Area Forecast Discussion
Issued by NWS Central Illinois

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

637
FXUS63 KILX 072359
AFDILX

AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
559 PM CST SUN FEB 7 2016

.SHORT TERM...(Tonight)
ISSUED AT 240 PM CST SUN FEB 7 2016

A band of mid level clouds of 10-15k ft along and east of the
IL river was associated with frontal boundary pushing east toward I-
55 at mid afternoon. Breezy WSW winds of 15 to 25 mph and gusts to
30 mph was giving mild temps in the upper 40s and lower 50s, with
mid 50s south of I-70 in southeast IL. May see some sprinkles out of
this band of clouds in eastern/se IL late this afternoon and early
evening. Relatively low dewpoints in the upper 20s/lower 30s over IL
and upstream into MO/AR so think this will tend to keep us drier
with lack of low level moisture ahead of this front that moves
toward the Wabash river by 00Z/6 pm.

A strong 526 dm 500 mb low over the arrowhead of NE MN and another
530 dm 500 low near the MN/IA border, will track into central and
northern Lake MI by dawn Monday. Associated 998 mb surface low
pressure near International Falls MN will track toward northern Lake
MI by 12Z/6 am Monday. Moisture still somewhat limited with this
feature over central IL, but strong short wave energy and lift
should be enough to likely develop light snow showers se across
central IL overnight with light snow showers more scattered over
southern counties later tonight into Monday morning. Snowfall
amounts overnight between midnight and 6 am should only range from
0.1-0.3 inches nw of I-70 with just trace amounts from I-70
southeast overnight. Lows overnight will range from the mid 20s
along and nw of the IL river, to the lower 30s in southeast IL. WSW
winds decrease to around 10 mph for a time this evening, and then
veer WNW and increase to 10-20 mph and gusts increase to 20-30 mph
by sunrise, with highest winds over western CWA.

.LONG TERM...(Monday through Sunday)
ISSUED AT 240 PM CST SUN FEB 7 2016

Back to winter again starting on Monday as a deep storm system
tracks across the Great Lakes drawing down Arctic air into the
region. Along with the cold air, a gusty northwest wind and
snow showers will dominate the weather scene over central Illinois
Monday through most of Tuesday. Although snowfall amounts will be
around an inch or an inch and a half in some locations, the gusty
winds will, on occasion, produce some blowing snow in outlying areas
with slippery roadways a good possibility, especially the bridge
decks, overpasses and secondary roads. Several vorticity lobes
will be rotating around the 500 mb closed low that is forecast to
drop south into our area on Monday.

The 500 mb shortwave on this morning`s upper air analysis already
had temperatures of -35 C with the trof expected to be very slow in
exiting our region over the next few days with strong cyclonic
curvature holding over the area at least through Wednesday. Models
again trending a bit colder as we head into late Tuesday night and
Wednesday as a secondary surge of Arctic air sinks south into the
Midwest with even a tighter pressure gradient Wednesday morning when
wind chills will range from around 5 below far southeast to as low as
15 below in our northwest counties. Wednesday looks to be a cold day
with the center of the cold air mass settling across the Midwest
with afternoon temperatures now forecast to struggle through the
teens most areas.

Thursday, Friday and Saturday look to be quiet as the cold high
pressure slowly edges across the Great Lakes with temperatures
slowly moderating back into the upper 20s to lower 30s by Friday
and Saturday, which is still about 5 to 10 degrees below normal.
Unfortunately, we are still seeing some model disagreements in the
fast northwesterly flow aloft with respect to a couple of low
amplitude shortwaves which are forecast to shift quickly southeast
across the Plains and Midwest Wednesday night and again on Friday.
Each model run has a different solution with once again the
Canadian the most aggressive with the wave late Wednesday
afternoon and night, while the ECMWF indicates the wave on Friday
may bring us some light snow. At this time, there is too much
spread with the model solutions that far out with the better
agreement coming along late next weekend when a more significant
trof settles southeast into the region bringing us a chance for
light snow.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 548 PM CST SUN FEB 7 2016

CIGS across the central Illinois terminals will thicken and lower
this evening, with MVFR CIGS developing overnight in the wake of
a strong cold front. Snow showers will also accompany the colder
air, but given expected coverage will only carry VCSH for the
remainder of the night. Snow showers will be more widespread after
sunrise Monday, so will carry restricted visibility in snow
during the daytime hours. The gusty winds have subsided for now,
but will develop again Monday morning.

&&

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

$$

SHORT TERM...07
LONG TERM...Smith
AVIATION...BAK



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.