129
FXUS63 KIWX 281727
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
127 PM EDT SAT JUN 28 2025
KEY MESSAGES
- BRIEF REPRIEVE FROM THE MUGGY CONDITIONS TODAY BEFORE
HUMIDITY LEVELS INCREASE SOMEWHAT FOR SUNDAY INTO MONDAY.
HIGHEST HEAT INDICIES SUNDAY IN THE MID TO UPPER 90S.
- COLD FRONT BRINGS A CHANCE FOR SHOWERS AND STORMS MONDAY
AFTERNOON AND EVENING. LOCALLY HEAVY RAIN AND GUSTY WINDS WILL
BE THE MAIN THREATS.
- REMAINDER OF THE PERIOD WILL BE DOMINATED MY HIGHS IN THE 80S
AND LOWS IN THE 60S WITH MORE TYPICAL HUMIDITY LEVELS. HEAT
RELATED IMPACTS ARE NOT EXPECTED.
DISCUSSION
ISSUED AT 332 AM EDT SAT JUN 28 2025
A SUBTLE BOUNDARY EXTENDED FROM CENTRAL IN TO OUR FAR SE CWA.
SOME NEW CONVECTION HAS BEEN DEVELOPING MORESO ACROSS CENTRAL IN
AND COULD POSSIBLY EXPAND SOMEWHAT NE TO CLIP THE FAR SE AREAS,
SO WILL MAINTAIN THE SLGT CHC POPS IN THAT AREA PRIOR TO 12Z.
THE MAIN "COOL FRONT" WAS TAKING ITS SWEET TIME WORKING SE
ACROSS NW IN/SW LOWER MI WITH MID 60 DEWPOINTS BEHIND IT AND
EVENT LOWER VALUES (MID TO UPPER 50S) IN PORTIONS OF WI. THE
"DRIER" AIR WILL SLOWLY WORK THROUGH THE FORECAST AREA TODAY,
WITH DEWPOINTS EVERYWHERE DROPPING INTO THE 60S (LOWEST NW) BY
AFTERNOON WHICH WILL FEEL MUCH BETTER AFTER THE EXTENDED
TROPICAL TYPE AIRMASS. SOME STRATUS WAS NOTED ACROSS WI BUT
MODELS SEEM TO EITHER DISSIPATE THIS OR SHIFT MORE EASTWARD SO
WE SHOULD SEE A GOOD DEAL OF SUNSHINE TODAY. THE FRONT WILL
BEGIN TO RETURN BACK NORTH SUNDAY INTO EARLY MONDAY, BRINGING
THE HIGHER DEWPOINTS BACK FOR ANOTHER, MUCH BRIEFER VISIT. HIGHS
SUNDAY WILL CLIMB WELL INTO THE 80S AND CAN'T RULE OUT A FEW
90S, BUT HEAT INDICIES SHOULD REMAIN JUST BELOW ADVISORY LEVELS
(IN THE 90S) SO HEADLINES DON'T APPEAR LIKELY AT THIS POINT.
A SOMEWHAT STRONGER TROUGH WILL DIVE SOUTHEAST AND DEEPEN SOMEWHAT
AS IT MOVES ACROSS THE GREAT LAKES MONDAY INTO EARLY TUESDAY. THE
OVERALL ATMOSPHERE WILL HAVE SIMILAR CHARACTERISTICS TO WHAT WE HAVE
DEALT WITH THE PAST SEVERAL DAYS WITH 1000 TO 1500 J/KG OF MLCAPE,
MODEST SHEAR AND MINIMAL LAPSE RATES RESULTING IN MORE OF A PULSE
STORM SETUP (MAYBE SOME LOOSELY ORGANIZED MULIT-CELL CLUSTERS) AND
ASSOCIATED MARGINAL WIND THREAT AND LOCALLY HEAVY RAIN. SOME MODELS
HINT AT MORE OF A PRE-FRONTAL TROUGH SPARKING SCATTERED TO NUMEROUS
SHOWERS AND STORMS THROUGH THE DAY MONDAY BEFORE THE MAIN COLD FRONT
ARRIVES MONDAY NIGHT WITH SOMEWHAT BETTER SHEAR PROFILES. BY THIS
TIME, THE AREA COULD BE WORKED OVER RESULTING IN LITTLE ADDITIONAL
DEVELOPMENT. THE NEW SPC DY3 HAS ADDED A MARGINAL RISK TO
ESSENTIALLY THE ENTIRE CWA TO ACCOUNT FOR THESE CONCERNS. IF
CONVECTION HAS LESS OVERALL COVERAGE AHEAD OF THE FRONT, A SOMEWHAT
HIGHER SEVERE THREAT COULD MATERIALIZE AS THE FRONT SWEEPS THROUGH.
MORE APPRECIABLE LOWERING OF DEWPOINTS WILL OCCUR LATE MONDAY AND
PERSIST THROUGH THE REMAINDER OF THE PERIOD (GENERALLY LOW TO MID
60S) WITH MORE SEASONABLE HIGHS IN THE LOW TO MID 80S. SOME TOKEN
SLIGHT CHC TO CHC POPS REMAIN IN THE LATER PERIODS AS A FRONTAL
BOUNDARY MAY BE DRAPED SOMEWHERE IN THE AREA ON THE EDGE OF THE
SOMEWHAT INCREASED RIDGING ALOFT.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 126 PM EDT SAT JUN 28 2025
AN AREA OF HIGH PRESSURE SLOWLY MOVES EASTWARD ALLOWING THE AREA TO
BE ON THE WESTERN SIDE OF IT BY SUNDAY, WHICH ALLOWS A RETURN OF THE
HUMIDITY WITH DEW POINTS RISING BACK INTO THE 70S. DEPENDING ON HOW
QUICKLY THIS LOW LEVEL MOISTURE MOVES IN, SOME FOG/BR COULD FORM,
BUT THE QUESTION IS HOW FAR IS IT ABLE TO GET. GIVEN THIS
UNCERTAINTY, HAVE LEFT IT OUT OF THIS TAF ISSUANCE. OTHERWISE,
EXPECT VFR CONDITIONS AS THE SURFACE HIGH PRESSURE MOVES THROUGH.
NORTHWEST WINDS THIS AFTERNOON REMAIN BELOW 10 KTS SUSTAINED, BUT
WILL BECOME SOUTHEAST TO SOUTH WINDS ON SUNDAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...FISHER
AVIATION...ROLLER
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