541 FXUS63 KIWX 111859 AFDIWXArea Forecast Discussion National Weather Service Northern Indiana 259 PM EDT Thu Sep 11 2025
.KEY MESSAGES...
- Pleasant weather continues with light winds and highs in the mid 80s on Friday.
- Minimum relative humidities of 30% to 40% each afternoon may be conducive for elevated fire danger.
- Low chances (around 20%) for showers and storms Saturday afternoon through Sunday morning; No significant rain is expected through the end of next week.
- A warm and dry pattern will become well established by the weekend into early next week with temperatures well above normal. Highs in the upper 80s to low 90s each day.
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.DISCUSSION... Issued at 258 PM EDT Thu Sep 11 2025
High pressure over the eastern Ontario is providing a clear, dry, and warm day today and the same is expected tomorrow. As a a strong, amplified upper level ridge builds across the central CONUS in the coming days, a gradual warming trend ensues through the weekend as we end up on the eastern periphery of the ridge. Temperatures will be in the mid 80s again tomorrow then rise into the upper 80s to low 90s by Sunday. The ridge builds through the Midwest early next week and an Omega Block pattern sets up over the CONUS; temperatures should warm into the low 90s on Monday and Tuesday. Have continued to stick with the NBM for temperatures over the weekend and into early next week; most models seem to be latching onto the upper 80s to low 90s for highs each day. The GFS still remains an outlier with near record highs well into the 90s. Persistent dry conditions will allow for large diurnal temperature spreads of 30+ degrees, so it isn`t out of the question that a few consecutive days of highs in the low 90s could happen this weekend through early next week. Much warmer than normal temperatures look to stick around through much of mid September.
Low chances (around 20%) for showers and storms exist on Saturday afternoon/evening into Sunday morning with a weak cold front. With a lack of Gulf moisture, limited instability, and antecedent dry conditions, chances for rain continue to diminish with each new NBM run. Forecast soundings show dry air in the low to mid levels over the weekend as the cold front slides south, which would suggest any rainfall will be very limited if at all. QPF should be limited to 0.1" or less, unless a heavy shower or isolated thunderstorm is able to develop. Any rain that falls over the weekend will not be enough to offset developing drought conditions. In fact, antecedent dry conditions over the past few weeks will likely contribute to rapid onset drought across the Ohio River Valley and Great Lakes regions in mid September. Per the most recent US Drought Monitor released this morning, areas of D1 Moderate Drought have already developed along the US 24 corridor and into northwest Ohio. Drought will likely expand in the coming weeks with no significant rainfall in sight.
One additional concern over the next several days given warm and dry conditions is fire danger. Clear skies and warming temperatures should allow for afternoon dewpoints to mix down into the upper 40s to low 50s. Minimum afternoon relative humidity values will be between 30 to 40 percent each afternoon for the next several days. However, should any grass or brush fires develop, winds will be light enough that it likely won`t spread quickly. Avoid outdoor burning!
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.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1144 AM EDT Thu Sep 11 2025
Patches of mid clouds (mainly west of KSBN) continue to quickly dissipate with increased mixing underway. NAM Cu rule points towards a very stable layer across the area with satellite suggesting little more than a few high clouds. Will keep VFR conditions through the period, with generally light winds.
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.IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None.
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DISCUSSION...Johnson AVIATION...Fisher
NWS IWX Office Area Forecast Discussion