195
FXUS63 KLOT 230659
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
159 AM CDT WED SEP 23 2026
KEY MESSAGES
- ISOLATED SPRINKLES POSSIBLE EARLY THIS MORNING, OTHERWISE
MOSTLY CLOUD, BREEZY AND DRY CONDITIONS EXPECTED TODAY.
- GENERALLY SLIGHTLY BELOW TO BELOW AVERAGE TEMPERATURES
EXPECTED INTO AT LEAST THE FIRST PART OF THE UPCOMING
WEEKEND.
DISCUSSION
ISSUED AT 158 AM CDT WED SEP 23 2026
LOOPING THE REGIONAL RADAR MOSAIC SINCE LAST EVENING INDICATES
THAT THE MID-LEVEL VORT ASSOCIATED WITH AN UPPER-LEVEL LOW WAS
CENTERED JUST WEST-SOUTHWEST OF CHICAGO EARLY THIS MORNING. THIS
FEATURE APPEARS TO BE BECOMING MORE SHEARED IN RESPONSE TO A
STRONGER MID- LEVEL SHORT WAVE TRACKING SOUTHEAST FROM SOUTHERN
IA INTO NORTHEAST MO AND WEST-CENTRAL IL. ISOLATED/WIDELY
SCATTERED SHOWERS BENEATH THE CENTER OF THE ORIGINAL VORT HAVE
DISSIPATED OVER THE LAST FEW HOURS, THOUGH HAVE MAINTAINED SOME
DECREASING SLIGHT CHANCE (15-20%) POPS NEAR THE CENTER OF THE
CIRCULATION DURING THE PREDAWN HOURS IN CASE ANYTHING
REDEVELOPS. CAN'T COMPLETELY RULE OUT SOME ISOLATED SPRINKLES OR
EVEN PATCHY DRIZZLE ACROSS THE EAST/SOUTHEAST PARTS OF THE CWA
THIS MORNING AS THE SHEARING VORT CONTINUES TO DRIFT SLOWLY OFF
TO THE EAST-SOUTHEAST, THOUGH RATHER SHALLOW MOISTURE PROFILES
IN FORECAST SOUNDINGS INDICATE LITTLE SUBSTANTIAL PRECIP THREAT.
EXTENSIVE (BUT SHALLOW) LOW-LEVEL CLOUD DECK WAS NOTED IN GOES
IMAGERY SPREADING WESTWARD ACROSS THE FORECAST AREA HOWEVER, AND
THIS SHOULD MAINTAIN CLOUDY/MOSTLY CLOUDY SKIES ACROSS THE AREA
TODAY, ESPECIALLY ACROSS THE SOUTHERN HALF/TWO THIRDS OF THE
AREA. CLOUD COVER AND STILL-BREEZY NORTHEAST WINDS WILL KEEP
TEMPERATURES ON THE COOL SIDE ONCE AGAIN, WITH HIGHS IN THE
MID-60S FOR MOST AREAS.
WITH OUR MID-LEVEL SHORT-WAVE ENERGY SLOWLY TRACKING OFF TO THE
SOUTHEAST OF THE REGION THOUGH THE END OF THE WEEK, WE'LL SEE
UPPER RIDGING DEVELOP INTO THE WESTERN GREAT LAKES REGION
(THOUGH TEMPERED BY THE PASSAGE OF A MID-LEVEL SHORT WAVE ALONG
THE U.S.CANADIAN BORDER THURSDAY NIGHT INTO FRIDAY). THIS WILL
ALLOW THE WESTERN PERIPHERY OF THE ELONGATED SURFACE RIDGE TO
OUR NORTH SETTLE ACROSS THE AREA, AND WILL MAINTAIN DRY AND
SEASONABLY COOL WEATHER CONDITIONS ALONG WITH DIMINISHING WINDS
FOR THE LOCAL AREA.
EVOLUTION OF A DEEP CUT-OFF LOW ALONG THE EAST COAST BY THE
WEEKEND WILL TEND TO SET UP A BLOCKY UPPER-AIR PATTERN ACROSS
THE EASTERN CONUS, PREVENTING MUCH IN THE WAY OF SIGNIFICANT
PRECIPITATION CHANCES FOR THE FORECAST AREA. GUIDANCE DOES
DEPICT ANOTHER MORE AMPLIFIED SHORT-WAVE PROPAGATING INTO THE
UPPER MIDWEST THIS WEEKEND, WITH THE POTENTIAL FOR A (LIKELY)
DECAYING AREA OF PRECIP TO APPROACH THE FORECAST AREA LATE
SATURDAY NIGHT/EARLY SUNDAY. THIS WAVE WILL BE PUSHING INTO THE
UPPER RIDGE AND FIGHTING DRIER LOW- LEVEL AIR, HOWEVER. GLOBAL
ENSEMBLE POPS REMAIN FOCUSED THE MISSISSIPPI RIVER THROUGH THE
WEEKEND. THE NBM INITIALIZED WITH SOME LOW-CHANCE POPS ACROSS
OUR WESTERN CWA LATE SATURDAY NIGHT/EARLY AND MADE NO CHANGES,
THOUGH IT DOESN'T LOOK LIKE A SIGNIFICANT RAIN THREAT FOR THE
DAYTIME WEEKEND HOURS. A GRADUAL MODEST WARM-UP BACK TO AVERAGE
TEMPS (LOW/MID 70S) IS EXPECTED LATER IN THE WEEKEND INTO EARLY
NEXT WEEK. EXTENDED GUIDANCE/ENSEMBLES EVENTUALLY EJECT THE DEEP
EAST COAST CUT-OFF LOW OFF TO THE NORTHEAST MONDAY/TUESDAY,
WITH THE NEXT CHANCE OF ANY SIGNIFICANT PRECIP LIKELY HOLDING
OFF UNTIL THE MIDDLE OF NEXT WEEK.
RATZER
AVIATION /06Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 1228 AM CDT WED SEP 23 2026
THE ONLY FORECAST CONCERN THIS PERIOD ARE MVFR CIGS AFTER
DAYBREAK THROUGH SUNSET. A 4KFT CLOUD DECK HAS SPREAD ACROSS
THE AREA AND IS EXPECTED TO LOWER INTO MVFR AFTER DAYBREAK FOR
MUCH OF THE AREA WITH PREVAILING MVFR CIGS EXPECTED THROUGH
MID/LATE AFTERNOON. CIGS ARE THEN EXPECTED TO SLOWLY LIFT BACK
INTO LOW VFR THIS EVENING.
THERE MAY BE AN ISOLATED SHOWER OR SOME SPRINKLES TODAY BUT
THERE CURRENTLY ARE NO FAVORED TIME PERIODS AND CHANCES FOR
PRECIPITATION TODAY ARE LOW AND NO MENTION IS NEEDED AT THIS
TIME.
EAST/NORTHEAST WINDS WILL CONTINUE THROUGH THE PERIOD WITH
SPEEDS INCREASING AFTER SUNRISE WITH GUSTS INTO THE 15-20KT
RANGE MAINLY DURING THE DAYLIGHT HOURS. GUSTS WILL END AFTER
SUNSET WITH SPEEDS DIMINISHING UNDER 10KT THIS EVENING. CMS
LOT WATCHES/WARNINGS/ADVISORIES
IL...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR ILZ006-ILZ103-
ILZ104.
IN...BEACH HAZARDS STATEMENT UNTIL 10 AM CDT THIS MORNING FOR
INZ001-INZ002.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR THE IL
NEARSHORE WATERS.
SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR CALUMET
HARBOR IL TO BURNS HARBOR IN.
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