Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 140152
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
852 PM CDT Wed Sep 13 2017

.UPDATE...
Issued at 845 PM CDT Wed Sep 13 2017

Upper low currently over eastern Indiana will continue to push
away from central Illinois tonight taking any lingering chances
of rain with it. Clouds continue to slowly drift off to the east
this evening and except for east central and parts of southeast
Illinois, should clear most of our area by morning. The combinaton
of low level moisture left behind by the remnants of Irma, light
winds and a decrease in cloud cover will lead to fog late tonight
into the mid-morning hours of Thursday. Some of the fog may be
dense for a time late tonight and during the drive into work
Thursday morning, but should quickly dissipate by 9 am, with a mix
of sun and clouds dominating for the remainder of the day with
temperatures responding nicely to the sun with most locations
rising quickly into the low to mid 80s by mid-afternoon.

Updated zone forecast should be out by 9 pm.

&&

.SHORT TERM...(This evening through Thursday)
ISSUED AT 223 PM CDT Wed Sep 13 2017

Upper level remnants of Irma were centered over southern Indiana
this afternoon. Associated isolated showers this far west have
been diminishing, though high-resolution models continue to
suggest a small chance over eastern Illinois into early evening.
However, the cloud shield will be much slower to diminish, and is
likely to hang firm across areas east of I-55 through the night.
With moisture trapped in the lower levels and winds pretty light
tonight, will add a mention of some fog.

The upper low will finally lift northeast Thursday morning, taking
the low clouds with it. A significant warming trend will commence,
with 850 mb temperatures up to the mid teens Celsius by midday.
Western CWA shouldn`t have trouble reaching the mid 80s, though
the east will be kept down some due to the initial cloudiness.

.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 223 PM CDT Wed Sep 13 2017

The main feature over the next several days will be the much
warmer conditions. As an upper low digs southward from the Pacific
Northwest early next week, 850 mb temperatures should rise into
the mid-upper teens Celsius and persist into midweek. Highs near
90 are likely Friday and Saturday, and will be well into the 80s
next week.

As the western trough sharpens early next week, shortwaves will
be tracking northeast into the Plains. Sunday and Monday will be
the main time frames for any shower and thunderstorm activity, as
a cold front pushes into central Illinois. However, this should be
pushed back north as 500 mb heights build across the Mississippi
Valley, resulting in a largely dry forecast beginning Tuesday
afternoon.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 610 PM CDT Wed Sep 13 2017

Main forecast concern late tonight and through the mid-morning
hours on Thursday will be with the potential for areas of dense
fog. The remnants of Irma continue to slowly edge away from our
area early this evening with clouds gradually decreasing from
west to east. Plenty of low level moisture left behind from the
system and combined with a clearing sky and light winds should
lead to fog development after 06z. IFR to LIFR vsbys can be
expected across the TAF sites late tonight before the fog begins
to dissipate by 14z, with VFR conditions expected for the
remainder of the TAF period. Forecast soundings do indicate
enough moisture will linger into the daylight hours of Thursday
to allow for some cumulus development with bases in the 3500-4500
foot range with the more widespread coverage being along and east
of I-55. Light and variable winds tonight will turn light southerly
late Thursday morning into the afternoon hours.


&&

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

$$

UPDATE...Smith
SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Smith



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