Downs, Illinois Weather Forecast Discussion

038
FXUS63 KILX 112325
AFDILX
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
625 PM CDT Thu Sep 11 2025
.KEY MESSAGES...
- An extended period of well above normal temperatures continues
  across central and southeast IL through at least next Thursday.
- Little to no precipitation is expected during the next 7 days,
  introducing the risk for flash drought conditions through mid
  September for central and southern IL.
&&
.DISCUSSION...
Issued at 230 PM CDT Thu Sep 11 2025
Mid afternoon surface map shows 1027-1029 mb high pressure over
James Bay Canada and ridging southward into the Great Lakes
region, and influencing central/ne IL with weak east to NE flow.
Scattered cumulus clouds were over central and eastern parts of
CWA with few cumulus clouds from Peoria and Springfield west. Warm
temps were in the low to mid 80s over central/se IL with Olney at
88F and Mt Carmel airport in southern Lawrence county at 89F.
Dewpoints were in the 50s over central IL 60-65F in southeast IL.
Aloft an omega block pattern was occurring over US, with a strong
mid/upper level ridge was over the central plains with upper
level trof over the Atlantic States and a stronger upper level
trof/low over the Pacific States (a 572 decameter 500 mb low was
near the OR/CA/NV border).
Broad surface high pressure ridge to slowly shift eastward into
Quebec, New England and into the central Appalachians on Friday
with south to SSE flow developing over central IL. Strong upper
level ridge to also build more over IL as 500 mb heights rise
above 588 decameters. Diurnally driven cu field to dissipate
after dusk with fair wx expected again tonight. Latest CAMs hint
at some fog develop over northeast IL, mainly ne of CWA and fog
more prevalent closer to Lake MI and marine layer. Far southern
IL also could see patchy fog develop overnight while most of our
CWA should not see too much fog. Lacon and Robinson had patchy fog
early this morning with vsbys 1-2 miles and may see a few spots
with similar conditions in eastern IL. Lows overnight in the upper
50s to around 60F. Hot on Friday with highs around 90F to lower
90s from Peoria to Effingham west. Few to scattered cumulus clouds
to develop by midday Fri into Fri afternoon with more cumulus
clouds expected over the IL river valley/western CWA by Fri
afternoon.
The stronger upper level ridge near IL this weekend into middle of
next week to continue the heat wave with highs in the low to mid
90s Saturday through Wednesday, and likely lower 90s yet next
Thursday. Continued to blend the raw NBM high temperatures from
Friday through Wed with the 50th percentile NBM to bring some of
the erroneously high values down. Temperatures remain elevated
through much of next work week, though should come down slightly
late next week.
Models begin to diverge with convection chances starting this
weekend as short waves start ridging over top of the subtropical
ridge and question is how far south convection chances can get and
coverage. Overnight Friday night could see isolated convection
move over northern IL though most of this convection appears to
miss central IL. But more model solutions show some convection
chances over parts of CWA especially ne CWA on Saturday and Sat
night. GFS still appears too wet over area this weekend and NBM
keeps pops closer to 10% over much of area. Cutoff lows moving
over the mid and southern Atlantic States by mid week with another
cutoff low moving into the central and northern high plains to
keep better convection chances se of IL and to our nw. Maybe a
better chance of needed convection later next week around next
Friday.
The Climate Prediction Center (CPC) 6-10 Day outlook for Sep 17-21
has 70-80% chance of above normal temperature over IL. CPC 8-14
Day outlook for Sep 19-25 has 50-60% chance of above normal
temperatures over IL. So we may need to keep our air conditioning
units going this month.
07
&&
.AVIATION...  (For the 00z TAFs through 00z Friday Evening)
Issued at 624 PM CDT Thu Sep 11 2025
Ridge of high pressure will continue to inch east across the Great
Lakes resulting in gradually veering flow across central
Illinois. Winds generally out of the east to northeast this
evening will set up out of the southeast Friday, but should remain
below 10 kt through the period. Due to the light magnitude, there
may be some variability at times in the direction, especially
overnight into early Friday. VFR conditions are expected through
the period.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS ILX Office Area Forecast Discussion