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Area forecast discussion 
National Weather Service Lincoln Illinois
555 PM CST Wed Dec 24 2014

Short term...(tonight)
issued at 310 PM CST Wednesday Dec 24 2014

Weak system turned out a lot warmer and a little further to the east
with the heavier precipitation today. Low clouds, rain and the
occasional mix with snow dominated central Illinois today. Showers
becoming far and few between as sunset approaches. Pops are reduced
considerably as the system lifts out of the region. Expecting cloud
cover to remain in place with plenty of llvl moisture and clearing
not seen until west of the Missouri River valley on Sat imagery.
Not dropping temps too far, though there is some concern as to
whether or not the lows will even drop that far into the 30s.
Precip ending before midnight as the system pulls all precip from
the state.


Long term...(thursday through wednesday)
issued at 310 PM CST Wednesday Dec 24 2014

High pressure will build into the region for Christmas day bringing
dry conditions, but expecting clearing to struggle as an inversion
traps low level moisture. Temperatures will be mild reaching into
the 40s as breezy southerly winds develop due to a gradient between
the high centered to the southeast and approaching low pressure from
the west.

GFS, NAM, and European model (ecmwf) are in relative agreement with holding off
precipitation until at least Friday evening with the next low
pressure trough and cold front approaching from the west. This
should start out as rain, changing over to snow Saturday as the cold
front crosses the area. However, most precipitation should fall
before the change-over, so not expecting much if any accumulation.

Cooler highs in the 30s on Sunday across region behind the cold
front. Latest model runs keep a consensus for dry conditions under a
low-amplitude high pressure ridge until at least Tuesday morning,
then perhaps another weather system for midweek, however large model
inconsistencies develop by that time indicating large uncertainty.
What does appear more likely is a continued push of northwesterly
flow bringing much colder temperatures as the week wears on.


Aviation...(for the 00z tafs through 00z Thursday evening)
issued at 555 PM CST Wednesday Dec 24 2014

Precip has been reduced to drizzle at the terminal sites, and a
deep enough layer of warm air near the ground will help keep
precip as drizzle instead of flurries. Upstream surface
observations show that sub-freezing wet-bulb air resides well to
the west of our forecast area, and will not arrive until after
precip comes to an end. We can't completely rule out a period of
flurries before precip ends, but impact will be minimal from any
snowfall. Will only include a mention of -dz for the first few
hours of this taf period at all sites, and maintain MVFR ceilings
at all sites as well. Bmi remains IFR, but should lift to MVFR by
03z. Light fog and a lowering of cloud heights to IFR could
develop in pockets toward sunrise, so a tempo was included across
the board for those conditions.

Winds will remain westerly overnight, as wind speeds hold in the
8-13kt range. Wind direction will shift to the southwest tomorrow
as high pressure centered SW of Illinois builds into the area.


Ilx watches/warnings/advisories...


Short term...hjs
long term...Onton

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