Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 241803

Area Forecast Discussion
National Weather Service Lincoln IL
103 PM CDT Sat Mar 24 2018

Issued at 1046 AM CDT Sat Mar 24 2018
Active weather day with ongoing precip across Central IL this
morning. Surface low to the SW, an increasing pressure gradient
is resulting in sustained easterly winds from 25-30 mph, gusting
in excess of 40. Cloudy and grey with intermittent rounds of
precip throughout the day. Interstate 74 is roughly where the
dividing line between all rain and a wintry mix of sleet and snow
to the north. That line is expected to shift slightly throughout
the day...with the occasional rumble of thunder in the southern
half of the state. So far, forecast is doing well and no updates
are anticipated at this time.


.SHORT TERM...(Today and tonight)
ISSUED AT 255 AM CDT Sat Mar 24 2018

Very complicated scenario for the forecast today. Initial band of
precipitation continues to push eastward early this morning.
Dual-pol data from the radar shows a band of sleet/mixed precip
from around Peoria southeast to Champaign, with snow to the north.
Have already received around 3 inches in Peoria and northeast of
Galesburg, but a sharp cutoff south. Here, we`ve had a
rain/snow/sleet mix going for a few hours now, with only a thin
coating of pellets.

General theme for the day will continue to focus on this sharp
gradient, as temperatures hover near or just above freezing along
the I-74 corridor. Precipitation will remain widespread as the
surface low tracks to just south of St. Louis early this
afternoon. Forecast soundings across the northern CWA show a
rather prominent warm nose between 5,000 and 10,000 feet this
morning, suggesting a period of sleet or maybe some freezing rain
at times. Snow/liquid ratios across the north will only be around
8:1 initially, before increasing this afternoon as the low passes
to our south. In areas north of the gradient, potential exists for
storm totals around 5-7 inches, though the extreme northern CWA
toward Toulon and Lacon may see closer to 8-10 inches.

Will bring the advisory counties into the Winter Storm Warning,
and extend the headline until 10 pm. The gradient continues to
focus immediately along I-74, and areas south of there stand a
good chance of only getting an inch or two if that. However,
winter headlines can`t be broken down into areas smaller than a
county, so the warning text will continue to emphasize the wide

Further south, rain and isolated thunderstorms will continue to be
the main issue. Storm totals of 1 to 1.5 inches are likely through
this evening.

.LONG TERM...(Sunday through Friday)
ISSUED AT 255 AM CDT Sat Mar 24 2018

Main concern during this period will be with rainfall totals with
the Monday-Tuesday storm system. Precipitable water values quickly
ramp up to around 1.4-1.5 inches by late Monday afternoon,
continuing there until passage of the front Tuesday afternoon.
Heavier focus right now will be more in the areas south of I-72,
where the front is parallel to the upper flow for a period of
time. Wouldn`t be surprised to see a couple inches in this area.
With the ground saturated from the current system, some flooding
issues may begin to arise.

Warmest temperatures during the period should be on Tuesday ahead
of the front, with most of the CWA reaching near 60 despite the
high rain chances. With a deep upper trough migrating eastward
across the CONUS late week, temperatures should cool off to around
50 degrees for highs, several degrees below normal for the end of


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1257 PM CDT Sat Mar 24 2018

IFR conditions dominate the area this morning, with scattered LIFR
through much of the day. Strong gusty winds in excess of 25-30kts
in all terminals. Rain/snow/sleet throughout Central IL...with
isolated thunder. Snow/frozen precip still a concern for the KPIA-
KCMI corridor, while rain prevails south. Concern for the
overnight hours when the models are quick to move in drier air and
clear out the FA. Have instead been a little conservative with
visbys...but winds stay up and potentially counter any visibility
drops with the enhanced LLVL RH from todays precipitation.


Winter Storm Warning until 10 PM CDT this evening for ILZ027>031-



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