198
FXUS63 KILX 060200
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
900 PM CDT Sat Oct 5 2024

.KEY MESSAGES...

- Northwest winds gusting to 25 mph tomorrow afternoon will
  combine with relative humidity of 20 to 25 percent to increase
  risk for rapid fire spread.

- There is less than a 15% chance for any measurable
  precipitation during the next 7 days, which will result in
  developing or worsening drought conditions across central and
  southeast IL.

&&

.UPDATE...
Issued at 900 PM CDT Sat Oct 5 2024

Skies will remain clear through the night and tomorrow. Winds will
be southerly tonight but then switch to west and then northwest
late tonight and through tomorrow. However, wind speed and gusts
were too high for current and expected conditions overnight. So,
made some changes there and lowered speeds. Did lower overnight
lows in northwest by a degree, but overall current forecast still
looked good. Update for the low temps and winds has been done with
updated text products forthcoming.

Auten

&&

.DISCUSSION...
Issued at 107 PM CDT Sat Oct 5 2024

An unseasonably warm Autumn day continues, with temps at 1pm
clocking in in the low to mid 80s. Southerly winds are gusting
around 20-25 mph; these will probably increase a little later this
afternoon into the evening when we should see a few 30+ mph gusts in
our northwest - nothing out of the ordinary for this time of year.
Dew points, which mixing has maintained in the upper 50s to around
60 so far today, should creep up a bit ahead of an approaching
cold front tonight when the HRRR brings them into the 61-64 degree
range in many locations along and east of the IL River. This will
be short-lived, however, with a dramatic plunge behind the cold
front which should reach the IL River around 2am and clear the CWA
by noon tomorrow.

Behind that front tomorrow afternoon, CAA will enhance mixing to
yield both northwest wind gusts around 20-25+ mph (highest north)
and dewpoints in the low 30s (which will result in RH values dipping
to around 20% for several hours). The 12z HREF suggests the joint
probability (i.e., a chance of multiple criteria being met
simultaneously) of wind gusts > 25 mph and RH < 25% is around 10-
30%, but personally I think this is a bit low because of the
NAMNest`s high bias in boundary layer moisture. Time will tell, but
in any case: (1) we shouldn`t need a Red Flag Warning (RFW) because
our 10 h fuel moisture is hovering near 15% (RFW criteria is 8%),
and (2) nonetheless it will be breezy and relatively dry implying
conditions are favorable for rapid fire spread. Farmers should use
caution when harvesting, and anyone burning should exercise caution.
Do not carelessly discard cigarettes or matches.

Conditions turn cooler by Monday when most locations are expected to
struggle to reach 70 degF. If winds end up on the lighter side of
guidance, the drier airmass and lack of clouds should result in
temps dipping well into the 40s tomorrow morning and low 40s to
locally upper 30s Tuesday morning; in fact, NBM suggests
probabilities as high as 30-40% for min temps less than 40 degF in
the lower-elevation, cold-prone locations Tuesday morning.

The LREF mean suggests 500mb heights will gradually rise as an upper
ridge slowly expands into the Midwest mid to late week, implying a
subtle warming trend and absence of appreciable precip chances into
the upcoming weekend. NBM suggests chances for highs over 80 degF
climb to more than 40% near and west of I-55 both Friday and
Saturday - suggesting a return to unseasonable warmth once again.

Bumgardner

&&

.AVIATION...  (For the 00z TAFs through 00z Sunday Evening)
Issued at 635 PM CDT Sat Oct 5 2024

VFR conditions will prevail at all TAF sites next 24hrs, with
clear skies through the period. Winds will be out of the south
this evening with wind speeds around 12-15kts. Then as a dry sfc
front slides across the area, winds will become westerly with
speeds less than 10kts. Daytime tomorrow, winds will become
northwesterly and become gusty, with speeds of 22-25kts.

Auten

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$