Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 051743
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1243 PM CDT THU MAY 5 2016

.UPDATE...
Issued at 1042 AM CDT Thu May 5 2016

Latest water vapor imagery shows deep upper low spinning over
eastern Kentucky...with trailing vort max extending northwestward
across Indiana into east-central Illinois. This feature is
providing plenty of clouds to the eastern KILX CWA this morning,
especially along and east of the I-57 corridor. As the wave sinks
southward, skies will clear from north to south as the day
progresses. Forecast soundings still show a good deal of cold air
aloft, so FEW-SCT diurnal clouds will develop further west across
the remainder of the area, yielding a mostly sunny afternoon
across the board. Thanks to the increasing amounts of sunshine,
high temperatures will be warmer than in recent days, with
readings topping out in the lower to middle 60s. Current forecast
is on track, so no major updates are planned at this time.

&&

.SHORT TERM...(Today)
ISSUED AT 258 AM CDT Thu May 5 2016

Quiet weather is expected today across central and southeast
Illinois, with temperatures warming up some from the levels seen
yesterday. A vigorous upper-level low, currently centered near
IN/OH/KY border area, will continue to dig today. A spoke of energy
wrapping around the back side of the upper low will push clouds back
into portions of east-central and southeast Illinois today, but do
not expect rainfall with this feature locally. The upper-level cold
pool associated with system will pull away as the upper low
continues to dig. The moderating low level thermal profile should
allow daytime highs across the forecast area to rebound back (or
climb higher) into the 60s. The coolest temperatures will be seen
across the eastern portions of the forecast area which will be
closest to the departing cold pool and also have the most
significant cloud cover.

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 258 AM CDT Thu May 5 2016

Upper ridge axis is slowly shifting eastward this morning, as our
nearby upper low drops across southeast Indiana. These features will
be sliding eastward late this week, with the ridge being flattened
by an upper wave/low that will be diving southeast toward Lake
Superior. This latter feature will push a frontal boundary southward
across the Midwest late Friday night and Saturday. The extent of its
southern journey remains a bit up in the air, as the front becomes
parallel to the upper flow between the Great Lakes wave/low and
what`s left of the ridge. In addition, an upper low currently off
the California coast will be slowly moving into the central Rockies,
forming a storm system over the central Plains that will become a
player as well late in the weekend.

The frontal boundary is expected to be near I-72 toward midday
Saturday and south of the forecast area by evening. Have
concentrated the highest daytime PoP`s in the afternoon. By evening,
as the front starts to hang up, the rain shield will be in more of a
northwest-southeast axis over the southwest half of the CWA, which
will likely continue into Sunday morning before the ridge axis
starts to nudge the front back northward. After that, rain chances
will be steadily increasing as the Plains storm system moves
eastward, and have included likely PoP`s over most of the forecast
area Monday night and Tuesday. Some question as to how long this
lingers, but the latest ECMWF/GFS runs are starting to indicate a
short break on Wednesday. Given that the current west coast upper
low is only projected to make it as far as South Dakota by mid week,
another surface cyclone is likely to form over the Plains. With the
uncertainty and how far out in time this is, have opted to keep some
PoP`s in the 30% range on Wednesday for now.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1243 PM CDT Thu May 5 2016

VFR conditions will prevail through the entire 18z TAF period.
While the main area of clouds associated with an upper-level
trough have cleared the easternmost terminals early this
afternoon, a CU field will develop/linger through the afternoon.
With temperatures aloft now slowly warming, only FEW-SCT diurnal
clouds are expected today. Clear skies will prevail overnight
before a few mid clouds at around 10000ft arrive Friday morning.
Winds will initially be from the north at 10-15kt this afternoon,
then will go light/variable tonight as high pressure builds into
the region.

&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...BAK
LONG TERM...Geelhart
AVIATION...Barnes


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