Mason Illinois Weather Forecast Discussion

266
FXUS63 KILX 080512
AFDILX
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1212 AM CDT Wed Oct 8 2025
.KEY MESSAGES...
- A cold front has pushed across central Illinois and will result
  in a return to more seasonable temps (highs in the upper 60s to
  mid 70s) Wednesday though Friday.
- Overnight lows will dip into the 30s for portions of central and
  east central Illinois Wednesday night and Thursday night. Some
  of the coldest spots could see some patchy frost.
&&
.DISCUSSION...
Issued at 152 PM CDT Tue Oct 7 2025
This afternoon, a cold front has pushed through central and
southeast Illinois. North winds are advecting temps in the 60s
into central Illinois along with dew points in the 50s and 40s.
Lingering low level cyclonic flow and shallow moisture behind the
front will produce a corridor of low ceilings, and cannot
completely rule out some patchy drizzle at times, though the bulk
of the precip has ended. Skies should generally clear from the
north this evening as 925mb anticyclonic flow starts to build into
the region. Temps will fall into the 40s or low 50s area-wide
overnight.
High pressure centered over the Canadian Prairies today will
settle over the Great Lakes and Midwest through the latter half
of the week. Cooler, more seasonable, conditions will be in place
under the influence of the high. Temps will top out in the upper
60s to lower 70s Wednesday and Thursday, followed by low to mid
70s Friday as winds turn back southerly behind the ridge axis.
Meanwhile, lows will drop into the lower 40s Thursday and Friday
mornings with a few spots dipping into the 30s. NBM probabilities
for dipping below 38 degrees is roughly 50-70 percent from a
Bloomington to Paris line north Thursday morning. The probability
jumps to 70-90 percent across portions of east central Illinois
Friday morning. Given these temps along with an otherwise
favorable radiational cooling setup both mornings, frost remains a
possibility.
Aloft, a strong ridge is expected to build through the latter half
of the week across the western CONUS, and is set to shift east
over the weekend. Attendant 850mb thermal ridge will begin to
shift east to and then across the Mississippi Valley over the
weekend and into early next week. This will allow temps to return
to well above normal starting Saturday when temps warm to near 80
degrees. Low 80s will be in place for most of the area Sunday
through Tuesday.
Deubelbeiss
&&
.AVIATION...  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1212 AM CDT Wed Oct 8 2025
Main aviation concern is with shallow fog, locally dense, in the
KSPI-KBMI corridor. Visibility has been fluctuating quite a bit,
occasionally getting down as low as 1/4SM, though webcams and
visual observations suggest the depth is probably about 50 feet
or less. Will keep this in the TAF`s at these two sites for about
3-4 more hours, until some drier air begins to work in from the
northwest. Outside of the fog, skies will be clear through the
period.
Otherwise, winds trend toward the northeast Wednesday morning, and
will approach 10 knots over eastern Illinois during the afternoon.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS ILX Office Area Forecast Discussion