Gary, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

202
FXUS63 KLOT 191700
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1200 PM CDT Thu Mar 19 2026

.KEY MESSAGES...

- The next three days will feature spring-like temperatures.
  Lake Michigan will influence temperatures along the shoreline
  from time to time.

- A cold front will deliver a cool-down to start next week.

- There are no signals for widespread or soaking precipitation
  in the region through at least the middle of next week.

&&

.DISCUSSION...
Issued at 119 AM CDT Thu Mar 19 2026

The early morning upper-air pattern is characterized by a
summer-like ridge positioned across the southwestern United
States with broad northwesterly flow across the Great Lakes.
Several upper-level ripples are propagating in the northwesterly
flow aloft, including one moving into Lower Michigan and
another moving across southern Canada early this morning.
Meanwhile, an expansive high pressure system centered along the
northern US/Canadian border dominates the surface pressure
fields, leading to nearly calm winds across Upper Mississippi
River Valley at press time. Generally speaking, the next three
days will feature spring-like temperatures and plenty of
opportunities to see the sun. After the recent stretch of cold
and, for some, snowy weather, the upcoming stretch will be quite
the welcome change.

As upper-level clouds clear toward daybreak, patches of ground
fog may develop in river valleys and fields. Thereafter,
diurnally-forced mixing into the warm low-level thermal field
(850mb temperatures near +7C) will support rapidly warming
temperatures with afternoon highs in the upper 50s to mid 60s.
The coolest temperatures will be along and north of Interstate
88 due to onshore flow. Tonight, upper-level clouds will
spread over the area on the southern side of the second upper-
level ripple propagating into the Upper Great Lakes. The
expectation is for lows to fall into the upper 30s (north) to
mid 40s (south).

While upper-level clouds will linger behind a weak/shallow cold
on Friday, diurnal mixing into the even warmer low-level
thermal field (850mb temperatures near +11C) will nevertheless
support widespread highs in the lower 60s to lower 70s. The
warmest readings are favored south of I-80 and east of I-55,
where mixing should be most efficient ahead of the front (the
more aggressive mixing scenarios actually support highs in the
mid 70s, but won`t quite bite yet). Temperatures along the
Indiana shore of Lake Michigan may fall back into the 50s by
early afternoon in the wake of the front mostly due to the
northwesterly wind direction advecting the cooler marine
airmass inland.

Saturday looks like it will be the warmest day of the upcoming
stretch as 850mb temperatures peak near +15C and mostly sunny
skies support highs climbing into the upper 60s to lower 70s. A
southwesterly breeze should hold the cooling influences of Lake
Michigan to within a mile or two of the lakeshore. Assuming
there isn`t some big shift in guidance between now and then,
Saturday is shaping up to be spectacular!

Saturday night into Sunday, the upper-level ridge across the
southwestern United States will flatten allowing for quasi-
zonal flow to develop across the entire northern United States.
While ensemble model guidance exhibits general agreement in
showing the passage of an upper-level shortwave and associated
cold front through the Great Lakes in the general time period,
differences remain in exactly when the front will move through
our area. As a result, the high temperature forecast for Sunday
remains somewhat uncertain with differences between the 25th and
75th percentile high temperature pushing nearly 20 degrees. So,
would not put too much stock in the forecast highs for Sunday
until there is better agreement in when the front will pass
through.

Even with disagreement in exactly when the front will come
through during the latter half of the weekend, ensemble
guidance is steadfast on showing a notable cooldown on Monday
thanks to a glancing blow of a pool of 850mb temperatures around
minus 6 to minus 8C. Highs are poised to stay in the 40s across
much of the area, perhaps even the upper 30s lakeside with
onshore flow. With that said, there is a signal for the
reestablishment of strong upper-level ridging across the western
United States, which would support temperatures warming by
midweek.

Borchardt

&&

.AVIATION /18Z TAFS THROUGH 00Z SATURDAY/...
Issued at 1200 PM CDT Thu Mar 19 2026

There are no significant aviation forecast concerns anticipated
through the period.

VFR conditions are expected through much of the TAF period,
with the only exception being the possibility for some bkn MVFR
CIGS moving in off the lake later Friday afternoon. Winds
should largely remain under 10 kts from the east this afternoon,
before turning southwesterly later tonight. Winds should trend
northwesterly 10 to 15 kt Friday morning, then flip northeast
off the lake in the afternoon.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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