Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 281952
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
252 PM CDT SUN AUG 28 2016

.SHORT TERM...(This evening through Monday)
ISSUED AT 252 PM CDT Sun Aug 28 2016

Slow-moving thunderstorms with locally heavy rainfall continue to
track across north-central Illinois this afternoon, with 1930z/230pm
radar imagery showing most of the activity along and north of a
Galesburg to Minonk line.  Will continue to monitor this area for
the next few hours, as training cells could produce localized flash
flooding through sunset.  Once evening arrives and daytime
instability begins to wane, the thunderstorms will diminish and come
to an end.  HRRR has been consistently showing the precip fading
away by 03z/10pm and this seems reasonable.  Main question tonight
will be whether or not additional convection forms late.  While the
HRRR remains dry through dawn Monday, the NAM suggests widely
scattered showers/thunder will re-develop over at least the western
KILX CWA.  Following a persistence forecast from the past several
nights, will trend toward the wetter NAM in this case.  As a result,
after a lull in the precip late this evening into the first part of
the overnight, have brought slight chance PoPs back into the picture
toward dawn everywhere west of the I-57 corridor.  With synoptic
frontal boundary remaining stalled just north of the area, think
scattered thunderstorms will once again develop everywhere during
the day Monday.  High temperatures will reach the middle to upper
80s, with readings around 90 along/south of I-70.

&&

.LONG TERM...(Monday night through Sunday)
ISSUED AT 252 PM CDT Sun Aug 28 2016

A broad subtropical high pressure ridge aloft will be in place
across the southern and central U.S. by Monday evening with surface
high pressure centered over the eastern Great Lakes. A moist air
mass with 1.75-2.0 inches of precipitable water will be in place
over much of the southern and central U.S. including central IL.
Expect a chance of mainly afternoon and evening thunderstorms
Tuesday with the moist and unstable conditions. Heavy localized
rainfall from slow moving thunderstorms will be the main threat.
Highs will range from 84 in Galesburg to 88 in Lawrenceville.
Lows Monday night and Tuesday night upper 60s to around 70.

The surface high over the eastern Great Lakes...trailing a cold
front moving into the northeast U.S. tonight and Monday...will keep
a light prevailing E-NE wind across central IL through
Tuesday...although it looks that any drier air associated with the
high will not make it as far west as Illinois. By Wednesday...a deep
upper level trough amplifying into the northeast U.S. will rapidly
push out the high pressure and drive a cold front into central IL
from the north bringing much drier air of around 0.5 to 0.75 inch
precipitable water into central IL. After a chance of thunderstorms
along the front...the drier air and high pressure building into the
midwest should bring dry conditions to central IL from Wednesday
night through Saturday...along with cooler highs in the upper 70s to
lower 80s, gradually rising through the period. Lows in the upper
50s and lower 60s will be typical. Wednesday`s highs expected to
range from near 80 along the I-74 corridor to the mid 80s south of I-
70, although the high will be sensitive to the exact timing of the
front and precipitation that day.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1242 PM CDT Sun Aug 28 2016

Scattered thunderstorms are beginning to develop across central
Illinois early this afternoon as a weak frontal boundary remains
in place along the I-80 corridor. MVFR Cu field has developed in
the very warm/moist airmass south of the front, but cloud bases
will rise to low VFR over the next couple of hours. With no storm
cells immediately threatening any of the terminals at the current
time, have only included VCTS from 18z through 02z. Once the
mainly diurnal convection dissipates, skies will become mostly
clear tonight. Could see some fog developing overnight,
particularly in locations that experience rain this afternoon.
Have dropped visbys to between 4 and 5 miles after 08z
accordingly.

&&

.CLIMATE...
Issued at 252 PM CDT Sun Aug 28 2016

As of noon today Springfield has reached the 2nd wettest summer on
record with 21.43 inches of precipitation since June 1st. The
wettest summer on record was in 1981 when 24.93 inches fell from
June-August.

&&

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

&&

$$

SHORT TERM...Barnes
LONG TERM...Onton
AVIATION...Barnes
CLIMATE...Onton



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