FXUS63 KIWX 191647

AFDIWX



Area Forecast Discussion

National Weather Service Northern Indiana

1247 PM EDT Tue Aug 19 2025



.KEY MESSAGES...



- Scattered showers and thunderstorms are expected this

  afternoon generally south of US Route 24 across northern 

  Indiana and northwest Ohio. A few strong storms are possible 

  with localized heavy rainfall and isolated wind gusts to 

  around 50 mph possible.



- A Beach Hazards Statement is in effect this afternoon through

  Wednesday night. There is a High Swim Risk for southeast Lake

  Michigan beaches this afternoon into Wednesday night.



- Cold frontal passage moving through today will bring less 

  humid conditions for the remainder of the week.



- Much cooler conditions arrive for late weekend into early next

  week.



&&



.DISCUSSION...

Issued at 1217 PM EDT Tue Aug 19 2025



A cold front currently draped northeast to southwest over 

northwestern IN/southwestern MI per latest visible satellite

data and surface observations will continue to move 

southeastward this afternoon. This will allow for some scattered

showers and thunderstorms to develop later this afternoon mainly

south of US-24. A few of the storms may become strong with wind

as the main threat with gusts up to 40 to 50 mph in the

strongest storms. Heavy downpours will also be possible with the

still very humid conditions present with surface dew points in 

the 70s. Effective bulk shear values will be minimal with less 

than 20 kts available. SPC does have our southern portions of

the CWA under a marginal severe storm risk this

afternoon/evening.



In the wake of the cold front along with breezy northwesterly

winds tonight with gusts 15 to 20 mph and a return to drier

weather conditions we will also see a noticeably more 

comfortable airmass push into the area over the next several 

days with values in the lower 60s to upper 50s. High 

temperatures will also be cooler with Wednesday values only in 

the upper 70s with slightly warmer temperatures in the lower to 

mid 80s through Saturday. This frontal passage will also bring 

high swim risk to area Lake Michigan beaches with waves 3 to 5 

feet with a few higher waves possible through Wednesday. This 

will allow for dangerous rip currents and structural currents. 

So best to stay out of the water and wear life-vests near the 

water. 



On Saturday, a trough originating over the Gulf of Alaska will 

move south trough central Canada into the Great Lakes region and

will bring in another reinforcing shot of cooler air into the 

area. High temperatures on Sunday and through at least Tuesday

will be in the 70s and low temperatures in the 50s. Seemingly

our first taste of whats to come in the Fall.



&&



.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...

Issued at 645 AM EDT Tue Aug 19 2025



An expansive shield of rain showers with some embedded

thunderstorms will continue to shift eastward across northern

Indiana this morning. These showers and storms are being aided

by an increasing upstream frontal response and the eastward

advection of some pre-frontal higher theta-e air from the Mid 

MS Rvr. By late morning/midday, the coverage of these showers

and storms should diminish, but southeast sagging frontal

boundary and a west-east oriented instability axis shifting

across northeast Indiana should allow for some isolated to

scattered redevelopment this afternoon. The big question will be

where effective boundary sets up after morning convection

diminishes and whether effective frontal boundary will be far

enough south to limit additional thunder chances at KFWA.

Current thinking is best instability will end up situated south

of KFWA, so have limited this mention to VCSH later today.



Deteriorating cigs are expected this morning in wake of morning

rain shower activity at KSBN as sfc front approaches from the

northwest. Some IFR cigs are possible this morning at KSBN, 

with MVFR conditions possibly lingering through much of the day

for both terminals. Post-frontal cold advection will have the 

potential to prolong MVFR cigs tonight or allow MVFR cigs to 

redevelop as low level cold advection strengthens.



&&



.IWX WATCHES/WARNINGS/ADVISORIES...

IN...Beach Hazards Statement from 4 PM CDT this afternoon through 

     late Wednesday night for INZ103.

OH...None.

MI...Beach Hazards Statement from 5 PM EDT this afternoon through 

     late Wednesday night for MIZ277.

     Beach Hazards Statement through Wednesday morning for MIZ177.

MARINE...Small Craft Advisory from 2 AM Wednesday to 2 AM EDT Thursday 

     for LMZ043.

     Small Craft Advisory from 2 AM Wednesday to 5 AM EDT Thursday 

     for LMZ046.



&&



$$



DISCUSSION...Andersen

AVIATION...Marsili