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FXUS63 KILX 270251

National Weather Service Lincoln IL
851 PM CST THU NOV 26 2015


Updated forecast for expected rainfall trends for the rest of the
night. The cold front has started to enter the far northwest
portion of the forecast area, and will continue its slow trek east
for the rest of the night, pushing east of the I-55 corridor by
daybreak. The bulk of the rainfall is occurring along/behind the
front, and have updated PoPs to reflect this fact. Aside from
adjusting PoPs, made minor tweaks to remaining fields.


.SHORT TERM...(Tonight)

A slow frontal boundary stretched across most of the CONUS will make
its way through the Midwest today and tonight.  Plenty of llvl
southerly flow ahead of the boundary feeding moisture and
unseasonably warm temperatures into the region.  The available
moisture will lend itself to plenty of rain for tonight into
tomorrow.  Models have been differing somewhat with the timing of
the boundary. However, for the most part, the rainfall will remain
NW of the Illinois River Valley before 03z, and west of I-55 through
midnight.  Rain will concentrate south and east of the Illinois
River by morning.  Rain is expected most everywhere before
morning...with only the far southeastern portions of the state
potentially still ahead of the boundary enough to see showers. Rain,
low visibility, and gusty southerly winds will keep holiday travel
concerns active, but little in the way of freezing temperatures will
moderate them somewhat.  Although severe weather is not expected,
rainfall totals by early morning is expected from 0.25 inches to 1

.LONG TERM...(Friday through Thursday)

Split flow pattern to continue across the lower 48 into early next
week with two distinct upper waves to affect our area. The first is
a northern stream shortwave that will track east across the upper
Great Lakes and shift a cold front across the region late tonight
across the far northwest, and over the remainder of the area during
the day Friday. Strong lift associated with the upper wave and
copious moisture along the frontal boundary, precipitable water
values up near 1.50 inches on the NAM-WRF, will fuel the rainfall
over the forecast area starting later tonight and slowly track from
northwest to southeast on Friday.

As the front settles into far southeast Illinois later Friday, the
better plume of moisture and low level convergence shifts southeast
as well bringing the threat for heavier rain along the I-70 corridor,
with lighter rainfall further north as colder air works its way into
the area. Latest NAM more bullish in bringing in drier air in the
lower levels late Friday night into Saturday, as a result, have
pushed the better POPs a bit further south. Still the outside chance
that we may see a brief period of light freezing rain or rain along
the far northwest periphery of the precip shield during this time
frame, but the probabilities have decreased from the last model run
so will hold off adding into the grids with this model run with just
a mention of light rain or snow for now. Forecast rainfall amounts
still focus the heaviest rains over southeast Illinois with the
potential for 1.5 to 2.5 inches, especially along and south of the
I-70 corridor.

The second and stronger upper wave over the southern Rockies will
shift slowly northeast into the Midwest by early next week bringing
a renewed threat for rain to the region. With the deeper tropical
moisture tied up long the frontal boundary to our south and Canadian
high pressure settling over the region, the better QPF with this
system looks to remain south of our area early next week. As the
upper low slowly shifts northeast into the Midwest late Sunday into
Monday, POPs start to increase again further north Sunday night and
especially on Monday. Forecast soundings, except in the far
northwest, suggest mostly light rain, with a mix of light rain or
snow far northwest later Monday night into Tuesday morning. The
upper low will shift into lower Michigan on Tuesday with POPs slowly
decreasing across the area from southwest to northeast. Coldest
temperatures will be close to the upper low early next week, but as
the system pushes away from our area late Wednesday into Thursday,
temperatures aloft start to warm as we head towards the end of the
week with mainly seasonably cold weather expected.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)

A slow moving frontal boundary will gradually shift across the
central Illinois terminal area tonight, likely clearing KCMI
around sunrise. Ahead of the front LLWS persists across most of
the area, and should linger until just before FROPA. VFR and
mostly rain free condtions prevail ahead of the front, with
conditions rapidly falling to IFR with widespread rain as the
front passes by. The low CIGS/VSBYs & rainfall, once they arrive,
should linger for the balance of the 00Z TAF valid time. The wind
shift with FROPA should be significant, changing from almost due
south to due north.


.ILX Watches/Warnings/Advisories...


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