Wwcm-Am Brazil, IN Hourly Weather Updates

Key Messages

• Heavy rain and localized flash flooding will be possible again late tonight and on Saturday morning.
• The additional rain may worsen an already significant flooding event.
• Additional storm chances on Sunday.
• Drier and cooler weather settles in Monday through early next week.

Discussion

(This evening through Friday)... Issued at 229 PM EDT Fri Aug 14 2026

Surface analysis this afternoon shows a trough of low pressure stretched from Central IL across central Indiana and then east to Dayton. GOES19 shows an extensive area clouds remnants from earlier thunderstorms. Cloud tops continued to warm as showers for the most part continued to dissipate. Radar still shows scattered showers stretching from IA across IL to Central Indiana. Clouds had limited daytime heating somewhat as most temperatures were in the 70s. Water Vapor imagery shows ridging in place over the Mississippi Valley. The ridge was allowing a tropical flow from the Pacific to stream up and around it before reaching Indiana and the Ohio valley. An embedded wave was found across IL and Indiana, pushing east within the flow.

Tonight and Saturday...

Cloud cover across the area this afternoon is expected to remain into the evening. This will prevent any additional diurnal convection as convective temperatures will not be reached. None the less, clouds will continue to linger through the evening and overnight, along with the lower level boundary remaining in place. Forecast soundings show plentiful moisture through the column overnight, with high pwats still available. However a forcing mechanism does not appear available much of the night. The HRRR suggests another MCS pushing toward Indiana near 09Z and beginning to cross the state at and around 12Z. Diurnal trends would suggest a gradual dissipation through the morning hours. However, again forecast soundings still show abundant moisture with high pwats through the day.

Thus we will use low pops this evening, but will ramp pops higher across the northern parts of the forecast area from late tonight through Saturday Morning. Due to saturated soils, this will require the extension of the flood watch across the northern parts of the forecast area. Given the expected cloud cover, will trim highs on Saturday to lower 80s, but higher values will be possible across the southwest area, farther away from precipitation.

Sunday and Sunday Night...

Northwest flow looks to remains in place on Sunday and yet another wave looks to pass across Indiana within the flow. A cold front is expected cross the state on Sunday and Central Indiana will spend Sunday afternoon within the warm sector ahead of the front. Again forecast soundings show favorable CAPE in excess of 2400 J/KG and the very high pwats near 2.2. Thus again, high pops will be needed in the afternoon and flood potential will still be in play.

Monday and Tuesday...

Dry weather will be expected on Monday and Tuesday as high pressure remains across the area. Northwest flow will be in place aloft, but little in the way of forcing dynamics is expected to pass. Subsidence will be in play as weak ridging will be occurring upstream over the Rockies. The Canadian high pressure will allow temperatures to return to near normal or slightly below normal temperatures with less humidity.

Wednesday...

Best chances for precipitation next week looks to be on Wednesday into Wednesday Night. A moderate upper short wave within the flow is expected to pass across the Great Lakes. This along with an associated cold front is expected to pass across Indiana. With warm and more humid southerly winds in place across Indiana due to the departing high pressure system, ample moisture will be available. Thus pops will be needed. At the moment, best timing looks to be in the afternoon and evening, but given this many days away this timing could change.

Thursday and Friday...

Dry weather looks to return for the end of the work week. The previous cold front will push to the Ohio river by Thursday morning, allowing high pressure to build across Central Indiana for the end of the work week. Aloft, stronger ridging is expected over the Rockies, that should result in more leeside subsidence over the upper midwest. A caveat is that a weak upper trough will still be passing across the Great Lakes that could provide some forcing.

Aviation

(00Z TAF Issuance)... Issued at 748 PM EDT Fri Aug 14 2026

• Thunderstorms expected at KLAF between 12-15Z. Low chances at KIND and KHUF
• Winds less than 10kt shifting from 160 to 250 throughout the day

Discussion:

VFR conditions expected tonight with light and variable winds, although the predominant wind direction is expected to be SE to S. Thunderstorms will arrive from the west tomorrow morning, reaching KLAF around 12Z. Storm may reach as far south as KHUF and KIND, but confidence in occurrence at these two sites is low. Conditions clear late morning into the early afternoon before scattered convection returns after 18Z (represented by VCSH). Any thunderstorms should dissipate and move off to the east by 23Z.

Watches / Warnings / Advisories

/WARNINGS/ADVISORIES... Flood Watch through Saturday evening for INZ021-028>031-035>049- 051>057-065.

Flood Watch until midnight EDT tonight for INZ060>064-069>072.

Heat Advisory from 11 AM Saturday to 8 PM EDT Sunday for INZ060>063-067>071.