861 
FXUS63 KILX 032320
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
620 PM CDT Fri Oct 3 2025

.KEY MESSAGES...

- Widely scattered (10-15% coverage) showers will continue through
  this afternoon across areas mainly near the I-72 corridor.

- South winds gusting over 20 mph both Saturday and Sunday 
  afternoons will combine with low RH values (25-35%) to increase 
  fire danger. Burning is discouraged and caution is urged with 
  outdoor equipment.

- Scattered showers and storms Monday into Tuesday will result in
  a 20-30% chance of a wetting rain.

&&

.DISCUSSION...
Issued at 152 PM CDT Fri Oct 3 2025

***** SLIGHT SHOWER CHANCES THROUGH THIS EVENING *****

Early Friday afternoon, central and southeast IL finds itself on the 
northeast periphery of a positively tilted ridge extending across 
the Great Plains. A piece of weak shortwave energy cresting the 
ridge today has sparked a couple showers and even thunderstorms 
amidst 500-1000 J/kg MLCAPE, and given the surface based nature of 
this activity there's no reason to suspect it will dissipate before 
the loss of surface heating this evening. Slight (15%) chance PoPs 
were expanded accordingly.

Around 1:30pm, we received a report of pair of landspout tornados 
with one of these cells in east-central IL, and the non-supercell 
tornado parameter is 0.5 to 1 for much of the region given the steep 
low level lapse rates. We'd like to stress that these tend to be 
brief, weak, and rarely cause damage; given their fickle nature and 
absence of any precursor signatures on radar which would allow us to 
issue a warning, we've highlighted the risk for one/two additional 
landspouts via a special weather statement.

***** WARM AND DRY WEEKEND IN STORE *****

Tomorrow into Sunday, the aforementioned ridge will shift east while 
a deep upper level low lifts across the Great Basin and into the 
Northern Plains. In response, surface pressure will lower over the 
Great Plains, causing a tightening gradient over the Plains and 
Midwest. While it will be much breezier further west, we'll still 
have southerly wind gusts to 20-25 mph tomorrow and 25-30 mph on 
Sunday; in fact, NBM gives a 50-70% chance peak gusts exceed 30 mph 
on Sunday west of roughly I-57. Given the combination of low 
afternoon RH values in the mid 20s to low 30s and low (5-8%) 10h 
fuel moisture values, these seasonably gusty winds will foster 
marginal fire weather conditions - not enough to warrant a Red Flag 
Warning, but enough that we'd continue to urge caution with outdoor 
equipment (or anything else that might generate a spark), and 
discourage burning in accordance with local burn bans. Otherwise, 
expect seasonably warm conditions through Monday with daily highs in 
the mid to upper 80s - just a handful of degrees shy of record 
values.

***** SHOWERS AND STORMS, COOLDOWN NEXT WORK WEEK *****

The upper level trough will lift into the Canadian Prairies by 
Monday, and as a consequence the trailing cold front across the 
Midwest will weaken and slow in its southern advance. Global 
deterministic models are not yet in agreement as to the timing of 
the front, with the ECMWF dropping it into the area Tuesday morning 
but the GFS holding off until late Tuesday night into Wednesday 
morning. Flow in the cloud-bearing layer will be roughly parallel to 
the front (i.e., west-east), which could favor multiple rounds of 
showers and perhaps a few thunderstorms Monday into Tuesday. Both 
LREF and NBM suggest a 20-40% of a wetting rain (>0.25") out of this 
activity, with the highest probabilities east of roughly I-55.

Later in the week, global models and their respective ensembles 
begin to diverge in the upper level pattern, with Empirical 
Orthogonal Functions (EOFs) suggesting the primary source of 
ensemble variability (hence low confidence) is in the 
timing/position of a ridge building across the nation's midsection. 
It appears we'll have a couple days of temperatures closer to 
seasonable normal values Wednesday into Thursday when forecast highs 
are in the low 70s. However, the general trend is for increasing 
heights and temperatures across the Midwest as the ridge builds 
northeastward by Friday (10/10) and beyond. CPC's 6-10 and 8-14 day 
outlooks suggest we're leaning towards (40-50% chance) above normal 
temperatures.

Bumgardner

&&

.AVIATION...  (For the 00z TAFs through 00z Saturday Evening)
Issued at 620 PM CDT Fri Oct 3 2025

Isolated showers/storms in east-central Illinois will dissipate in 
the next hour or two as we lose daytime heating. Otherwise, VFR 
conditions will prevail the next 24 hours. South-southwest winds 
will be light overnight, then increase by late Saturday morning with 
occasional gusts up to 20 kts through the afternoon hours. 

NMA

&&

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

$$