Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 231939
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
239 PM CDT Tue Sep 23 2014

.SHORT TERM...(Tonight)
ISSUED AT 238 PM CDT TUE SEP 23 2014

Center of high pressure over Ohio early this afternoon. Skies
remaining mostly clear at the moment, although a fairly large shield
of mid and high clouds has edged into far western Illinois. This is
ahead of a storm system centered in south central South Dakota. Much
of the clouds and energy with this system will be tracking to our
northwest, so not much more than an increase in cirrus is expected
for us tonight. Temperatures should be a few degrees warmer tonight,
with more of an east/southeast flow on the back side of the high.
However, some mid 40s are still likely in eastern Illinois, where
the clouds will be less of a factor.


&&

.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 238 PM CDT TUE SEP 23 2014

The low pressure system churning across South Dakota/Nebraska on
Tuesday will move northeast into the western Great Lakes on
Wednesday. A trailing surface trough will advance across Iowa and N
Missouri, but dissipate as it reaches western Illinois. No rain is
expected in central IL from that system, with just residual mid and
high clouds on Wednesday. The additional cloud cover may keep high
temps similar to Tuesday`s readings in the mid 70s. However, the
warming trend will return for Thursday into Friday as high pressure
builds back across the region in the wake of the dissipating trough.

The upper levels will be dominated by a long wave ridge all through
the rest of this week and into this coming weekend, with various
waves trying to flatten the northern part of the ridge along the
Canadian border. Eventually a low pressure system originating near
the Gulf Coast will be drawn into the ridge toward southern
Illinois. There are large differences between the ECMWF and the GFS
on the timing of the arrival of that system in Illinois. The 12z
ECMWF brings the low into the area Monday night and Tuesday, while
the GFS holds off until next week Wednesday. We trended up with the
PoPs on Tuesday to an area of low Chance in the east, just to show a
trend toward rain potential in the forecast for sometime the first
half of next week. We kept just slights elsewhere from Mon night
through Tues night.


&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 1210 PM CDT TUE SEP 23 2014

VFR conditions expected through the period, with only a gradual
increase in high clouds. High pressure over Indiana will keep a
general east/southeast flow over the TAF sites through sunrise,
before becoming more southeast on Wednesday ahead of an upper
disturbance approaching the Mississippi River.


&&

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

$$

SHORT TERM...GEELHART
LONG TERM...SHIMON
AVIATION...GEELHART






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