649 
FXUS63 KILX 071103
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
603 AM CDT Sat Jul 7 2018

.SHORT TERM...(Today and tonight)
ISSUED AT 259 AM CDT Sat Jul 7 2018

High pressure anchored over the Great Lakes will provide another
pleasant day across central Illinois...with ample sunshine, low
relative humidity, and afternoon high temperatures in the lower
80s. Clear skies and light winds beneath the ridge axis will allow
low temperatures tonight to drop into the middle to upper 50s.

.LONG TERM...(Sunday through Friday)
ISSUED AT 259 AM CDT Sat Jul 7 2018

As the high shifts further away, the very warm/humid airmass 
poised just to the south across the Ozarks/lower Ohio River Valley
will flow back northward early next week. Highs on Sunday will be
in the middle 80s, then will climb into the upper 80s to around 90
degrees by Monday. While the airmass will initially be quite dry,
once the boundary layer flow becomes southerly, surface dewpoints
will soar into the lower to middle 70s on Monday...producing peak
afternoon heat index values approaching 100 degrees.

00z Jul 7 models all show a significant short-wave trough digging
into Quebec/New England on Tuesday, which will help push a weak
cold front southward into central Illinois. While timing of the
front is well agreed upon, the amount of precipitation it triggers
is not. The GFS is the wettest of the models, while the ECMWF/GEM 
suggest a mostly dry FROPA. Think the GFS is likely suffering from
its typical summertime wet bias...but with a boundary interacting
with a moist environment during peak heating, feel slight chance 
PoPs are warranted Tuesday afternoon.

Once the front passes, another brief break in the heat/humidity 
will take place on Wednesday before hot weather returns for the 
end of the week. Some fairly significant model differences exist
concerning the strength of the upper ridge in place over the
Midwest by Thursday/Friday...with the ECMWF indicating a stronger
ridge. Current forecast features high temperatures returning to
the lower 90s: however, if the ECMWF trend continues, these
numbers may need to be boosted into the middle 90s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 600 AM CDT Sat Jul 7 2018

VFR conditions are expected through this forecast period. Easterly
winds at 8 to 15 kts today will diminish to around 5 kts tonight. 

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith