Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 220436
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1136 PM CDT Thu Sep 21 2017

.UPDATE...
Issued at 926 PM CDT Thu Sep 21 2017

Quiet weather is expected across central and southeast Illinois
overnight. Made some changes earlier tonight to increase cloud
cover, and recently tweaked sky condition again, due to remaining
debris from upstream convection last night. Otherwise, another
very warm night and southerly winds is anticipated.

&&

.SHORT TERM...(This evening through Friday)
ISSUED AT 240 PM CDT Thu Sep 21 2017
Expansive area of high pressure dominates the eastern half of the
CONUS this afternoon as southwesterly flow stretches from the
southern California coast into the Upper Midwest. Highly amplified
pattern has set up with plenty of warm air building over the
region keeping the temperatures well above climatological normals.
This heat is expected to remain in place through the weekend as
well as southerly winds keeping surface dewpoints elevated. Humid
conditions will push the heat indices even higher into the upper
90s/near 100F. Cirrus blow off from overnight convection to the
northwest the only thing that has kept the temperatures down NW of
the IL river valley. That cirrus is expected to dissipate and
overnight lows will drop into the upper 60s/lower 70s. Some of the
short term high res models had been developing some of the cu to
the north/northeast this afternoon/evening. Some weak returns
starting to show up on radar but not to the same extent. Between
that and the dry air that is in the region to overcome, will leave
mention out for now. Tomorrows weather will likely be similar to
today, hot and muggy, with chances for a scattered cu field in the
afternoon.

.LONG TERM...(Friday night through Thursday)
ISSUED AT 240 PM CDT Thu Sep 21 2017

Hot and muggy weather expected through the weekend with daytime
max temps reaching into the 90s, and heat indices
approaching/around 100F. Overall, the extended is dominated by a
pattern shift as Hurricane Maria hangs up off the Atlantic Coast
and a deep wave digs in over the desert SW. The ridge is
compressed slightly as it starts to break down. Another deep wave
moves across southern Canada, bringing slightly cooler air behind
a weak cold front midweek. So far, minimal precip associated with
the boundary given the airmass shift. Central IL then comes under
the influence of the deep SWrly flow as the ridge shifts to the
east coast and breaks down. Best chances for precip in the
extended for Wednesday, and cooler air behind it, should the
current solutions hold.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1134 PM CDT Thu Sep 21 2017

VFR conditions will prevail through the 06Z TAF valid time across
the central Illinois terminals. Generally light southerly winds
will persist, along with patchy high level cloudiness.

&&

.CLIMATE...
Issued at 410 PM CDT Thu Sep 21 2017

Record highs through the weekend:

Location         Thu       Fri       Sat       Sun
--------       -------   -------   -------   -------
Bloomington    94/1908   94/1930   92/1937   94/1933
Champaign      95/1891   95/1891   94/1891   94/1891
Charleston     95/1940   95/2005   93/2010   93/1933
Decatur        95/1955   94/2005   92/2007   93/1933
Galesburg      90/1940   92/1988   89/1937   90/2007
Olney         100/1940   96/2010   94/1960   94/2010
Peoria         93/1940   93/1930   92/1937   92/2007
Springfield    96/1931   95/2005   93/2007   93/2007

&&

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

$$

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



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