789
FXUS63 KIWX 222244
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
644 PM EDT TUE SEP 22 2026
KEY MESSAGES
- EXTENDED STRETCH OF SEASONABLY COOL CONDITIONS WILL PERSIST THROUGH
THE WEEKEND BEFORE TEMPERATURES MODERATE FOR MONDAY AND
TUESDAY.
- SOME POCKETS OF LIGHT RAIN AND DRIZZLE POSSIBLE TONIGHT. LOW CHANCES
OF RAIN (20-40%) MAINLY EAST OF INTERSTATE 69 FOR WEDNESDAY,
BUT RAINFALL AMOUNTS ARE EXPECTED TO REMAIN LIGHT.
- DRY THURSDAY THROUGH THIS WEEKEND.
- THERE IS A MODERATE SWIM RISK THROUGH THIS EVENING FOR NORTHERN
LA PORTE COUNTY.
DISCUSSION
ISSUED AT 240 PM EDT TUE SEP 22 2026
A COOL/CLOUDY PATTERN SHOULD PERSIST THROUGH WEDNESDAY. A CUT-OFF
UPPER LEVEL LOW ACROSS NORTHERN ILLINOIS HAS BEEN RESPONSIBLE
FOR THE BULK OF SCATTERED SHOWER/ISOLATED THUNDERSTORM ACTIVITY
THIS AFTERNOON. IT IS POSSIBLE AS THIS MID/UPPER LEVEL WAVE
SHIFTS EAST INTO THIS EVENING A FEW RAIN SHOWERS/SPRINKLES COULD
MOVE INTO NW INDIANA. ACROSS THE LOCAL AREA, MODEL TIME/HEIGHT
SECTIONS DO INDICATE SOME WEAK FORCING/LIFT IN THE 800-700 MB
LAYER LIKELY DUE TO SOME ELEVATED WARM ADVECTION FORCING
DOWNSTREAM OF THE NORTHERN IL SHORT WAVE TROUGH. MOISTURE
PROFILES ARE RELATIVELY SHALLOW IN NATURE WITH INDICATIONS IN
CROSS SECTION DATA THAT THIS BETTER LIFT REMAINS JUST OFFSET
VERTICALLY ABOVE THE SHALLOW BETTER LOW LEVEL RH. THE RESULT OF
THIS LACK OF JUXTAPOSITION HAS MADE PRECIP PRODUCTION SOMEWHAT
INEFFICIENT TODAY WITH JUST SOME POCKETS OF LIGHT DRIZZLE AT
TIMES.
THROUGH TIME TONIGHT THE UPPER LEVEL SHORT WAVE ACROSS IL WILL
SHIFT EAST WITH SOME WEAK PHASING OF ANOTHER MID LEVEL HEIGHT
MINIMUM ACROSS NW OHIO. THIS GRADUAL PHASING SHOULD SUPPORT
CONTINUED RESPECTABLE EASTERLY FLOW AND SLIGHTLY DEEPER MOISTURE
PROFILES BEING ADVECTED WESTWARD INTO NE IN/NW OHIO OVERNIGHT
AND ESPECIALLY INTO WEDNESDAY. GIVEN MARGINAL MOISTURE DEPTHS
LINGERING THIS EVENING INTO THE OVERNIGHT, SOME QUESTION AS TO
EXTENT OF ANY RAIN GIVEN OVERALL WEAKLY FORCED NATURE OF THIS
SYNOPTIC SETUP AND OVERALL PREFERENCE TO WEAK SYNOPTIC SCALE
SUBSIDENCE. HOWEVER, COULD SEE JUST ENOUGH LIFT IN SLIGHTLY
DEEPENING MOISTURE PROFILES TO PROMOTE SOME POCKETS OF VERY
LIGHT RAIN OR DRIZZLE AND WILL LIKELY MAINTAIN THE 15 POPS.
DIURNAL RANGES FOR TEMPS SHOULD CONTINUE TO BE LIMITED TONIGHT
BY LACK OF DECOUPLING AND THE POTENTIAL OF LOW CLOUDS LINGERING.
