968 FXUS63 KIWX 141014 AFDIWXArea Forecast Discussion National Weather Service Northern Indiana 614 AM EDT Sun Sep 14 2025
.KEY MESSAGES...
- Very warm through Thursday with highs in the mid to upper 80s.
- Dry through Thursday with chances for showers and thunderstorms starting Friday.
- Afternoon relative humidities will drop below 40 percent most days this coming week.
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.DISCUSSION... Issued at 141 AM EDT Sun Sep 14 2025
There was a very weak pressure gradient over the region with a light east flow over much of the forecast area. Weak high pressure will continue over the area and should keep winds under 10 mph. Clouds with bases near 5K to 6K feet were over the area at the onset of the forecast. These clouds should scatter out and then dissipate as large scale subsidence increases over the area as reflected in the latest GFS BUFKIT forecast soundings. There are very few if any chances for rain until late this week as the low and mid layers of the atmosphere remain too dry to support precipitation.
An upper level ridge will continue to build into the region through Thursday and keep very warm temperatures over the area. Temperatures may even rise above 90 degrees south of Highway 30 this upcoming week as the ridge builds east into the Upper Great Lakes region and as drought feedback increases. The latest GFS indicates the ridge heights will rise to near 300 meters above climatological norms (anomaly).
The ridge will break down rapidly Friday as an upper level system moves into the area. Conditions will become much more favorable for showers and thunderstorms into the weekend. The latest GFS has steep lapse rates with CAPEs rising above 1000 J/Kg Saturday. Although environment winds are not very strong, these steep lapse rates and the instability will likely be sufficient to produce gusty winds with any of the stronger showers and storms.
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.AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 608 AM EDT Sun Sep 14 2025
KSBN is reporting a 4 degree dew point depression this hour. As a result, have removed the TEMPO BR.
Pesky VFR stratus deck persists but its presentation on satellite is waning. Therefore, high confidence in BKN stratus becoming SCT/FEW near 14z or so at KFWA. High pressure today will once again provide tranquil conditions and a light ESE wind. Wind near 5 knots overnight may be enough to limit the overall patchy fog potential as well.
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.IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None.
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DISCUSSION...Skipper AVIATION...Brown
NWS IWX Office Area Forecast Discussion