300 FXUS63 KIND 051329 AFDINDArea Forecast Discussion National Weather Service Indianapolis IN 929 AM EDT Fri Sep 5 2025
.KEY MESSAGES...
- Low threat for additional rain late today into Saturday, mainly across the south
- Dry and much cooler this weekend, near record lows in the low 40s for Central and North Central Indiana
- Slow warming trend back to the 80s next week, abnormally dry weather continues
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.FORECAST UPDATE... Issued at 929 AM EDT Fri Sep 5 2025
Hazy morning ongoing courtesy of the smoke aloft from fires in the Pacific Northwest. A cold front was moving through the northwest counties of central Indiana currently with gusty winds already noted with its approach and passage across the northern Wabash Valley. 13Z temperatures ranged from the upper 50s to mid 60s.
The frontal boundary will press southeast through the forecast area into the early afternoon with winds veering to westerly and become gusty. Peak gusts to 30-35mph are possible at times focused especially across the northern half of the forecast area. Despite the frontal passage...CAMs progs highlight the layer of smoke lingering for much of the day as it gradually shifts southeast in response to an amplifying upper level trough over the upper Midwest. May see some improvement to the haze from the north by later in the afternoon.
Even as the boundary shifts south of the Ohio River by late afternoon...broad moisture advection from the southern Plains will ride northeast along the boundary and may generate lighter showers by late day into the evening focused primarily over south central Indiana.
There will be a broad range in highs dependent on timing of the frontal passage. Expect a range from the upper 60s in the northern Wabash Valley to near 80 across far southern portions of central Indiana. Zone and grid updates out.
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.SHORT TERM (Today and tonight)... Issued at 236 AM EDT Fri Sep 5 2025
A cold front approaches Central Indiana from the northwest today bringing an increase in clouds and a chance for rain over portions of the area by tonight. But first, relatively dry conditions are forecast during the day, despite an incoming system, due to such dry antecedent conditions. Mainly clear skies are seen over Central Indiana this morning, but as the front approaches, expect high level clouds to increase this afternoon and evening. A strong N-S temperature gradient will likely exist this afternoon as the front pushes in from the north. Highs over North Central Indiana may struggle to reach 70 due to increasing clouds and winds becoming west northwesterly earlier in the day. Further south along and south of the I-70 corridor, greater boundary layer heating and more southwesterly flow will promote warmer highs ranging from the mid 70s to the lower 80s. Before clouds overspread the region, expect hazy skies as upper level smoke from wildfires in the PNW advect in overhead. Any smoke is expected to remain above the surface and not cause visibility or air quality issues locally.
The main focus in the long term will be the slight chance for rain later this evening for South Central Indiana. Latest satellite imagery clearly depicts the incoming system over the Upper Great Lakes and associated cloud cover and cold front in Wisconsin and Illinois. Further southwest, energy from a wave along the trailing cold front in the Panhandle of Texas spreads east today as the cold front becomes elongated and sags southward toward the Ohio River. This is not the best set up for precipitation in Central Indiana as the main upper level system and better dynamics remain north of the region as everything pivots around a large upper trough in Southern Ontario. ACARs soundings locally show very dry environment through the column. Weak moisture return ahead of the front is likely not enough to saturated the environment enough before FROPA to support much, if any, precipitation develop. The aforementioned wave in Texas rides along the frontal system this evening and tonight, working to increase moisture advection along the front and provide just enough forcing for rainfall development. By this time, the front will have pushed south of the Ohio River, keeping the best chance for rain over Kentucky, while cool and drier air advects in behind the front. Guidance over the past several days has hinted at the possibility of moisture overrunning the front, bringing low rain chances to Southern and South Central Indiana. Today`s guidance has backed off on PoPs somewhat, keeping much of the region dry tonight. Kept chance wording for rain in South Central Indiana this evening into the overnight hours, but have lowered PoPs overall, taking out any "rainfall likely" wording to the forecast. PoPs drop off rather quickly as one heads north, with low confidence in any measurable rainfall along and north of I-70.
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.LONG TERM (Saturday through Thursday)... Issued at 301 AM EDT Fri Sep 5 2025
Despite light rain over the past day or two, abnormally dry conditions persist through the next 7-14 days for Central Indiana with little to no chances for precipitation in the extended forecast.
The period begins with large upper troughing over the entire Great Lakes and NE CONUS this weekend. The surface low is located in Ontario while high pressure stretches from the Canadian Prairies southeastward into the Midwest, keeping northwesterly flow through Indiana. Troughing overhead results in a much cooler Canadian airmass aloft with well below normal heights and temperature anomalies. Despite sunny skies this weekend, below average temperature anomalies through the column will only support highs in the upper 60s across the north to low to mid 70s further south. The main focus for this weekend will be near record lows once again Sunday and Monday morning as good conditions for radiational cooling and a cold airmass aloft set the stage for temperatures in the low to mid 40s those morning`s. Coldest locations will be across the Wabash River Valley and in North Central Indiana, where a stray upper 30s observations could be possible, especially Monday morning.
The overall pattern begins to shift going into next week, leading to a slow warming trend back to the 80s... but still without any rain chances locally. Upper troughing pulls off to the northeast with increasing heights toward seasonal norms by Monday. Surface high pressure briefly moves overhead Monday then moves off to the northeast, switching low level flow around to the south and advecting warmer air northward. Upper level height increases and slowly warming 850mb temps indicate a pattern favorable for a warming trend through the week with highs reaching the upper 70s to mid 80s Tuesday through Friday. Dry conditions will still lead to larger diurnal ranges as temperatures quickly fall after sunset, with lows in the upper 40s to low 50s Tuesday then increasing to the mid to upper 50s by late in the week.
Forecast confidence somewhat decreases toward the end of the period as longer range guidance and ensembles struggle to resolve how this pattern evolves as weak storm systems approach from the west. For now, higher confidence exists in a warmer, drier forecast through much of next week and beyond.
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.AVIATION (12Z TAF Issuance)... Issued at 633 AM EDT Fri Sep 5 2025
Impacts:
- Wind gusts near 20kt this afternoon and evening - Borderline low level wind shear conditions through 14z
Discussion:
VFR conditions are expected through the period. Satellite imagery this morning shows an area of clouds along a cold front over the Great Lakes region and a separate area of clouds and showers further west over Kansas. Expect these upper clouds to slowly push into Central Indiana through the day, but with such dry air in the mid and lower levels, cloud bases should stay above 20 kft through this evening. Even overnight tonight, cigs are expected to remain VFR.
An increasing nocturnal low level jet ahead of the front will create borderline LLWS conditions early this morning as surface winds remain weak through around 14z. Expect southerly winds of 5-10 kts this morning, then by late morning winds become westerly and increase to 10-15 kts with gusts of 20-25 kts at times. The front pushes south of the region tonight with a wind shift to the WNW and speeds diminishing to 6 kts or less. Winds/clouds should prevent ground fog formation overnight at KHUF/KBMG, but odds are nonzero.
Dry air should inhibit precipitation development along the front, with the exception of South Central Indiana. Added VCSH tonight up to the I-70 corridor including KIND and KHUF, but not expecting any impacts to cigs or vis as any rainfall should be scattered and fairly light. Best chance for any rain this evening and tonight is at KBMG, but cigs and vis will likely remain VFR as well.
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.IND WATCHES/WARNINGS/ADVISORIES...None.
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UPDATE...Ryan SHORT TERM...CM LONG TERM...CM AVIATION...CM
NWS IND Office Area Forecast Discussion