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fxus63 kilx 171546 
afdilx

Area forecast discussion
National Weather Service Lincoln Illinois
1046 am CDT Tue Sep 17 2019

Synopsis...
issued at 328 am CDT Tue Sep 17 2019

After an extended period of warm and dry weather through the
remainder of the work week, the next significant chance for
widespread rain will arrive by the weekend.

&&

Update...
issued at 1045 am CDT Tue Sep 17 2019

Updated the forecast for cloud cover a bit slower dissipation of
the fog in northern parts of the forecast area - north of a
Rushville to Bloomington/normal line. Satellite imagery is showing
quite a bit of high cloudiness moving around the west and north
side of the upper level ridge axis. This has decreased the amount
of sunshine to heat up the lower atmosphere, thus resulting in a
slower fog/low cloud dissipation. The fog and clouds are expected
to hang around west of the Illinois River the longest, so will
drop high temps a few degrees in that area. Otherwise, still looks
like another very warm day today with mid to upper 80s in the rest
of central and all of southeast Illinois.

&&

Short term...(today and tonight)
issued at 302 am CDT Tue Sep 17 2019

Fog is once again beginning to develop beneath a sprawling ridge
of high pressure extending from the Great Lakes to the Southern
Plains early this morning. As was the case last night, the most
widespread fog has been concentrated north of the I-72 corridor,
primarily along/north of a Lacon...to Bloomington...to Rantoul
line where visibilities have occasionally dropped below 1 mile. Infrared
fog channel has been showing the fog and/or low stratus deck
gradually advecting west/SW, so am expecting the thicker fog to
eventually reach Lincoln and perhaps even Peoria over the next
couple of hours. Based on satellite trends and latest model
guidance, have carried patchy fog across the entire kilx
County Warning Area...with areas of fog noted from Peoria/Lincoln northeastward.
Despite temp/dewpoint spreads of 0-2 degrees and clear fog signal
on satellite, think NE winds of 5-10 mph will mix the boundary
layer sufficiently to prevent widespread dense fog. The fog will
dissipate by mid-morning, followed by partly to mostly sunny skies
for the balance of the day. Afternoon highs will top out in the
middle 80s. Under mostly clear skies, lows tonight will drop into
the lower to middle 60s.

Long term...(wednesday through monday)
issued at 328 am CDT Tue Sep 17 2019

Upper ridging will remain in control of the weather through the
first half of the extended, with warm/dry conditions and highs
well into the 80s expected through Friday. After that, a series of
short-waves will begin to break the ridge down and try to push a
cold front into the region over the weekend. 00z Sep 17 models are
in poor agreement with the timing of this process and the arrival
of the front, with the GFS being about 12-24 hours faster than the
ECMWF/Gem. The GFS shows the cold front along the Mississippi
River by 00z sun...while the European model (ecmwf)/Gem keep the boundary much
further northwest across northwest Iowa. Given strength of upper ridge,
think the slower model consensus is probably the way to go. As a
result, have confined best rain chances on Saturday to areas
along/west of I-55. Have also boosted highs across the east/southeast County Warning Area
into the middle 80s as conditions will likely remain dry there
through the entire day. The front will gradually shift east/southeast into
Illinois and stall early next week as it becomes parallel to the
upper flow. Given copious amounts of deep-layer moisture to work
with, the potential exists for heavy rainfall from Saturday night
through Monday. There are still questions as to how quickly the
front arrives and exactly where it stalls, so its still too early
to pin down precise rain totals. However, it appears most of
central and southeast Illinois will see a much-needed significant
rainfall this weekend.

&&

Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 620 am CDT Tue Sep 17 2019

LIFR conditions are affecting pia and bmi this morning with
spi/Dec/cmi seeing MVFR or IFR conditions. The low stratus
affecting pia and bmi could cause the any fog to hang around this
morning, but should eventually burn off later this morning. The
other three sites do not have the lower clouds, so the fog there
should burn off quickly this morning. Hires models differ on
timing of this but consshort model looks OK and keeps some cloud
cover at pia and bmi this morning, and has it lifting. High cirrus
should be seen at the other three sites through the day and into
this evening. Pia and bmi will improve later this morning and they
will have just cirrus during the late afternoon through the night.
Winds will be easterly through the period with speeds of 10kts of
less.



&&

Ilx watches/warnings/advisories...
none.
&&

$$

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