Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KILX 261738

Area Forecast Discussion
National Weather Service Lincoln IL
1238 PM CDT MON SEP 26 2016

Issued at 1033 AM CDT Mon Sep 26 2016

High clouds trailing the cold front that has moved through the
Midwest and the Ohio River Valley is quickly clearing out of the
region as well. High pressure is building into the Midwest and the
cooler and drier air is sinking into Central Illinois. Quiet and
cool weather anticipated for the remains of the day. No updates
anticipated at this time. Will issue a quick update just to remove
the precip wording in the forecast for the afternoon.


.SHORT TERM...(Today and tonight)
ISSUED AT 341 AM CDT Mon Sep 26 2016

Light rain will continue across the eastern half of central and
southeast Illinois today as the 500mb short wave moves through the
area. Clouds will also be on the decrease from west to east through
the day. This should dry things out nicely today with ridging
building in. Northwest winds will return to the area and these winds
should become breezy with gusts of over 20-25mph at times...with
highest gusts in the north. Conditions this afternoon will
definitely feel fall-like as temperatures will only reach into the
lower to middle 70s and combine with the breezy winds out of the
northwest. Overnight lows are expected to drop into the upper 40s
under clear skies.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 341 AM CDT Mon Sep 26 2016

The main weather story for much of the upcoming week will be
something we haven`t seen for awhile - several days of below normal
temperatures. An upper level low from the western Great Lakes will
bring cooler air into the Midwest through the end of the week.
However, the medium range models disagree as to the position of this
low and how long it may linger in the region.

Many of the forecast details hinge on the upper low position Tuesday
through Friday. Most of the models drop the low southward from the
Michigan UP later Tuesday into Wednesday. The European model
continues to be the outlier by moving the low more SW/W than the
GFS, Canadian and the last few model run hours of the NAM. This is
significant for us since the farther SW/W track of the European
would result in several periods of clouds and light rain much of
this week.

For now will introduce slight chance PoPs for isolated showers
mainly along and north of the I-74 corridor for Tuesday evening
ahead of developing secondary cold front dropping in from the north.
This front and advancing upper low will reinforce the low level cold
air advection for Wednesday resulting in a very cool, autumn day. A
few more clouds could also keep temperatures down, with highs
Wednesday mainly in the mid 60s, which is about 10 degrees below

Toward late week the models diverge even further as the upper low
becomes cut off. They all depict the low just wobbling around, with
spokes of energy creating areas of light rainfall. The GFS is
farthest to the east with the low mainly located around West
Virginia, while the European model is the furthest west (eastern
Indiana), and the Canadian model in between the other two. Due to
the high level of uncertainty will keep the mention of rain out of
the late week forecast for now as the model blends keep central and
eastern IL dry with a very gradual warming trend.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1232 PM CDT Mon Sep 26 2016

High pressure moving in with significantly drier air resulting in
SKC, and breezy W/NW winds. Keeping the gusts up throughout the
day with the mixing down of some stronger 20-25 kt winds just off
the sfc. Losing gusts around sunset, and clear skies through the
overnight as well. VFR throughout.


.ILX Watches/Warnings/Advisories...


LONG TERM...Miller
AVIATION...HJS is the U.S. government's official web portal to all federal, state and local government web resources and services.