Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 180000
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
600 PM CST Wed Jan 17 2018

.SHORT TERM...(This evening through Thursday)
ISSUED AT 153 PM CST Wed Jan 17 2018

With high pressure drifting into the lower Mississippi Valley,
winds have started to turn southwest across central Illinois.
A tightening pressure gradient will keep the speeds up somewhat
overnight, which should help keep temperatures from free-falling.
Lows should be 10-15 degrees (above zero), coldest over the south
where the winds will be lighter. The warming trend should begin in
earnest on Thursday, as temperatures reach above freezing over the
CWA. Mostly clear skies are expected to prevail through the
period.

.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 153 PM CST Wed Jan 17 2018

Upper ridging will build eastward through the end of the week,
with the warming trend continuing. Little change needed for
temperatures through the weekend, with 40s returning Friday and
most areas in the 50s by Sunday.

Main concern during the period remains with the late weekend storm
system. An upper level trough will dig across the southwest U.S.
early in the weekend, with a low closing off on Sunday over the
central Plains. The latest GFS is a bit quicker than the European
or Canadian models on the speed of this low lifting northeast.
This results in the cold front coming through late Sunday night
vs. Monday morning. While the shear with this front is fairly
decent, the timing results in little in the way of instability.
Can`t rule out a few rumbles of thunder, but chances are low
enough to keep a mention out of the forecast at this point.
Highest rain chances will be Sunday night into Monday morning.
However, wraparound moisture will keep some scattered rain or snow
showers lingering into early Tuesday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 600 PM CST Wed Jan 17 2018

The cold dry air mass will produce nearly cloud-free skies over
the next 24 hours. The main issue tonight will be the potential
for LLWS conditions, mainly for our northern terminals. A speed
max between 925-850mb will advance across northern Illinois, with
the 40KT contour down to the PIA and BMI areas 04z and 15z. Have
continued with LLWS in those two TAFs, but may be adding the other
sites based on VAD wind observations and RAP/HRRR updates. BUFKIT
analysis show the remaining terminals only a few knots below 40kt
at 1000FT AGL.

After initial decoupling of the winds early this evening, surface
winds look to increase from the southwest to 10-14KT for a
majority of the night. After sunrise tomorrow, and an increasing
mixing heights, wind gusts could increase over 20KT at times.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Shimon



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