Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 121747

Area Forecast Discussion
National Weather Service Lincoln IL
1247 PM CDT Mon Mar 12 2018

Issued at 945 AM CDT Mon Mar 12 2018

Upper level shortwave dropping southward this morning, with much
of its associated precipitation across Indiana. However, surface
reports showing some light sprinkles or flurries as far west as
Rantoul. Another wave was upstream, and will be capable of a few
more sprinkles/flurries through the afternoon over the northeast
CWA. Meanwhile, back edge of the cloud deck is approaching
Galesburg and Lacon this hour, and some clearing will be taking
place across the western CWA through midday. The east will be a
bit slower to clear, due to the next wave arriving, but some
breaks in the clouds are expected to develop during the afternoon.

Sent some minor updates for the sprinkles/flurries and the cloud
trends, but the forecast was largely on track.


.SHORT TERM...(Today and tonight)
ISSUED AT 345 AM CDT Mon Mar 12 2018

A 544 dm 500 mb low near Nashville TN at predawn will scoot off
to the GA/SC border by 18Z today and off the Carolina coast by
sunset. Meanwhile a 526 dm 500 mb low will drop southeast into the
central Great Lakes by sunset and near western Lake Erie Tue
morning. IL will stay firmly entrenched in the trof`s cyclonic
flow through Tue evening, bringing chilly weather along with some
passing stratocumulus clouds. Clouds from upper level low over TN
have exit southeast of IL early this morning. However, a large
area of stratocumulus clouds was pressing southeast across the IL
river valley and will move across rest of central and eastern IL
during this morning. Western/sw CWA has best chances of seeing
skies become partly to mostly sunny during the afternoon, while
staying cloudier over eastern IL along with isolated light snow
showers or flurries by afternoon from Danville ne. Highs today of
40-45F, coolest over ne CWA, as 850 mb temps lower to minus 6-8C
by sunset. Brisk nw winds increasing to 12-18 mph during the
morning with gusts of 20-25 mph, will make it feel cooler.

Chance of flurries near the Indiana border early this evening,
otherwise decreasing clouds as skies become mostly clear to partly
cloudy. Lows mostly in the mid 20s and still have gusty nw winds
15-20 mph into mid evening adding a chill factor.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 345 AM CDT Mon Mar 12 2018

The large upper level low deepens to 519 mb southeast of the Great
Lakes during Tue and brings 850 mb temps down to minus 10-12C over
central IL by 18Z/Tue. Broken stratocumulus clouds will likely
redevelop during Tue especially over eastern IL where scattered
flurries likely and isolated light snow showers near the IN
border. Highs only 35-40F on Tue with coldest readings over ne
CWA. Brisk nw winds again on Tue with gusts of 20-25 mph making it
feel colder. After chances of flurries in eastern IL early Tue
evening, stratocumulus clouds to decrease during Tue night and nw
winds to diminish to 5-10 mph overnight, bringing colder lows in
the lower 20s. 1034 mb Canadian high pressure over southern
Saskatchewan and western Dakotas, to settle into the southern MS
river valley by sunset Wed. This will bring mostly sunny skies Wed
and slightly higher temps with highs in the lower 40s near the IN
border and upper 40s over western CWA. Lows Wed night in the
lower 30s, with a few upper 20s northeast of I-74 as a weak front
drops southward over CWA overnight Wed night into Thu morning and
passes thru dry with weak wind flow.

High pressure to drift over FL and northeast gulf of mexico on Thu
with milder temps into central/se IL with mostly sunny skies as
upper level ridge shifts east toward MS river valley, and strong
cutoff upper level low moves over the Canadian Maritimes. Highs
Thu in the mid to upper 50s, and near 60F from Jacksonville wsw.

Chances of rain showers spreads into sw CWA later Thu night and
could be mixed with some light snow showers but no accumulations
expected. Rain shower chances over central and especially southeast
CWA on Friday. Highs Fri in the low to mid 50s, held back by more
clouds and shower chances. High pressure over the Great Lakes Fri
night brings drier air into central IL Fri night into Sat morning.
Then chances of rain showers spreads back ne over area during Sat
afternoon into Sat night and could also be isolated thunderstorms
sw CWA. Highs Sat range from the mid 50s to around 60F. Models
still differ with handling wx systems ejecting ne from upper level
trof over the Rockies during this weekend into early next week and
stayed close to consensus. Could be another lull in shower chances
Sunday and appears mild with highs in the lower 60s. Another wx
system ejects ne over Midwest Sunday night into Monday returning
chances of showers and isolated thunderstorms.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1247 PM CDT Mon Mar 12 2018

MVFR cigs over areas from KBMI-KDEC eastward will clear out during
the afternoon then VFR conditions are expected through the night.
Another disturbance will move over the area after 12Z Tuesday
bringing a decrease in ceilings, likely to eventually drop to near
or below MVFR thresholds. A chance of snow flurries will also
develop for mainly KPIA-KDEC eastward, but probabilities of
significant visibility reduction is low. Winds NW 12-15 kts with
gusts to around 20 kts until 21-24Z then decreasing to around 10





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