Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 122324
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
624 PM CDT Sat Aug 12 2017

.SHORT TERM...(This evening through Sunday)
ISSUED AT 259 PM CDT Sat Aug 12 2017

High pressure is keeping mild and quiet weather in place for the
weekend in the Midwest. Todays highs are mainly in the upper
70s/near 80 for most of Central IL. Fair weather cumulus clouds
across the sky and light northerly winds on the east side of the
surface ridge. Overnight, winds light and variable as the ridge
remains anchored in the region. Clear skies and cool again
tonight. Radiational cooling overnight will be relatively
efficient and areas to the north could see some patchy fog with
the more significant lull in the surface winds. Not enough
confidence in the guidance to go with a mention, but may need to
adjust after the sun sets and a better idea of where the xover
temps land. Tomorrow, the quiet weather continues with some diurnal
cu and light easterly winds. Temps very similar to today.

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 259 PM CDT Sat Aug 12 2017

Quiet weather continues at least through midday Monday. Previous
models brought a quick wave just to the south of the FA on Sun
night but have since evened out. However, the GFS maintains the
threat of the second wave Monday night/Tuesday for the potential
of at least some weak showers/TS, although at this point the
blends are barely catching it, so it remains the lowest of slights
in the forecast. Into midweek remains mild and dry for Central IL
as a slow warming trend kicks in Wednesday/Thursday as the winds
slowly come around to more southerly to end the forecast. Btwn the
GFS and the ECMWF, the surface parameters look suspiciously
similar compared to their far more divergent 500mb charts. Almost
zonal flow aloft in the ECMWF and a much more amplified pattern in
the GFS point to something being worked out a bit. And to that
end, the GFS has made some progress phasing in a southern
shortwave into the more significant trough over the western half
of the CONUS. Even so, the models still producing copious
potential storms from a series of shortwaves through at least the
end of the week. Confidence in the precipitation forecast beyond
Wednesday is far from optimal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 615 PM CDT Sat Aug 12 2017

VFR conditions are expected for most of this forecast period. Will
have to watch for the potential for some patchy fog between 10z
and 13z which would bring MVFR vsbys. At this time, will lower
vsbys to 5-6mi across the TAF sites for a few hours early Sun.
morning. Forecast soundings still suggest some scattered cumulus
developing again by late Sunday morning with bases in the 4000-5000
foot range. Light and variable winds tonight with become light
easterly on Sunday with speeds of 10 kts or less.

&&

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

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith



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