379
FXUS63 KLOT 260801
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
301 AM CDT SUN OCT 26 2025
KEY MESSAGES
- EXPECT SEASONABLE TEMPERAURES THROUGH NEXT WEEKEND, WITH RAIN
CHANCES INCREASING LATER TUESDAY THROUGH WEDNESDAY.
DISCUSSION
ISSUED AT 301 AM CDT SUN OCT 26 2025
A REX BLOCK EXTENDING FROM SOUTHERN HUDSON BAY TO THE SOUTHERN
GREAT PLAINS WILL SLOWLY DRIFT EASTWARD THROUGH MONDAY. THE
NORTHERN EXTENT OF THE ASSOCIATED UPPER-LEVEL LOW OVER OKLAHOMA
CONTINUES TO FILTER MID TO UPPER-LEVEL CLOUDS NORTHWARD OVER THE
AREA EARLY THIS MORNING. MEANWHILE, MID-LEVEL DRYING BEHIND A
DEPARTING TROUGH OVER THE EASTERN GREAT LAKES WILL ADVECT
SOUTHWARD TODAY. A RESULTANT 600 HPA THERMAL CONTRACTION AND
DEFORMATION AXIS WITHIN A COINCIDENT LAYER OF MODEST MOISTURE
SHOULD CONTINUE TO GENERATE ISOLATED SPRINKLES OR LIGHT SHOWERS
ACROSS FAR SOUTHWEST PORTIONS OF THE CWA THROUGH DAYBREAK. THIS
ACTIVITY SHOULD SHIFT INTO CENTRAL ILLINOIS AFTER SUNRISE AS THE
DRIER AIR ADVECTS FARTHER SOUTH, RESULTING IN GRADUALLY
CLEARING SKIES FROM NORTH TO SOUTH TODAY. WITH THE MAIN UPPER-
LEVEL LOW REMAINING WELL SOUTH OF THE AREA THROUGH MONDAY,
MOSTLY CLEAR SKIES WILL PREVAIL AMID SEASONABLE TEMPERATURES.
AS THE UPPER LOW (RIDGE) DRIFTS EASTWARD TO THE SOUTHEASTERN
STATES (WESTERN QUEBEC) BY TUESDAY, A MID-LEVEL LOW DISLODGING
FROM A BROADER TROUGH OVER THE NORTHWEST U.S. WILL UNRAVEL WHILE
ATTEMPTING TO PHASE WITH THE EASTERN LOW. CONSENSUS GUIDANCE IS
GRADUALLY COMING INTO BETTER AGREEMENT THAT THE TROUGH/LOW WILL
PIVOT FROM THE MISSOURI RIVER VALLEY ON TUESDAY TO OVER CENTRAL
KENTUCKY AND TENNESSEE BY WEDNESDAY NIGHT. REMAINING MID-LEVEL
MOISTURE IN THE WAKE OF THE CURRENT LOW TO THE SOUTH WILL BEGIN
TO ADVECT BACK NORTHWESTWARD AHEAD OF THE APPROACHING WAVE
THROUGH THE DAY TUESDAY AND ESPECIALLY ON WEDNESDAY. UPPER-LEVEL
SUPPORT FROM THE ENTRANCE REGION OF A NORTHWESTWARD DIRECTED
UPPER-LEVEL JET STREAK OVER MINNESOTA WILL SUPPORT PRECIP
GENERATION WEST OF THE AREA BY TUESDAY MORNING. THE NORTHEAST
EXTENT OF THIS RAIN BAND REMAINS UNCLEAR, HOWEVER, AS EXTENSIVE
LOW-LEVEL DRYING FROM A PSUEDO-HUDSON BAY HIGH TO THE NORTHEAST
ERODES PRECIP. WITH MOST COOL SEASON SYSTEMS EXHIBITING A STOUT
EASTERLY FLOW OF DRY AIR LIKE THIS, THE PERIPHERY OF THE PRECIP
SHIELD USUALLY UNDER-PERFORMS COMPARED TO GUIDANCE. ULTIMATELY,
THERE WILL LIKELY BE A SHARP PRECIP GRADIENT SOMEWHERE ACROSS
THE CWA TUESDAY NIGHT AND WEDNESDAY.
INTERACTIONS WITH THE CURRENT SOUTHERN LOW, THE INCOMING
WESTERN TROUGH/LOW, AND HURRICANE MELISSA SHOULD TREND TOWARD A
LONGWAVE TROUGH ACROSS THE NORTHEAST U.S. LATE IN THE WEEK.
ENSEMBLE GUIDANCE THEN HINTS AT A POTENTIAL OMEGA BLOCK
DEVELOPING LATE NEXT WEEKEND INTO THE SUBSEQUENT WEEK. OUR AREA
WOULD BE SITUATED ON THE WESTERN EDGE OF THE MAIN LONGWAVE
TROUGH TO THE EAST, YIELDING SPORADIC BOUTS OF SCATTERED RAIN
SHOWERS AND PERHAPS SOME LAKE EFFECT RAIN SHOWERS LATE WEEK
THROUGH NEXT WEEKEND. TEMPS WILL REMAIN SEASONABLE DURING THIS
PERIOD AS ARCTIC AIR MASSES REMAINS WELL NORTH OF THE AREA.
KLUBER
AVIATION /06Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 1237 AM CDT SUN OCT 26 2025
VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD.
THE ONGOING BKN TO OVC CLOUDS (~6000-8000FT) WILL GRADUALLY
SCATTER OUT AND SHIFT SOUTH OF THE AREA TOWARD DAYBREAK WITH
MOSTLY CLEAR SKIES EXPECTED THEREAFTER OTHER THAN A FEW VFR
CUMULUS IN THE AFTERNOON.
WINDS WILL BE GENERALLY EAST TO EAST SOUTHEASTERLY THROUGH THE
PERIOD INCREASING TO AROUND 10-15KT DURING THE DAYTIME HOURS.
PETR
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM CDT
TUESDAY FOR THE IL NEARSHORE WATERS.
VISIT US AT WEATHER.GOV/CHICAGO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page