Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 170306
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
906 PM CST Fri Feb 16 2018

.UPDATE...
Issued at 906 PM CST Fri Feb 16 2018

Current forecast looks on track with high pressure bringing light
winds, partly cloudy skies, dry weather and colder temps. High
clouds continue to spread over the area tonight and will remain
there overnight and into the morning hours. Only real concern is
will temps get colder than current forecast. Believe current low
forecast looks good so only changes to the grids will be some
minor tweaks to sky cover. Therefore update will not be sent out
tonight.

&&

.SHORT TERM...(This evening through Saturday)
ISSUED AT 237 PM CST Fri Feb 16 2018

Back edge of the low clouds have made it just east of the I-55
corridor early this afternoon, though there are still plenty of
high clouds streaming northeast south of I-72. That should settle
southward with time, with a period of mostly clear skies expected
this evening. However, the cirrus will be moving back in from the
southwest overnight, ahead of the next storm system. Precipitation
with this system should start moving into the far southern CWA mid
to late morning. While it may start as snow or a mix, a quick
transition to rain is expected. With the upper wave passing by
Saturday afternoon, the rain should end by late afternoon.

.LONG TERM...(Saturday night through Friday)
ISSUED AT 237 PM CST Fri Feb 16 2018

Main forecast concern remains with the heavy rain potential during
the Monday night through Wednesday time frame. Heaviest QPF axis
on the models has shifted a tad northward from the earlier runs,
primarily from a slower frontal passage indicated on the morning
European and Canadian models. Still focused on the southeast third
of the forecast area.

Before that, strong southerly flow will help bring another round
of very mild air to the region, with 50s widespread Sunday and 60s
Monday. Can`t rule out some 70 degree readings in a few areas.
With a slower frontal passage, these temperatures will linger into
Tuesday in areas along and east of I-57. Rain will begin in
earnest late Sunday night, tapering off for a time Monday as the
warm front lifts north of the area. However, PoP`s significantly
ramp up again by late Monday evening. Plenty of Gulf moisture
will be surging into the area (precipitable water values near 1.3
inches), to enhance some of the rain totals. Currently looks like
a more prolonged rain event vs. a significant short-range
dumping, suggesting any flooding would be more focused on rivers
and low spots rather than flash flooding. Still far out to get too
narrowly focused on that potential, especially if any
thunderstorms form.

With the speed of the frontal passage in question, there is also
some concern for transition back to winter precipitation.
Soundings from the slower ECMWF model suggest a period of mixed
precipitation or ice as the precipitation ends. Given the model
inconsistencies over the last couple runs, this is not a high
confidence occurrence. Thus, will leave just the mention of a
rain/snow transition for now.

Another storm system is progged to lift northeast toward the area
late in the week. Enough model confidence exists for some very
high PoP`s over the southeast CWA for the introduction of Friday`s
forecast period. Currently, with a southwest flow setting up again
late week, it appears this precipitation should be all liquid.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 540 PM CST Fri Feb 16 2018

All sites will begin as VFR and should continue through the night
and into tomorrow morning. Cloud heights will be cirrus and then
get thicker early tomorrow morning. Then AC should move into the
area ahead of the round of light precip around noon. Low levels
will be dry to start, but precip falling through the layer should
moisten things up in a couple of hours, resulting in light rain
occurring during the early afternoon. Precip will move through
quickly but will keep VCSH in TAFs for late afternoon. Cigs during
precip will drop into MVFR category for the afternoon with BMI and
PIA dropping last. Winds will be northwest tonight but then become
south-southwest for early morning into the afternoon. Speeds will
be less than 10kts tonight, but then 10-15kts tomorrow.


&&

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

$$

UPDATE...Auten
SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Auten



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