611
FXUS63 KIWX 281030
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
630 AM EDT SUN JUN 28 2026
KEY MESSAGES
- ISOLATED (15-20%) SHOWERS EARLY THIS MORNING MAINLY
ALONG/SOUTH OF ROUTE 24.
- DANGEROUS HEAT AND HUMIDITY STARTING MONDAY AS HEAT INDICES
CLIMB ABOVE 100 DEGREES EACH AFTERNOON WITH LITTLE COOLING AT
NIGHT. AN EXTREME HEAT WATCH IS IN EFFECT.
DISCUSSION
ISSUED AT 217 AM EDT SUN JUN 28 2026
ISOLATED SHOWERS EARLY THIS MORNING IN THE VICINITY OF OUR PERSISTENT
STATIONARY FRONT BISECTING CENTRAL-NORTHERN INDIANA. AN AMPLIFYING
UPPER-LEVEL RIDGE FINALLY KICKS THIS FRONT OUT OF THE AREA THIS
AFTERNOON. THIS RIDGE PUSHES HIGHS INTO THE MID-80S WITH DEW POINTS
RISING INTO THE 70S SOUTH OF US 30. AS MENTIONED IN THE PRECEDING
FORECAST DISCUSSION, AN MCS EARLY THIS MORNING IS FORECAST TO MOVE
INTO MINNESOTA AS THE DAY PROGRESSES. MODELS ARE IN FAIR AGREEMENT
THAT THIS MCS WILL DECAY PRIOR TO REACHING INDIANA NEAR OR JUST
BEFORE SUNSET. WE'LL CARRY ON WITH THE DRY FORECAST AS INHERITED
OWING IN PART TO A CONTINUED STEADY, STABLE EASTERLY WIND WHICH HAS
KEPT SHOWERS LARGELY AT BAY SINCE FRIDAY.
FOR THIS MORNING, FINALLY OPTED TO ISSUE A EXTREME HEAT WATCH FOR
THE UPCOMING DAYS OF HEAT. DESPITE IN-HOUSE MODEL BLEND BIASES, WHEN
USING OTHER BLENDS OF GUIDANCE FOR TEMPERATURE AND DEW POINTS, HIGHS
IN THE 90S AND HEAT INDICIES OF 100-105 OFFER HIGH ENOUGH
CONFIDENCE IN HAZARDOUS HEAT MONDAY THROUGH AT LEAST THURSDAY TO
WARRANT A WATCH. GIVEN THE DURATION OF THESE TRIPLE-DIGIT HEAT
INDICIES, WE HAVE THE FLEXIBILITY TO CONSIDER AN EXTREME HEAT
WARNING IN PLACE OF DAILY ADVISORIES (105 HEAT INDEX VS 100 HEAT
INDEX). GIVEN THE PRECEDING TWO WEEKS OF BELOW-NORMAL
TEMPERATURES AND A GENERAL ABSENCE OF HEAT SO FAR THIS SUMMER, A
100 HEAT INDEX VS 105 HEAT INDEX OVER FOUR DAYS SEEMS TO BE
SPLITTING HAIRS. ANYWAY, EXTREME HEAT WATCH GETS THE BALL
ROLLING.
THE 594DM RIDGE IS POISED TO BE OVERHEAD TUESDAY AND WEDNESDAY,
MARKING THE PEAK OF THIS HEAT WAVE. THURSDAY NIGHT AND MORESO
FRIDAY, THE RIDGE SHOWS SIGNS OF WEAKENING IN THE GUIDANCE AS A
SHORTWAVE EMERGES FROM THE FOUR CORNERS AND THE RIDGE CENTROID FAVORS
THE APPALACHIANS. THIS WOULD ALLOW GULF MOISTURE TO STREAM POLEWARD
PERHAPS ALLOWING FOR AN ACTIVE PERIOD OF SHOWERS AND THUNDERSTORMS
TO BREW LATE-WEEK. WHILE THE 594DM RIDGE BECOME DISPLACED LATE-WEEK,
MARKING AN END TO "EXTREME HEAT" THE OVERALL UPPER AIR PATTERN
CHARACTERIZED BY CENTRAL US RIDGING LOOKS TO KEEP SUMMER HEAT IN
PLACE THROUGH THE HOLIDAY WEEKEND.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 627 AM EDT SUN JUN 28 2026
MVFR STRATUS IS SEEPING EAST-WEST ALONG A STATIONARY FRONT
SOUTH OF KFWA. WATER VAPOR IMAGERY SHOWS THIS AREA OF STRATUS
DRIFTING EAST WITH THE MEAN FLOW, THUS, MEDIUM-HIGH CONFIDENCE
IN CONDITIONS IMPROVING LATER THIS MORNING AS UPPER-LEVEL
RIDGING TAKE SHAPE. IN CONTRAST, IT APPEARS KSBN STILL HAS AN
OPPORTUNITY TO REMAIN VFR WITH LOCAL HIGH PRESSURE MAINTAINING
JUST ENOUGH INFLUENCE TO FEND OFF THIS STRATUS AREA A LITTLE
LONGER. STEADY EAST WIND TODAY BECOMING SOUTHEAST LATE, ALONG
WITH DEBRIS CLOUDS FROM UPSTREAM CONVECTION FILLING IN LATE.
IWX WATCHES/WARNINGS/ADVISORIES
IN...EXTREME HEAT WATCH FROM MONDAY AFTERNOON THROUGH THURSDAY
EVENING FOR INZ005>009-012>015-017-018-020-022>027-
032>034-103-104-116-203-204-216.
OH...EXTREME HEAT WATCH FROM MONDAY AFTERNOON THROUGH THURSDAY
EVENING FOR OHZ001-002-004-005-015-016-024-025.
MI...EXTREME HEAT WATCH FROM MONDAY AFTERNOON THROUGH THURSDAY
EVENING FOR MIZ078>081-177-277.
MARINE...NONE.
DISCUSSION...BROWN
AVIATION...BROWN
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