Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 190204

Area Forecast Discussion
National Weather Service Lincoln IL
904 PM CDT Sun Jun 18 2017

Issued at 904 PM CDT Sun Jun 18 2017

Scattered mid-level clouds continue to drift southeastward across
the area this evening, resulting in partly to mostly clear skies.
02z/9pm temperatures have dropped into the lower 70s...well on
their way to projected overnight lows in the upper 50s and lower
60s. Current forecast is right on track, so no updates are needed
at this time.


.SHORT TERM...(This evening through Monday)
ISSUED AT 255 PM CDT Sun Jun 18 2017
In the wake of last nights showers and thunderstorms...the region
is under increasingly northwesterly flow at 500mb as the trough
amplifies over the Midwest aloft. West to northwesterly flow
dominates the weather map over Central Illinois this
afternoon...with little more than fair weather clouds for much of
the region. With mostly clear skies anticipated this evening...and
dewpoints a little lower in the upper 50s and lower 60s...have
dropped the overnight lows a few degrees from guidance. Then
tomorrow...highs will set up from the upper 70s to the lower
80s...similar to today...but with the gradient oriented from NE to
SW, parallel to the flow aloft. The first in a series of short
waves bringing the potential for some afternoon showers/TS...
particulary in the north, assisted by a weak cyclonic flow aloft.

.LONG TERM...(Monday night through Sunday)
ISSUED AT 255 PM CDT Sun Jun 18 2017
Dry Monday night with lows a couple degrees warmer than tonight.
Tuesday, another quick impulse dives into the northwesterly flow
aloft, but the axis of the trough has shifted east slightly...and
less of a cyclonic turn as well. For now, Tuesday night is mostly
dry but that would be something to watch in the forecasts to come
as the 12z and 18z runs are showing some slight differences about
the westward reach of showers and thunderstorms back into IL.
Wednesday, the flow at 850mb becomes quasi zonal again...and the
flow at 850mb backs to more southwesterly, moving perpendicular to
isotherms, kicking off a warming period through the end of the
week. Increasing temps and moisture in the boundary layer through
the end of the week setting up for the next storm system that
moves through the region. Models differ considerably with handling
the wave diving into the Upper Midwest...bringing precip as early
as Thursday night. For now, the forecast is diffuse and
conservative as the weekend has the potential to look a bit stormy


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 629 PM CDT Sun Jun 18 2017

VFR conditions will prevail through the entire 00z TAF period.
SCT-BKN diurnal clouds at 5000-8000ft will persist at the
terminals for the next couple of hours before gradually
dissipating. Am expecting mostly clear skies overnight into Monday
morning...with only a few passing mid-level clouds. As a weak
upper disturbance approaches from the northwest, the clouds will
once again become more robust by peak heating Monday afternoon.
Several models continue to produce widely scattered convection
across north-central Illinois, so have included VCSH at the I-74
TAF sites after 18z. Winds will initially be NW at around 10kt
early this evening before backing to the W and decreasing to
around 5kt tonight. Gusty NW winds will resume Monday afternoon.




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