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000
FXUS63 KILX 070302
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
902 PM CST Fri Dec 6 2013

.DISCUSSION...
ISSUED 900 PM CST Fri Dec 6 2013

The accumulating snowfall ended before 6 pm and clouds have begun
to clear from NW to SE as cold and dry high pressure builds into
IL. Some bands of mid-level clouds at 9-10k ft are lingering
across SE Iowa and NE Missouri, but the overall trend the rest of
the night will be for clearing to prevail.

Enough of a pressure gradient will be present between the storm to
the east and high pressure to the west for our winds to sustain at
8-13 mph overnight. Those winds will create wind chill readings
between -5 and -10F after midnight as low temps drop into the
single digits in most areas. The areas with new snowfall in the
southeast counties will have a good shot at being the coldest
spots in our forecast area. GBG may reach down to 3 for a
low, but LWV in the SE may get down near 4 as new snow allows for
enhanced cooling.

Grid updates focused on the clouds and temps, along with winds.
The latest forecast info will be available shortly.

Shimon
&&

.AVIATION...
ISSUED 538 PM CST Fri Dec 6 2013

Dry high pressure will continue to work into Illinois from the
west and will push the mid clouds east of the terminal sites. A
few radar returns this evening southeast of the Illinois river may
indicate a few flurries trying to reach the ground from the 8k-9k
ft level. No VCSH was included in any TAFs this evening as any
snow will be very light or flurries and will not affect travel
surfaces.

VFR conditions will prevail the next 24 hours under the advancing
high pressure. Winds will remain NNW around 8kt-12kt. Wind chills
will drop below zero in most of the area.

Shimon
&&

.PREV DISCUSSION...
ISSUED 311 PM CST Fri Dec 6 2013

Overall, models look very similar in the short term with the upper
level pattern through the weekend and into the beginning of next
week. On the surface, the models look in good agreement with
handling of the high pressure area. The models have some minor
differences with a weaker weather system coming through the area
Sunday/Sunday night, so resulting weather forecast will be the
same. Main concern is the weak weather system Sunday/Sun night as
it moves through the area. The other concern is ending of the
current winter storm warning in southeast Illinois. Radar loops
show snow rapidly moving east and northeast through the area. Snow
is still falling over the area and should be out of the cwa around
6pm. So will let the warning continue until 6pm and the evening
shift can cancel it as needed.

SHORT TERM...Tonight through Monday

Moderate snow continues over the southeast and should be out of
the area by 6pm. Winter storm warning will continue until 6pm.
Then after 6pm there will remain a slight chance of snow in the
southeast that should completely end around 9pm. Then dry weather
will dominate the area through sat night. Then a weak weather
system/surface lower pressure area will move across the area
Sunday and Sunday night. This system will have some lower level
moisture but not a lot of mid and upper level moisture.
Temperatures on the surface will remain below freezing so pcpn
should be in the form of snow. However, at the top of the cloud
deck, temps will be around -10C. This means that the location of
where the pcpn will start as it descends through the cloud will
have a mix of ice crystals and super cooled water droplets. With
the temperatures in the atmosphere remaining below freezing, the
pcpn as it falls will change much. So, believe the pcpn that
reaches the ground could be a mix of snow and freezing drizzle.
So, given that it`s a weak system as it moves over our area, will
have chance of snow and occasional freezing drizzle in the
forecast for Sunday afternoon through Sunday evening. As this
system moves northeast, the pcpn will quickly end over the cwa.
Once this moves through, dry weather will return for Monday.

Temps through the period will remain well below normal. Coldest
temps will be tonight, with many areas experiencing single digits.
Combined with the northwest winds, wind chills will be below zero
tonight and several times through the period. The warmest
afternoon highs will be Sunday afternoon, though still below freezing.

LONG TERM...Monday night through Friday

Dry weather is expected through the period as the upper level
pattern becomes zonal. By the end of the period, Fri of next
week, the pattern begins to shift some. Temps through most of the
period will remain below freezing, however, with the small change
to the pattern, temps should rise to above freezing by Friday.

Auten

&&

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

$$