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000
FXUS63 KILX 070303
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
903 PM CST Thu Mar 6 2014

.DISCUSSION...
ISSUED 859 PM CST Thu Mar 6 2014

A ridge of high pressure at the surface and increasingly neutral
flow aloft will provide quiet weather across central and southeast
Illinois through the night. Winds are beginning to trend southerly
on the back side of the surface ridge, a fact that should help to
keep overnight lows a little warmer than last night. However,
these southerly winds will be offset to some degree by the mostly
clear skies and better radiational cooling scenario than earlier
today.

Going forecast is in good shape overall. Only plan a few tweaks to
the hourly trends for the rest of the night.

Bak
&&

.AVIATION...
ISSUED 600 PM CST Thu Mar 6 2014

Quiet/VFR aviation weather conditions expected across the central
Illinois terminals through the 00Z TAF valid time. High pressure
will continue to build across the area through the period. High
level cigs will gradually develop on Friday, but will be of
little consequence to flight operations. Light easterly winds will
trend southerly on Friday as the high pressure ridge pulls further
away.

Bak
&&

.PREV DISCUSSION...
ISSUED 215 PM CST Thu Mar 6 2014

Quiet weather prevails over central through southeast Illinois early
this afternoon as high pressure holds to our northeast. Quite a
contrast in temperatures depending on snow cover, with readings in
the lower 40s over parts of west central Illinois with no snow on
the ground, to the mid and upper 20s over the northern areas of
the CWA where the deepest snow cover was located. The band of stratus
clouds that was just west of the Mississippi River earlier this
morning has edged further to the northwest and has dissipated quite
a bit from earlier today, while a thicker deck of altocumulus and
cirrus was tracking southeast into central Illinois.

SHORT TERM...Tonight through Sunday

The main forecast challenge will be with temperatures over the next
several days and precip type later Friday night into Saturday morning
as a weak upper level wave and attendant frontal boundary pushes across
our area.

High pressure shifting slowly away from our area over the next 24
hours will continue to control our weather through Friday. Winds will
continue to shift more into a southerly direction tonight and then
increase some on Friday ahead of the aforementioned frontal boundary.
This should allow a nice warmup most areas Friday afternoon with even
our northern counties where the deeper snow cover was located warming
into the low to mid 40s, while further south, afternoon temperatures
will climb into the low to mid 50s. Weak upper level shortwave forecast
to track to our north Friday night into Saturday dragging a cold front
thru the area. Stronger low to mid level forcing mainly post frontal
with this system with moisture profiles not very impressive which will
continue to warrant chance POPs late Friday evening thru the day
on Saturday. Ensemble forecast soundings suggest more of a rain or snow
threat in the evening, with the threat going more over to light snow
by Saturday morning, especially across the north. Will continue
with chance POPs Saturday as the upper wave shifts off to our northeast
and the frontal boundary settles south of our area. Mainly a snow and
rain threat north, with forecast soundings supporting mostly rain in
the southeast. Upper wave should be far enough to our east to take most
of the precip out of the forecast later Saturday evening over our far
southeast counties.

Quiet weather returns to the region on Sunday with Pacific high
pressure settling over our area for 24 hours bringing afternoon
temperatures close to normal most areas as winds turn more into the
southwest by afternoon.

LONG TERM...Monday through Thursday

A fast moving northern stream wave on Monday will track well to our
north with an increasing southwest flow at the low levels helping
to push temperatures above normal for a change over central thru
southeast Illinois. Will trend closer to the ECMWF guid for Monday
afternoon with temperatures ranging from the lower 50s far north
to the lower 60s west and south.

The mild weather will continue into Tuesday, however, a stronger
shortwave is forecast to amplify as it drops southeast into the
central Plains on Tuesday, and then phases with a cutoff low (as
depicted on the latest ECMWF model) over the southern Plains
Tuesday night. At this point, the ECMWF is the only model showing
this phasing process occurring to our south late Tuesday night
while other models indicating the northern stream would become
the dominant trof with very little if any phasing occurring until
the southern stream system pushes off the southeast coast of the
U.S. next Wednesday. Ensembles showing quite a bit of spread with
this system early next week so will not make any significant changes
to the going forecast at this point. Will keep precip chances to our
north during the day with one more mild day in store, and then start
to increase POPs Tuesday night into Wednesday as the upper trof
approaches the forecast area and trend temps back down again.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$