521
FXUS63 KIWX 150517
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
117 AM EDT FRI AUG 15 2025
KEY MESSAGES
- HOT AND HUMID CONDITIONS RETURN THIS WEEKEND WITH PEAK AFTERNOON
HEAT INDICES IN THE MID 90S TO NEAR 100 DEGREES.
- PERIODIC CHANCES FOR STORMS (20-40%) SUNDAY THROUGH TUESDAY.
- COOLER AND LESS HUMID CONDITIONS FOLLOWS WEDNESDAY THROUGH
FRIDAY.
DISCUSSION
ISSUED AT 210 PM EDT THU AUG 14 2025
A FEW SHOWERS HAVE DEVELOPED NEAR A SUBTLE LOW LEVEL CONVERGENT
BOUNDARY IN NW OH AND SC MI THIS AFTERNOON THANKS TO LINGERING
BOUNDARY LAYER MOISTURE AND SUFFICIENT HEATING. THESE SHOWERS MAY
CONTINUE TO FESTER NEAR THIS BOUNDARY THROUGH THE REMAINDER OF THE
AFTERNOON. STABLE AND DRY CONDITIONS ON THE SOUTHERN FRINGE OF SFC
HIGH PRESSURE WILL DOMINATE OTHERWISE INTO TONIGHT AND FRIDAY WITH
DRY CONDITIONS AND PLEASANT HUMIDITY LEVELS. A WEAK SHORTWAVE WILL
TRACK EAST THROUGH THE GREAT LAKES TONIGHT INTO FRIDAY MORNING WITH
NOTHING MORE THAN SOME PASSING CLOUDS GIVEN AN OVERALL DEARTH OF
MOISTURE. FRIDAY WILL BE A FEW DEGREES WARMER THAN TODAY OTHERWISE
AS LOW LEVEL FLOW TRAJECTORIES VEER MORE SOUTHERLY IN WAKE OF THE
SFC HIGH PRESSURE CENTER.
THE NORTHERN PERIPHERY OF THE HEAT DOME (SUBTROPICAL UPPER RIDGE)
BUILDS NORTHEAST INTO THE LOWER GREAT LAKES REGION THIS WEEKEND WITH
A RETURN TO HOT AND HUMID CONDITIONS. PEAK PM HEAT INDICES WILL
LIKELY MAKE A RUN AT THE MID 90S TO NEAR 100F IN MANY LOCATIONS EACH
DAY. SEVERAL CONVECTIVE COMPLEXES WILL LIKELY CREST THIS RIDGE
OVER THE WEEKEND, MAINLY IMPACTING AREAS OFF TO THE NORTH ACROSS THE
UPPER MIDWEST AND NORTHERN/CENTRAL GREAT LAKES. WITH THAT SAID,
CANNOT RULE OUT CLOUD DEBRIS AND COMPOSITE OUTFLOWS CLIPPING
NORTHERN AND EASTERN PORTIONS OF THE LOCAL AREA, BEST CHANCES (20-
40% STORMS) MAINLY IN THE SATURDAY NIGHT-SUNDAY PERIODS.
SUBTROPICAL UPPER LEVEL RIDGE RETROGRADES BACK TO THE WEST NEXT WEEK
WITH A COLD FRONTAL PASSAGE ANTICIPATED AROUND TUESDAY IN THIS
TRANSITION WITH CHANCES (30-50%) FOR CONVECTION. DRIER AND LESS
HUMID AIR SHOULD THEN SETTLE IN FOR THE MID-LATE WEEK PERIODS PER A
MODEL CONSENSUS.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 116 AM EDT FRI AUG 15 2025
AN UPPER LEVEL RIDGE WILL BUILD NORTHEAST INTO THE OHIO VALLEY AND
MIDWEST. VERY WEAK ENERGY MAY BE ABLE TO TOP THE RIDGE, BUT
GIVEN THE VERY STABLE CONDITIONS, ONLY AN ISOLATED SHOWER OR
STORM IS EXPECTED FRIDAY AFTERNOON. HAVE KEPT SHOWERS AND STORMS
OUT OF TAFS. PATCHY GROUND FOG IS POSSIBLE IN THE 1130Z TO
1330Z WINDOW, BUT HAVE ALSO KEPT FOG OUT OF TAFS GIVEN
UNCERTAINTY WITH DRIER AIR. WINDS SHOULD REMAIN UNDER 10 KNOTS
GIVEN THE WEAK SURFACE FLOW.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...NONE.
DISCUSSION...STEINWEDEL
AVIATION...SKIPPER/MCD
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