Area Forecast Discussion

KEY MESSAGES

- Breezy today with wind gusts of 30 to 40 mph this afternoon

- A Freeze Warning is in effect tonight into early Monday for the northern half of central Indiana; A Frost Advisory is in effect tonight for the remainder of central Indiana.

- Warming trend beginning on Tuesday, with storm chances Tuesday night into Wednesday

DISCUSSION (This evening through Sunday)

Issued at 211 PM EDT Sun Apr 19 2026

Central Indiana has been under a pattern change the last 24 hours as a large low pressure system has pushed off to the northeast allowing cool northwest flow to reach the Ohio Valley. That said, low level winds have backed towards W/WSW throughout the day ahead of a weak mid level short wave, embedded within the CAA. Confluence along this wave will tap into the limited moisture to aid in cumulus development throughout the afternoon. A modest low level jet and deep mixing will create gusty winds this afternoon, peaking around 40 MPH.

While any rain should be sparse, steep lapse rates combined with the forcing might just be enough to get a few isolated showers over NE portions of central Indiana. The steep lapse rates will promote good mixing, which will bring down some of the stronger winds aloft. This will likely result in wind gusts peaking in the 30 to 40 mph range this afternoon. The inverted V soundings indicate the potential for higher gusts from any showers that do develop.

Reinforced CAA behind the wave along with broad AVA will aid in pressure gains throughout the column. This will bring mostly clear skies and keep temperatures below normal. All of central Indiana is likely to be slightly cooler tonight, dropping temperatures into the low to mid 30s over most of the area. Given this, a Freeze Warning has been continued for the northern half of central Indiana, with a a Frost Advisory for the rest of the area.

The rest of the forecast period will be focused on temperature recovery as deep troughing over the Atlantic Coast helps induce ridging upstream and strong WAA throughout the middle of the week. A weak shortwave will pass through late Tuesday into Wednesday providing chances for showers and storms, but otherwise most of the forecast period prior to Friday night will remain dry. Temperatures will begin cool on Monday but quickly increase within the aforementioned WAA, reaching back above normal by Wednesday with highs in the mid to upper 70s.

Late week, deep pressure depletion within a coupled upper level jet will likely provide increases in rain chances late Friday through the beginning of the weekend. Dynamics aloft should be stronger within this system, leading to increases in potential hazards, but there is still a lot of uncertainty regarding the systems evolution and progression. As of the latest ensemble run, the best chances for severe weather will likely remain west of central Indiana.

AVIATION (18Z TAF Issuance)

Issued at 142 PM EDT Sun Apr 19 2026

Impacts:

- Wind gusts near 30kt this afternoon with potentially higher gusts - Isolated rain shower possible this afternoon

Discussion:

A cold front will move into the area this afternoon. Winds will veer to west and northwest through 00Z Monday as the front moves through. Stronger winds aloft will mix down, with gusts around 30kt expected this afternoon. If mixing gets higher than expected, stronger gusts may occur.

Isolated showers will be with the front, but coverage will be too low to mention. VFR ceilings will develop with the front.

Surface high pressure rapidly builds in tonight allowing winds to decrease substantially. Light and variable winds and clear skies are anticipated by 08z.

IND WATCHES / WARNINGS / ADVISORIES

Freeze Warning from 2 AM to 9 AM EDT Monday for INZ021-028>031- 035>049-054>057.

Frost Advisory from 2 AM to 9 AM EDT Monday for INZ051>053- 060>065-067>072.