Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 152033
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
233 PM CST Thu Feb 15 2018

.SHORT TERM...(This evening through Friday)
ISSUED AT 232 PM CST Thu Feb 15 2018

Looks like the warm front made it about as far north as a Macomb
to Peoria to Chenoa line today, with the fog still lingering to
the north early this afternoon. High-res models suggesting this
fog may hang on for a few more hours. Current advisory expires
at 4 pm, and will make a last minute decision on whether it needs
to be extended or not.

Surface low is currently centered near Quincy, and will ride
northeast along the boundary the rest of the afternoon as the
associated cold front pushes southeast. Short-range models have
this latter boundary near I-70 around sunset, but only slowly
moving across the southeast CWA this evening. Temperatures south
of the front have reached the 60s, with a few lower 70s south of
I-70, where wind gusts have been in the 30-40 mph range. This has
contributed to some surface based CAPE`s around 200-300 J/kg down
there, which the RAP suggests could come up a bit more this
afternoon. SPC Day1 outlook around midday added a marginal risk
of severe weather near and south of I-70. Will keep a mention of
isolated thunder into early evening. High-res models show more of
a widespread shower issue there much of the evening, before the
front finally pushes south.

Much colder conditions still on tap for Friday, as an upper level
wave passes to our north. No significant push of Arctic air is
expected, so temperatures in much of the CWA should still reach
into the 30s outside of any lingering snow cover.


&&

.LONG TERM...(Friday night through Thursday)
ISSUED AT 232 PM CST Thu Feb 15 2018

Upper level pattern gradually will feature a southwest flow into
our area by early next week. Temperatures should get back into the
50s by Sunday and 60s Monday. GFS and ECMWF show more of a split
flow by mid week, which should keep the coldest air further
north.

Main issue in the longer term will be with an extended period of
rain chances, which could result in some hefty totals over parts
of the CWA. This is mainly beginning early next week, when a
storm system develops over the central Plains early Monday. Our
forecast area will remain in the warm and more humid sector
through the first part of Tuesday, before an upper wave over the
northern Plains gives the cold front an eastward shove.
Precipitable water values off the GFS are around 1.3-1.4 inches
Monday night and early Tuesday, which is near record territory for
this area for the latter part of February. WPC guidance and model
blends suggest a few inches of rain possible over the southeast
CWA through mid week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1112 AM CST Thu Feb 15 2018

Area of dense fog continues to lift northward, and was only
impacting KPIA at 17Z. Some improvements are expected early in the
afternoon, as a cold front begins to move into the area. Further
south, low ceilings have been trending more into the low VFR range
over the last couple hours, and this trend is expected to
continue. Have added a mention of VCTS at KDEC/KCMI for mid to
late afternoon, as instability increases ahead of the front. This
front should be through the TAF sites by 00Z, though a period of
lower visibilities is expected immediately behind the front near
KPIA/KBMI due to the colder air over the melting snow pack. A more
general period of MVFR ceilings is expected late night into Friday
morning, before skies begin to clear.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 4 PM CST this afternoon for ILZ027>031-
036.

&&

$$

SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Geelhart



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