Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 181750
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1250 PM CDT Wed Oct 18 2017

.UPDATE...
Issued at 1042 AM CDT Wed Oct 18 2017

Central and southeast Illinois remain sandwiched between slowly
departing high pressure and a slowly approaching frontal system.
The local airmass remains very dry. This scenario supports another
day with minimal cloud cover and gusty southerly winds. The
abundant insolation and southerly winds will push temperatures a
little warmer than yesterday, with most areas topping out around
70 degrees. Going forecast is in good shape with only minor tweaks
needed to the hourly trends.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 338 AM CDT Wed Oct 18 2017

A shift in the models continue to evolve the forecast for the
weekend, while the remainder of the week continues in a dry warming
trend. High pressure ridge axis stretches from the Southern
Plains to the Mid Atlantic coast. A wave moving across the
southern tier of Canada dragging a surface low and associated cold
front into the Northern Plains this morning. High pressure
maintains control for Central IL with another mild day for the
second half of October. Todays highs will climb into the lower 70s,
with southerly winds continuing the warm air advection for the
region. The warmer airmass in place will keep the overnight lows
tonight in the lower 50s/upper 40s.

.LONG TERM...(Thursday through Tuesday)
ISSUED AT 338 AM CDT Wed Oct 18 2017

Unseasonably warm temperatures expected to wrap up the work
week...with max temps in the mid to upper 70s by Friday. 850 mb
temps climb to 15C-16C with continued warm air advection out of
the southwest. Have boosted the max temps a degree or two above
guidance through Fri. At 500mb, the trof shifts eastward,
beginning a trend to a more zonal flow for the end of the week.
With the ridging over the south/southeastern CONUS, the more
active stream is just to the north. Forecast remains dry and well
above normal through the end of the work week. Temperatures on
Saturday in the forecast remaining very close to the
consensus...as increasing cloud cover may inhibit the temps from
climbing as high as Thu/Fri.

Models agree with a break in the pattern moving into the weekend
with a more amplified wave digging in over the western half of the
CONUS. However, the GFS is now coming around to a solution seen in
yesterdays 00z ECMWF. Both models are dropping the energy into a
cut off low to the south, chopping the QPF depiction in half...and
potentially putting Central IL in a break in the heavier precip.
For now, forecast keeping to a fropa and associated pops this
weekend. Should the trend continue...may end up seeing a great
reduction of the QPF. Concern remains that the blended guidance
is shooting high with the pops for a potentially showery setup.
The cold front is slated to move through the region late
Saturday/early Sunday, resulting in a rainy weekend. Cooler temps
in the forecast on the other side of the front...cooling into
closer to normal temps by next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1247 PM CDT Wed Oct 18 2017

VFR conditions will prevail across the central Illinois terminals
through the 18Z TAF valid time. There will be little/no cloud
cover, with changing winds the primary forecast concern. The
gusty southerly winds will drop off around sunset, with winds
remaining light for the balance of the TAF valid time.

&&

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

$$

UPDATE...Bak
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Bak


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