textproduct: Indianapolis

KEY MESSAGES

- Mainly dry weather tonight with isolated showers possible this afternoon

- Mainly dry and warmer on Friday, an isolated late afternoon thunderstorm possible.

- Generally very warm/humid into next week; greatest rain/storm chances through this weekend.

SHORT TERM (This evening through Friday)

Issued at 332 PM EDT Thu Jul 10 2025

Surface Analysis early this afternoon shows shows broad but disorganized high pressure stretching from eastern Ontario, across MI to Indiana and then to eastern TX and the deep south. A decaying MCV and thunderstorm complex was found over south east MN. This system continued to wane with its eastward progression toward the high pressure system. Water vapor showed strong subsidence in place over Indiana on the lee side of an upper ridge over the upper midwest. This large area of subsidence stretched from the ST. Lawrence Valley...across Indiana to Arkansas and TX. Lower level flow across Indiana was weak and variable due to the broad high pressure system. GOES16 shows expected diurnal CU development over Central Indiana.

Tonight...

Little overall change in our weather will be expected the weak high over the area and the upper ridging over the western Great Lakes will begin to drift eastward. However subsidence, a dry column and a lack of any forcing will continue to to result in quiet, fair weather. As the high drifts a bit to the east tonight, a southerly and warmer lower level flow will begin to set-up for Friday. Dew points remain humid, in the upper 60s to around 70. Expect lows in the mid 60s to around 70, near persistence.

Friday -

As the surface high remains farther east of Indiana, a more southerly flow will begin to set up within the lower levels. This will put an end to the subsidence aloft, and bring about a gradual increase in moisture through the column by 12Z. Forecast soundings fail to show a saturated level, but CAPE over 2600 J/KG appears present by late afternoon as convective temperatures in the upper 80s are reached. Upstream, an upper disturbance is expected to generate showers and thunderstorms over WI and NRN IL. Some of these may impact Indiana on Friday night, but during the afternoon hours Central Indiana will just remain in this warm and moist sector with diurnal instability arriving late in the day. Thus most of the day and most areas should remain dry, but a few stray, isolated late afternoon showers and storms cannot be ruled out. Will likely include a 20 pop for this possibility.

With southerly and warmer flow in place, highs should be slightly warmer on Friday, in the upper 80s to around 90.

LONG TERM (Friday night through Thursday)

Issued at 332 PM EDT Thu Jul 10 2025

Overall typical midsummer weather is expected through the long term as generally warm and humid conditions. Most days have at least a slight chance of showers and storms, with best chances late day Saturday and Sunday, then additional chances midweek.

Aloft, troughing will help bring shower and storm chances this weekend while a surface low passes through the Great Lakes. Saturday will see the best chances, mainly for the latter part of the day and into the overnight hours. Above normal PWATs are expected for late Saturday as well, so could see some localized flooding potential within heavy showers or should storms pass over the same area numerous times. Also can't rule out a few stronger storms producing higher wind gusts; otherwise, widespread severe weather is not expected at this time.

Models show the potential for another surface low in the region that could bring additional shower and storm chances for late day Sunday. There lacks agreement on where exactly the low will track so lacking confidence on where the best rain chances will be that day at this time.

High pressure still looks to bring a brief break in precipitation early next week before another upper wave returns midweek, bringing additional storms and continued warmth. Behind this midweek system, central Indiana could see at least a brief break from the heat and humidity as high temperatures late next week could only be as high as the upper 70s to low 80s. Will continue to monitor trends as it gets closer. Otherwise, high temperatures through the next week will be in the upper 80s to potentially low 90s with lows in the 60s and 70s.

AVIATION (00Z TAF Issuance)

Issued at 715 PM EDT Thu Jul 10 2025

Impacts:

- VFR this period. - S-SW wind gusts up to 20 kts tomorrow afternoon.

Discussion:

Diurnal cumulus is expected to end in the next 1-2 hrs with loss of heating. Winds will be light overnight, but slightly stronger than last night and therefore am not expecting any reductions of visibility into MVFR or IFR categories. S-SW winds will begin to pick up by early afternoon tomorrow with gusts close to 20 kts as high pressure remains centered over the SE and several low pressure areas move closer to Central Indiana from the upper MS valley region.

IND WATCHES/WARNINGS/ADVISORIES

None.