153
FXUS63 KILX 131003
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
503 AM CDT MON JUL 13 2026
KEY MESSAGES
- HOT AND HUMID WEATHER RETURNS TO CENTRAL AND SOUTHEAST IL
TUESDAY THROUGH THIS WEEKEND. MAXIMUM HEAT INDICES TO RANGE
FROM 95 TO 105 DEGREES EACH AFTERNOON TUESDAY THROUGH SATURDAY
WITH HIGHS IN THE LOWER 90S COMMON.
DISCUSSION
ISSUED AT 145 AM CDT MON JUL 13 2026
THE 06Z/1 AM SURFACE MAP SHOWS 1023 MB HIGH PRESSURE OVER
SOUTHEAST IOWA AND NORTHERN MO AND RIDGING OVER NORTHERN IL
AND SOUTHERN LOWER MI. MEANWHILE A WEAK 1016 MB LOW WAS IN SOUTH
CENTRAL TN. ALOFT A STRONG 600 DECAMETER 500 MB HIGH WAS ALONG
THE EASTERN DAKOTAS BORDER, WHILE WEAK 588 DECAMETER LOW WAS IN
SOUTHEAST KY. CLEAR SKIES PREVAIL ACROSS IL WITH LIGHT NORTHEAST
TO CALM WINDS OVER CWA. DEWPOINTS WERE IN THE LOW TO MID 60S
WHILE TEMPS IN MID TO UPPER 60S CENTRAL IL AND LOWER 70S
SOUTHEAST IL. VERY PATCHY SHALLOW LIGHT FOG WAS NEAR THE IN
BORDER WITH VSBYS 5 MILES DANVILLE AND 6 MILES AT ROBINSON.
THE STRONG MID/UPPER LEVEL HIGH PRESSURE RIDGE OVER THE UPPER
MIDWEST WILL BUILD EASTWARD ACROSS THE GREAT LAKES AND INTO
CENTRAL/NORTHERN IL NEXT FEW DAYS, BRINGING IN A HEAT WAVE TO
IL. THOUGH THIS UPCOMING HEAT WAVE DOES NOT LOOK AS STRONG AS
THE WEEK LONG HEAT WAVE FROM JUN 28 TO JULY 4TH. HIGHS TODAY IN
THE UPPER 80S TO NEAR 90F, WARMEST FROM THE IL RIVER NW WHERE
HEAT INDICES THIS AFTERNOON TO PEAK IN THE MID 90S. THE ECMWF
EXTREME FORECAST INDEX SHOWS VALUES BETWEEN 0.95-1 FROM TUESDAY
THROUGH SATURDAY, WHICH INDICATES THAT THERE IS HIGH CONFIDENCE
OF AN ANOMALOUS EVENT. DEWPOINTS IN THE LOWER TO MIDDLE 70S
OVERALL DURING THIS HEAT WAVE, THOUGH MATURE CORN AND SOYBEAN
PLANTS TO PROVIDE EXTRA LOW LEVEL MOISTURE FROM EVAPOTRANSPIRATION,
SO DEWPOINTS MAY OVERPERFORM AT TIMES. PEAK HEAT INDICES LOOK
TO TOP OUT FROM 90 TO 95 THIS AFTERNOON AND 95 TO 105 DEGREES
EACH AFTERNOON FROM TUE THROUGH SATURDAY.
PRECIPITATION CHANCES CONTINUE TO LOOK SLIM OVER CENTRAL/SE IL
THROUGH THIS WEEKEND AS WE ARE INFLUENCED BY STRONG MID/UPPER
LEVEL HIGH PRESSURE RIDGE. A WEAK UPPER LEVEL LOW TO DRIFT
WESTWARD OVER THE SOUTHERN TN RIVER VALLEY THIS EVENING, AND
INTO AR ON WED. WE WILL LIKELY BE CAPPED WITH NEARBY STRONG
UPPER LEVEL HIGH PRESSURE JUST TO OUR NORTH/NW SO CONTINUED A
DRY FORECAST INTO MID WEEK. MOST MODELS KEEP CONVECTION SOUTH
OF CWA THROUGH MID WEEK. GFS APPEARS TOO FAR NORTH AND IS AN
OUTLIER WITH QPF INTO CENTRAL IL ON WED. AS THE STRONG MID/UPPER
LEVEL RIDGE RETROGRADES WESTWARD INTO THE CENTRAL GREAT PLAINS
AND ROCKIES LATE THIS WEEK, WITH UPPER LEVEL TROFFING INTO THE
NORTHEAST QUARTER OF THE COUNTRY, THIS MAY BRING LOW END CHANCES
FOR SHOWERS AND STORMS TO IL THIS WEEKEND. THOUGH BETTER
CHANCES OF CONVECTION APPEARS TO BE NE OF CENTRAL IL CLOSER TO
THE GREAT LAKES REGION WITH SHORT WAVES TRACK SE THROUGH THAT
PART OF THE COUNTRY WITH BETTER FORCING.
THE CLIMATE PREDICTION CENTER (CPC) 8-14 DAY OUTLOOK FOR JULY
20-26TH IS TRENDING NEAR NORMAL FOR TEMPERATURES AND
PRECIPITATION OVER ILLINOIS, EXCEPT SLIGHTLY ABOVE NORMAL
PRECIPITATION ALONG THE INDIANA BORDER. SO OVERALL A DRIER
PATTERN LIKELY IN STORE FOR CENTRAL AND SOUTHEAST NEXT TWO WEEKS
AFTER A VERY WET PERIOD SINCE SUN/JUN 7TH WHEN WE RECEIVED 7-14
INCHES OF RAIN AND A FEW SPOTS OVER 15 INCHES.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 500 AM CDT MON JUL 13 2026
VERY PATCHY SHALLOW GROUND FOG NEAR A SOME RIVER VALLEYS AND
LAKES EARLY THIS MORNING PER NIGHTTIME MICROPHYSICS SATELLITE
IMAGERY. BRIEF IFR TO MVFR VSBYS WITH THIS FOG MAY OCCUR UNTIL
13Z, BUT KEPT OUT OF CENTRAL IL AIRPORTS AS CHANCES FOR THIS IS
LESS THAN 20%. OTHERWISE VFR CONDITIONS ARE FORECAST TO CONTINUE
THROUGH 12Z/7 AM TUE OVER CENTRAL IL AIRFIELDS WITH NEARBY
SURFACE HIGH PRESSURE RIDGE OVER SOUTHEAST IA AND NORTHERN PARTS
OF IL/MO. FEW CUMULUS CLOUDS WITH 5K FT BASES MAY APPEAR LATE
MORNING/AFTERNOON ALONG WITH A FEW PASSING CIRRUS CLOUDS. LIGHT
NNE TO CALM WINDS AT DAWN, TO BECOME NE AT 5-10 KTS AFTER 15Z/10
AM, AND DIMINISH LIGHT AT SUNSET/01Z.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...07
DISCUSSION...07
AVIATION...07
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