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Area forecast discussion
National Weather Service Lincoln Illinois
302 PM CST Tue Nov 21 2017

Short term...(this evening through wednesday)
issued at 300 PM CST Tue Nov 21 2017

The cold front will sweep out of our southeast counties by early
this evening, but not before dropping some flurries or sprinkles
across our northern and eastern counties this afternoon. The
night will be highlighted by gusty northwest winds this evening,
and clearing skies. Winds will diminish overnight, to less than
10mph, as the pressure rises weaken and the center of high
pressure gets closer to Illinois from the plains. Plenty of cold
air will settle into the area behind the front, with lows dropping
into the low to mid 20s.

Light winds and mostly sunny skies will prevail on Wednesday as
the surface ridge axis drifts eastward directly across Illinois.
Full sunshine will not be of much help, as the cold Canadian air
limits the highs to the mid to upper 30s.


Long term...(wednesday night through tuesday)
issued at 300 PM CST Tue Nov 21 2017

The surface high pressure axis will drift southeast of Illinois
on Wednesday night, setting up a return flow for Thursday into
Friday. A warming trend will result, as the next cold front
approaches from the northwest. High temps will return to around
normal on Thanksgiving. On Friday, gusty south-southwest winds at
15 to 25 mph will help to push highs above normal.

A cold frontal passage on Friday night looks similar to today's
fropa, in terms of moisture content and strength of the system.
The models are likely under-doing precipitation coverage, just
like they did for this afternoon's cold front. While the blended
extended removed the slight chance pops Friday evening with the
12z model run update, thinking that we will see at least some
sprinkles across our forecast area Friday evening/overnight as
the front moves across Illinois. Minimal impact, so a major concern

Clearing skies on Saturday will set the stage for a mostly sunny
Thanksgiving weekend. However, another round of cold Canadian high
pressure will cause saturday's highs to dip to around normal, with
below normal temps for Sunday afternoon (40-45f).

Yet another warm-up is projected for Monday and Tuesday, ahead of
the next low pressure system. Highs should return to the 50s on
Tuesday, as clouds increase along with a slight chance of rain in
the afternoon.


Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1139 am CST Tue Nov 21 2017

VFR conditions will prevail through the 18z taf period, despite
the cold frontal passage this afternoon. The initially dry air
mass is limiting precip potential with the front, but some light
rain/sleet has been reported this morning. The hrrr does show the
frontal circulation weakening this afternoon, but until that
occurs, have added vcsh to all the tafs for a few hours this
afternoon with frontal passage. Clearing should develop quickly this
evening, if not late this afternoon northwest of the Illinois River.

Winds have shifted to west-SW at 12g22kt, and a shift to northwest will
occur Post-fropa. Wind speeds are slated to increase to 15g27kt
this afternoon from the northwest. Winds will weaken this evening, and
remain light northwest through the morning tomorrow under minimal cloud


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