THIS SHOULD LIMIT LOWS FROM DROPPING TOO MUCH, HOLDING IN THE
50 TO 55 DEGREE RANGE.
HAVE NOT MADE SIGNIFICANT CHANGES TO THE FORECAST FOR WEDNESDAY WITH
GREATER RAIN CHANCES (20-40%) GENERALLY ALONG AND EAST OF THE
INTERSTATE 69 CORRIDOR. HIGHER RES GUIDANCE DOES SUGGEST PRESENCE OF
POCKET OF WEAK MUCAPE AROUND 500 J/KG WORKING WESTWARD INTO NE IN/NW
OH GIVEN THE WEAK AFOREMENTIONED PHASING OF MID LEVEL FEATURES. THE
DEPTH OF INSTABILITY COULD BE JUST ENOUGH TO REALIZE THE WEAK
ELEVATED INSTABILITY. STILL SOME UNCERTAINTY PERSISTS REGARDING
COVERAGE AS DESPITE MID LEVEL TROUGH IN THE VICINITY THIS
APPEARS TO BE OTHERWISE A VERY WEAKLY FORCED SETUP. BY WEDNESDAY
EVENING, PRIMARY UPPER LOW SHOULD BEGIN TO SINK SOUTHEAST
ALLOWING ANY LINGER SHOWERS ACROSS NORTHEAST IN/NORTHWEST OH TO
DROP SOUTHEAST OF THE AREA. ANY ADDITIONAL RAINFALL ON WEDNESDAY
IS NOT EXPECTED TO SIGNIFICANTLY IMPACT ONGOING RIVER FLOOD
CONCERNS ACROSS MAUMEE/WABASH BASINS.
THE REMAINDER OF THE WORK WEEK INTO MUCH OF THE WEEKEND WILL FEATURE
A RATHER STAGNANT, BLOCKY PATTERN AS LARGE SCALE FLOW BEGINS TO
AMPLIFY. TEMPERATURE ADVECTIONS IN THIS PATTERN WILL REMAIN WEAK
THROUGH SUNDAY WHICH WILL KEEP BELOW NORMAL TEMPERATURES GOING INTO
SUNDAY. MEDIUM RANGE GUIDANCE HAS INDICATED A PACIFIC WAVE DAMPENING
THROUGH THE LONGWAVE RIDGE EARLY NEXT WEEK WITH PROSPECTS FOR PRECIP
LOOKING MINIMAL WITH THIS WAVE AS MOISTURE SHOULD STILL BE ON THE
MARGINAL SIDE. TEMPERATURES SHOULD MODERATE TOWARD THE END OF THIS
PERIOD AS WAVE PROGRESSION BEGINS TO INCREASE AND STRONGER SOUTHWEST
FLOW DEVELOPS.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 637 PM EDT TUE SEP 22 2026
A CLOUDY PATTERN WITH BREEZY NORTHEAST WINDS WILL PREVAIL
THROUGH THE TAF FORECAST PERIOD AS HIGH PRESSURE CENTERED OVER
ONTARIO AND QUEBEC BUILDS INTO THE GREAT LAKES REGION. VISIBLE
SATELLITE IMAGERY SHOWS MOSTLY CLOUDY TO OVERCAST SKIES ACROSS
THE AREA WITH SURFACE OBSERVATIONS REVEALING CEILINGS BETWEEN
1500-3000 FT. IFR CEILINGS PREVAIL AT KFWA CURRENTLY WITH LOW
END VFR AT KSBN, ALTHOUGH ADDITIONAL CLOUD COVER BY WEDNESDAY
MORNING LIFTS NORTH WITH WIDESPREAD IFR CEILINGS EXPECTED.
SCATTERED SHOWERS AND DRIZZLE MAY DEVELOP, ESPECIALLY NEAR AND
EAST OF KFWA TOMORROW. NORTHEAST WINDS WILL CONTINUE TO BE
SUSTAINED AROUND 10-12 KTS THROUGH THIS EVENING WITH GUSTS AS
HIGH AS 20 KTS, ESPECIALLY AT KFWA. WINDS REMAIN ELEVATED
OVERNIGHT AND THROUGH THE DAY WEDNESDAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...BEACH HAZARDS STATEMENT UNTIL 4 AM CDT WEDNESDAY FOR INZ103.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...JOHNSON
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