321
FXUS63 KIWX 261044
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
644 AM EDT MON OCT 26 2026
KEY MESSAGES
- WARM AND DRY CONDITIONS PERSIST FOR MUCH OF THIS WEEK WITH HIGHS
IN THE 70S AND LOWS AROUND 50.
- THERE IS A CHANCE FOR LIGHT RAIN NEAR LAKE MICHIGAN ON
THURSDAY WITH A BETTER CHANCE FOR MORE WIDESPREAD RAIN EARLY
NEXT WEEK.
DISCUSSION
ISSUED AT 130 AM EDT MON OCT 26 2026
A WEAK CONVERGENT BOUNDARY IS NOTED ON RADAR MOSAIC AND SURFACE OBS
JUST TO OUR NORTHWEST THIS MORNING. THIS FRONT IS ASSOCIATED WITH AN
UPPER LOW CROSSING HUDSON BAY AND IS BECOMING INCREASINGLY DIFFUSE
AS THE PARENT FORCING ZIPS EAST AND STRONG MID/UPPER RIDGE HOLDS
OVER THE OHIO VALLEY. NO RAIN IS EXPECTED LOCALLY, JUST A STEADY
STREAM OF HIGH CLOUDS GIVEN INCREDIBLY DRY AND STABLE LOW LEVELS.
OUR AREA DOES SEE A WIND SHIFT LATER TODAY INTO TONIGHT TO NNE AND
EVENTUALLY EAST. WILL HAVE TO KEEP AN EYE ON FOG POTENTIAL GIVEN
RETURN OF LAKE ERIE CONTRIBUTION BUT AMPLE HIGH CLOUDS MAY LIMIT
DEVELOPMENT AS IS OCCURRING NOW. HIGHS TODAY STILL REACH LOW 70S
AHEAD OF THE FRONT AND FLOW VEERS BACK TO A MORE SOUTHERLY DIRECTION
BY TUE AFTERNOON SO HIGHS ON TUE ARE STILL AROUND 70 (SLIGHTLY
COOLER FAR NE).
S/SW FLOW AND WARM/MOIST AIR ADVECTION RAMP UP AGAIN TUE NIGHT
THROUGH THU AS ANOTHER FRONT TAKE AIMS AT THE REGION. A MORE
SOUTHWARD TRACK OF THE PARENT TROUGH AND A MUCH BETTER PREFRONTAL
LLJ/THETA-E SURGE SUGGEST AT LEAST SOME CHANCES FOR RAIN ON THU. THE
TROUGH IS STILL WELL TO THE NORTH THOUGH AND LOCAL AREAS REMAIN
RELATIVELY DRY AND STABLE. BEST CHANCES FOR SOME LIGHT RAIN WILL BE
IN OUR FAR NW THU AFTERNOON. LATEST NBM EVEN THROWS IN A CHANCE FOR
THUNDER IN OUR NW BUT NOT EXPECTING ANYTHING SIGNIFICANT AND AREAS
ALONG/SOUTH OF US-24 LIKELY REMAIN DRY. HIGHS DO CLIMB NEAR 80 ON
THU, WHICH IS THE RECORD (SET IN 2024).
UPPER RIDGE FINALLY BREAKS DOWN THIS WEEKEND WITH POTENTIAL FOR A
SOUTHERN STREAM TROUGH TO TAP INTO BETTER MOISTURE AND BRING OUR
BEST CHANCES FOR RAIN IN A WHILE. STILL A TON OF SPREAD REGARDING
THE TIMING AND EVOLUTION THOUGH. HALLOWEEN STILL LOOKS MOSTLY DRY
BUT NBM IS MAINTAINING SOME SLIGHT CHANCE POPS. BETTER CHANCES
ARRIVE SUNDAY INTO MONDAY BUT CONFIDENCE ON TIMING AND AMOUNTS
COULDN'T BE MUCH LOWER.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 644 AM EDT MON OCT 26 2026
A WEAK COLD FRONT WILL DROP ACROSS THE SOUTHERN GREAT LAKES
TODAY. THIS FRONT IS EXPECTED TO HAVE LIMITED IMPACTS AT THE
TERMINALS AS A BROAD UPPER LEVEL TROUGH ACROSS SOUTH CENTRAL
CANADA SHIFTS OFF TO THE EAST. THE DEPARTURE OF THIS UPPER
FORCING WILL ALLOW THE FRONT TO HANG UP ACROSS THE SOUTHERN
GREAT LAKES AND LOSE ITS INTEGRITY OVER THE NEXT 24 HOURS. SOME
POST-FRONTAL IFR/MVFR LOW CLOUDS HAVE BEEN WORKING DOWN WESTERN
LAKESHORE AREAS IN NORTHEAST ILLINOIS AND CURRENT EXPECTATION IS
THAT OUTSIDE OF SOME LINGERING MVFR VSBYS IN FOG AT KSBN THROUGH
13Z, VFR CONDITIONS SHOULD HOLD THIS FORECAST VALID PERIOD.
BASED ON FRONTAL PROGRESSION, HIGHER RES GUIDANCE DOES SUGGEST
BETTER POTENTIAL OF FOG TONIGHT WILL LIKELY REMAIN SOUTH OF THE
TERMINALS. WINDS WILL REMAIN LIGHT THROUGH THE PERIOD, ALTHOUGH
SOME NORTHWEST WINDS OF 5 TO 10 KNOTS ARE EXPECTED AT KSBN
BEHIND THE FRONT THIS AFTERNOON. WINDS WILL VEER TO NORTHEAST
TONIGHT WITH SPEEDS AT 5 KNOTS OR LESS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...AGD
AVIATION...MARSILI
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