417
FXUS63 KIWX 301846
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
246 PM EDT Thu Jul 30 2026

.KEY MESSAGES...

- Dry weather continues through the day Friday with seasonably warm
  temperatures.

- Chances for showers and storms Friday evening into the
  weekend, best potential (60-80 percent) Friday night into
  Saturday night. Scattered showers and storms are likely to
  persist into Sunday, especially along and east of Interstate
  69.

- Widespread severe weather is not expected with storms this
  weekend, but an isolated strong storm with wind gusts over 50
  mph and some localized heavy rainfall cannot be ruled out.

- There is a moderate swim risk for Lake Michigan Beaches along
  the La Porte County, IN shoreline on Saturday. Breaking waves
  and currents are expected. There is a high swim risk for
  beaches along both La Porte County, IN and Berrien County, MI
  Sunday.

&&

.DISCUSSION...
Issued at 234 PM EDT Thu Jul 30 2026

Quiet weather conditions will continue through the day Friday, with
a trend toward a more active weekend in terms of shower and storm
chances.

Progression of upper level pattern will allow an upstream upper
level ridge to build across the Great Lakes region into Friday
morning. Corresponding low level anticyclone will be centered across
the region tonight providing light and variable winds. Some high
clouds may spill over the dampening ridge across the northern
Plains, but are not expected to have a significant impact on temps
tonight (seasonable low temps from upper 50s to lower 60s) with
decent radiational cooling conditions.

Attention for later Friday into the weekend will be on evolution of
an upper level short evident across Idaho/western Montana this
afternoon. This short wave is progged to drop southeast down the
ridge through the day Friday and into the Lower Ohio River Valley by
Sunday morning. Convection is expected to develop tonight across the
Dakotas as a low level jet preceding this disturbance enhances low
level moisture convergence. Convection associated with this feature
will act to modify this short wave from tonight through Friday night
which leads to some uncertainty in strength and track of associated
low/mid level features. Some dProg/dT trends have indicated a slight
slowing trend with the mid level trough evolution which may keep
higher rain chances into Sunday east of Interstate 69. Still a good
deal of uncertainty remains with track of this system given upper
level synoptic tendencies favoring a more suppressed track of low
level reflection into southern IL/southern IN, while
diabatically generated low/mid level PV anomalies will tend to
want to steer track across the southern Great Lakes. It remains
unclear to what extent this northward displaced diabatic PV
anomaly influences track. Nonetheless, will continue idea of
previous forecast with rain chances increasing sharply from
west to east Friday night into Saturday morning as advective
forcing increases downstream of the wave. May need to watch for
potential of some locally heavier rainfall amounts Friday night
into Saturday particularly if deformation forcing can anchor for
a time across portions of the area. PWATs of 1.75+ inches are
possible, and potential does exist for warm cloud depths in
excess of 12k feet. If the more amplified/northward solution
pans out, cannot completely discount some isolated wind
potential during the afternoon/early evening Saturday given this
solution would at least be moderately sheared in weakly
unstable environment. Early indications would suggest if
isolated severe threat does evolve, it would be most likely
south of US-24 across northeast IN/northwest OH which may be
located at nose of instability axis.

For Sunday and Monday, pattern features a bit of a rex-block look
with the possibility that upper low becomes stagnant across the
Lower OH Valley as longwave ridging pushes across eastern Ontario
and western Quebec. This blocking will likely slow the warming trend
and delay arrival of next significant low level thermal ridge, or
keep brunt of this west-east thermal ridging back across the
Plains/Corn Belt. An active southern Canada pattern will likely
dampen upstream longwave ridging enough for periodic chances of
showers and storms Wednesday through Friday along with near
seasonable temps.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 121 PM EDT Thu Jul 30 2026

Surface high pressure overhead gives way to approaching low pressure
just after this period allowing for the continuation of dry
weather and wind trajectories to back from west-northwesterly
today to more southerly by Friday morning. Winds stay below 10
kts sustained through the forecast period.

&&

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

&&

$$

DISCUSSION...Marsili
AVIATION...Roller