Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 191537
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1037 AM 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 12Z TAFS through 12Z Sunday morning)
Issued at 600 AM CDT Sat Aug 19 2017

Models handling small cluster of convection passing just north of
KPIA this morning. With strong shortwave rapidly moving out of the
area still feel the trend should be to weaken this area and keep
it north of KBMI. Will keep a tempo group of bkn VFR cigs there,
but will not mention precip due to uncertainty.

Weak boundary evident e-w across central Illinois this morning
would be the focus of any afternoon enhanced cumulus. However,
with heights building in wake of aforementioned wave and much
drier air advecting into the region above 700mb any chance of
storms will not be high enough to warrent a mention attm.

Otherwise, light winds and mostly clear skies tonight may lead to
some patchy fog but since it would be toward the end of the valid
period will allow later packages to decide if its inclusion is
necessary.


&&

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

$$

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



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