Area Forecast Discussion
Issued by NWS Central Illinois

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438
FXUS63 KILX 231021
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
521 AM CDT Sun Apr 23 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 315 AM CDT Sun Apr 23 2017

Very little going on in the short term, as the forecast area is
influenced by a southwest-northeast high pressure axis. The upper
low currently over the southeast tip of Missouri will settle into
northern Alabama by late afternoon, keeping the northeast flow
across our area. With the abundant sunshine and dry air in place,
temperatures should reach the 70 degree mark across the entire
forecast area today.

.LONG TERM...(Monday through Saturday)
ISSUED AT 315 AM CDT Sun Apr 23 2017

Main focus remains on the periodic storm systems that will begin
arriving around Tuesday.

Beginnings of the first system are currently seen on water vapor
imagery west of Washington state. This will come onshore Monday
and drop southeast, resulting in a rather broad upper trough just
east of the Rockies by midday Tuesday. A shortwave forming over
the Dakotas will help draw a cold front into Illinois by early
Wednesday. This general concept is agreed to among the models,
although the ECMWF is a bit on the weaker side overall. Showers
and scattered storms should be most prominent west of I-55 between
midnight and late afternoon, while the eastern CWA focuses more on
the afternoon and evening.

Latter part of the week is more of a challenge. While the GFS and
ECMWF are both agreeable on a fairly large upper low forming near
the 4-corners region by late Friday, the ECMWF is much slower in
lifting out the midweek system, as it forms an upper low just
north of Lake Superior later Thursday. This would result in a much
slower arrival of rain late week, and development of a nearly
stationary frontal boundary near I-70 which would take much of the
weekend to lift north of our area. The GFS brings this front and
associated rainfall into the area about 18-24 hours earlier. While
some low PoP`s are mentioned as early as late Thursday night,
would not be surprised to see the rain hold off until later Friday
as a drier easterly flow will initially be in place. Forecast
confidence that far out is low at this time.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 521 AM CDT Sun Apr 23 2017

Skies will remain clear over the next 24 hours, so the only real
issue is with the wind. Northeast winds over most of the TAF sites
today should get up to around 10 knots, although KPIA will be
lighter as that area will be under a high pressure axis. As this
axis sinks southward, winds will decrease to less than 5 knots at
all sites early evening.


&&

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

$$

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



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