Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 241743
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1243 PM CDT Tue Apr 24 2018

.UPDATE...
Issued at 1046 AM CDT Tue Apr 24 2018

Satellite data continues to indicate the slow moving upper low
across western Kentucky late this morning with another band of
rain swinging back to the west and southwest over our far
southeast counties. We should see some scattered light showers
across far east central and especially southeast Illinois as
we head into the afternoon hours with the activity slowly edging
away from our area by evening. Further to the west and north,
the latest visible satellite loop showing clearing taking place
across west central Illinois and expect that to edge slowly
east this afternoon as the upper low shifts away from our
area. Have adjusted the afternoon highs up several degrees
across the west to take into account more sunshine and adjusted
the precipitation wording over far southeast Illinois for this
afternoon. We should have the updated ZFP out by 11 am.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT Tue Apr 24 2018

Mostly northerly winds to be expected across Central Illinois for
today as the upper low stalls over far western Kentucky. Surface
representation is quickly losing structure, and the precip
associated with the cyclonic flow is not well defined. Short term
models continue that trend with more scattered qpf, if that.
Keeping the rest of the pops for today in the slight chance/low
chance range. Plenty of cloud cover however, and will keep the
highs from climbing too far southeast of the IL river valley. That
being said, highs in the 60s is far more seasonal for the end of
April. NW of the Illinois River, more sun is possible and some
locations could see afternoon highs in the low 70s. Tonight, the
low and its associated precip continues to drift to the ENE. Will
need to keep an eye on how much the llvl RH mixes out in the
afternoon hours. Should clearing happen quickly in the afternoon,
the near surface could end up seeing RHs approaching saturation.
However, about the times that the overnight low would be reached,
winds are also starting to pick up in the east and southeast.
Crossovers this afternoon and getting a better handle on the
remnant cloud cover from this slow moving low will give better
confidence in the overnight forecast.

.LONG TERM...(Wednesday through Monday)
ISSUED AT 323 AM CDT Tue Apr 24 2018
Forecast enters a dry patch for Wednesday and Thursday as the prev
wave dives into the southeastern CONUS and leaves IL out of the
precip. Wednesday is a few degrees below normals, but more seasonable
temperatures expected by Thursday. The warm up gets put on pause
for Thurs night/Friday as a front moves through the Midwest and an
upper trof moves through the region. The shift in the flow aloft
to more NWrly pushes some cooler temps into the area at least
briefly. Chance for rain with the front as well. Chances are
brief, and forecast dries out for the weekend as another slow
warming trend kicks in. Expansive ridge at 500 mb setting up over
the center of the country this weekend, drifting into the Midwest
by the beginning of the work week. With the ridge drifting east,
the more southwesterly flow sets up some efficient waa, and temps
will likely climb to well above normal for Mon/Tues time frame
should this pattern continue. Until then, the weekend is looking
like fair weather with highs in the upper 60s and lower 70s,
sunshine, and dry.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1230 PM CDT Tue Apr 24 2018

Satellite data and the latest surface observations indicate the
backedge of the lower cloud deck is roughly along and east of
I-55. The MVFR cigs will prevail over DEC and CMI the longest
this afternoon with areas along and west of I-55 seeing mainly
VFR conditions. Tonight, the main forecast concern will be with
the potential for some patchy fog, although models continue to
suggest we may see the wind hold up enough to prevent much in
the way of any significant vsby issues. For now, will limit any
vsbys to 5 mi in fog late tonight. Surface winds will be northerly
this afternoon at 10 to 15 kts with a few gusts near 20 kts at
times, especially across the west with more sunshine.  Will keep
winds mainly from a northerly direction tonight into Wed. with
speeds around 10 kts.

&&

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

$$

UPDATE...Smith
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith


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