434 FXUS63 KIND 041648 AFDINDArea Forecast Discussion National Weather Service Indianapolis IN 1248 PM EDT Sat Oct 4 2025
.KEY MESSAGES...
- Mostly sunny and very warm today and Sunday.
- Next best chance for rain is late Monday night through Tuesday night.
- Dry weather with seasonable temperatures return on Wednesday and Thursday.
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.FORECAST UPDATE... Issued at 955 AM EDT Sat Oct 4 2025
A weakness in the upper ridge continues across the northwest forecast area this morning, and some weak elevated instability lingers there. Satellite and webcams show some mid cloud with vertical growth across portions of the western and northern forecast areas.
The weakness in the upper ridge will diminish/move north today as the upper high to the southeast increases its influence across the area. This should help put a cap on/diminish the elevated instability. Cannot rule out an isolated shower later this morning into the afternoon in the northwest, but for now believe odds are too low to mention.
Otherwise, look for dry and very warm conditions with highs in the middle and upper 80s once again. Tweaked high temperatures but no significant changes were made.
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.SHORT TERM (Today and tonight)... Issued at 225 AM EDT Sat Oct 4 2025
Surface analysis this morning shows strong high pressure in place over the middle Atlantic States, with a surface ridge axis extending west across Kentucky to Arkansas and MO. Light southerly winds were in place and dew point temps were rather moist, in the lower 60s. Satellite shows a few lingering CU clouds over NW Central Indiana, Otherwise, skies were mostly clear across much of the region. Aloft, water vapor showed a large, broad ridge in place over the eastern half of the country, with a ridge axis set up near IL and IN. Subsidence was found over Indiana and much of the Mississippi Valley.
Today and Tonight...
Little change is expected in our overall weather today and tonight. models suggest the strong ridging aloft will slowly move across Central Indiana reaching the east coast by Sunday morning. This will result in continued subsidence today and tonight, as seen within the forecast soundings and time height sections. Forecast soundings do show CU development today, but a mid level inversion in place aloft along with the overall subsidence should prevent and CU from developing into showers or storms. Cu will dissipate tonight as forecast sounding become dry and daytime heating is lost, leading to mostly clear skies.
With little overall change in the airmass, expect highs at or slightly above persistence and similar lows.
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.LONG TERM (Sunday through Friday)... Issued at 225 AM EDT Sat Oct 4 2025
Sunday and Sunday Night...
More Dry and warm weather will be expected on Sunday and Sunday night as little overall change in the air mass occurs. The ridging aloft will have drifted east allowing for a more southwesterly flow aloft flowing into Indiana. The strong surface high and ridge looks to still be in control, and once again forecast soundings appear dry. Thus another warm, mostly sunny day and mostly clear night will be expected.
Monday through Tuesday...
This will be our next best chance for rain. Models here suggest forcing dynamics will be arriving with the southwest flow aloft and combining with more forcing dynamics arriving from the northwest as an upper trough and associated cold front begin to push out of the northern plains. All of this does not appear to come together until later in the day across Indiana and into Monday night and Tuesday. Thus, Monday should start dry, with rain chances increasing through the day and best chances arriving on Monday night into Tuesday as forecast soundings show deep saturation at that point with pwats over 1.60 inches. Thus high pops will be expected on Monday Night. The cold front will associated with this system is shown to be slowly pushing across the state on Tuesday and at the moment forecast soundings remain mostly saturated through the day. Thus some lingering showers through the day, particularly in the morning, cannot be ruled out and pops will be needed. Increasing clouds and rain will result in some cooler highs, with noticeably cooler temps on Tuesday.
Wednesday Through Friday...
Much cooler weather will arrive behind the frontal passage as strong Canadian surface high pressure builds into Indiana with ridging and subsidence aloft. This will return our temperatures much closer to seasonal normals with the potential for some below normal temperatures. Another upper trough is shown for now to arrive on Thursday Night into Friday, however moisture may be a problem for this feature. NBM may include some pops.
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.AVIATION (18Z TAF Issuance)... Issued at 1248 PM EDT Sat Oct 4 2025
Impacts:
- None
Discussion:
VFR conditions are expected throughout the period, but ground fog cannot be ruled out near sunrise at all but KIND.
Scattered to perhaps broken at times VFR cumulus will persist into early evening before dissipating. Scattered cumulus may pop up again on Sunday.
Ground fog may develop again 10-12Z Sunday at all but KIND, but confidence is not high enough to include at this time.
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.IND WATCHES/WARNINGS/ADVISORIES... None. &&
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UPDATE...50 SHORT TERM...Puma LONG TERM...Puma AVIATION...50
NWS IND Office Area Forecast Discussion