Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 191729
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1229 PM CDT Sat Aug 19 2017

.UPDATE...
Issued at 1035 AM CDT Sat Aug 19 2017

Moisture channel imagery and upper air data shows upper trough
moving across midwest, with axis from northern Lake Micigan to
southern IL. Subsidence behind wave signficant, and will keep most
of central IL fair today. Minor low level convergence still keeps
slight chance of minor convective development over eastern IL
possible, though drier low level air is filtering in from the
north and limiting window of development this afternoon. Pleasant
day with mid 80s highs and mid 60s dew points.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 230 AM CDT Sat Aug 19 2017

Sharp shortwave now moving across the state has pushed a weak
convergence line into the central cwa this morning. Despite
synoptic scale subsidence and significant drying aloft weak
convergence along the remnant boundary may be sufficient for
isolated convection late this afternoon. Otherwise, most of the
region will have a dry Saturday. Heights build fairly rapidly
behind tonight`s wave and will likely keep highs today near
yesterday though maybe with a tad less humidity.

Light winds and mostly clear skies may lead to some patchy fog
late tonight. Otherwise near normal temps and dry.

.LONG TERM...(Sunday through Friday)
ISSUED AT 230 AM CDT Sat Aug 19 2017

Warm advection becomes more prenounced early next week as the flow
returns to a blocking ridge in the west and a deepening trough in
the east. With southerly flow developing, dew points will rebound
well into the 60s with even some lower 70s possible Monday. Heat
index values should be well into the 90s both Sunday and Monday.

The increasing humidity will combine with the leading wave in the
developing eastern U.S. trough to bring a good chance of storms
back into Illinois on Monday and Tuesday. likely PoPs can expected
late Monday Night in the northwest portion of the forecast area
and over most of the area Tuesday.

With deep moisture in place and the approaching wave, clouds will
be on the increase on Monday. Monday afternoon will likely be
mostly cloudy from Champaign to Springfield and northwest. At this
time, better eclipse viewing conditions are expected across
southeast Illinois.

The wave moves past late Tuesday ushering drier and cooler northwest
flow. Highs the rest of the week should be in the 70s to around 80
degrees. Dry weather will dominate the forecast area Wednesday
through Friday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1228 PM CDT Sat Aug 19 2017

Morning sounding and progs shows enough leftover low level
moisture to produc some CU development over southeast half of
central IL. This also seen in VSB satellite imagery. Even with
dryier air flowing slowly into region overnight, lingering
moisture over eastern TAF sites enough for patchy possible fog
late tonight reducing VSB into MVFR category. Will have to watch
that, with some restriction also noted at other TAF sites to west.
Winds will shift to the south and southeast by Sunday with some
SCt CU again possible.

&&

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

$$

UPDATE...Goetsch
SHORT TERM...Barker
LONG TERM...Barker
AVIATION...Goetsch



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