251
FXUS63 KLOT 250819
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
319 AM CDT SAT OCT 25 2025
KEY MESSAGES
- SEASONABLE TEMPERATURES THROUGH THE END OF THE MONTH.
- A FEW SPRINKLES ACROSS NORTHERN ILLINOIS TODAY, THEN
INCREASING RAIN CHANCES FOR PORTIONS OF THE AREA TUESDAY INTO
WEDNESDAY.
DISCUSSION
ISSUED AT 319 AM CDT SAT OCT 25 2025
BLOCKING FROM A PROMINENT RIDGE OVER CENTRAL CANADA AND UPPER-
LEVEL LOW CENTERED OVER OKLAHOMA TODAY WILL PERSIST INTO EARLY
NEXT WEEK, RESULTING IN A SLOW EVOLUTION OF THE BROADER FLOW
ACROSS CENTRAL NORTH AMERICA. PRECIP CHANCES DURING THIS PERIOD
LOOK TO BE QUITE LOW AMID GENERALLY SEASONABLE TEMPERATURES FOR
LATE OCTOBER.
MOSTLY CLEAR SKIES EARLY THIS MORNING WILL GRADUALLY FILL IN
WITH MID AND UPPER-LEVEL CLOUDS FROM BOTH THE NORTHWEST AND
SOUTH THROUGH THE REMAINDER OF THE MORNING. AN AREA OF MODEST
MID-LEVEL MOISTURE EVIDENT IN SATELLITE AND OBS OVER IOWA EARLY
THIS MORNING WILL GRADUALLY ADVECT EASTWARD TODAY AS A COMPACT
WAVE JUST EAST OF THE TWIN CITIES TRACKS SOUTHEASTWARD.
SCATTERED MID-LEVEL SHOWERS HAVE BEEN COMMON ACROSS SOUTHEAST
MINNESOTA AND NORTHERN IOWA THIS MORNING. WITH THE ADDED MID-
LEVEL MOISTURE INTERACTING WITH THE APPROACHING WAVE,
EXPECTATIONS ARE FOR AT LEAST ISOLATED LIGHT SHOWERS OR
SPRINKLES OVER NORTHERN ILLINOIS LATER THIS MORNING INTO THE
AFTERNOON HOURS. FARTHER SOUTH, THE NORTHERN PERIPHERY OF THE
UPPER-LEVEL LOW MAY BRING A FEW SPRINKLES ACROSS CENTRAL
ILLINOIS LATER THIS AFTERNOON AND THIS EVENING, BUT EXPECTATIONS
ARE FOR PRECIP TO REMAIN SOUTH OF THE FORECAST AREA.
MOSTLY CLEAR SKIES ARE THEN IN STORE SUNDAY THROUGH MONDAY AS
SOME ADDITIONAL CIRRUS FROM THE LOW TO THE SOUTH FILTERS
NORTHWARD ACROSS THE AREA.
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
CONTINUES TO COME INTO BETTER AGREEMENT THAT THE LOW WILL PASS
SOUTHWEST OF THE FORECAST AREA TUESDAY AFTERNOON THROUGH
WEDNESDAY. HOWEVER, A RESIDUAL RESERVOIR OF MID-LEVEL MOISTURE
FROM THE EASTERN LOW WILL BE DRAWN INTO THE APPROACHING WAVE AS
THE ENTRANCE REGION OF A NORTHWESTWARD DIRECTED UPPER-LEVEL JET
STREAK SETTLES JUST WEST OF THE FORECAST AREA. THIS SHOULD
SUPPORT A NW TO SE ORIENTED BAND OF RAIN OVER AT LEAST SOME OF
THE FORECAST AREA (ESPECIALLY THE SOUTHWEST HALF) DURING THIS
TIME.
INTERACTIONS WITH THE TWO LOWS LATER IN THE WEEK, AS WELL THE
ANY POTENTIAL INTERACTIONS FROM (CURRENTLY) TROPICAL STORM
MELISSA, SEEM TO POINT TOWARD AN OVERALL TRANSITION TO A
LONGWAVE TROUGH DEVELOPING ACROSS THE EASTERN GREAT LAKES,
NORTHEAST, AND EASTERN CANADA BY EARLY NEXT WEEKEND. ANY WEAK
WAVE ROTATING ON THE WESTERN FLANK OF THE LOW WILL LIKELY YIELD
ISOLATED TO SCATTERED SHOWERS AND PERHAPS SOME A FEW LAKE EFFECT
RAIN SHOWERS DURING THIS TIME. WITH NO ARTIC AIR MASSES BEHIND
THE BROAD TROUGH, TEMPS SHOULD REMAIN SEASONABLE AS WE CLOSE OUT
OCTOBER.
KLUBER
AVIATION /06Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 1240 AM CDT SAT OCT 25 2025
VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD. LIGHT AND
VARIABLE WINDS OVERNIGHT WILL RETURN TO A PREVAILING EAST
SOUTHEAST DIRECTION AFTER DAYBREAK AROUND 5-10 KT THEN EASE
AGAIN WITH SUNSET.
INCREASING CLOUD COVERAGE IS EXPECTED BY DAYBREAK AS A MID-
LEVEL IMPULSE MOVES THROUGH THE REGION. THE LOW-LEVELS REMAIN
RATHER DRY AND SUSPECT THE MAJORITY OF THIS WILL REMAIN VIRGA.
HOWEVER, A FEW SPRINKLES/SPOTTY SHOWERS CAN'T BE FULLY RULED
OUT EARLY TO MID AFTERNOON (<30% CHANCE). FOR NOW HAVE KEPT THE
TAF'S DRY.
PETR
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
VISIT US AT WEATHER.GOV/CHICAGO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page