Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 231103
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
503 AM CST Fri Jan 23 2015

.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015

08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb.  With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon.  HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon.  Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day.  High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.


&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015

Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight.  Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.

Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system.  Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening.  With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature.  Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday.  Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday.  May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.

After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south.  Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday.  The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.


&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 500 AM CST FRI JAN 23 2015

Backedge of MVFR cigs making slow progress into extreme eastern
Iowa this morning and should push into our western TAF areas
between 16 and 18z. Based on the latest movement, it appears
the clouds won`t push east of CMI until after 22z. Forecast
soundings suggest that once the skies clear, we can expect VFR
conditions thru at least the first half of tonight before a
weak frontal boundary tracks thru the region switching our
flow from southwest to northwest and ushering in another batch
of MVFR cigs for Saturday. Surface flow today will increase out
of the southwest at 10 to 15 kts and then diminish some from the
southwest early this evening before switching into the west and
northwest later tonight with speeds of 10 kts or less.

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith



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