FXUS63 KIND 181324

AFDIND



Area Forecast Discussion

National Weather Service Indianapolis IN

924 AM EDT Sat Jul 18 2026



.KEY MESSAGES...



- Peak heat indices nearing 100 degrees today



- A line of showers and t-storms expected this evening and 

additional storms possible late Monday into Tuesday



- Isolated strong to severe thunderstorms are possible this evening, 

damaging wind gusts are the primary threat



&&



.FORECAST UPDATE...

Issued at 924 AM EDT Sat Jul 18 2026



Mostly sunny start for much of the area this morning with only a 

small broken line of showers tracking across far northern portions 

of the forecast area currently. 13Z temperatures were already rising 

into the low 80s in many locations.



The primary focus for the morning update remains on the potential 

for severe weather late afternoon and especially this evening as a 

convective line tracks south in association with a cold front. 

Largely quiet yet muggy weather is expected through mid afternoon 

with only an isolated shower or storm within the increasingly 

unstable airmass over central Indiana. 



Convection already ongoing across parts of lower Michigan with the 

expectation of westward development ahead of the southward moving 

cold front through mid afternoon as storms interact with a strongly 

unstable airmass over the lower Great Lakes and points south. Timing 

remains consistent for impacts across central Indiana...with the 

convective line arriving over far northern portions of the forecast 

area after 21Z and progressing south through the region during the 

evening and into the early overnight. Damaging straight line winds 

will be the primary threat with DCAPE values comfortably within the 

800-1200 j/kg range and modest lapse rates present below 700mb. 

While storms should move at a decent clip...torrential downpours and 

the potential for localized flash flooding will exist as PWATs south 

of the boundary will hover near 2 inches with freezing levels in the 

15-16kft range aiding in highly efficient rainfall rates. 



Highs will likely make it to around 90 in many locales this 

afternoon with max heat indices near 100 by late day. Zone and 

grid updates out.



&&



.DISCUSSION (Today through Friday)...

Issued at 310 AM EDT Sat Jul 18 2026



Active weather is expected again today as well as another day with 

highs near 90 and heat indices nearing 100. Can't rule out a few 

showers through the day, but the best chance of showers and storms 

will come this evening along a cold front pushing southward across 

central Indiana. Latest CAMs show that the timing will generally be 

about 6pm to a little after midnight before fully exiting to the 

south. Strong destabilization ahead of the approaching cold front 

along with modest enhancement of mid-upper level flow could promote 

isolated severe thunderstorms, primarily across northern portions of 

central Indiana. Forecast soundings depict around 20-30 kt of 

effective shear, strong instability with steep low-level lapse 

rates, and DCAPE values as high as 1000 to 1300 J/KG which support 

the threat. The primary convective hazard is damaging wind gusts. 

The severe hail threat will be largely limited by the linear storm 

mode.



Behind the front, surface high pressure will move in and bring 

slightly cooler and drier air. Unfortunately, smoke from Canadian

wildfires could also return to the area for the start of the new 

week. 



Models continue to show a shortwave bringing additional 

precipitation chances sometime late Monday through Tuesday. Behind 

this system, guidance has much cooler and drier air for the latter 

half of next week, with highs likely in the upper 70s to low 80s and 

overnight lows potentially dropping below 60.



&&



.AVIATION (06Z TAF Issuance)...

Issued at 1258 AM EDT Sat Jul 18 2026



Impacts:



- Possiblebrief MVFR in BR later tonight

- MVFR/worse possible after 20Z Saturday in stronger convection

- Wind shift to northerly at end of TAF period



Discussion:



Expect mainly VFR conditions near central Indiana terminals through

midday Saturday...with non-zero chances of MVFR from fog later tonight

although confidence too low to include in TAF. 



TSRA to return later Saturday with an west-east aligned cool front

that will cross the region from north to south into the evening,

with greatest chances for stronger winds/MVFR within 22Z-03Z.



Winds through dawn will be light and variable or most often from the

southwest...with flow near 7KT at times at KIND.  Westerly winds

Saturday will increase to 8-13KT for most sites after 15Z, with

gusts nearing 20KT at KIND/KLAF after 18Z. 



&&



.IND WATCHES/WARNINGS/ADVISORIES...None. 



&&



$$



UPDATE...Ryan

AVIATION...AGM

DISCUSSION...KF