Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 132109
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
309 PM CST Wed Dec 13 2017

.SHORT TERM...(This evening through Thursday)
ISSUED AT 308 PM CST Wed Dec 13 2017

A 992 mb low is centered near Milwaukee this afternoon and a cold
front trailing from the low southwestward through roughly the I-55
corridor, pushing southeastward. Brisk winds were gusting up to 40
mph well ahead of the front, with a short lull in winds until behind
the cold front where gusts to around 45 mph are prevalent, with the
winds shifted to WNW. Expecting the strongest winds to push east to
the IN border by around sunset, then winds will begin to taper off a
few hours after sunset across central IL as the parent low moves
rapidly east and the strongest winds aloft and surface pressure
gradients shift east. A wind advisory remains in effect until 9 p.m.
for most of central Illinois except for Richland, Lawrence, and
Crawford Counties. Light showers can also be expected along the
front this afternoon, with little or no measurable precipitation.
Overnight, winds will gradually decrease as a high pressure ridge
approaches from the west. Winds will end up light WNW only around 5
mph during the day Thursday as a result of the ridge. Expect lows
tonight back down to the low to mid 20s as cold post-frontal air
moves back in from the northwest, with highs Thursday only in the
low to mid 30s.

&&

.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 308 PM CST Wed Dec 13 2017

The next weather system will arrive early Friday morning as a
shortwave trough arrives from the northwest. Models produce only
scattered and very light precipitation with this feature, however it
will likely be able to produce some flurries north of I-70. After
this, the pattern begins to shift as the large-scale eastern
trough/western ridge move east with ridging and southerly flow
developing into the central U.S. bringing warmer temperatures
reaching the 40s in central IL through early next week. A
disturbance embedded in the southwesterly flow aloft will provide a
chance of rain Sunday, potentially beginning as light snow early
Sunday morning. After that, models disagree on timing and track of
precipitation, however general trends in the pattern suggest
precipitation gravitating toward the southeast U.S. early next week
as the west coast ridge and eastern trough re-establish.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1134 AM CST Wed Dec 13 2017

Strong winds to affect central IL terminals through evening today,
along with a period of MVFR cigs and a few light rain showers.
Currently, winds generally SW 15-25 kts with gusts 25-35 kts, and
decreasing slowly as a cold front approaches from the NW, roughly
at the Mississippi River currently. As the front moves across the
area, winds from the WNW will increase markedly, reaching 25 kts
with gusts as high as 40 kts. A period of light rain showers can
also be expected along the front, with cigs dropping to MVFR
behind the front. Expect the front to pass through KPIA-KSPI
around 19Z, and KDEC-KCMI around 21Z. NW winds will gradually
diminish overnight, while cloud cover gradually diminishes as
well.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 9 PM CST this evening for ILZ027>031-036>038-
040>057-061>063-066-067-071.

&&

$$

SHORT TERM...37
LONG TERM...37
AVIATION...37



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