Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 150449
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1149 PM CDT Mon Oct 14 2019

.SYNOPSIS...
Issued at 218 PM CDT Mon Oct 14 2019

Expect increasing cloud cover tonight as low pressure lifts from
the Great Plains into the Upper Midwest. There could be a few
showers mainly along and west of the Illinois River Valley by day
break Tuesday. The chance for showers and a few storms will shift
east across central Illinois through the remainder of morning and
afternoon as a cold front moves across the region. Temperatures
will only top out in the low to mid 60s near the Illinois River
Valley with falling temperatures during the afternoon. Across east
central Illinois, temperatures may warm into the low to mid 70s.

&&

.UPDATE...
Issued at 909 PM CDT Mon Oct 14 2019

Skies are clear across the area and winds are light and variable.
HiRes models suggest these conditions will continue into the
overnight hours. However, as a frontal boundary in the middle
plains moves toward the state, warm air advection clouds and
precip will begin to develop out ahead of the boundary across west
central Illinois after 3 am and toward morning. Atmosphere over
the area is very dry, as is evident on this evenings ILX and DVN
soundings. So any precip that does develop toward morning will
have to overcome the dry air first. So believe scattered showers
are possible in the west and then across central IL during the
morning hours as the area of precip moves east through the day.
Current forecast appears to have a good handle on this and the
timing of any precip for late tonight and into tomorrow morning.
Forecasted winds and temps through the rest of the night, along
with the overnight lows looks fine as well; therefore, no update
planned at this time.

&&

.SHORT TERM...(This evening through Tuesday)
ISSUED AT 218 PM CDT Mon Oct 14 2019

High pressure is over the Midwest this afternoon providing sunny
skies and mild/warm temperatures this afternoon. Meanwhile, water
vapor imagery reveals a shortwave trough digging into Montana this
afternoon, and guidance brings this waves across portions of the
Upper Midwest tomorrow. Warm advection will ramp up across the mid
and upper Mississippi River Valley overnight and will help to
saturate the column, with a few showers and an isolated storm or
two possible west of the Illinois River Valley by around daybreak
Tuesday. Widely scattered showers may continue east across the
remainder of the CWA Tuesday morning.

A surface low will develop over Iowa tonight and lift across
Wisconsin Tuesday and Tuesday evening while a trailing cold front
sweeps across central Illinois during the afternoon and evening
hours. While the front may traverse western portions of the CWA
without any additional precip, shower and thunderstorm chances
will increase particularly along and east of the I-57 corridor
during the afternoon and evening. Temperatures will warm into the
low to mid 70s in this area ahead of the front. Further west,
anticipate temperatures will only top out in the 60s then begin
falling as increasingly gusty northwest winds develop behind the
cold front.

.LONG TERM...(Tuesday night through Monday)
ISSUED AT 218 PM CDT Mon Oct 14 2019

High pressure will build from the central and northern Great
Plains Wednesday to the Upper Ohio Valley by late Friday. This
should bring another dry period of weather to central Illinois
through the latter half of the week. Temperatures look to be
coldest on Wednesday immediately behind the cold front, with
afternoon highs only in the low to mid 50s. Temperatures moderate
back to around 60F Thursday and into the mid to upper 60s Friday.

A quickly moving cold front is expected to move across the Midwest
on Saturday bringing scattered showers and perhaps a couple
thunderstorms. There is not much in the way of cooler air behind
the front with the overall pattern fairly zonal over the weekend.

Meanwhile, a strong Pacific shortwave is progged to carve out a
deep trough as it moves onshore over the Pacific NW over the
weekend and digs into the southern Great Plains early next week. A
deep surface low will form in response, lifting from KS Sunday
evening to the western Great Lakes or Midwest Monday and Monday
night, while pushing a strong cold front across central Illinois.
At this distance, there are still fairly large difference in the
model track and timing to get a good sense of specific timing and
any hazards that may accompany this strong low. Models indicate
that an unusually moist air mass will be advected across portions
of the Midwest ahead of the cold front. GFS indicates a narrow
corridor of 1.5-1.6 inch PWats. Meanwhile, the low track depicted
by the GFS would also be favorable for severe weather across or
very near the local area on Monday. Given model differences,
though, it still too early to say much more than we will have to
keep a close eye on this system in the coming days.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1149 PM CDT Mon Oct 14 2019

Clear skies and light winds will prevail overnight at all TAF
sites. Then clouds will begin to move in late tonight and early
tomorrow morning ahead of the approaching cold front that will
bring scattered showers and lower cigs to the sites during the
morning hours. Scattered showers expected to last only 3-4hrs so
will just have VCSH as all HiRes models indicate more scattered
than continuous. Cigs will then lift in the afternoon from west to
east with CMI returning to VFR around 23z. Only expecting MVFR
cigs with the precip and then after as well. Precip could return
in the late afternoon as the actual front moves through, so
another round of VCSH. Winds will be light and variable tonight
and then become breezy around 20kts with the front and. Wind
direction will be southerly during the morning and then southwest
during the afternoon, then westerly at FROPA...then northwest.
Low level wind shear still looks borderline.

&&

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

$$

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


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