Terre Haute, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

253
FXUS63 KLOT 022348
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
648 PM CDT Fri May 2 2025

.KEY MESSAGES...

- Periods of showers tonight through the weekend, although with
  many dry hours in between.

- Monitoring a low-probability locally heavy rainfall threat
  Saturday afternoon/evening. Latest indications are this threat
  will focus south of the forecast area.

- Expect cooler-than-normal conditions this weekend followed by
  a mild stretch during the middle of next week. Cooler
  conditions will prevail along the lakeshore next week with
  persistent onshore flow.

&&

.DISCUSSION...
Issued at 226 PM CDT Fri May 2 2025

Through Saturday:

Through the rest of this afternoon: continue to carry some slight
chance/low end chance PoPs, mainly for locales roughly west of
the Fox River and north of I-80. In this region, dewpoints in
the upper 40s/near 50 degrees in the vicinity of a stalled
surface boundary, coupled with slightly cooler 700 mb
temperatures near -5 C may yield an erosion of lingering
inhibition. At the same time, some increase in forcing from an
encroaching mid-level wave/trough axis is advertised. Taken
together, this may facilitate the development of isolated to
perhaps widely scattered showers. Have noted some deepening of
the cumulus field on recent visible satellite imagery across
NW Illinois over the last half hour or so. The lightning threat
(should activity materialize) appears pretty minimal given
equilibrium levels near -20 C, and activity should tend to
diminish as it tracks northeastward into stable/cooler air
behind a quasistationary frontal zone. If this activity gets
going, can`t entirely rule out some "festering" showers into the
evening given the arrival of more robust DCVA. Additional
showers may also develop this evening and overnight south of
I-80 as a zone of intense shear vorticity sets up along the I-55
corridor, and have boosted PoPs a bit into early Saturday
morning as a result.

Through Saturday morning, strengthening north to northeasterly
flow should tend to gradually push lingering showers southward
as slightly drier air pushes south out of Wisconsin and off the
lake. Forecast soundings do suggest some potential for
sprinkles/drizzle may continue north of I-80 through the
morning, but with time, the bulk of any additional shower/storm
chances should tend to focus south of I-80 and potentially even
south of the Kankakee River.

During the afternoon, enhanced convergence in the vicinity of an
inverted surface trough looks like it`ll be the primary focus of
renewed convective development. While instability won`t be high,
inhibition also won`t be significant, suggesting it won`t take
much heating/insolation to allow parcels to breach their LFCs.
Guidance has recently been all over the place with the
placement of the main 500 mb low, but recent trends suggest
things are settling on a preferred location across central to
even downstate Illinois tomorrow afternoon. This would end up
maximizing both low-level convergence (from the aforementioned
inverted trough) and ascent (via upper jet forcing) primarily
just south of our forecast area.

Will need to monitor this closely, however, as cloud-bearing
flow will trend under 5-10 knots as surface northerlies
transition to south to the SW above 600 mb. Guidance--to varying
degrees--has suggested the potential for nearly stationary
heavier showers (and embedded storms) where this minima in
cloud-bearing flow materializes. As it stands right now, the
highest potential for this remains just south of our forecast
area, but given the pretty wild swings in guidance recently,
have a bit lower confidence in this.


Saturday Night through Friday:

Unfortunately, a cutoff upper low looks set to park itself in
our immediate vicinity on Saturday night and into early next
week before eventually getting kicked east during the
Tuesday/Tuesday night timeframe as the next shortwave ejects out
across the central plains. While thermodynamic parameters
through this timeframe appear unimpressive with an overall
dearth of MUCAPE/instability, bouts of enhanced forcing coupled
with narrow ribbons of increased tropospheric moisture (PWATs
nearing an inch at times), should support periods of showers
pinwheeling into the region Sunday into Monday. It certainly
won`t be raining every hour during this period, although
coverage does look like it might peak through the day on Sunday,
at least across parts of the forecast area (mainly the
southeast third during the day). Could end up seeing some
locally heavier rainfall set up on Sunday where jet forcing (low
and upper level) focuses, although with the limited
instability, this would be from persistent heavier showers as
opposed to training thunderstorms.

Precipitation coverage looks to diminish Sunday night, although
persistent/broad ascent necessitates continuing at least chance
PoPs into Monday. Showers may gradually increase once again on
Monday with heating although--at this time--coverage looks
decidedly more scattered than Sunday.

By Tuesday, it looks like we`ll finally enter a more subsident
regime as this upper low kicks east across the Ohio River Valley.
Weak gradient flow will allow an afternoon lake breeze to push
westward, holding lakeside temperatures in the upper 50s, while
inland locales will push into the upper 60s/perhaps to near 70
degrees. The pattern upstairs looks like it may end up
transitioning into a Rex-type blocking pattern during the
middle and end of next week. Depending on where embedded
vorticity maxima set up, this could end up bringing a renewed
chance for showers to the region.

Carlaw

&&

.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 648 PM CDT Fri May 2 2025

Forecast concerns include...

Chance of showers this evening and overnight/Saturday morning.
Mvfr cigs, possible ifr cigs, overnight/Saturday morning.
Gusty northeast winds Saturday.

An area of rain continues to move east across far northern IL
early this evening. Earlier pockets of heavier rain are slowly
dissipating and there is uncertainty for how far east this rain
will move but close enough to include tempo mention this evening
for ORD/MDW/DPA. With the expectation that this activity will
continue to weaken, only brief mvfr cigs/vis are expected but
should a longer duration moderate rain persist, then prevailing
mvfr cigs/vis may last longer.

There will be another chance of showers overnight into the mid
morning hours Saturday. Confidence remains low for this time
period with much of the guidance now shifting the best chance
for showers south of the terminals. Maintained prob mention for
now and trends will need to be monitored into tonight.

Cigs may remain mvfr across northwest IL and at RFD this evening
and then lower back to low mvfr tonight and continue through
midday Saturday for the entire area, before lifting and
scattering. Ifr cigs are also possible overnight/Saturday
morning and would be dependent on how widespread the showers
become.

The current showers have a weak outflow with a northwest wind
shift. This is not expected to reach ORD/MDW where easterly
winds should prevail. Northeast winds are expected tonight and
Saturday with speeds increasing into the 10-15kt range and gusts
into the 20kt range. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory from 10 AM Saturday to 3 AM CDT Sunday
     for the IL and IN nearshore waters.

&&

$$

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