Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 220439

Area Forecast Discussion
National Weather Service Lincoln IL
1139 PM CDT SUN AUG 21 2016

Issued at 843 PM CDT Sun Aug 21 2016

Clear skies prevail across central and southeast Illinois this
evening, with 8pm temperatures generally in the middle to upper
60s. As high pressure slides overhead and winds go nearly calm,
overnight low temperatures will bottom out in the middle 50s.
Current forecast is on track, so no updates are needed at this


.SHORT TERM...(This evening through Monday)
ISSUED AT 257 PM CDT Sun Aug 21 2016

Surface ridge will build and move from Missouri to Indiana over
the next day providing mostly clear skies for central and
southeast IL as it does so...aside from scattered shallow
afternoon cumulus clouds. A cool night is in store as cool air
settles in behind yesterday`s cold front and winds taper off
overnight allowing good radiational cooling. Expect lows in the
mid 50s tonight...down a few to several degrees further from last
night. Dewpoints have fallen to the upper 50s this afternoon and
forecast soundings indicate a further drying through tonight just
above the surface. As a result...fog should not be able to form as
moisture depth will be too shallow. Highs around 80 expected
Monday...up a few degrees from southerly flow and warm
advection return with the high positioned east of the area for the

.LONG TERM...(Monday night through Sunday)
ISSUED AT 257 PM CDT Sun Aug 21 2016

Quiet weather should prevail across central and southeast Illinois
through the daytime hours Tuesday. However, changes in the local
weather pattern will be occurring that will lead to a periodically
wet mid-week forecast period. The surface high that is helping to
provide our current dry/cool weather will drift off the east, with
southerly low-level return flow developing. At the same time, upper-
level heights will be rising considerably from their current levels
by Tuesday. This scenario supports conditions turning warmer and
more humid once again by Tuesday, but the rainfall threat should
still hold off until late Tuesday night for the most part. Then, a
vigorous upper wave, currently pushing into British Columbia and the
Pacific Northwest, will track along the U.S./Canada border and reach
the Upper Midwest/Northwest Ontario area by early Wednesday. This
wave, and a weaker lead wave ejecting out of the southwest U.S.,
will push a weather system/frontal boundary into the area by late
Tuesday night into Thursday. The main frontal boundary will be slow
moving as it nearly parallels the upper flow, keeping area under
this extended risk of showers/storms. The latest model consensus has
the front moving a little more quickly, suggesting Thursday night
will be mostly dry.

After a brief break in the precipitation risk on Friday, chances
return during the weekend. The upper-level flow remains pretty zonal
behind the mid-week front, allowing upstream short wave energy to
quickly return.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1139 PM CDT Sun Aug 21 2016

VFR conditions will prevail through the entire 06z TAF high pressure dominates the weather. Winds will remain
nearly calm tonight, then will back to the south at 5-10kt by
Monday morning as the high begins to shift off to the east.


.ILX Watches/Warnings/Advisories...


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