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Area forecast discussion
National Weather Service Lincoln Illinois
622 PM CDT sun Oct 13 2019

issued at 216 PM CDT sun Oct 13 2019

High pressure will build from the Central Plains across the mid
Mississippi Valley tonight into Monday. Winds will diminish and
fair weather will continue as a result across central Illinois.
Temperatures will fall into the 30s overnight, and many areas
north of I-70 may see frost Monday morning. Temperatures will warm
back into the 60s on Monday under sunny skies. The next chance for
precip will be on Tuesday as an area of low pressure moves across
the region.


Short term...(this evening through monday)
issued at 216 PM CDT sun Oct 13 2019

Slow moving areas of low pressure is centered over Ontario this
afternoon while a ridge of high pressure stretches from the
northern plains into the lower Mississippi Valley. A tight
pressure gradient is in place between these features, including
over central Illinois resulting in gusty winds. 925mb winds into
the low to mid 20 kt range should be able to mix down to the
surface through early evening, then decoupling around sunset
should allow gusty winds to subside through the remainder of the
night. In addition, the gradient will relax as the high shifts
east across the mid Mississippi Valley overnight in Monday
morning. Weakening winds in combination with already clear skies
should set the stage for favorable radiational cooling overnight.
Temperatures are expected to drop into the low 30s northwest of
the Ohio River valley with upper 30s expected southeast of I-70.
Mid 30s are likely for much of the remainder of central Illinois.
Frost will be possible overnight for much of central Illinois, and
a frost advisory will be hoisted mainly for counties north of the
I-70 corridor for late tonight into Monday morning.

High pressure will build across central Illinois on Monday
resulting in another day of sunny skies. Winds will be lighter
closer to the ridge axis and temperatures should be a degree or
two warmer than today.

Long term...(monday night through sunday)
issued at 216 PM CDT sun Oct 13 2019

A clipper like system will dig from the northern Great Plains into
the upper Midwest Monday night into Tuesday. Warm advection Wing
of this system will overspread portions of central Illinois late
Monday night into Tuesday morning resulting in some rain chances.
Initially dry soundings don't begin to saturate west of the I-55
corridor until late Monday night, so have confined pops to the
western County Warning Area through daybreak. Temperatures are expected to top out
in the upper 60s to 70s across the forecast area, but could fall
during the day in some western locations depending on timing of
the trailing cold front. The cold front will sweep across central
Illinois through the day Tuesday bringing an additional chance for
showers and thunderstorms to the remainder of the forecast area.
Strong cold advection will drive steepening low level lapse rates
in the wake of the front and a strong high building across the
central Great Plains will result in breezy conditions again
Tuesday night into Wednesday. Soundings show top of The Channel
winds of just over 30 kts which partially mix down to the surface.
Temperatures are only expected to top out in the 50s on
Wednesday, and fall back into the mid 30s area wide Wednesday

Besides lingering breezy conditions on Wednesday, fair weather and
a gradual warming trend is expected through the latter half of
the week as high pressure gradually translates east across the
region. 70s should return Friday through the weekend as southwest
flow returns behind the ridge late in the week. The overall
pattern is progged to become more amplified again late in the
weekend into early next week and a deep low will gather strength
over the Central Plains as a result. This low is progged to lift
into the western Great Lakes by early next week bringing the
potential for heavy rain to central Illinois along a trailing cold


Aviation...(for the 00z tafs through 00z Monday evening)
issued at 622 PM CDT sun Oct 13 2019

VFR conditions will prevail at all taf sites next 24hrs. Scattered
ac will be seen at pia and bmi for a 2-3 hrs this evening, but
clear skies will prevail rest of taf period. Spi/Dec/cmi will also
see clear skies through the taf period. Winds will be west-
northwest this evening for a few hours at all sites and then
become light as high pressure begins to build into the area.
Expecting light and variable winds remainder of the night and
through tomorrow morning. Around noon winds will increase in
speed to around 6kts and be southwest.


Ilx watches/warnings/advisories...
frost advisory from 4 am to 8 am CDT Monday for ilz027>031-



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