187
FXUS63 KLOT 262326
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
626 PM CDT SUN OCT 26 2025
KEY MESSAGES
- A PASSING STORM SYSTEM MAY PROVIDE PERIODS OF RAIN ACROSS THE
AREA DURING THE MIDDLE OF THE WEEK, FAVORING AREAS SOUTH OF
INTERSTATE 80.
- EXPECT SEASONABLE TEMPERATURES THROUGH NEXT WEEKEND.
DISCUSSION
ISSUED AT 129 PM CDT SUN OCT 26 2025
A REX BLOCK EXTENDING FROM SOUTHERN HUDSON BAY TO THE SOUTHERN
GREAT PLAINS WILL SLOWLY DRIFT EASTWARD THROUGH MONDAY. WITH
THE MAIN UPPER-LEVEL LOW REMAINING WELL SOUTH OF THE AREA,
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.
TUESDAY AFTERNOON ONWARD, THE SHIELD OF RAIN SHOULD EXPAND
NORTHEASTWARD AND THE NORTHWARD TOWARD OUR AREA. HOWEVER, JUST
HOW FAR INTO OUR FORECAST AREA THE RAIN EXPANDS REMAINS UNCLEAR,
AS EXTENSIVE LOW-LEVEL DRYING FROM A PSUEDO-HUDSON BAY HIGH TO
THE NORTHEAST IS A COMMON TRAP SCENARIO FOR UNDER-PERFORMING
RAIN IN OUR AREA. BLENDED NBM POPS ARE BULLISH WITH LIKELY
(>55%) VALUES AS FAR NORTH AS I-80 AND MID-RANGE CHANCE (>40%)
VALUES TOWARD THE WISCONSIN STATE LINE BY TUESDAY NIGHT, WITH A
CONTINUATION OF POPS ALL THE WAY INTO THURSDAY. WHILE PARTS OF
THE AREA MAY ULTIMATELY SEE RAIN, THERE REMAIN VERY REALISTIC
SCENARIOS WHERE MUCH OF OUR AREA REMAINS COMPLETELY DRY AS THE
SYSTEM PASSES TO OUR SOUTH. WE'LL LET FUTURE FORECAST SHIFTS
TIGHTEN UP THE GRADIENT IN POPS AS WE GET CLOSER.
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/BORCHARDT
AVIATION /00Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 626 PM CDT SUN OCT 26 2025
NO MAJOR FORECAST CONCERNS FOR THIS TAF PERIOD.
A SURFACE HIGH WILL CONTINUE TO RESIDE OVER THE GREAT LAKES
THROUGH MONDAY RESULTING IN MOSTLY CLEAR SKIES AND EASTERLY
WINDS. WIND SPEEDS TONIGHT WILL EASE TO AROUND 5-7 KTS BEFORE
INCREASING TO AROUND 10-12 KTS MONDAY AFTERNOON. WITH THE CLEAR
SKIES, THE ATMOSPHERE SHOULD BE ABLE TO MIX INTO SOME UPPER TEEN
TO LOW 20 KT GUSTS MONDAY AFTERNOON BEFORE GUSTS TAPER MONDAY
EVENING.
YACK
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.
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