Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 031936

Area Forecast Discussion
National Weather Service Lincoln IL
236 PM CDT TUE MAY 3 2016

.SHORT TERM...(Tonight)
ISSUED AT 225 PM CDT Tue May 3 2016

A Strong shortwave associated with 100kt jet will plunge into the
eastern U.S. trough that has been over the region the past few days.
Relatively strong dynamics with this fast system will have little in
way of deep moisture to work with. An associated cold front will
move across the region after midnight bringing a chance of showers.
The lower layers of the atmosphere are relatively dry and
precipitation amounts should be less than a quarter of an inch.


.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 225 PM CDT Tue May 3 2016

Upper low forecast to dive south-southeast into the lower Great
Lakes on Wednesday with the associated cold front and shower
activity expected to be southeast of our forecast area during
the morning. However, 500 mb temperatures forecast to drop to
between -24C to -27C by afternoon over roughly the eastern half
of the forecast area. Will continue to hold onto scattered
showers for the afternoon with some thunder possible as well due
to the steep mid level lapse rates. Seeing some occasional
lightning this afternoon with the deep trof just north of Lake
Superior so will continue to hold with the thunder mention,
especially across the east where the temperatures aloft are the
coldest. The upper low should drift off to our east tomorrow night
with high pressure settling into the region for a couple of quiet
days for Thursday and Friday. After a rather cool couple of
days/nights for Wednesday and Thursday, we should see a nice
warmup for Friday and the weekend when the mercury will rise back
into the 70s, with a few 80s possible ahead of a cool front
Saturday afternoon.

The short lived omega block will begin to break down towards the
end of the week as a vigorous northern stream upper wave shifts
southeast into the upper Great Lakes by Saturday This will drive
another cold front into our area by Saturday afternoon with most
models now suggesting the trof amplifying to our east late
Saturday into Sunday will be strong enough to push the front
further south than earlier expected on Sunday. This would normally
shift the better rain chances further south as well but because a
couple of models have a further north solution to the boundary and
higher POPs, the concensus has mentionable POPs for Sunday into
early Sunday evening, although lower than what we had before,
before the boundary starts to edge back north Sunday night and
Monday resulting in 30-40 Pops CWA-wide again. If this further
south solution continues with the next several runs, we may be
able to lower POPs over most of the area on Sunday. Unfortunately,
with the evolving pattern late in the weekend and especially for
the first half of next week, it appears there will be a daily
threat for showers and thunderstorms through at least next


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1138 AM CDT Tue May 3 2016

Strong low-level lapse rates are combining with daytime heating to
develop cumulus field at midday. Most terminals in central
Illinois will likely have broken VFR ceilings by early this
afternoon. As heating diminishes so will the cumulus field.

A fast moving system over western ontario will race south pushing
a cold front through the state late tonight. Dynamics are
relatively strong, but moisture - particularly in boundary layer -
is somewhat limited. Will introduce a tempo group of MVFR precip for
the period suggested by NAM.


.ILX Watches/Warnings/Advisories...


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