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FXUS63 KILX 062346
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
646 PM CDT Sun Oct 6 2024

.KEY MESSAGES...

- Northwest winds gusting to 25 mph and relative humidity values
  of 18 to 25 percent have made the environment this afternoon
  favorable for rapid spread of any bush or field fires.

- There is a 20-40% chance for patchy frost tonight in rural, low
  lying areas northwest of a roughly Peoria to Havana line.
  Tomorrow, lower chances will exist across all of central and
  southeast IL.

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

&&

.DISCUSSION...
Issued at 121 PM CDT Sun Oct 6 2024

Mid level water vapor imagery shows the upper trough responsible for
the cold front which passed through central Illinois this morning is
spinning across western Ontario, with cool and dry advection in its
wake. Dewpoints have fallen into the 30s across areas near and north
of the I-70 corridor, and these are likely to dip a couple more
degrees before the day`s over given sufficient mixing. Temps remain
above normal this afternoon due to all the sunshine and drier
airmass, but given northwest winds currently gusting 20 to 25 mph it
doesn`t feel overly warm for most.

Surface high pressure will strengthen over the region tonight into
tomorrow - diminishing winds, maintaining subsidence to continue
ushering drier air (from the mid-levels) to the surface, and of
course maintaining clear skies. This will favor a sharp drop in
temps both tonight and tomorrow night, with the 12z HREF suggesting
probabilities as high as 30-50% for low temps less than 37 degF
northwest of a Peoria to Havana line tonight. What`s somewhat
perplexing is that HREF probs for such temps tomorrow night are
virtually non-existant, while climatology-calibrated NBM (which
has a less than 5% chance for temps falling to less than 37
tonight) has pockets of 5-15% chances tomorrow night. Likely, the
frost will be confined to low lying areas each night, and it will
be conditional on whether winds go as light as our forecast
currently suggests, but we`ve done a little blending to NBM`s 10th
percentile for min temps tonight to account for this potential
and have maintained the mention of patchy frost in those areas; at
this time, confidence just isn`t high enough to warrant a Frost
Advisory, but we`ll continue to message in other places lest
anyone be caught off guard and their plants suffer damage.

Despite an even drier airmass in place with dew points in the 20s,
weaker winds will favor a less favorable environment for fire spread
tomorrow. Despite how dry and sunny it`s expected to be, Monday`s
forecast highs fall shy of 70 in most places given how cool we`ll
start the day. A gradual warming trend will begin Tuesday and
continue through the remainder of the week as a ridge of high
pressure slowly expands into the region from the west. Precipitation
chances remain less than 15% through next Sunday, October 13th.

Bumgardner

&&

.AVIATION...  (For the 00z TAFs through 00z Monday Evening)
Issued at 645 PM CDT Sun Oct 6 2024

VFR conditions will prevail at all TAF sites next 24hrs with clear
skies through the period. Northwest winds should decrease around
issuance time and be 12kts or less during the evening. Winds will
become more northerly overnight as the high pressure ridge gets
closer to the area. Light wind speeds expected overnight as well.
Tomorrow winds will become more northwesterly with speeds
increasing slightly, but still less than 10kts at all sites.

Auten

&&

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

$$