Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/10/23

Area Forecast Discussion

National Weather Service Lincoln IL

 829 PM CST Thu Mar 9 2023

.SYNOPSIS...
Issued at 208 PM CST Thu Mar 9 2023

A storm system will bring widespread rain to central and southeast
Illinois through this evening, thought the potential for a rain
snow mixture increases north of a Macomb to Bloomington line. Some
slushy accumulations over an inch may occur near Galesburg, though
the best chances of significant snowfall is closer to the
Wisconsin border. Another system will bring additional light rain
and snow Saturday into early Sunday, with minor accumulations
possible near and north of I-74.

&&

.UPDATE...
Issued at 828 PM CST Thu Mar 9 2023

Precip has tapered off to sprinkles or drizzle across most of
central Illinois north of I-72 and should end for most of the area
south of I-74 by around midnight tonight. Temps are on track to
fall into the lower to mid 30s under cloudy skies, holding fairly
steady across the Illinois River Valley.

&&

.SHORT TERM...(This evening through Friday)
ISSUED AT 208 PM CST Thu Mar 9 2023

Dry layer around 800 mb persists across the eastern half of the
forecast area, verified by a 1600Z AMDAR sounding from
Indianapolis. The precipitation shield has been struggling to get
east of I-55, but is starting to make more of a push early this
afternoon as the column moistens from the top down. While much of
this has been rain, there has been some sleet mixed in at times,
and dual-pol radar data from Davenport as well as recent webcams
show more of a snow component up around Galesburg and Toulon with
some grassy accumulations.

The main precip type and accumulation issues will remain north of
a Macomb to Bloomington line through this evening, with a
rain/snow mix or periods of all snow. Ground temperatures in the
area are around 40 degrees at 4 inches per the Illinois State
Water Survey. Morning HREF indicates the heaviest rates of snow
are likely to be through late afternoon, with probabilities of
1-hour snowfall of an inch around 30% near Galesburg. A few
recent reports from northern Knox County indicate the snow there
is becoming heavy enough to overcome the ground temperatures, and
slushy accumulations of an inch or two are still reasonable in
that area over the next few hours. By midnight, any lingering rain
or snow should mainly be north of I-74.

The persistent easterly flow has begun to swing around as this
system moves into Illinois, and winds become northwest tonight
with gusts up to 30 mph. This should settle down on Friday as an
axis of high pressure drifts overhead.

.LONG TERM...(Friday night through Thursday)
ISSUED AT 208 PM CST Thu Mar 9 2023

The main forecast concern in this period remains with the next
system that passes through during the weekend. Not much has
changed with the evolution of this system, consisting of an upper
low over the northern Plains and a broader trough approaching the
Mississippi River. Probability graphics from WPC and the European
ensembles show about 40-50% chances of an inch of snow north of
Peoria Saturday night, with the GFS ensembles more bullish.
However, temperatures will continue to be a issue, with lows in
the mid 30s over that area. Will mention increasing chances of a
rain/snow mix through Saturday night, but keep accumulations on
the lower side at this time.

Going into next week, the upper low strengthens as it emerges off
the New England coast. Depending on how strong this gets, ridging
over the central Plains may amplify more through midweek as the
low is slower to exit, as the European model has been suggesting
for a few runs. That would result in a warmer trend for mid week.
The GFS has more of a split flow by Wednesday. Blended guidance do
show a warming trend around midweek though, with highs returning
to the 50s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 527 PM CST Thu Mar 9 2023

Precip is close to ending across central Illinois by around 01Z,
though there could be some lingering flurries or drizzle mainly at
PIA late into the evening (low confidence). Otherwise expect IFR
ceilings to continue to overspread the area and persist into
Friday morning. Easterly winds in place this evening will swing
around to the northwest by late this evening and become gusty at
times overnight and Friday. Ceilings will very gradually improve
back to MVFR by late morning or early afternoon.


&&

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

$$

UPDATE...Deubelbeiss
SYNOPSIS...Geelhart
SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Deubelbeiss