Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 262323

Area Forecast Discussion
National Weather Service Lincoln IL
623 PM CDT Wed Apr 26 2017

.SHORT TERM...(This evening through Thursday)
ISSUED AT 316 PM CDT Wed Apr 26 2017

A wet night is on tap across central and southeast Illinois as
periods of showers and thunderstorms accompany a slow moving cold
front and upper-level energy tracking along the boundary. The bulk
of the heavier rainfall and thunderstorms should be east of the area
by Midnight with the passage of the front and/or loss of diurnal

Aside from a low risk of showers in the morning, Thursday should end
up a mostly dry day as weak high pressure builds across the area.
Temperatures will be noticeably cooler in many areas than today, with
peak  readings mainly around 60 degrees.

.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 316 PM CDT Wed Apr 26 2017

The next stronger piece of upper-level energy will amplify the
broad/shallow troffing across the lower 48 states to start the
period. After a brief dry break, this will being a extended wet
weather period across the region through the weekend. Initially,
Thursday night into Friday night, the bulk of the heavier rainfall
will occur over the southeast 1/2 of the forecast area, closer to a
nearly stationary frontal boundary and associated richer moisture.

A vigorous wave within the mean troffing will lift northeast from the
southern/central Plains into the Great Lakes from Saturday into
Sunday night. The passage of this system will likely be accompanied
by significant rainfall across much of the forecast area, with the
heaviest rainfall likely to fall Saturday night. Much of the
forecast area is likely to see several inches of rainfall by the end
of the weekend. This much rain will result in significant rises on
area rivers, as well as non-river related flooding/flash flooding.
However, it is still too soon to pin-point exact locations/amounts.
So, do not plan to issue any flooding related watches at this time.


.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 608 PM CDT Wed Apr 26 2017

Band of showers and storms associated with a cold front, currently
just west of BMI and SPI, continues to track north and northeast
across the TAF sites early this evening. To the east of the front,
mainly VFR cigs were observed except in an near any TSRA, while to
the west of the front MVFR and local IFR cigs were observed.
Timing of the cold front is the main forecast concern as that will
be the transition from VFR to MVFR cigs this evening. Latest
satellite data indicates several more surges of rain and isolated
thunderstorms from south to north this evening as the front slowly
edges into eastern IL by 05z. Forecast soundings suggest MVFR and
local IFR cigs to hold into the mid-morning before drier air works
in from the northwest and gradually erodes the lower cloud deck
by afternoon. South to southwest winds ahead of the front this
evening will become west to northwest behind the frontal boundary
overnight. Speeds will range from 8 to 15 kts.




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