Area Forecast Discussion

KEY MESSAGES

* Slightly elevated fire danger today with the combination of gusty 25-30 mph southwest winds, minimum RH values in the mid/upper 20s and current dry/drought conditions.

* Mainly dry and unseasonably warm starting today through the end of the week with temperatures 5 to 10 degrees above normal (upper 70s to low 80s)

* Our best chance at precipitation appears to be for the end of the week into the start of the weekend.

SHORT TERM /THROUGH TONIGHT/

Issued at 317 AM EDT Tue Apr 21 2026

Today starts a warming trend as our weather remains mainly dry through Thursday. Sfc high pressure will continue to push eastward as a weak sfc low over the Dakotas and Northern Plains works towards the Great Lakes later this evening. Sfc pressure gradient will tighten up over the Ohio Valley as these two systems interact over the Ohio Valley today. This will result in gusty southwesterly winds. After collaboration with our neighbors, we all agreed to increase winds and wind gusts for later this afternoon. We will also see a LLJ out ahead of an approaching weak boundary associated with the sfc low coming out of the Northern Plains. Looking at model soundings, there is plenty of dry and and subsidence, so also went ahead and lowered dewpoints into the mid/upper 30s to around 40 in the afternoon with the potential for some dry air mix down. With the ongoing abnormally dry/drought conditions over the region, gusty winds and minimum RH values falling into the upper 20s with some isolated mid 20s, want to highlight the possibility of some elevated fire weather concerns.

After highs in the 60s yesterday day, highs will be about 15 degrees warmer climbing into the upper 70s with a few locations breaking into the low 80s.

The aforementioned front along with the weak sfc system will pass by to the north through the Great Lakes and northern IN later tonight. As the front sags southward towards southern IN and the Ohio River by Wednesday morning, we could see a slight increase in PoPs (around 20%) for our southern IN counties but confidence is not very high and wouldn't be surprised if things remain mostly dry.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 317 AM EDT Tue Apr 21 2026

Wednesday - Thursday...

Weak embedded shortwave trough will work through the Ohio Valley at the start of the long term. This will try and push the sfc boundary mentioned in the short term towards our CWA from the north. It appears that this boundary may fall short of reaching the CWA but went ahead and kept low end PoPs (20%) for parts of southern IN and the Bluegrass for the first part of the day Wednesday. Other than that, the forecast for the middle of the week remains warm and mainly dry as upper ridging over the central CONUS builds over the Ohio Valley. This will also help to boost temperatures into the upper 70s and low 80s.

Friday - Saturday Night...

Upper pattern is expected to flatten out Thursday night into Friday as a closed upper low develops and deepens over the Northern Plains and the Dakotas. At the surface, low pressure will deepen over North Dakota. A weak shortwave along with the associated sfc cold front will advance towards the region by Friday morning and bring a couple waves of showers and embedded thunderstorms both Friday and again on Saturday. While there appears to be fair amount of model agreement and confidence that we will see this pattern change and increase rain/storm chances for the end of the week and into the start of the weekend, there remains low confidence on timing and specific details as is usually the case in situations this far out as models diverge on overall timing of features. Current forecast has rain amounts ranging from around 0.60 to 0.80 across the CWA. Temperatures will remain warm with highs near 80 on Friday and around the mid 70s on Saturday.

Sunday - Monday...

Forecast confidence for late weekend into early next week remains low. We will continue to monitor the overall setup on Monday into Tuesday as we have the potential for a few systems working across the Ohio Valley. While confidence is low, as was mentioned in the previous AFD that this setup could result in a strong storm threat for the start of early next week.

AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 109 AM EDT Tue Apr 21 2026

Sfc high pressure will continue to drift eastward as we go through the overnight and into the start of the day. At the same time a sfc low coming out of the Dakotas and the Northern Plains will tighten the sfc pressure gradient over the Ohio Valley. While VFR flight categories will remain through the forecast period. The main impacts will be strong gusty winds out of the SW in the afternoon as gusts could be around 25kts and LLWS developing near the end of the forecast period for most terminal sites. Went ahead and put it into the SDF TAF but left it out for LEX for now. Likely will be added for the 12z update.

LMK WATCHES / WARNINGS / ADVISORIES

KY...None. IN...None.