Burt, Illinois Weather Forecast Discussion

743
FXUS63 KILX 231733
AFDILX
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1233 PM CDT Tue Sep 23 2025
.KEY MESSAGES...
- An unsettled weather pattern will result in additional chances
  for showers and storms through Wednesday. A few isolated pockets
  of 2 inches of rain will be possible this afternoon and evening
  in slow moving storms north of I-72. There is a 50-60 percent
  chance for a more widespread area of 2+ inches of rain south of
  I-72 late tonight through Wednesday evening.
- A stretch of dry weather returns Friday through at least early
  next week with temps returning to above normal (highs in the mid
  80s).
&&
.UPDATE...
Issued at 1121 AM CDT Tue Sep 23 2025
Made updates this morning to account for thicker cloud cover
spreading into the area ahead of an approaching shortwave, which
should limit high temperatures a few degrees from mainly from
around Jacksonville to Effingham area. Also delayed onset of
precipitation chances early this afternoon along a cold front
trailing a departing low to the northeast. 12Z high resolution
model suite depicts no shower activity along that boundary until
mid-afternoon. Finally, increased PoPs this afternoon as the
approaching shortwave/low tracks northeastward from Missouri,
spreading precipitation into the area a bit earlier, or at least
with a higher chances than previously forecast as current radar
indicates this system is tracking well with model data.
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&&
.DISCUSSION...
Issued at 149 AM CDT Tue Sep 23 2025
Slow moving upper low that has been anchored over the Great Lakes
will continue to result in unsettled weather through at least
Thursday across central Illinois.
Elongated upper trough that stretches from the Canadian Maritimes
back into the Upper Midwest will make little southward progress
today, while at the surface, an attendant trough is expected to
inch into the Illinois River Valley this afternoon. A damping H5
shortwave trough is expected to move across the mid Mississippi
Valley late this afternoon into the evening, while coupled jet
streaks with favorable right entrance and left exit regions will
accompany this feature and overspread central Illinois. Synoptic
scale forcing for ascent associated with these features will
result in the next round of scattered showers and storms moving
across central Illinois later today with some additional
development along the aforementioned surface boundary. Modest
instability is expected across central Illinois with the GFS
suggesting only up to around 500 J/kg MLCAPE will be present this
afternoon. Favorable deep layer shear may be present under the
aforementioned jet streaks to our north and areas south of I-72,
but weak shear is present in between for much of central IL north
of I-72. HREF joint probs for exceeding 500 J/kg CAPE and 30kt
deep layer shear peaks around 40-60 percent south I-72 and around
70% south of I-70. This appears to be the area where parameter
space is most favorable for severe weather, albeit only marginally
so. Where the deep layer shear is much weaker near the Illinois
River Valley, slow storm motions are expected with some pockets of
locally heavy rain possible. HREF LPMM suggests isolated totals
of 2-4 inches of rain will be possible north of I-72.
Tuesday night into Wednesday, main upper trough axis is finally
expected to push across central Illinois with a weak surface low
tracking across southern Illinois. Strong isentropic ascent will
begin to overspread central Illinois ahead of the low Tuesday
night and will persist across portions of central Illinois into
Wednesday morning. Heavy rain appears possible near the surface
low track, but expect a sharp gradient in rainfall amounts across
portions of central Illinois on the northern edge of this system.
NBM probabilities for exceeding 2 inches of rain in 24 hours
ending Wednesday evening peaks south of I-70 in the 50-60 percent
range, but drops off to around 20 percent or less north of I-70.
NBM 50th percentile QPF for this same time range shows the one
inch contour running roughly Taylorville to Terre Haute, and
ranges from less than a tenth of an inch near Galesburg to around
2.5 inches near Lawrenceville.
Thursday will be the transition day between the wetter pattern
we`ve been under to another stretch of dry and warmer weather as
a strong upper ridge builds back across the middle of the country
through the weekend and into next week. Thursday will see a few
lingering showers in the low level cyclonic flow and weak diurnal
instability. Forecast sounding show strong capping around 700mb
which will limit the depth of any diurnally favored showers and
keep the overall thunder threat low. Dry weather should prevail
Friday into early next week, while temps warm back above normal
with highs in the mid 80s under the influence of the strong upper
ridge.
Deubelbeiss
&&
.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1233 PM CDT Tue Sep 23 2025
A cold frontal boundary trailing across the area and a low
pressure system approaching from the southwest will provide a few
chances for showers and thunderstorms mainly before 12Z. First,
some isolated thunderstorms could develop over the area from
around 20Z-23Z with peak diurnal heating. Second, the system
approaching from the southwest will bring more widespread shower
activity with a few embedded thunderstorms spreading into the
KSPI area around 23Z and rapidly spreading northeast. The KPIA
area will likely be near the northwest extent of this system. VFR
conditions can be expected until around 06Z-08Z when lowering cigs
develop and MVFR to locally IFR develop, except isolated MVFR
cigs/vsbys in TSRA. Winds VRB to SW around 5 kts this afternoon,
becoming NE 6-12 kts by 06Z-10Z.
37
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS ILX Office Area Forecast Discussion