Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 220441
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1141 PM CDT Tue Oct 21 2014

.UPDATE...
ISSUED AT 851 PM CDT TUE OCT 21 2014

Surface high pressure continues to settle over Illinois this
evening while a 500 mb high pressure ridge approaches from the
west. As a result...skies continue to clear over east central
portions of the state while clear skies remain to the west.
Pressure gradients remain strong enough for persistent light
northeast winds. Overnight, patchy fog development over portions
of east central Illinois still looks reasonable given dewpoints
in the low 40s with expected lows in the upper 30s, so forecast
continues to show patchy fog in this area. Only changes this
evening have been to adjust for cloud cover dissipating slower
than expected from around Champaign eastward.

&&

.SHORT TERM...(Tonight)
ISSUED AT 251 PM CDT TUE OCT 21 2014

Deep low over Lake Erie this afternoon, with north-northwesterly
flow over Illinois.  Cool air advecting in and some cloud cover
mostly to the north and the east.  Afternoon cu will clear shortly
before sunset, leaving the more persistent clouds out of ILX
territory.  Clearing overnight with light winds will allow some
pretty efficient radiational cooling and the temps will drop into
the upper 30s.  Forecast lows are in the middle of the MOS guidance
this afternoon. Shallow moisture will further mix out as the
afternoon progresses and will have to monitor for xover temps this
evening with regards to fog development.  Biggest concern will be in
the eastern portion of the CWA with dwpts still in the 40s and slow
to mix out with so many clouds aloft.

&&

.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 251 PM CDT TUE OCT 21 2014

Models continue in good agreement with the mid level ridging
tracking toward the area tomorrow and to the east of IL by Thur
morning. This will keep pleasant and dry weather in the area through
tomorrow night. Then, I mid level trough and associated surface
front will push into the area on Thursday and bring a chance of
showers to the CWA for Thursday through Thursday evening. This front
will push into the sfc high pressure area and pinch it off with some
of the ridging going south. The weather system will also weaken some
as it moves into the area and this will lead to the pcpn diminishing
while moving east. Once this system weakens and moves east of IL,
dry weather will return for the rest of the week.

Temps through the short term will start cool but then warm back to
close to normal for Friday.

A pleasant weekend is in store for central and southeast Illinois as
high pressure returns with dry and warmer conditions. Mid level
ridging will also be in place for the weekend and the beginning of
next week. Unfortunately, this ridge will be short lived and another
weather system is forecast to move toward the are from the west.
Models handle this system similarly and bring pcpn chances into the
area for mainly Monday night. Pops will remain small until models
have a better handle on the moisture return ahead of the system.

Temps will very warm through Monday, for the later part of October,
but then cool-down for Tue as the next system moves through the
area.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1141 PM CDT TUE OCT 21 2014

Areas of MVFR cigs will continue to affect KPRG-KCMI-KBMI
northward until 12z. Otherwise, mostly clear skies expected for
the next 24 hours as a 500 mb ridge axis approaches from the
west. Surface high pressure settling over Illinois will bring
light winds veering from northeasterly to southeasterly over the
next 24 hours. Low level moisture indicates fog possible
overnight, however persistent light winds should keep fog thin,
generally no worse than MVFR visibility. Therefore, have continued
temporary MVFR fog from 10Z-12Z in TAFS.

&&

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

$$

UPDATE...Onton
SHORT TERM...HJS
LONG TERM...Auten
AVIATION...Onton






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