FXUS63 KIWX 051821

AFDIWX



Area Forecast Discussion

National Weather Service Northern Indiana

221 PM EDT Wed Aug 5 2026



.KEY MESSAGES...



- Dry conditions through early evening especially southeast of

  Intestate 90 corridor.



- Chances (30-70 percent) for showers and storms this evening

  and persist at times into through Thursday and into Friday

  morning. Locally heavy rain is possible.



- Low chances for showers and storms Saturday into Tuesday (20-40

  percent).



&&



.DISCUSSION...

Issued at 151 PM EDT Wed Aug 5 2026



For this forecast period did further trend lower with pops and

further pushed back timing as uncertainty remains high in the 

exact evolution of this abnormal synoptic setup. The slow 

moving, weakening, and washed out cool frontal boundary with 

fairly low amounts of forcing and instability less than 2000 

J/kg is not being handled well at all by guidance. There still 

is the chance for some locally heavy rainfall at times if 

thunderstorms can develop and drift slowly along the boundary in

pretty unidirectional flow and as the environment is rich in 

moisture with PWATs 1.5 to 2 inches available. However, the 

higher rainfall amounts will be very localized and hit or miss 

with the showers nature. WPC still has portions of our are under

a marginal risk for exceeding flash flood guidance tonight 

through Friday morning. This event sure has the earmarks of 

having bust potential especially with the increased uncertainty 

and a majority of the troughs energy being pushed well north of 

the area into Canada.



A pretty stagnant pattern seems to set up over the area with

troughing remaining in place to the north of the region and

cyclonic to zonal flow aloft will remain over the area. This

will keep the high temperature trend stable with seasonal 

values in the low to mid 80s well into next week. There will

also be periods of showers and thunderstorms mainly in the

afternoon early evening time frame but with the convective

nature will be again a hit or miss coverage.  



&&



.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...

Issued at 108 PM EDT Wed Aug 5 2026



A tale of two TAFs this afternoon: one-liner at KFWA while KSBN

faces episodes of -SHRA. 



Preexisting high pressure still exerts some influence over 

eastern Indiana, as evidenced by dew points in the low-60s. 

Modest low pressure of 1016mb over far northern Lower Michigan 

is struggling to exert its trailing precipitation shield 

eastward. A much better organized area of -SHRA is noted over 

far western Illinois and guidance has a fair handle on this, 

bringing it toward KSBN near 00z. Time height cross sections 

depict modest forcing through the column which bolsters 

confidence in -SHRA there.



As upper-level forcing lingers, but remains modest, a second

period of rain is probable near 12z. At FWA, lingering dry air

below 10k FT and poor forcing on time-heights really diminishes

any confidence in showers there. As a result, the inherited dry

TAF continues. Perhaps a better opportunity for -SHRA just 

beyond 18z.



&&



.IWX WATCHES/WARNINGS/ADVISORIES...

IN...None.

OH...None.

MI...None.

MARINE...None.



&&



$$



DISCUSSION...Andersen

AVIATION...Brown