055 FXUS63 KIND 091812 AFDINDArea Forecast Discussion National Weather Service Indianapolis IN 212 PM EDT Thu Oct 9 2025
.KEY MESSAGES...
- Frost Advisory tonight for Central and North Central Indiana
- Dry weather is expected through next week, outside of very isolated showers Friday night
- Above normal temperatures return next week.
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.SHORT TERM (This evening through Friday)... Issued at 212 PM EDT Thu Oct 9 2025
Main focus in the short term is the frost potential tonight for Central and North Central Indiana. High pressure remains the dominant weather influence across the region this week, keeping a relatively cooler airmass in place. A weakness in the pressure gradient tonight allows for winds to become very light or calm, making for great conditions for radiational cooling overnight as skies will be mainly clear. Dew points today are ranging from the mid 30s in the north to low 40s across the south, which can be a good indicator for how low temperatures may fall tonight. Hi-res guidance does show weak moisture advection across South Central Indiana this evening and tonight keeping dew points in the 40s, which should help limit the frost threat in the south. Along and north of the I-70 corridor outside of urban areas have the best chance at dropping into the 33-36 degree range by tomorrow morning. Confidence is high enough in frost tonight along and north of I-70 to warrant a frost advisory from 06z-13z. While the advisory includes Marion County, thinking the frost threat will mainly be confined to less urban areas, especially in eastern portions of the county. The urban heat island should prevent frost around downtown and highly developed areas. Coldest locations expected to be in the Wabash River Valley and rural locations in North Central Indiana.
Despite a cold start to the morning Friday, temperatures quickly rebound into the low 70s as winds become southerly ahead of an approaching front. An upper low and associated surface reflection and frontal boundary drop southeast through the Great Lakes tomorrow and tomorrow night. Warm air advection increases ahead of the front, but with such a dry airmass in place, not expecting precipitation to be able to sustain itself as it moves toward Indiana. Expect increasing clouds Friday afternoon and evening to be the main impact from this passing system.
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.LONG TERM (Friday night through Thursday)... Issued at 212 PM EDT Thu Oct 9 2025
The next 7 days look very dry once again as high pressure builds on the northern edge of an Atlantic low this weekend through early next week. This airmass will have continental origins leading to abnormally dry surface conditions throughout this period as well. The one caveat to this pattern will be a very weak thermal low pushing SE/E late tomorrow through Saturday with an associated frontal system. Although the air mass will be rather dry, modest moisture convergence along the front along with a good amount of lift will likely lead to numerous clouds with a few showers across northern Indiana.
The diurnal temperature curve will amplify throughout this period due to the continental air mass` efficient radiative conditions. This should allow for lows to dip below guidance most night and for highs to exceed guidance. This should push afternoon temperatures slightly above climatology this weekend despite weak CAA be hind the frontal boundary late Saturday and Saturday night. By next week, height anomalies within midlevel ridging should result in a 5-10 degree temperature increase early next week with highs likely in the 80s once again.
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.AVIATION (18Z TAF Issuance)... Issued at 102 PM EDT Thu Oct 9 2025
Impacts:
- None
Discussion:
High pressure will dominate the area during the period, leading to clear skies, unrestricted visibility, and winds less than 10KT. Winds will generally be easterly throughout the period shifting from 060-090 deg today to 180-210 deg tomorrow afternoon. There is a slight chance for fog at KHUF and KBMG tonight but confidence in this occurrence is low, so will not include it in the TAFs.
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.IND WATCHES/WARNINGS/ADVISORIES... Frost Advisory from 2 AM to 9 AM EDT Friday for INZ021-028>031- 035>049-051-052-057.
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SHORT TERM...CM LONG TERM...Updike AVIATION...CM
NWS IND Office Area Forecast Discussion