928
FXUS63 KIWX 031850
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
250 PM EDT FRI OCT 3 2025
KEY MESSAGES
- WARM AND DRY FOR THE WEEKEND THROUGH EARLY MONDAY. HIGH TEMPERATURES
WELL ABOVE NORMAL IN THE MID TO UPPER 80S.
- MINIMUM RELATIVE HUMIDITIES AS LOW AS 25% TO 40% OVER THE
WEEKEND MAY BE CONDUCIVE FOR ELEVATED FIRE DANGER. THE DAY
WITH THE GREATEST POTENTIAL OF AN ELEVATED FIRE DANGER APPEARS
TO BE SUNDAY DUE TO LOWER AMOUNTS OF MOISTURE AND AN INCREASE
IN WIND GUSTS.
- CHANCES FOR RAIN ARRIVE LATE MONDAY NIGHT THROUGH TUESDAY. RAINFALL
AMOUNTS OF 0.25" TO 0.50" EXPECTED (LOCALLY HIGHER AMOUNTS
POSSIBLE). RAINFALL THIS PERIOD IS NOT EXPECTED TO HAVE A
SIGNIFICANT IMPACT ON THE ONGOING DROUGHT CONDITIONS.
- NOTICEABLY COOLER BY MIDWEEK WITH TEMPERATURES CLOSER TO SEASONABLE
LEVELS. HIGHS IN THE LOW TO MID 60S WITH LOWS IN THE 40S TO
UPPER 30S POSSIBLE.
DISCUSSION
ISSUED AT 250 PM EDT FRI OCT 3 2025
WARM AND DRY CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEKEND
AND LIKELY INTO AT LEAST THE EARLY PORTIONS OF MONDAY.
AN UPPER LEVEL SHORT WAVE WHICH HAS BEEN INGESTED FROM THE SOUTHERN
PLAINS OVER THE PAST FEW DAYS WILL CONTINUE TO GET SHEARED AND
WEAKEN ACROSS THE WESTERN GREAT LAKES REGION INTO THIS EVENING. RAP
ANALYSES INDICATE A COUPLE OF LOW LEVEL WEST-EAST ORIENTED THETA-E
GRADIENTS THIS AFTERNOON, THE FIRST ACROSS NORTH CENTRAL INDIANA,
AND A SECOND ACROSS EXTREME NORTHWEST INDIANA. THIS WESTWARD
DISPLACED THETA-E GRADIENT ACCOMPANYING THE WEAKENING SHORT WAVE
REPRESENTS THE PRIMARY SFC BASED INSTABILITY GRADIENT INTO EARLY
THIS EVENING. EARLIER THIS MORNING, DID HAVE A FEW SHOWERS/SPRINKLES
ATTEMPT TO DEVELOP ACROSS NORTHEAST ILLINOIS AND WOULD SUSPECT A FEW
ISOLATED SHOWERS MAY TRY TO REDEVELOP THIS AFTERNOON/EVENING ACROSS
NW IN NEAR THIS WEAK INSTABILITY GRADIENT. A WEAK MID LEVEL
SUBSIDENCE INVERSION MAY TEND TO DISCOURAGE ANY LONGER "SKINNY" CAPE
PROFILES THIS AFTERNOON. GIVEN MARGINAL INSTABILITY AND DRY SUBCLOUD
LAYER, WILL KEEP POPS BELOW MENTIONABLE LEVELS INTO THIS EVENING BUT
IT IS POSSIBLE SOME ISOLD SHOWER/SPRINKLE MENTION MAY BE NEEDED
FOR LATE AFTERNOON/EARLY EVENING.
OTHERWISE FOR TONIGHT, QUIET WEATHER CONTINUES. EASTWARD ADVECTION
OF THIS HIGHER THETA-E AIR SHOULD PROMOTE WARMER MINS TONIGHT IN
COMPARISON TO YESTERDAY, GENERALLY FROM THE MID 50S TO LOWER 60S
(COOLEST READINGS ACROSS THE FAR EAST WHERE DRIER LOW LEVEL AIR
MAY LINGER).
