000
FXUS63 KILX 101545
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1045 AM CDT Mon Mar 10 2014

.DISCUSSION...
ISSUED 1045 AM CDT Mon Mar 10 2014

A nice day ahead for central and southeast IL with partly to
mostly sunny skies and milder highs in the low to mid 60s with
breezy sw winds 10 to 20 mph. Forecast overall on track and just a
few updates to sky cover today and nudged highs up a bit into the
upper 60s to near 70F sw of Springfield. Above normal temperatures
today and have not seen that across CWA since Fri/Feb 21.

Rather tight pressure gradient over central IL this morning with
strong 995 mb low pressure north northwest of Lake Superior and
1022 mb high pressure near the gulf coast. Southwest winds of 10
to 18 mph and few gusts 18-23 mph. Temps have risen into the 40s
at 1030 am. A band of mid and high clouds was from I-70 north
while sunny skies south of I-70. Thicker band of mid level clouds
from I-72 south to I-70 will thin out and decrease during the
afternoon giving mostly sunny skies across the area. Surface trof
over central parts of WI/IA late this morning to move into nw IL
by sunset and stay nw of central IL this afternoon keeping mild
highs in the lower to middle 60s with upper 60s to near 70 sw of
Springfield.

07

&&

.AVIATION...
ISSUED 607 AM CDT Mon Mar 10 2014
Main concern in the forecast is LLWS as models hinting at strong
westerly winds just off the sfc. ILX 12Z sounding so far tracing
40-45 kt winds btwn 270 and 285 degrees... from 1500 ft to 2500
ft. Mid level clouds streaming through the Midwest showing up on
radar this morning but not producing much in the way of precip.
Vis in the VFR category so far. SCT/BKN mid level clouds
throughout the forecast. Winds southwesterly through the
morning... more westerly at the end of day...becoming light and
variable through the overnight as a weak boundary makes its way
through the region.

HJS
&&

.PREV DISCUSSION...
ISSUED 255 AM CDT Mon Mar 10 2014

SHORT TERM...Today through Tuesday:

Primary concern in this period remains with temperatures today and
Tuesday. Frontal boundary is expected to settle over central
Illinois later tonight, before becoming stationary for a time.
Still looking like lower to mid 60s will prevail today, with more
of a temperature spread Tuesday on either side of the boundary.
While the front may slip as far south as I-70 by afternoon, main
thermal gradient aloft is closer to I-80, and thus we should still
see some 50s across the north and 60s south on Tuesday.

LONG TERM...Tuesday Night through Sunday:

Main focus remains with storm system and accumulating snowfall
Tuesday night/Wednesday.

Upper trough currently off the Pacific Northwest coast will come
onshore this morning and dig across the northern Rockies. A cutoff
low in the southern jet stream over northwest Mexico will move
offshore of Texas by midday Tuesday. Models still trying to
resolve the amount of phasing that will take place between the two
jet streams as the northern wave moves into the mid-Mississippi
Valley Tuesday night. A surface low will develop over Kansas
tonight along the stationary boundary, then move east. Evening
model runs continue to favor a track along the Ohio River Tuesday
night, with the NAM settling southward into this solution,
although the GEM is faster in tracking the system through the
region. The ECMWF and GFS remain pretty close to each other, and
relied on their solutions.

Rain expected to rapidly develop across the forecast area Tuesday
evening. Forecast soundings showing potential for some sleet mixed
in for a time along the I-72 corridor, before the precipitation
quickly changes to snow after midnight. Best forcing and omega is
focused on the period between midnight and sunrise, and steeper
lapse rates suggest some convective enhancement as well. Still
looking like a broad 2-3 inches or so across the north half of the
forecast area, although the QPF values progged by the NAM and
ECMWF would suggest this could end up higher. SREF and WPC
guidance suggest highest probabilities of at least 4 inches of
snow just east and northeast of Bloomington into Indiana,
especially since this area is likely to switch over to snow during
the evening. In southeast Illinois, have kept the precip as all
rain during the night, and would not be surprised to see some
rumbles of thunder as well due to the steep lapse rates. The
precip will likely start mixing with snow before ending on
Wednesday morning, so accumulations in this area are not
anticipated. North/northeast winds expected to ramp up to around
20 mph with gusts 30-35 mph. Have held off on any blowing snow
mention for now, as the snow should be fairly wet and temperatures
warm enough to keep it under control.

Following the passage of the deep upper trough later Wednesday, a
warming trend quickly sets up once again, with highs back into the
50s by Friday. Considerable model spread exists in regards to
precipitation chances this weekend, as we remain in an area where
upper level phasing will still be a concern. Have limited
mentionable PoP`s to Sunday, although even then this is of low
confidence.

Geelhart

&&

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

$$