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FXUS63 KILX 291749

National Weather Service Lincoln IL
1149 AM CST SUN NOV 29 2015

High pressure building into the region, but a small disturbance to
the SW moving up through the state bringing precip NW of the
Illinois River Valley. Temps rising a bit over freezing in the obs
sites just as the precip moves in, keeping the precip liquid this
morning. Made some minor updates to the area to extend the precip
mention into the afternoon. Drier air from the north still eroding
the precip advance too far to the east in the HRRR. The 12z
soundings, as well as the model soundings, have a distinct, very
dry layer just off the sfc that will also help in limiting the
precip this morning.


.SHORT TERM...(Today)

08z/2am surface analysis shows a nearly stationary frontal boundary
draped from eastern Kentucky to Louisiana, while a 1031mb high
remains in place over western Wisconsin.  While the bulk of the
precipitation associated with the front has shifted well south and
east of Illinois, weak short-wave energy embedded within the
southwesterly flow pattern aloft has been triggering areas of very
light precipitation much further north into the cooler/drier
airmass.  Latest radar mosaic shows a few showers tracking across
northern Missouri/southern Iowa toward west-central Illinois.  Most
high-res models dissipate the showers as they cross the Mississippi
River and encounter a dry N/NE low-level flow around the Wisconsin
high: however, radar trends suggest otherwise.  Based on forward
progress of precip and surface obs showing precip reaching the
ground at a few sites in southeast Iowa, have decided to include a
slight chance PoP across the far W/NW KILX CWA for a few hours early
this morning.  With temperatures hovering near or slightly below
freezing in that area, have mentioned the potential for some very
light freezing rain across portions of Knox, Fulton, and Schuyler
counties through 7-8am.  Think precip will eventually dissipate as
it tracks further east toward the Illinois River, so will maintain a
dry forecast further east.  Aside from the early morning precip
potential across the west, much of the day will be dry.  Another
short-wave will begin to approach from the southwest late in the
day, with the Rapid Refresh consistently showing precip trying to
work back into west-central Illinois after 3pm.  Have therefore
included slight chance PoPs for rain showers along/west of a
Galesburg to Jacksonville line late in the day.  Due to overcast
conditions and a continued cool N/NE flow, have undercut MAV
guidance numbers by a few degrees...with afternoon highs only
reaching the lower to middle 40s.

.LONG TERM...(Tonight through Saturday)

00z Nov 29 models are in very good agreement concerning the break
down of the western CONUS Rex Block and the arrival of a storm
system late tonight into Monday.  As a closed upper low currently
over the Great Basin begins to pivot eastward, moisture poised just
upstream across the Southern Plains will begin to move back
northward into the area tonight.  This moisture will initially be
fighting a dry E/NE flow, so think much of the N/NE CWA will remain
dry through the entire night.  Have therefore introduced chance PoPs
for light rain southwest of the I-74 corridor, but have maintained a
dry forecast further northeast.  Best rain chances develop on
Monday, as profile saturates and stronger forcing associated with
approaching upper low arrives.  Will carry high chance to likely
PoPs across the board.  Surface low pressure will develop in advance
of the upper system across Kansas Monday morning, then will track
into western Wisconsin by Tuesday morning.  Once the low passes to
the north, a pronounced mid-level dry slot will work into the area
from the southwest late Monday night into Tuesday.  As a result,
precip chances will come to an end from southwest to northeast, with
dry conditions expected everywhere on Tuesday.  Will be a very
breezy day however, with southwesterly winds gusting to between 25
and 30mph.  The upper low will track across Wisconsin into the Great
Lakes Tuesday night into Wednesday morning, with wrap-around
moisture potentially affecting the northern CWA.  Models are in much
better agreement with their QPF, suggesting areas along/north of
I-74 may see a few snow-showers Tuesday night as the low skirts
by to the north.

Once the early week system exits the region, the remainder of the
extended will be quiet.  Models continue to show pronounced upper
ridging developing by the end of the week, so temperatures will
likely rise several degrees above normal.  Have therefore boosted
highs into the lower 50s on Friday, with lower to middle 50s by


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
925-950mb RH in models a little complex towards the morning
causing some complications in the forecast. Today, mid/high
clouds, and northeasterly winds, 5-10kts, VFR. However, in the
overnight the llvl moisture starting to surge north and east from
the shower activity in the SW. Have timed out the advance of
clouds at 3kft across ILX terminals from 09Z-15Z. Winds also
becoming more easterly in that time frame. Further adding to the
complications is the shower activity NW of IL River this morning
altering the llvl moisture content. Peoria may end up with
MVFR/IFR conditions before dawn as these current showers were
underestimated in prev model runs.


.ILX Watches/Warnings/Advisories...


LONG TERM...Barnes
AVIATION...HJS is the U.S. government's official web portal to all federal, state and local government web resources and services.