THE MAIN WEATHER STORY FOR SATURDAY WILL BE WARMER CONDITIONS AS
SOME SUBTLE INCREASES IN SOUTHWEST LOW LEVEL FLOW ALLOW MID MS
VALLEY LOW LEVEL THERMAL RIDGE TO ADVECT ACROSS THE SOUTHERN GREAT
LAKES. THE WARMEST LOW LEVEL THERMALS APPEAR TO ADVECT ACROSS
NORTHERN HALF OR THIRD OF THE FORECAST AREA FOR SATURDAY, BUT VERY
DRY SOILS AND ONGOING DROUGHT CONDITIONS MAXIMIZED ACROSS FAR NE
IN/NW OH COULD SUPPORT SOME BETTER SUPERADIABATS FOR THESE
LOCATIONS. THE END RESULT SHOULD BE A FAIRLY UNIFORM MAX TEMPERATURE
DISTRIBUTION FOR SATURDAY WITH HIGHS IN THE MID TO UPPER 80S.
MINIMUM RH VALUES MAY DROP TO AROUND 30 PERCENT IN THE AFTERNOON AS
LOW LEVEL DEW POINTS MIX OUT. THIS MAY RESULT SOME ADDITIONAL
GRASS/FIELD FIRES ACROSS THE AREA, BUT WIND GUSTS SHOULD BE LIMITED
TO THE 10 TO 15 MPH RANGE.
SUNDAY COULD FEATURE THE GREATEST POTENTIAL OF ELEVATED FIRE DANGER.
LOW LEVEL ANTICYCLONIC FLOW MAY ACTUALLY YIELD SOME VERY WEAK
LOW LEVEL CAA ON SUNDAY WHICH COULD TAKE A FEW DEGREES OFF HIGH
TEMPS IN COMPARISON TO SUNDAY. HOWEVER, THE POTENTIAL OF SOME
BETTER MIXING AND INFLUX OF SOME DRIER LOW LEVEL AIR MAY RESULT
IN MINIMUM AFTERNOON RH VALUES INTO THE 20 TO 30 PERCENT RANGE.
BOUNDARY LAYER AVERAGED WINDS OF AROUND 20 KNOTS SHOULD ALLOW
FOR PEAK AFTERNOON GUSTS TO AROUND 25 MPH AT TIMES, MAINLY
ACROSS THE WEST/NORTHWEST WHERE STRONGEST LOW LEVEL HEIGHT
GRADIENT IS EXPECTED.
OVERALL, NOT MUCH HAS CHANGED WITH REGARD TO THE INCREASING PRECIP
POTENTIAL LATER MONDAY THROUGH TUESDAY. A FEW DISTINCT AREAS OF
FORCING WILL BE MONITORED INCLUDING FRONTALLY FORCED PRECIP ACROSS
THE NORTHWEST, AND A SECOND POSSIBLE FOCUS OF BETTER PRE-FRONTAL
MOISTURE TRANSPORT FROM THE LOWER OHIO RVR VALLEY INTO NORTHEAST
IN/NORTHWEST OH. THE BEST MOISTURE WILL BE TIED TO THIS SECOND AREA
OF PRE-FRONTAL MOISTURE TRANSPORT, BUT SLOW MOVING NATURE OF LOW/MID
LEVEL BAROCLINIC AND SOME POOLING OF MOISTURE COULD COMPENSATE.
A BIT OF A CONCERN THAT THE NATURE OF THESE TWO FORCING
MECHANISMS COULD SPLIT LOCAL AREA WITH THE MORE ROBUST RAINFALL
AMOUNTS. HOWEVER GIVEN LARGE SCALE POSITIVELY TILTED TROUGH
EVOLUTION AND ANOMALOUS MOISTURE PROFILES, WILL CONTINUE TO
CARRY LIKELY POPS THIS PERIOD. EARLY INDICATIONS MIGHT ALSO
SUGGEST GREATEST POTENTIAL OF GREATER THAN 0.50" OF RAIN WOULD
BE ACROSS NE IN/NW OH WHERE FRONT MAY HAVE SOME BETTER DEPTH OF
PRE-FRONTAL MOISTURE TO WORK WITH.
NO MAJOR CHANGES TO REMAINDER OF THE FORECAST WITH PRIMARILY DRY
CONDITIONS AND TEMPERATURES DROPPING TO NEAR NORMAL OR SLIGHTLY
BELOW NORMAL LEVELS.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1203 PM EDT FRI OCT 3 2025
VFR CONDITIONS, LIGHT WINDS, AND MAINLY CLEAR SKIES WILL PERSIST
AGAIN THIS PERIOD ON THE BACKSIDE OF HIGH PRESSURE.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...MARSILI
AVIATION...STEINWEDEL
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