563
FXUS63 KILX 291648
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1148 AM CDT WED APR 29 2026
KEY MESSAGES
- A COOLER WEATHER PATTERN WILL REMAIN IN PLACE THE REMAINDER OF
THE WEEK, AND HIGH TEMPERATURES FOR THE START OF MAY WILL BE
ABOUT 10 TO 15 DEGREES BELOW NORMAL.
- THERE IS ABOUT A 30-50% CHANCE OF TEMPERATURES COOL ENOUGH FOR
FROST FORMATION FRIDAY NIGHT, MAINLY NORTH OF I-72, POSING A
RISK FOR TENDER YOUNG VEGETATION.
- AFTER THIS MORNING'S RAIN EXITS EASTERN ILLINOIS, ADDITIONAL
SHOWERS THROUGH THURSDAY WILL BE FAIRLY SCATTERED (ABOUT A
20-30% CHANCE) AND LIGHT.
DISCUSSION
ISSUED AT 230 AM CDT WED APR 29 2026
THE BIG PICTURE:
THE COOLER WEATHER PATTERN WILL REMAIN IN PLACE THE REMAINDER
OF THE WEEK. WATER VAPOR IMAGERY THIS MORNING SHOWS A BROAD
UPPER LOW PATTERN STRETCHING FROM ONTARIO TO NORTHWEST
MINNESOTA, AND THE SYNOPTIC MODELS SHOW THIS PATTERN SETTLING
OVER THE GREAT LAKES. SOME WARMUP IS ANTICIPATED DURING THE
WEEKEND INTO EARLY NEXT WEEK, AS THE LOW BECOMES MORE CENTERED
SOUTH OF HUDSON BAY. HOWEVER, THE CPC 6-10 DAY TEMPERATURE
OUTLOOK DOES FAVOR BELOW NORMAL TEMPERATURES FOR NEXT WEEK,
LIKELY TO ARRIVE MORE TOWARD THE SECOND HALF OF THE WORK WEEK.
SHORT TERM (THROUGH FRIDAY):
OVERNIGHT SHOWERS SHOULD LARGELY BE EAST OF THE ILLINOIS BORDER
BY THE MORNING COMMUTE, AS A SHORTWAVE PUSHES EAST OF THE AREA.
HOWEVER, WITHIN THE BROADER PATTERN, ADDITIONAL SHORTWAVES WILL
PIVOT SOUTHEAST ACROSS THE WESTERN GREAT LAKES THE NEXT FEW
DAYS. WITH STEEP LOW LEVEL LAPSE RATES EACH AFTERNOON, AT LEAST
SOME ISOLATED SHOWERS SHOULD DEVELOP. MUCH OF IT THIS AFTERNOON
WOULD BE MORE ASSOCIATED WITH A WAVE SWINGING ACROSS MINNESOTA,
WITH SOME SHOWERS POTENTIALLY AS FAR SOUTH AS DANVILLE. BETTER
CHANCES WILL ACCOMPANY A SHORTWAVE DROPPING SOUTHEAST ACROSS
ILLINOIS THURSDAY AFTERNOON AND EVENING. HOWEVER, LOW LEVEL
MOISTURE WITH THIS SYSTEM IS FAIRLY MEAGER, WITH NAM AND GFS
SOUNDINGS RATHER DRY BELOW 5,000 FEET. 20-ISH POP'S SEEM
REASONABLE AT THIS POINT, AND ADDED SOME TO THURSDAY AFTERNOON
AND EVENING. SOME ADJUSTMENT MAY EVENTUALLY BE NEEDED FOR FRIDAY
AS WELL, BUT MORE MODEL VARIANCE SUGGESTS HOLDING OFF AT THIS
TIME.
LONGER TERM (FRIDAY NIGHT THROUGH TUESDAY):
FROST CONCERN REMAINS FOR FRIDAY NIGHT, WITH LREF PROBABILITIES
OF LOWS 36F OR COLDER ABOUT 30-50% NEAR THE I-74 CORRIDOR AND
SOUTHEAST TO NEAR TERRE HAUTE. WILL CONTINUE TO MENTION AREAS OF
FROST FOR ABOUT THE NORTH HALF OF THE FORECAST AREA. AFTER THAT,
THE UPPER LOW FINALLY GETS FAR ENOUGH EAST TO ALLOW FOR SOME
WARMER AIR TO SPREAD BACK INTO THE AREA. NBM GUIDANCE BRINGS
HIGHS BACK TO NEAR 70 ACROSS THE ILLINOIS RIVER VALLEY BY
SUNDAY, WITH HIGHS 70-75 DEGREES PREVAILING MONDAY AND TUESDAY.
HIGH PRESSURE WILL KEEP THE FIRST PART OF THE WEEKEND DRY, BUT
AS THE UPPER LOW GETS REESTABLISHED OVER ONTARIO AND QUEBEC,
WE'LL GET BACK INTO A PATTERN OF FAST MOVING SHORTWAVES DROPPING
SOUTHEAST ACROSS THE GREAT LAKES. THIS WILL BRING PERIODIC
CHANCES OF SHOWERS EARLY NEXT WEEK, THOUGH NOTHING THAT WOULD
FAVOR SEVERE WEATHER.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1148 AM CDT WED APR 29 2026
SCT TO OCCASIONALLY BKN DIURNAL CU WITH BASES AROUND 4K FEET
WILL DISSIPATE EARLY THIS EVENING, THEN RE-FORM THU MORNING.
NORTHWEST WINDS WILL GUST 20-25 KT THIS AFTERNOON AND THEN
DIMINISH THIS EVENING.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...GEELHART
DISCUSSION...GEELHART
AVIATION...25
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