746
FXUS63 KIWX 291026
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
626 AM EDT MON JUN 29 2026
KEY MESSAGES
- ISOLATED SHOWERS AND EMBEDDED THUNDERSTORMS TOWARD THE I-69
CORRIDOR EARLY THIS MORNING.
- EXTREME HEAT WARNING IS IN EFFECT THROUGH THURSDAY EVENING
FOR AN EXTENDED PERIOD OF HIGH HEAT INDICES AND LIMITED
NIGHTTIME COOLING.
- HEAT MAY REMAIN A CONCERN FRIDAY, BUT CHANCES FOR SHOWERS AND
THUNDERSTORMS BEGIN TO INCREASE RESULTING IN LOWER CONFIDENCE
ON THE AMOUNT OF IMPACTS.
DISCUSSION
ISSUED AT 208 AM EDT MON JUN 29 2026
AN ISOLATED AREA OF SHOWERS PERSISTS EARLY THIS MORNING ASSOCIATED
WITH UPSTREAM CONVECTION EARLIER IN THE DAY, EMBEDDED WITHIN AN
UPPER-LEVEL DISTURBANCE NOW SPILLING OVER THE EASTERN GREAT LAKES.
DESPITE AN OVERALL ABSENCE OF MEANINGFUL UPPER-LEVEL SUPPORT, THIS
ACTIVITY HAS SURVIVED WITHIN A NARROW CORRIDOR OF 500 J/KG OF MUCAPE
AND MID-LEVEL LAPSE RATES NEAR 7.5 C/KM.
AN EXTREME HEAT WARNING REMAINS IN EFFECT THROUGH THURSDAY AS A 594
DM RIDGE BUILDS OVER THE AREA. DAILY HIGHS IN THE 90S WITH AFTERNOON
HEAT INDICIES OF 100-105 CAN TAKE ITS TOLL. AS MENTIONED IN THIS
SPACE, HEAT HEADLINES MAY NEED TO CARRY ON INTO FRIDAY BUT THE
POSSIBILITY OF SHOWERS AND STORMS DIMINISHES CONFIDENCE SOMEWHAT.
DURING THIS STRETCH OF HEAT, THE NAEFS DEPICTS 99TH PERCENTILE
TEMPERATURES AND UPPER-LEVEL HEIGHTS RELATIVE TO 1979-2009
CLIMATOLOGY. THIS HIGHLIGHTS THE MAGNITUDE OF THIS BOUT OF HEAT.
PRECIPITABLE WATER VALUES ARE IN THE 90TH PERCENTILE, MARKING AN
UNSEASONABLY HUMID AIR MASS.
HIGH TEMPERATURES ARE LIKELY SAFE THIS WEEK, WITH RECORDS OF 98 TO
101 NOTED AT FORT WAYNE AND SOUTH BEND. HOWEVER, "WARM" LOW
TEMPERATURE RECORDS MAY BE SET, WITH RECORDS CURRENTLY IN THE MID-
70S.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 621 AM EDT MON JUN 29 2026
VARIABLE CLOUDINESS THIS MORNING WITH DEBRIS CLOUDS FROM EARLIER
SHOWERS AND THUNDERSTORMS, AND EVEN FROM CONVECTION CROSSING FAR
NORTHERN LAKE MICHIGAN THIS HOUR. A WARM FRONT LIFTS NORTH TODAY
WHICH SHOULD ALLOW CEILINGS SHOULD SCT OUT. A FEW WIND GUST
NEAR 20 KNOTS THIS AFTERNOON WITH AN INCREASING PRESSURE
GRADIENT.
DURING THIS HOT AND HUMID STRETCH, CANNOT RULE OUT PATCHY
GROUND FOG DAILY NEAR SUNRISE. TIME HEIGHT CROSS SECTIONS
DEPICT LOW- LEVEL MOISTURE POOLING BENEATH A WEAK INVERSION, BUT
WIND TUESDAY MORNING ABOVE 5 KNOTS MAY KEEP ANY BR AT BAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...EXTREME HEAT WARNING FROM 2 PM EDT /1 PM CDT/ THIS AFTERNOON
TO 8 PM EDT /7 PM CDT/ THURSDAY FOR INZ005>009-012>015-
017-018-020-022>027-032>034-103-104-116-203-204-216.
OH...EXTREME HEAT WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT
THURSDAY FOR OHZ001-002-004-005-015-016-024-025.
MI...EXTREME HEAT WARNING FROM 2 PM THIS AFTERNOON TO 8 PM EDT
THURSDAY FOR MIZ078>081-177-277.
MARINE...NONE.
DISCUSSION...BROWN
AVIATION...BROWN
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