Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 162353
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
653 PM CDT Sun Jul 16 2017

.SHORT TERM...(This evening through Monday)
ISSUED AT 232 PM CDT Sun Jul 16 2017

Cold front is dropping southward early this afternoon and has
recently cleared Galesburg and Peoria. Clusters of thunderstorms
are developing over southeast Iowa and central Illinois just ahead
of the front, in an area where CAPE`s have reached 3500-4000 J/kg.
With freezing levels above 14kft, large hail may have a hard time
making it to the surface, but some storms may pulse up enough for
some brief hail/wind threats. The front should be near I-72 toward
6-7 pm and be south of I-70 after sunset, so the threat of storms
will diminish from north to south following the passage of the
front.

High pressure will move across the Midwest on Monday, with a brief
period of less humid air to enjoy, before the heat wave arrives.

.LONG TERM...(Monday night through Sunday)
ISSUED AT 232 PM CDT Sun Jul 16 2017

Main concern remains with the extended period of heat beginning on
Tuesday, followed by any potential ridge-rider MCS`s late in the
week.

Not much change in the setup for this week, as the heat dome
spreads eastward. No headlines planned yet as the more juicy air
is a bit slower to arrive, with heat index values above 100
degrees appearing more likely beginning on Wednesday. Highs in the
mid 90s most likely everywhere by Wednesday and likely over the
southwest half of the CWA on Thursday.

Core of the upper level high starts to shift into the southeast
U.S. Thursday night, which would allow more of the MCS type
activity along the periphery of the ridge to impact our area. With
this concern, the northeast half of the CWA will be subject to
more in the way of clouds and precipitation late week, which would
keep temperatures down some. Both the GFS and ECMWF models favor
that area being close to the MCS track Thursday night and Friday,
although the GFS shifts it a bit further south by Friday night.
The two models start getting well out of sync during the weekend,
as the GFS is more aggressive in pushing a cold front through on
Saturday. Meanwhile, the latest ECMWF MOS guidance keeps highs
well into the 90s. Thus, confidence in the weekend forecast is
lower than usual.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 650 PM CDT Sun Jul 16 2017

Radar and satellite imagery shows the storms that fired in area of
instability that pooled along and just ahead of slowly southward
moving front. Front will continue to move south, with some low VFR
cigs near storms, then clouds breaking up with light northeast
winds overnight and through day Monday.

&&

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

$$

SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Goetsch



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