Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 242106

Area Forecast Discussion
National Weather Service Lincoln IL
306 PM CST Fri Nov 24 2017

.SHORT TERM...(This evening through Saturday)
ISSUED AT 250 PM CST Fri Nov 24 2017
Cold front is approaching the region from the NW this afternoon,
compressing the pressure gradient and resulting in a blustery
afternoon. These winds are out of the SW with a mid level thermal
ridge drifting east...all contributing to a significant warm up
for Central Illinois for late November. Warm temperatures this
afternoon will mitigate the diurnal swing somewhat ahead of the
boundary. But after the front moves through, the temperatures will
drop by dawn into the 40s and upper 30s. A significant lack of
clouds out ahead of the boundary, but some midlevel clouds are
expected just behind it. There is a lack of rich moisture
available, and dewpoints are still in the 30s for much of the
area...but slowly climbing. Cannot rule out a sprinkle or two in
the overnight hours, but certainly not expansive in cover across
the region. Tomorrow, cool air will keep the highs in the low 50s,
with light NW winds.


.LONG TERM...(Saturday night through Friday)
ISSUED AT 250 PM CST Fri Nov 24 2017

The pattern sets up to repeat again with a cooler weekend behind
the front...then a slow warm up starting Sunday night as the winds
come around to more southerly behind the ridge axis. Monday gets
warmer again (and have pulled forecast above blended MOS again as
a result). Front is dragged back through the region with cooler
air and chance pops late Wed/Wed night. Models having issues
resolving everything about this system. Both the ECMWF and GFS
have the GFS is keeping a phased wave at 500 mb, but
lagging on progression. The ECMWF is closing off the low and
slowing. Either way, both are 24 hrs behind their solutions on
23/12Z runs. Without timing specifics, tracks are varied as much
as the thermal profiles, making the precip type another argument
with little reasoning support. Blended models have a mostly rain
event with some mix late Wednesday night. Have pushed pops out a
little bit later Thursday night with a more rapid movement through
the region. Still think there will be additional adjustments until
the ECMWF and GFS can find more of a consensus in the handling of
the upper low, much less the sfc reflection.


.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1149 AM CST Fri Nov 24 2017

No changes to the forecast this afternoon. Still expect some
gusts...starting to show in obs...and breezy S/SW winds ahead of
approaching system gusting to 25 to 30kts. Mostly sunny, with
some cirrus across the region. Mid level clouds anticipated later
this evening with the cold front and wind shift. Some sprinkles
are possible with the boundary, but far from widespread enough to
warrant a mention at this time. VFR throughout.




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