Bloomington, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

509
FXUS63 KILX 051923
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
223 PM CDT Sun Apr 5 2026

.KEY MESSAGES...

- Freezing temperatures Monday night: There is a high chance
  (50-60%) of a hard freeze (28F or colder) along the I-74
  corridor Monday night into Tuesday morning. A Freeze Watch is
  in effect; residents should protect sensitive early-season
  vegetation.

- Wintry mix potential: A narrow corridor of light snow or rain
  is possible (10-20% chance) across west-central Illinois
  Monday night. No significant accumulation is expected.

- Significant midweek warmup: Temperatures will trend much
  warmer starting Wednesday. Highs are forecast to reach the 60s
  and 70s Wednesday through the weekend.

- Thunderstorm chances return: Scattered showers and storms are
  possible (30-50% chance) Wednesday through the weekend. While
  the mid-week severe weather threat is low, confidence is
  increasing for stronger storms by Sunday.

&&

.DISCUSSION...
Issued at 219 PM CDT Sun Apr 5 2026

Tonight: Quieter Weather Before the Next System...
High pressure currently dominating the central and southern
Great Plains, with a robust center near 1030mb, is responsible
for the moderate northwesterly breeze across central Illinois
this afternoon. These breezy conditions will gradually diminish
this evening and overnight as the high builds eastward into the
Lower and Mid Mississippi Valley, allowing the pressure gradient
to relax locally.

A weak clipper system currently over the Dakotas will quickly
dive across the Upper Midwest and Great Lakes tonight. The
associated weak moisture and lift may bring a chance for light
precipitation to northern portions of the state tonight.
However, the latest ILX 12Z RAOB data indicates an exceptionally
dry column with a precipitable water (PWat) value of only 0.28
inches, suggesting the majority of central Illinois will remain
dry. A brief period of backed surface flow (southwesterly) ahead
of the incoming shortwave will offer some minor resistance to
falling temperatures, but overnight lows are still forecast to
settle into the upper 30s across the majority of the region.

Colder With Freeze Potential Early This Week...
The main weather story for the start of the week revolves
around a powerful high pressure system (1040 mb) over the
Canadian Prairies that will build southeastward into the Upper
Midwest and Midwest for Monday and Tuesday. This deep, cold high
will reinforce the unseasonably cold airmass.

On the southern periphery of this reinforcing ridge, a strong
and deep corridor of mid-level frontogenesis is progged to
develop and stretch from western Iowa into west-central
Illinois. This feature could generate a narrow corridor of light
wintry precipitation, which has shifted slightly east compared
to previous forecast cycles, now creeping into portions of west
central Illinois. Non-zero probabilities for minor snow
accumulations (generally 10-20% per NBM) now extend into the
lower Illinois River Valley Monday night into Tuesday morning.
While confidence in measurable precipitation remains low, the
increase in cloud cover associated with this system may slightly
moderate overnight temperatures.

Despite the potential for clouds, Tuesday morning is still
expected to be the coldest period of the week. Low temperatures
are forecast to fall to or below freezing across the majority of
the area north of a Havana to Paris line. The LREF continues to
indicate elevated probabilities for a hard freeze (28F or
colder), topping out around 50-60% along the I-74 corridor, with
probabilities increasing further north. Given these
probabilities, a Freeze Watch has been issued for locations near
and along the I-74 corridor Monday night through Tuesday
morning. The exception is for Knox, Stark, and Marshall
counties, where coordination with agricultural partners
indicates the growing season has not yet commenced in earnest.
All other residents with sensitive early-season vegetation
should take protective measures.

Midweek Warm-Up and Increased Convective Potential...
The persistent upper-level troughing that dominates the region
during the first half of the week will begin to flatten and
transition to a more zonal flow regime toward the latter half of
the week. As the surface high shifts east toward New England, a
strong southwesterly return flow will establish across the
Mississippi Valley. This pattern shift will allow temperatures
to moderate significantly back to above-normal levels. High
temperatures are forecast to reach the upper 60s and 70s from
Wednesday through the upcoming weekend, with overnight lows
generally holding in the 50s.

A surface low pressure system is progged to track along the US-
Canada border before lifting toward James Bay Thursday. A warm
front preceding this low will lift through central Illinois
early Wednesday, bringing a 30% chance for light precipitation.
Slightly better chances (40%) for showers and thunderstorms will
materialize along the trailing cold front on Thursday and
Friday as the boundary stalls over the region. Early analysis
suggests the initial southwesterly return flow will be too brief
to advect significant moisture into the region ahead of the
Thursday cold frontal passage, with surface dew points likely
struggling to reach 50F. This limited moisture advection is
expected to greatly mitigate any severe weather threat on
Thursday. However, an open Gulf and continued southwest flow
through the remainder of the week will lead to a gradual
increase in surface dew points and instability. Confidence is
increasing for stronger/severe storms, especially toward the end
of the weekend (Sunday), supported by increasing signals from
CIPS analogs and CSU machine-learning products.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1251 PM CDT Sun Apr 5 2026

A weak upper level disturbance is expected to dig across
northern  Illinois this evening and overnight. Across central
Illinois northwest winds currently in place are expected to back
to the southwest this evening ahead of the feature, then veer
to the northwest again overnight in its wake. VFR conditions are
expected through the period.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Freeze Watch from late Monday night through Tuesday morning
for ILZ029-031-036>038-041>046.

&&

$$

KEY MESSAGES...Deubelbeiss
DISCUSSION...Deubelbeiss
AVIATION...Deubelbeiss