Area Forecast Discussion
Issued by NWS Central Illinois

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600
FXUS63 KILX 061759
AFDILX

AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1159 AM CST SAT FEB 6 2016

.UPDATE...
ISSUED AT 1045 AM CST SAT FEB 6 2016

Needed to update the forecast for more sunshine today especially into
early afternoon. Otherwise rest of forecast on track with milder
Pacific air arriving this weekend. Highs in the lower to middle 40s
this afternoon, with upper 40s SW CWA. Expect sw winds of 7-14 mph
today.

&&

.SHORT TERM...(Today)
ISSUED AT 321 AM CST SAT FEB 6 2016

A weak shortwave low-pressure trough aloft will cross central IL
from early morning to early afternoon today spreading additional
low and mid cloud cover over the area. By afternoon the trough
axis should be east of IL causing subsidence to help this cloud
cover erode somewhat. Thin high clouds associated with a low over
southern Canada will already be approaching by late afternoon.
Winds will be light and variable to start the day as weak pressure
gradients associated with the departing high continue. By late
morning and afternoon...the approaching southern Canada low will
start SW winds in the 5-10 mph range. High temperatures will be up
to the low and mid 40s north of I-72, and mid to upper 40s to the
south as the SW winds advect milder air of Pacific origin into the
area.

.LONG TERM...(Tonight through Friday)
ISSUED AT 321 AM CST SAT FEB 6 2016

Weak high pressure at the surface and generally southwesterly winds
will both play a role in keeping the temperatures and weather rather
mild across the Midwest for the remainder of the weekend.  One
exception persists late Sunday in the GFS with smaller
representation in both the NAM and the ECMWF.  The NAM solution
putting a small area of qpf ahead of the approaching upper wave, but
mainly east and southeast of ILX...the ECMWF a little weaker, with
the GFS more widespread across the IN/IL border later on Sunday.  A
little bit of a gap in btwn systems will result in a very weak sfc
trof passing through at that time, and although there will be little
in the way of surface convergence...see no reason to eliminate the
slight chance pops that are in there for now.  If the trend in the
NAM/ECMWF continues, potentially pull the low pop entirely in the
next run or so.

The bigger issue for the forecast is the main system approaching and
spreading precip across the area Sunday night through Tuesday.  Deep
upper low moving into the Midwest and plenty of colder Arctic air
moving in with it. What may start as rain early Sunday
evening/night, will slowly change over to all snow by Monday.  QPFs
are generally low, but with high ratios in place, could end up
seeing a widespread inch or so between Monday/Monday night.  Chilly
temps are moving in behind the snow.  Whereas highs on Sunday will
be in the 40s and 50s for Illinois... by Tuesday, the high
temperatures will be chopped down into the teens and 20s.  850mb
temps will be dropping to -16C to -19C.  After the coldest portions
of the forecast midweek, a slow warming trend will bring the temps
back up to more seasonal values by the end of the week and into the
weekend.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1159 AM CST SAT FEB 6 2016

VFR conditions expected to prevail across the central IL airports
next 24 hours through 18Z/noon Sunday. A band of low clouds below
1k ft along with some fog over central and nw IA into WI and far
northern IL should stay well north of central IL today. Cirrus
clouds will increase from the nw later today and evening with a A
band of mid level clouds around 10k ft will spread into PIA
between 06-07Z and to CMI by 10Z. These clouds due to a northern
stream short wave/trof over MT that tracks into the upper MS river
valley Sunday morning. SSW winds to become sw near 10 kts during
this afternoon and increase to 10-15 kts with gusts 17-22 kts
after 14Z/Sunday.

&&

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

&&

$$

UPDATE...07
SHORT TERM...Onton
LONG TERM...HJS
AVIATION...07



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