929
FXUS63 KLOT 260537
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
1237 AM CDT SUN OCT 26 2025
KEY MESSAGES
- RAIN CHANCES RETURN TUESDAY INTO WEDNESDAY (30-50%).
DISCUSSION
ISSUED AT 146 PM CDT SAT OCT 25 2025
THROUGH WEDNESDAY:
VISIBLE SATELLITE IMAGERY SHOWS MOSTLY CLOUDY SKIES THIS
AFTERNOON ACROSS THE FORECAST AREA. A SHORT WAVE TROUGH IS
DESCENDING INTO NORTHERN ILLINOIS FROM WISCONSIN AND WITH IT,
FAIRLY STOUT MID LEVEL MOISTURE. THE BEST FORCING HAS BEEN NORTH
OF THE STATE LINE WHERE BETTER ORGANIZED SHOWERS HAVE DEVELOPED.
HOWEVER, EVEN UP NORTH, SURFACE DEW POINT DEPRESSIONS ARE
RUNNING 10 TO 15 DEGREES AND MODEL SOUNDING SHOWING FAIRLY
ROBUST LOW LEVEL DRY AIR. THE FORECAST MAINTAINED THE SLIGHT
CHANCE FOR A SHOWER DEVELOPING, BUT ANY ACCUMULATIONS SHOULD BE
MINUSCULE. HOWEVER, THERE IS SOME UNCERTAINTY ON HOW QUICKLY
THE TROUGH WILL EXIT TO THE EAST AND SUPPRESS THE MOISTURE TO
THE SOUTH. SO THE FORECAST EXTENDED THE MENTION OF SPRINKLES
THROUGH AT LEAST THIS EVENING, BUT THE HIGHER CONFIDENCE IS FOR
MORE AREAS TO REMAIN DRY.
BASED ON RECENT MESOANALYSIS, AN UPPER LEVEL RIDGE CURRENTLY
SITS OVER THE NORTHERN PLAINS AS WELL AS AN UPPER LEVEL LOW
OVER OKLAHOMA. THIS MERIDIONALLY STACKED RIDGE/TROUGH IS
EXPECTED TO DRIFT EAST INTO SUNDAY. WITH BETTER HEIGHT RISES,
THE RIDGE IS EXPECTED TO STRENGTHEN, KEEPING THE LOW OVER THE
OHIO RIVER VALLEY. WHILE A SPRINKLE TOMORROW CANNOT BE
COMPLETELY RULED OUT IN THE FAR SOUTHERN PARTS OF THE FORECAST
AREA, THE POPS WERE KEPT DRY TOMORROW. WITH DECREASING CLOUDS
FROM NORTH TO SOUTH, IT SHOULD BE FAIRLY NICE DAY WITH
SEASONABLE TEMPERATURES CLIMBING TOWARD THE LOW 60S. SIMILAR
CONDITIONS, IF NOT SLIGHTLY COOLER, ARE EXPECTED ON MONDAY.
AN UPPER LEVEL TROUGH CURRENTLY OVER THE PACIFIC NORTHWEST IS
PROJECTED TO MOVE EASTWARD THROUGH THE EARLY PART OF NEXT WEEK.
A MID LEVEL LOW IS EXPECTED TO DISLODGE FROM THE BROADER TROUGH
ON TUESDAY WITH SURFACE CYCLOGENESIS DEVELOPING ON TUESDAY INTO
WEDNESDAY. GUIDANCE IS CONSISTENTLY SUGGESTING THE SURFACE LOW
WILL DEVELOP AND REMAIN SOUTH OF THE FORECAST AREA. HOWEVER,
WITH A STOUT 120+ KNOT JET ALOFT AND BETTER MID LEVEL MOISTURE,
THERE IS A GROWING SIGNAL FOR A MORE APPRECIABLE RAINFALL, WITH
HIGHEST POPS SOUTH OF I-88. BETTER LAPSE RATES AND INSTABILITY
IS EXPECTED TO REMAIN SOUTH OF THE LOW SO THUNDER WAS KEPT OUT
OF THE FORECAST.
DK
WEDNESDAY NIGHT THROUGH SATURDAY:
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 ARCTIC AIR MASSES BEHIND
THE BROAD TROUGH, TEMPS SHOULD REMAIN SEASONABLE AS WE CLOSE
OUT OCTOBER.
DK/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.
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