866
FXUS63 KIWX 130915
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
515 AM EDT MON OCT 13 2025
KEY MESSAGES
- FOG, LOCALLY DENSE, WILL QUICKLY LIFT THIS MORNING.
- HIGHS IN THE 70S ARE EXPECTED INTO TUESDAY AND AGAIN FRIDAY
INTO SATURDAY, WITH MORE SEASONABLE TEMPERATURES IN THE 60S IN
BETWEEN AS WELL AS FOR THE WEEKEND.
- CHANCES FOR SHOWERS AND POSSIBLY THUNDERSTORMS (30 TO 55%)
ARRIVE FOR THE WEEKEND.
UPDATE
ISSUED AT 511 AM EDT MON OCT 13 2025
VSBYS RAPIDLY DROPPING IN THE NE THIRD TO HALF OF THE AREA,
WARRANTING ISSUANCE OF A DENSE FOG ADVISORY. HIGH CLOUDS ARE
MOVING IN FROM THE WEST AND NORTH WHICH MAY LIMIT WESTWARD
EXTENT OF THE FOG AND COULD ERODE THE LOWER VSBYS ON THE WESTERN
EDGE OF THE HEADLINES (GENERALLY SR 15/US 131). STILL WENT
AHEAD AND INCLUDED THESE AREAS. MUCH LIKE YESTERDAY, ANTICIPATE
IMPROVEMENT IN THE 13-14Z TIME FRAME, SO ENDED THE ADVISORY AT
14Z. OTHERWISE, NO CHANGES TO THE FORECAST.
DISCUSSION
ISSUED AT 252 AM EDT MON OCT 13 2025
WEAK NE FLOW IS ONCE AGAIN ADVECTING IN A MOIST, SHALLOW MARINE
LAYER WITH SHALLOW GROUND FOG ALREADY IN PLACE IN PORTIONS OF NW
OHIO. GRIDS IN DECENT SHAPE WITH FOG MENTION ALREADY, BUT WILL
MONITOR OBS FOR POSSIBLE DENSE FOG ADVISORY. ANY FOG WILL QUICKLY
BURN OFF BY 13-14Z AS TEMPERATURES CLIMB INTO THE LOW TO MID 70S AS
UPPER LEVEL RIDGING TAKES HOLD FOR THE NEXT COUPLE OF DAYS.
THE RIDGE AXIS WILL FLATTEN TUESDAY NIGHT, THEN REBUILD BACK TO THE
WEST OF THE REGION AS A WEAK TROUGH PASSES TO OUR NE. A COLD FRONT
WILL DROP INTO THE AREA LATE TUESDAY NIGHT, BUT MAJORITY OF ANY
PRECIP (WHICH WILL STILL BE LIGHT) LOOKS TO FIZZLE AS IT ARRIVES IN
OUR NW COUNTIES LATE TUESDAY NIGHT, ENCOUNTERING A DRY LOW LEVEL
AIRMASS. MODEL BLENDS STILL HOLDING ONTO SLGT CHC TO CHC POPS IN
THESE AREA, WHICH WILL BE LEFT ALONE FOR NOW. TEMPERATURES WILL
SETTLE BACK TO SEASONABLE LEVELS IN THE MID 60S WED AND MID 60S NE
TO LOW 70S SW AS THE HEIGHTS BEGIN TO INCREASE ONCE AGAIN.
