859
FXUS63 KIWX 011645
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
1245 PM EDT Sun Jun 1 2025

.KEY MESSAGES...

-Partly to mostly clear skies and dry conditions expected
 through Tuesday. Canadian wildfire smoke will remain elevated
 over the area through at least Monday. Minimal, if any, impacts
 to air quality as smoke should remain aloft.

-High temperatures today will be in the upper 60s and low to mid 70s,
 then rise into the mid to upper 80s by Tuesday and Wednesday.
 Highs fall back into the 70s and low 80s Thursday into next
 weekend.

-Rain chances return Tuesday night, and persist through the end
 of the work week. The best potential is Wednesday into Thursday
 night (45 to 85 percent). There are chances for thunderstorms
 as well, particularly Wednesday afternoon into Friday evening.

&&

.DISCUSSION...
Issued at 359 AM EDT Sun Jun 1 2025

Dry conditions with partly to mostly sunny skies (outside of the
wildfire smoke aloft) will persist through Tuesday thanks to high
pressure at the surface and a building ridge aloft. Temperatures
today will be in the 60s and low to mid 70s, warmest inland and
along/south of US 24. Lows tonight will drop back into the 40s. As
the ridge builds in through Tuesday, highs will climb towards the
mid to upper 80s.

By Tuesday night, the upper ridge will shift eastward as a broad
trough fills in the central CONUS (stemming from an upper low over
the Canadian Prairies). A cold front will make a run eastward into
the ridge, reaching just west of our CWA by Wed AM and eventually
exiting by Friday morning. The front will likely stall somewhere
over our CWA between Wednesday night and Thursday before it
eventually is forced eastward by another shortwave rippling through
the edge of the weakening ridge (ECMWF brings a weak surface low up
along the front, but other guidance is inconsistent with this). For
now have 40-85 percent chances Wed, then widespread 60-80 percent
Wed night into Thu, tapering off from NW to SE Thu PM-Friday. Have
the best potential for thunder along the front and during daytime
hours. Moisture transport during the Tue night-Thu night period is
right off the Gulf into our CWA, with a 35-45 kt LLJ in place
parallel to our potentially stalled frontal boundary. We could see
periods of heavy rain with this, and WPC has us in a marginal risk
for the Excessive Rainfall Outlook for Tuesday night-Friday morning
accordingly. Severe weather is not expected at this point. Highs on
Wednesday are somewhat challenging as the ridge is exiting eastward
and there are timing differences re: the progress of the cold front.
Have mid to upper 80s still generally along and south of US 24 and
east of US 31, warmest east of I 69. Further north and west highs
will likely be in the upper 70s and low 80s-coolest near Lake MI.

Have lower confidence in pops beyond thursday night because of model
disagreement-but mainly with respect to timing/exact placement of
precipitation vs. the potential for overall precipitation. There
will be periods of rain and perhaps some thunderstorms beyond Thu
night-so left the consensus pops for now (20-50 percent, highest Fri
and then again on Sun afternoon). Highs will be in the mid to upper
70s.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1243 PM EDT Sun Jun 1 2025

No flight concerns through the period with little in the way of
cloud cover or winds to deal with.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.

&&

$$

DISCUSSION...MCD
AVIATION...Fisher