Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 230419

Area Forecast Discussion
National Weather Service Lincoln IL
1119 PM CDT SAT OCT 22 2016

Issued at 902 PM CDT Sat Oct 22 2016

High pressure will maintain it`s influence on Illinois tonight as
the surface ridge axis remains nearly stationary to the southeast
of Illinois. There will be enough of a pressure gradient for some
light S-SW winds to continue at 4-8mph. A cold front approaching
from the Plains will arrive in NW IL around 16z/10am tomorrow.
Surface winds will increase ahead of the front and become gusty at
20-25mph at times from the SW.

Dewpoints have dipped into the low to mid 40s already this
evening, but steady S-SW winds will be pulling higher dewpoint air
into central IL. Therefore, it looks reasonable that low temps
should bottom out in the mid to upper 40s. Made some minor updates
to low temps to drop them a couple degrees N of I-74 where the
lighter winds have already allowed temps to dip into the low 50s.
Otherwise, the forecast for the next 24 hours looks on track.


.SHORT TERM...(This evening through Sunday)
ISSUED AT 205 PM CDT Sat Oct 22 2016

High pressure will slide off to the east over the next 24 hours,
allowing a weak cold front poised across the Northern Plains to drop
into central Illinois by late Sunday afternoon.  Southerly winds
ahead of the front will keep things on the warm side through the
period, with overnight lows remaining in the middle to upper 40s and
high temperatures on Sunday soaring well into the 70s.  As the
pressure gradient tightens ahead of the approaching front,
southwesterly winds will gust to between 25 and 30mph at times
Sunday afternoon.

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 205 PM CDT Sat Oct 22 2016

A cold front will drop through the CWA Sunday night, but due to the
lack of return moisture this weekend, will come through dry. Behind
this front, a Canadian air mass will move into the region from the
northwest and bring dry and seasonable temperatures for Mon through
Tue. This high pressure ridge will quickly slide east through the
Great Lakes region and allow southerly winds to return to the area
for Tue into Tue night. Along with this, a weather system will
develop out in the central plains Tue evening and then move east
toward the area Tue night. Models have begun to slow down the onset
of any precip in the CWA, but will be keeping a chance of showers
and thunderstorms in the extreme northwest part of the CWA. As the
system moves into the area on Wed, the showers and thunderstorms
will become likely Wed afternoon over the western half of the CWA,
and then over the eastern half of the CWA Wed evening. With the mid
level flow being somewhat zonal, this weather system will quickly
exit the CWA Wed night. After this system, models differ and lack
consistency, so dry weather is forecasted for the rest of the week
and into the first part of the weekend.

High temps in the 60s, to near 70 will be very seasonable for the
latter part of October. Overnight lows will also remain in the 40s,
so expecting any frost or freezing through the period.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1119 PM CDT Sat Oct 22 2016

VFR conditions will prevail through the entire 06z TAF period, as
high pressure gradually pulls away to the southeast. Winds the
rest of tonight will remain S-SW at 5 to 8 kt. Tomorrow, an
approaching cold front will increase the mixing of gusty LLJ winds
down to the surface. Wind gusts will increase to 16-18kt between
15z-18z, then increase to gusts of 22-25kt after 18z as winds
veer from SW to W-SW. Little to no clouds are expected, as the air
mass remains very dry. The dry cold frontal passage will occur
during the afternoon, and winds will shift W to W-NW as we
progress through tomorrow evening.


.ILX Watches/Warnings/Advisories...


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