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FXUS63 KILX 300905

National Weather Service Lincoln IL
305 AM CST MON NOV 30 2015

.SHORT TERM...(Today)

Deep upper low over the Rockies continues to pivot slowly eastward,
with a pronounced short-wave trough evident on 08z/2am water vapor
imagery rotating around this feature across the Texas/Oklahoma
panhandles.  Synoptic lift ahead of the short-wave has led to the
development of widespread showers from eastern Kansas eastward into
Missouri/southwest Illinois.  As expected, this precipitation is
having difficulty working northward into a dry airmass currently in
place across central Illinois.  00z KILX upper air sounding showed
this very dry air below 850mb quite nicely, while more recent LAPS
soundings show the column gradually moistening from the top-down.
Latest surface obs are showing sprinkles across the W/SW CWA...with
steadier rain poised just upstream across southwest Illinois.  As
airmass moistens and showers currently in the St. Louis metro area
lift northward, light rain will overspread locations west of I-57
and south of I-74 over the next couple of hours.  Have therefore
started the morning with likely PoPs across this area.  Further
north and east, it will take longer for the environment to saturate,
resulting in a delay in higher PoPs until closer to midday.  While
the deepest moisture will remain well to the southeast along an old
frontal boundary across the Tennessee River Valley and further
northwest in closer proximity to the approaching upper low, high
chance to likely PoPs are warranted across the board this afternoon.
Due to overcast conditions, light rain, and a continued easterly low-
level flow, have undercut MAV guidance numbers, with high
temperatures mainly in the lower to middle 40s.


.LONG TERM...(Tonight through Sunday)

Surface low pressure currently developing over northeast New Mexico
will track to southwest Iowa by this evening, then into southern
Minnesota by Tuesday morning.  Showers will continue across the area
ahead of the low this evening, then will come to an end from
southwest to northeast overnight as a mid-level dry slot spreads
into the area.  Total rainfall from this system will be on the light
side, generally ranging from one tenth to one third of an inch. Will
carry high chance to likely PoPs during the evening, decreasing to
low chance after midnight.

Closed upper low will remain W/NW of Illinois on Tuesday, keeping
the KILX CWA firmly in the dry slot.  As a result, am expecting a
dry day with skies becoming partly to mostly sunny along/east of the
Illinois River.  Will be a breezy day as well, with southwesterly
winds gusting to around 25mph.  The upper system will track slowly
eastward across Wisconsin into the Great Lakes Tuesday night into
Wednesday, spreading clouds and some light precip back into the
area.  Based on GFS/ECMWF low track and QPF, have included slight
chance PoPs for light snow along/north of the I-74 corridor Tuesday
night into Wednesday morning.  May eventually need to extend the low
PoPs into Wednesday afternoon as well if the current slowing
trend with the amplified system continues.  Despite the snow
chances, am expecting little or no accumulation.

Once the upper low departs, heights will rise markedly across the
Midwest by the end of the week.  Both the GFS and ECMWF show a
secondary wave dropping southeastward into the building upper ridge,
but this feature will have very little moisture to work with and
will have no impact on the weather across central Illinois.  Main
story will be the warming trend, with numeric guidance suggesting
high temperatures reaching the lower to middle 50s by next


.AVIATION...(For the 06Z TAFS through 06Z Monday night)

VFR mid-level CIGS will persist through most of the night as a
slow moving storm system approaches the Midwest. A very dry low-
level airmass will keep CIGS relatively high, although a few
light showers may break through from time to time. Then, the
lower layers of the atmosphere will finally saturate across the
central Illinois terminal area, a few hours either side of
sunrise. Once saturation occurs, expect conditions to rapidly
degrade to IFR, and periodic rain showers through the day Monday.


.ILX Watches/Warnings/Advisories...


LONG TERM...Barnes
AVIATION...BAK is the U.S. government's official web portal to all federal, state and local government web resources and services.