Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KILX 160913
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
313 AM CST Tue Dec 16 2014

.SHORT TERM...(Today)
ISSUED AT 312 AM CST TUE DEC 16 2014

The surface and upper level low pressure center of today`s storm
system is crossing northern Illinois early this morning with an
occluded frontal zone wrapping around the low and bringing scattered
showers mainly in the northern half of the state. This system will
accelerate eastward today as a northern stream trough drops out of
Manitoba into the western Great Lakes region. Cold northwesterly
flow will develop across central IL with brisk northwesterly winds
at the surface reaching 15-20 mph from mid-morning on. Forecast
soundings indicate mixed layer winds reaching around 30 mph below an
inversion based around 900 mb, thus we can expect gusts reaching up
to around 30 mph from late morning through afternoon. Temperatures
will hold fairly steady through morning then steadily decline
through afternoon as cold advection takes place. Based on expected
movement of the current storm system, will expect scattered showers
mainly north of Springfield until mid-morning gradually lifting
northeastward late morning/early afternoon. Isolated showers
possible to the south.


&&

.LONG TERM...(Tonight through Monday)
ISSUED AT 312 AM CST TUE DEC 16 2014

Tranquil weather on tap for tonight and Wednesday, as surface high
pressure ridge drifts through the area. NAM forecast soundings
retain a rather stout inversion around 950 mb. The GFS is a little
more optimistic in the inversion breaking, but still shows some
decent mid-level cloud cover, so am reluctant to go any more
optimistic than partly cloudy at this time.

Southern branch of the jet stream to be the most active over the
next several days, with several shortwaves advancing along it.
Wednesday night/Thursday system remains just to our southwest, but a
more prominent trough digs across the Plains on Friday as the next
wave moves into southern Texas. The evening model trends continue to
trend more toward the lower portion of the Mississippi Valley with
the track of the developing storm this weekend, with the surface low
generally along the Gulf Coast. The latest ECMWF bypasses us
completely with any precipitation, with the GFS bringing some light
snow as far north as about I-70 late Friday night. Have kept some of
the GFS solution in mind and focused the precipitation chances
across the southeast CWA Friday night and early Saturday. While the
precipitation fields off these models would keep much of the CWA dry
on Saturday, have kept some slight chances in for now east of I-55,
and 30% chances south of I-70.

Remainder of the current forecast is dry, with the main concern more
late Monday night into Tuesday as an upper low carves a position
into the upper Mississippi Valley. Any associated precipitation
chances for that time frame will be introduced with the afternoon
forecast package.


&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1129 PM CST MON DEC 15 2014

The threat of steadier rains has come to an end across the central
Illinois terminals, although drizzle and spotty showers will
linger through the night. Still expect IFR conditions to prevail
through the night, but a few periods of MVFR conditions are
possible (especially at KSPI/KDEC). Gusty northwest winds on the
back side of the storm system will develop Tuesday morning, slowly
bringing drier air into the area. All terminals should trend into
the MVFR category during the day, but it looks like these cigs
will linger until at least Wednesday.


&&

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

$$

SHORT TERM...Onton
LONG TERM...Geelhart
AVIATION...Bak





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.