443
FXUS63 KLOT 241805
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
105 PM CDT THU SEP 24 2026
KEY MESSAGES
- BELOW AVERAGE TEMPERATURES ARE EXPECTED THROUGH THE WEEKEND
BEFORE TEMPERATURES TURN MORE SEASONABLE EARLY NEXT WEEK.
- NO SIGNIFICANT WIDESPREAD PRECIPITATION CHANCES ARE EXPECTED
AT THIS TIME UNTIL THE MIDDLE OF NEXT WEEK.
DISCUSSION
ISSUED AT 105 PM CDT THU SEP 24 2026
THE FORECAST AREA REMAINS ON THE NORTHWESTERN PERIPHERY OF AN
UPPER-LEVEL LOW WHICH IS PROGGED TO DEEPEN ACROSS THE MID-
ATLANTIC REGION OVER THE NEXT COUPLE OF DAYS. VARIOUS MODEL
GUIDANCE INDICATES THE POTENTIAL FOR SOME SPOTTY SHOWERS TO
SPREAD INTO FAR NORTH/NORTHWEST IL TOWARD DAYBREAK FRIDAY, IN
ASSOCIATION WITH AN SHORT WAVE PROPAGATING INTO THE UPPER
MIDWEST. THIS WAVE WILL BE RUNNING INTO SHORT WAVE RIDGING ALOFT
ON THE NORTHWESTERN FRINGE OF THE DEEPENING EAST COAST LOW
HOWEVER, WHICH ALONG WITH EASTERLY LOW-LEVEL DRY AIR ADVECTION
IS EXPECTED TO LIMIT THE EASTWARD DEVELOPMENT OF PRECIPITATION.
HAVE MAINTAINED SOME SLIGHT CHANCE (<=20%) POPS FOR THESE
DECAYING SHOWERS MAINLY WEST OF THE FOX RIVER VALLEY ACROSS
NORTHERN AND NORTHWEST IL BETWEEN ABOUT 4AM-10AM FRIDAY MORNING.
BEHIND FRIDAY'S WAVE, THE NARROW UPPER-LEVEL RIDGE IS THEN
PROGGED TO BRIEFLY REDEVELOP INTO THE UPPER-MIDWEST FRIDAY NIGHT
INTO SATURDAY BEFORE ANOTHER SHORT WAVE APPROACHES THE UPPER-
MIDWEST SATURDAY EVENING. SIMILAR TO FRIDAY MORNING'S SCENARIO,
THIS WAVE WILL ALSO BE FIGHTING THE RIDGE AND DRY EASTERLY LOW-
LEVEL FLOW. SOME DECAYING SHOWERS WILL AGAIN BE POSSIBLE
SATURDAY NIGHT ACROSS OUR FAR WESTERN COUNTIES OF THE FORECAST
AREA, BUT DID NOT INCLUDE A FORMAL MENTION IN THE OUTGOING
FORECAST. PARTLY TO MOSTLY CLOUDY SKIES AND CONTINUED MODEST
EAST-NORTHEAST SURFACE WINDS WILL LIKELY KEEP OUR TEMPERATURES
SLIGHTLY BELOW AVERAGE IN THE MID-60S TO LOWER 70S BOTH SATURDAY
AND SUNDAY.
A SLOWER EVOLUTION IS NOT UNUSUAL IN SUCH HIGHLY-AMPLIFIED
UPPER AIR PATTERNS, AND THE LATEST GLOBAL MODEL/ENSEMBLE
SOLUTIONS HAVE DELAYED KICKING OUT THE EASTERN LOW UNTIL EARLY-
MID NEXT WEEK. AS THIS OCCURS, THERE ARE INDICATIONS THAT THE
PATTERN WILL BECOME MORE ACTIVE WITH AN EASTWARD-MOVING FRONTAL
ZONE AND SURFACE LOW DEVELOPING INTO THE REGION TOWARD MID-
WEEK. NBM INITIALIZATION DEPICTS THIS WITH 40-60% POPS LATER
TUESDAY INTO WEDNESDAY AND MADE NO CHANGES AT THIS DISTANCE,
THOUGH THERE IS QUITE A BIT OF ENSEMBLE SPREAD IN THE CURRENT
EPS/GEFS/CMCE SOLUTIONS WITH THE TIMING/STRENGTH AND PLACEMENT
OF FEATURES AT THIS TIME.
RATZER/BORCHARDT
AVIATION /18Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 1246 PM CDT THU SEP 24 2026
THERE ARE NO MAJOR AVIATION WEATHER CONCERNS ANTICIPATED
THROUGH THE PERIOD.
SURFACE HIGH PRESSURE IS EXPECTED TO REMAIN LOCKED IN ACROSS THE
GREAT LAKES REGION THROUGH THE WEEKEND. THIS WILL RESULT IN
EASTERLY SURFACE WINDS TILL FURTHER NOTICE. OTHERWISE,
OCCASIONAL CIGS (MAINLY VFR) ARE EXPECTED THROUGH FRIDAY. ALSO
CANNOT RULE OUT A FEW NON-IMPACTFUL SPRINKLES FRIDAY MORNING.
KJB
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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