031
FXUS63 KIWX 121004
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
604 AM EDT SUN JUL 12 2026
KEY MESSAGES
- DRY AND TRENDING WARMER THROUGH THE MIDDLE OF THE WEEK.
- HIGHS IN THE UPPER 80S TO MID 90S BY TUESDAY AND WEDNESDAY,
WITH PEAK AFTERNOON HEAT INDICES UP NEAR 100 DEGREES.
- LOW CHANCES (20-30%) FOR SHOWERS AND STORMS RETURN LATE THIS
WEEK INTO NEXT WEEKEND.
DISCUSSION
ISSUED AT 225 AM EDT SUN JUL 12 2026
BUILDING HEAT AND HUMIDITY THE STORY THROUGH MIDWEEK AS AN EXPANSIVE
595-600 DAM 5H RIDGE OVER THE INTERMOUNTAIN WEST AND HIGH PLAINS
FOLDS EAST INTO THE GREAT LAKES BY TUESDAY AND WEDNESDAY. THIS WILL
CONTINUE TO FORCE THE OH VALLEY FRONTAL ZONE SOUTH WITH SFC HIGH
PRESSURE GENERALLY IN CONTROL WITH PLENTIFUL SUNSHINE AND DRY
CONDITIONS.
THE PEAK OF THIS NEXT SHOT OF MID SUMMER HEAT LOOKS TO BE TUESDAY
INTO WEDNESDAY AS THE UPPER LEVEL RIDGE FOLDS IN. THE POSITIONING OF
THIS FEATURE SHOULD GENERALLY KEEP DEEPER GULF MOISTURE OFF TO THE
WEST WHICH COULD ALLOW FOR PM SFC DEWPOINTS TO MIXOUT MORE INTO MID-
UPPER 60S, KEEPING PEAK PM HEAT INDICES JUST BELOW ADVISORY CRITERIA
(100F). THIS MAY BE OFFSET HOWEVER WITH HIGHER 70F PLUS DEWPOINTS
POSSIBLE GIVEN THE CLIMATOLOGICAL PEAK OF EVAPOTRANSPIRATION AND THE
POTENTIAL FOR MORE LIMITED MIXING DEPTHS UNDER THE RIDGE AXIS.
REGARDLESS OF HOW EXACTLY THIS PLAYS OUT IT WILL BE HOT/HUMID WITH
PEAK PM HEAT INDICES SOMEWHERE IN THE MID 90S TO NEAR 100F.
A MODEL CONSENSUS CONTINUES TO FAVOR A TREND TOWARD A MORE ACTIVE
NORTHWEST FLOW REGIME THURSDAY THROUGH NEXT WEEKEND. THIS
EVENTUALLY PUTS THE LOCAL AREA IN A FAVORED CORRIDOR FOR CONVECTIVE
COMPLEXES AS AN OSCILLATING THETA-E GRADIENT LAYS OUT FROM THE UPPER
MIDWEST INTO THE WESTERN/SOUTHERN GREAT LAKES WITH AT LEAST
LOW DAILY CHANCES (20-30%) FOR A ROUND OR TWO OF CONVECTION.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 604 AM EDT SUN JUL 12 2026
VFR/DRY THROUGH THE PERIOD WITH NORTHEASTERLY WINDS GENERALLY
5-10 KNOTS AS RIDGING CONTINUES TO BUILD IN.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...STEINWEDEL
AVIATION...STEINWEDEL
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