTH OF CWA TUE AND WED WITH
20-30% POPS IN FAR SOUTHERN/SW IL (SOUTH OF I-64) TUE AFTERNOON
AND WED AFTERNOON. HIGHS TUE IN THE UPPER 80S/LOWER 90S, WARMEST
FROM I-72 NORTH WHERE HEAT INDICES TUE AFTERNOON LIKELY REACH
AROUND 100F, WITH MID TO UPPER 90S HEAT INDICES IN SOUTHEAST IL.
CURRENTLY WED APPEARS TO HAVE HIGHS IN THE LOWER 90S OVER MUCH
OF CWA WITH HEAT INDICES IN THE UPPER 90S AND LOWER 100S WED
AFTERNOON, HIGHEST FROM I-72 NORTH. NBM STILL APPEARS TO BE
SUPPRESSING DEW POINTS A BIT TOO MUCH, GIVEN THE RECENT WET
WEATHER AND EVAPOTRANSPIRATION FORM MATURE CROPS (CORN/SOYBEANS).
DEWPOINTS AT LEAST IN THE LOW TO MID 70S EXPECTED TUE THROUGH AT
LEAST SATURDAY. HEAT INDICES IN THE UPPER 90S TO AROUND 100
DEGREES LOOK LIKELY EACH AFTERNOON/EARLY EVENING FROM THU
THROUGH AT LEAST SATURDAY AND POSSIBLY HIGHER.
THE STRONG MID/UPPER LEVEL RIDGE RETROGRADES WESTWARD INTO THE
CENTRAL PLAINS AND ROCKIES LATE THIS WEEK WITH UPPER LEVEL
TROFFING OVER THE EASTERN GREAT LAKES, NEW ENGLAND AND MID
ATLANTIC REGION. THIS PUTS IL IN A NORTHWEST UPPER LEVEL FLOW
AND MAY SEE SOME NORTHERN STREAM SHORT WAVES/DISTURBANCES
TRACKING INTO THE GREAT LAKES AND OHIO RIVER VALLEY FROM FRIDAY
INTO NEXT WEEKEND. BEST CHANCES OF CONVECTION STILL APPEARS TO
BE NORTHEAST OF CENTRAL IL CLOSER TO THE GREAT LAKES WHERE THERE
WILL LIKELY BE FRONTAL BOUNDARIES, BUT WE DO HAVE SLIGHT
CHANCES OF SHOWERS/THUNDERSTORMS AT TIMES FROM FRI THROUGH NEXT
WEEKEND.
THE CLIMATE PREDICTION CENTER (CPC) 8-14 DAY OUTLOOK JULY
19-25TH HAS A 35-40% CHANCE OF ABOVE NORMAL TEMPERATURES OVER
IL. PRECIPITATION IS TRENDING NEAR NORMAL, EXCEPT AROUND A 35%
CHANCE OF ABOVE NORMAL PRECIPITATION IN EAST CENTRAL AND
SOUTHEAST IL.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 550 AM CDT SUN JUL 12 2026
HIGH PRESSURE RIDGE OVER CENTRAL PARTS OF WI AND LOWER MI AND
RIDGING INTO CENTRAL IOWA, WILL SETTLE INTO THE SOUTHERN GREAT
LAKES REGION DURING TONIGHT INTO MONDAY MORNING. THIS SHOULD
PROVIDE FAIR WEATHER TO THE CENTRAL IL AIRPORTS THROUGH 12Z/7 AM
MONDAY. A LIGHT FOG/HAZE COULD OCCUR UNTIL 13Z AT DEC AND CMI
WITH 20% CHANCE OF MVFR VSBYS. OTHERWISE, FEW TO SCATTERED
CUMULUS CLOUDS WITH 3-5K FT BASES TO APPEAR BETWEEN 14-15Z AND
DISSIPATE BY SUNSET. NNE TO NE WINDS AROUND 5 KTS AT DAWN TO BE
NE AND INCREASE TO 7-12 KTS AFTER 14-15Z WITH FEW GUSTS OF
14-19 KTS POSSIBLE OVER EASTERN AIRPORTS (BMI, DEC AND CMI). NE
WINDS DIMINISH BACK TO AROUND 5 KTS AT 00-01Z. CAMS ARE LIMITED
WITH PATCHY FOG FORMATION OVERNIGHT AND KEPT OUT OF TAFS WITH
SOMEWHAT DRIER AIR IN PLACE.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...07
DISCUSSION...07
AVIATION...07
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