Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 131121
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
521 AM CST Mon Nov 13 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 245 AM CST Mon Nov 13 2017

Main challenge for this part of the forecast is with the
stratocumulus deck currently over much of the area. Early morning
GOES-16 nighttime microphysics imagery shows the clearing line
nicely, extending from about Chicago to Peoria to northwest
Missouri. However, the Missouri portion has started to push
northward again. The models are struggling with adequately
depicting the current trends, so their progs for later today and
tonight are uncertain. The 950 mb humidity plot off the RAP and
NAM may be handling it the best, suggesting most of the CWA
remains cloudy at least until afternoon. This is also supported by
the HRRR. With the high pressure area drifting overhead today,
the inversion is expected to remain in place to support the more
generous cloud cover. The northern CWA is most likely to see any
sunshine, but will keep the central and southern areas mostly
cloudy.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 245 AM CST Mon Nov 13 2017

Our midweek storm system is seen on water vapor imagery off the
Washington coast early this morning. Not a lot of change in the
evening models regarding this system`s arrival, with the main cold
front passing through on Wednesday. Main precipitation period will
be between midnight and midday, with a few thunderstorms possible
before sunrise.

The late week storm system remains a challenge, with the GFS
about 12 hours faster than either the European or Canadian
solutions. While all solutions feature widespread showers at least
on Friday, thunder chances will be more dependent on the frontal
timing. As such, will only mention isolated storms at this point.
Any lingering rain should exit the area early Saturday.

High temperatures will be up and down through the week, warmest
Wednesday and Friday with the storm systems. By late in the week,
a decent slug of cold air will be dropping southeast into the
Midwest. The extended models are in agreement with the coldest
air staying up near the Great Lakes, but temperatures will still
be well below normal this far south.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 520 AM CST Mon Nov 13 2017

Very challenging forecast. Large expanse of MVFR stratocumulus was
edging southward earlier, but has started migrating north again.
KPIA is on the fringe and went scattered recently, but this is
probably a brief occurrence and will go with a ceiling there from
the outset. Will bring VFR conditions back there by 15Z, but will
keep ceilings below 3,000 feet at the other TAF sites into the
afternoon hours. Some evidence being seen on satellite imagery of
some thinning occurring near KCMI, and will need to monitor this
to see if that trend manages to hang on.

&&

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

$$

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



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