THE RIDGE AXIS WILL SHIFT OVERHEAD FRIDAY AND THEN EAST SATURDAY
WITH AN INCREASING SW FLOW ALOFT ALLOWING HIGHS BACK INTO THE LOW TO
MID 70S. AS THIS FLOW CONTINUES, LOW LEVEL MOISTURE WILL BEGIN TO
INCREASE AS A LONGWAVE TROUGH AND SERIES OF WAVES ATTEMPT TO BRING
SHOWER AND THUNDERSTORM CHANCES BACK INTO THE FORECAST. MODEL BLEND
INTRODUCED SOME LOW END LIKELY POPS IN NW AREAS SAT INTO SAT
EVENING, LIKELY KEYING IN ON THE MORE AGGRESSIVE GFS WITH A
STRONGER WAVE MOVING INTO THE AREA VS MAJORITY OF THE TROUGH
STILL TO THE WEST ON THE ECMWF. ALTHOUGH THIS MAY BE OVERDONE,
WILL LEAVE IT IN AS IT IS LIKELY TO KEEP CHANGING IN THE COMING
DAYS. ADDITIONAL CHANCES FOR RAIN WILL LINGER THROUGH THE END OF
THE PERIOD.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 141 AM EDT MON OCT 13 2025
PREDOMINANTLY VFR CONDITIONS FOR BOTH TERMINALS THROUGH THE
PERIOD, WITH THE EXCEPTION OF POTENTIAL FOG/STRATUS DEVELOPMENT
CAUSING MVFR/IFR CONDITIONS (POTENTIALLY LOWER AT KFWA) LATE
TONIGHT INTO EARLY MONDAY MORNING. LIGHT E-SE FLOW WILL PERSIST
THROUGH MONDAY, WITH PERIODS OF NEARLY CALM/LIGHT AND VARIABLE
WINDS (ESPECIALLY EARLY THIS MORNING AND THEN AGAIN THIS EVENING
INTO THE OVERNIGHT). PERSISTED WITH THE PREVIOUS FORECAST RE:
FOG AS IT APPEARS TO BE ON TRACK BASED ON THE LATEST GUIDANCE
AND CURRENT OBSERVATIONS. MAINTAINED THE 4SM BR AT KSBN GIVEN
LOWER CONFIDENCE--IT'S POSSIBLE HIGH CLOUDS (10K-25K) TO THE
WEST BUILD IN TOWARDS DAYBREAK AND LIMIT RADIATIONAL COOLING
(SOME GUIDANCE ONLY DROPS TO 6SM).
THE MAIN CHANGE THIS ISSUANCE WAS TO LOWER KFWA FROM AN MVFR
TEMPO DOWN TO IFR BETWEEN 10-13Z. AS THE PREVIOUS DISCUSSION
MENTIONED, LIGHT FLOW OFF THE LOWER LAKES IS ADVECTING HIGHER
SURFACE DEWPOINTS FURTHER WESTWARD. AT THE MOMENT, KUSE (FULTON,
OH) AND THE TOLEDO AREA ARE REPORTING VISIBILITIES BETWEEN
1/4SM AND 2SM. FURTHER NORTH NEAR DETROIT, ANN ARBOR HAS BEEN
REPORTING 1/4SM TO 3SM THROUGH THE EVENING. SKIES WILL REMAIN
MOSTLY CLEAR OUTSIDE OF A FEW CLOUDS AROUND 25KFT (IT'S UNCLEAR
HOW FAR EASTWARD THE CLOUDS OVER WESTERN IL WILL MAKE IT),
CREATING OPTIMAL CONDITIONS FOR RADIATIONAL COOLING. FOR NOW THE
TEMPO HAS 3SM BETWEEN 10-13Z, HOWEVER ITS VERY POSSIBLE WE DROP
TO LIFR/VLIFR CONDITIONS (EITHER WITH VERY LOW STRATUS OR
VISIBILITIES). GUIDANCE SUGGESTS BETWEEN 2-4SM, EXCEPT THE NAM
WHICH SUGGESTS 1/4 TO 1/2SM BETWEEN 11-13Z WITH POTENTIAL FOR
BKN003. AT THE MOMENT MOST OF THE SURROUNDING SITES ARE 10SM,
WITH THE EXCEPTION OF KGWB (2 1/2 SM) AND KC62/KDFI (5SM). WILL
MONITOR TRENDS AND AMEND IF THE LOWER VISIBILITIES/CEILINGS
BECOME MORE WIDESPREAD AND LOOK TO IMPACT THE TERMINAL.
IWX WATCHES/WARNINGS/ADVISORIES
IN...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR INZ005>009-
017-018-024>027-033-034-116-216.
OH...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR OHZ001-002-
004-005-015-016-024-025.
MI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MIZ079>081.
MARINE...NONE.
UPDATE...FISHER
DISCUSSION...FISHER
AVIATION...MCD
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