Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 181951

Area Forecast Discussion
National Weather Service Lincoln IL
251 PM CDT Mon Sep 18 2017

.SHORT TERM...(This evening through Tuesday)
ISSUED AT 251 PM CDT Mon Sep 18 2017

A broad longwave trough over the western U.S. and ridge centered
over the east coast is the basic pattern at this time. A shortwave
embedded in the southwesterly flow between the two features is over
western MO/IA and heading toward central IL. This feature will help
the stalled out front across central MO/southern IL and associated
higher temp/dewpoint air to move back northward and will result in
showers and thunderstorms spreading back northeastward across
central IL late this afternoon into tonight. As the shortwave passes
east...precipitation will end from west to east Tuesday starting
early in the morning. With partially clearing skies, light winds,
and recent rainfall patchy fog should be able to form across the
area by morning. Lows tonight will be mild...several degrees above the mid 60s as a result of the warm moist air mass and
cloud cover. Highs Tuesday in the mid to upper 80s.

.LONG TERM...(Tuesday night through Monday)
ISSUED AT 251 PM CDT Mon Sep 18 2017

The basic western trough/eastern ridge pattern will become more
amplified toward the end of the week and through the weekend. This
will result in persistent warm weather with highs near 90 degrees
through the week and possibly through the weekend. With record high
temperatures generally in the low 90s by the upcoming weekend...this
would eventually be near record levels if 90 degree highs continue.
For now, have forecast highs in the upper 80s over the weekend, up a
few degrees from previous forecast. The ridge will also promote
general subsidence over the area bringing generally dry weather. The
main chance for precipitation in the extended forecast will be from
a weakening cold front dragging into the mid Mississippi River
Valley region Wednesday into Thursday morning. Only a slight
chance of precipitation with this feature for most of central IL,
although keeping a small area of chance/30 percent PoPs north/west
of Peoria.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1234 PM CDT Mon Sep 18 2017

Scattered showers and thunderstorms will move into the central IL
terminal sites by this evening as an upper level disturbance from
the central Plains reaches the area. Aside from isolated MVFR
cigs/vsbys in stronger thunderstorms, primarily VFR conditions
will continue into tonight. After several hours of scattered
shra/tsra, partial clearing will begin to take place from the
west, which will likely result in patchy fog development toward
morning. Have included TEMPO IFR vsby due to fog as a result.
Winds E-SE 3-6 mph initially, then becoming S-SW following a warm
front lifting across the area during the evening. Winds remaining
under 8 kts aside from gusty winds in the vicinity of





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