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Area forecast discussion 
National Weather Service Lincoln Illinois
1149 PM CDT Thu Mar 26 2015

issued at 856 PM CDT Thursday Mar 26 2015

Quiet, but continued much cooler than normal. Weather is expected
across central and southeast Illinois overnight. Canadian high
pressure will gradually build into the area from the northwest.
However, an upper-level disturbance will also cross the area
overnight. This feature will come through dry, but cloud cover
associated with it will keep temperatures a little milder
overnight than they might otherwise be.

Going forecast is in good shape overall depicting the quiet
weather anticipated. Only a few tweaks to the hourly trends are
needed at this time.


Short term...(tonight)
issued at 300 PM CDT Thursday Mar 26 2015

Lingering precipitation has shifted to our southeast early this
afternoon, and skies west of I-55 have been mostly sunny. The areas
east of I-55 have been a little slower to clear out, though. Upper
level trough rather prominent on water vapor satellite imagery this
afternoon, generally marking the back edge of the cloud line.
Another fast moving shortwave is dropping southward across northern
Minnesota, and this will be moving into northern Illinois overnight.
No precipitation is expected our area from this feature, but this
will help to keep some of the stratocumulus deck to our north from
scattering out quite as fast before it arrives. Thus, overnight
forecast will generally be partly cloudy across the area. Little
change made to the temperatures, with mid to upper 20s across the
entire County Warning Area.


Long term...(friday through thursday)
issued at 300 PM CDT Thursday Mar 26 2015

Morning upper air and moisture satellite loop shows digging upper
trough over upper MS valley with shortwave moving east over Illinois
region. Strong upper jet southeastward plunging over Montana. 850mb cold
air advection into area after the cold front that has moved east of
region, with pcpn cleared area.

Models consistent in maintaining northwest upper level flow and
resulting cool conditions due to cold high pressure into Saturday.
Upper flow then flattens some and surface return flow late Saturday
into Sunday that begins warming.

Shortwave in the northwest flow progged to move from northern plains
through Illinois Sunday. Appears to be enough southerly flow ahead of
wave for moisture and with lift and some moisture coming with
system, will have chance pops over most of cwa, but heaviest pcpn
over northern 1/3 of state. Timing is still an issue, as GFS is
much faster than the new eur model. Pcpn moves off overnight, with
only a week high ridge moving in. Another week low moves north of
the region through the Great Lakes on Tuesday, and then a final
system approaches Wednesday. Again the models are in disagreement on
track with the eur more aggressive with pops. Just went with chance
pops for that period til more agreement.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1149 PM CDT Thursday Mar 26 2015

VFR aviation weather conditions expected across the central
Illinois terminals through the 06z taf valid time. High pressure
will gradually build into the area during the period, helping to
ensure this fact. North-northeast winds may bring some Lower Lake
effect clouds off Lake Michigan Friday morning, but at this point it
looks like they should stay VFR. However, a period of MVFR cigs
can't be ruled out.


Ilx watches/warnings/advisories...


short term...geelhart
long term...goetsch

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