Area Forecast Discussion
Issued by NWS Central Illinois

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627
FXUS63 KILX 022318
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
618 PM CDT MON MAY 2 2016

.SHORT TERM...(Tonight)
ISSUED AT 313 PM CDT Mon May 2 2016

Main short-term forecast concern will be timing of potential
clearing tonight.  While the main surface boundary has dropped south
of the Ohio River, a trailing upper trough extending from Wisconsin
southwestward to Kansas has provided enough synoptic lift to produce
widespread overcast conditions today.  Visible satellite loops show
the low cloud cover pivoting southward on the back side of a subtle
upper wave currently over central Illinois.  As this feature tracks
further eastward, think clouds will gradually dissipate/clear the
Illinois River Valley this evening.  Due to trajectory of cloud
cover and relatively light flow, clouds will likely hold throughout
the entire night along/east of the I-57 corridor.  May see a few
isolated light showers this evening: however, most locations will
remain dry.  Overnight low temperatures will range from the lower
40s northwest of the Illinois River where clearing will occur
earliest...to around 50 degrees far southeast around Robinson and
Lawrenceville.

.LONG TERM...(Tuesday through Monday)
ISSUED AT 313 PM CDT Mon May 2 2016

Cyclonic flow will continue over the area through Wed. A lull in the
pcpn chances will be seen Tuesday as CWA will be in between troughs
rotating through the area. However, will still keep a slight chance
of showers in the east and southeast Tuesday due to a 500mb trough
moving south through the area...just without any surface reflection.
A bigger and more dominate trough will drop into the area Tue night
through Wed. Pcpn will start in the north Tue evening and then move
south through the area the remainder of the night and then in the
east on Wed. Isolated thunder will also be possible given greater
lapse rates due to cold 500mb temps moving over the area in
association with the upper level low. The pcpn will move off to the
east Wed night, which will allow high pressure to build into the
region with dry weather and slowly warming temps for Thur through
Fri. This surface high pressure ridge will get flattened by the end
of the week as another frontal system drops into the area for the
weekend. With warm and moist air being advected into the area Friday
and Saturday, will be plenty of instability for thunderstorms along
and ahead of the front Sat night through Monday. The front does seem
to hang around the area through the weekend since there will be an
upper level low just east of the US and another one over the
southwest US.

Temps will remain below normal most of the week, but begin to warm
back up as the high pressure that builds in Thursday moves off to
the east, bringing back southerly winds. The warmer temps will
continue through the weekend and into the beginning of next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 618 PM CDT Mon May 2 2016

Ceilings have lifted to VFR levels by late afternoon, and should
erode tonight as a weak shortwave shifts east of the region and
drier air works in from the north. Scattered cumulus will develop
by mid morning and may periodically go broken with bases
remaining above MVFR levels through afternoon. A weak high
pressure ridge will bring light/variable winds overnight before
veering to the WNW near/under 10 kts on Tuesday, ahead of a cold
front approaching from the north.

&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...25



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