Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 291723
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1223 PM CDT Sun Mar 29 2015

.UPDATE...
ISSUED AT 940 AM CDT SUN MAR 29 2015

The rain has made some steady progress eastward, and was generally
along a Lacon to Jacksonville line at 930 am. Dual-pol radar data
suggests some mixed precipitation across the far northern CWA,
which has also been reported at the Galesburg airport, although
web cams are not showing much of an issue with it. HRRR guidance
has been handling this fairly well, and it was used to fine-tune
the precipitation trends today. Bumped up PoP`s to the categorical
range for a few hours across the north as this band moves through.
Secondary band is expected to develop between the Illinois River
and I-55 early this afternoon, and the HRRR suggests perhaps one
final band toward sunset with the front itself. Winds have been
picking up in many areas and gusts over 30 mph already being
reported across the central and western CWA. Area of 35-40 mph
gusts will be working its way eastward with time and should linger
into early afternoon before starting to diminish a bit.

&&

.SHORT TERM...(Today)
ISSUED AT 334 AM CDT SUN MAR 29 2015

A shortwave moving into northwest Iowa early this morning will
continue moving rapidly ESE-ward through the morning arriving in
central IL later this morning. Precipitation with this feature
should intensify as it approaches as southerly return flow ahead of
it feeds more moisture into the region. Warm frontal boundary will
be followed closely by a cold frontal boundary, causing temperatures
to increase about 10 degrees from yesterday`s readings by late
afternoon, however cold air behind the system will not be very
pronounced. Precipitation amounts still look to be relatively light,
generally under one tenth of an inch. Southerly winds will be fairly
strong and gusty today, as model soundings showing winds into the
30-40 kt range in the near-surface mixed layer. Expect S-SW winds
15-25 mph with gusts 30-40 mph. Strongest gusts looking to be I-74
northward around noon. An outside chance for brief freezing rain
early in the morning in Knox and Stark counties, but looks like rain
will hold off until a few hours after sunrise, and temperatures
likely to rise above freezing just in time for start of
precipitation. Precipitation will be tapering off from west to east
late in the afternoon as the wave continues moving eastward.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 334 AM CDT SUN MAR 29 2015

Wave moving through the forecast area rather quickly today and the
precipitation should be coming to an end this evening.  Keeping the
slight chances in the east.  Brief dry pd expected for the first
couple days of the work week with daytime highs more seasonable into
the 60s with 850mb temps warming from 4-5C tomorrow...to 10-11C by
Wednesday.  Westerly/southwesterly winds helping to bring some of
the heat in from the western ridging.  However, the next system
will be moving on the Pac coast Mon night/Tuesday and making its way
towards the Midwest.  Agreement on this system is not happening yet
between the GFS and the ECMWF.  The GFS is quicker and cleaner with
the development of the sfc low and progression across the region.
00Z ECMWF is starting to look more like the GFS...bringing precip
Wed night through Thursday. GFS stalling the boundary just to the SE
along the Ohio River Valley and putting the southeastern CWA on the
edge of some weak waves moving along the boundary for Thurs night
and Fri. The ECMWF is still a messier solution with the QPF,
stalling the boundary further to the north and keeping the CWA wet
from Wed night through Friday. Trending the forecast to the GFS is
preferred at this point, particularly with the trend of the ECMWF to
the GFS...but the SuperBlend is a little slower to respond.
Onset of precipitation being delayed to later on Wednesday night is
cutting down the potential thunder activity, but still keeping the
mention in for the initial FROPA. Still concerned that the temps for
Thursday may be too warm considering the proximity of the cloud
cover/rain potential.  Unless the clearing behind the boundary is
clean and quick early Thursday, the sun will have little chance to
rebound the sfc temps in the wake of the precip.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1222 PM CDT SUN MAR 29 2015

Initial band of rain is now exiting KCMI, although another band is
expected to develop around mid-afternoon. KCMI/KDEC are most
likely to be affected by this next band in the 21-23Z time frame.
Like the earlier rain, mainly VFR conditions expected, with
perhaps visibility briefly dipping to around 4-5SM if one of the
heavier showers happens to pass over the airport. The strongest
wind gusts will be early in the afternoon, but gusts to around 25
knots still likely mid-late afternoon. A frontal boundary will be
moving through the TAF sites in the 23Z-02Z time frame, switching
winds around to the northwest. These winds will diminish and turn
more southwest overnight, as an area of high pressure settles
across Missouri.

&&

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

$$

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





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