Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 030302
AFDILX

AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
902 PM CST TUE FEB 2 2016

.UPDATE...
ISSUED AT 851 PM CST TUE FEB 2 2016

Low pressure center associated with ongoing strong storm system is
currently near the western Iowa/Missouri border area. An occluded
boundary extends east southeast from the low across the northern
2/3 or so of the forecast area. The weak pressure gradient in the
vicinity of this boundary and associated light winds, coupled with
moisture from today`s rains and a strong low level inversion, has
allowed dense fog to develop. The dense fog has been spreading
east with time behind the convective line that is currently just
east of the I-57 corridor. Have recently expanded Dense Fog
Advisory across all but far SE portion of forecast area to account
for current and expected fog development. As the surface low lifts
slowly northeast overnight, winds will become gusty out of the
southwest and help to dissipate the fog.

Otherwise, once the thin convective line in far eastern portion of
the forecast area departs, the balance of the night should be dry.
West central Illinois may see some light snow/flurries by daybreak
as the deformation zone of the system slides by. But, by and
large, expect any snow to hold off until the morning hours
Wednesday. However, do not expect any accumulation at this time.

&&

.SHORT TERM...(Tonight)
ISSUED AT 233 PM CST TUE FEB 2 2016

Surface map at 20Z/2 pm showed strong 993 mb low pressure along the
eastern KS/NE border with an occluding front extending through
northern MO into southern IL. Another boundary/warm front was just
south of Peoria and just north of BMI with some fog along and north
of this boundary. Scattered showers and isolated thunderstorms were
over central IL at mid afternoon mainly east of a Galesburg to St
Louis line and tracking NNE. A narrow band of heavier rains with
some thunder was along I-55 from Springfield to Bloomington.
Meanwhile a dry slot with clearing skies was over central and
southern MO and moving northeast toward SW IL.

Temps ranged from 37F at Galesburg and Lacon where east winds
persisted to 57F along highway 50 at Flora, Lawrenceville and Mount
Carmel airports where se winds were veering SSE. Pressure gradient
has weakened a bit during the day across central IL so ESE winds not
quite as strong ranging from 10-20 mph and gusts of 20-30 mph at mid
afternoon.

The HRRR model has been doing fairly well with convection so far
today and leaned on this model going into this evening. It has the
showers and isolated thunderstorms ending over western CWA late this
afternoon and in eastern IL during early/mid evening with most areas
dry by 9 or 10 pm. SPC still have slight risk of severe storms this
afternoon southeast of Terre Haute to Flora line where 15% risk of
damaging wind gusts and 5% risk of tornadoes and large hail. Better
threat of severe storms is over more unstable airmass in far
southeast IL into KY and sw IN from I-64 south.

Low pressure to track northeast to near Dubuque by 09Z/3 am and into
southeast WI by sunrise Wed. A strong short wave/trof to push into
the IL river valley between 09-12Z Wed (3-6 am Wed) and have slight
chances of light rain or light snow later tonight. Lows late tonight
to range from mid 30s over the IL river valley (33F at Galesburg) to
the lower 40s near the Wabash river (42F at Lawrenceville). SE winds
to turn SW by overnight and range from 8-16 mph overall tonight.

.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 233 PM CST TUE FEB 2 2016

Tomorrow, the low will be pushing through the Great Lakes region
with a trailing sfc trough that will rotate through northern IL.
This sfc trough will also coincide with the 500mb trough that will
mover through the area. The combination of these two features will
bring a slight chance of light snow or rain to northwestern parts of
the CWA Wed morning. By afternoon all pcpn will have moved off to
the northeast, out of the CWA. Brief high pressure will move through
the area after this weather system moves through, along with the
pattern changing to a long wave trough pattern. This trough pattern
will bring another sfc trough through the area Thursday night, but
there will be a severe lack of moisture, so no pcpn is expected.
Then dry weather will be expected through the rest of the week and
into the the weekend. Temps will hover around normal through the
rest of the week and then will warm to above normal levels for the
weekend.

At the end of the weekend and the beginning of next week a northwest
flow pattern will setup over the area and looks like it may hang
around for an extended period. This northwest flow will allow a
series of clippers to move southeast through the Great Lakes area,
Sunday night through Tuesday. For now, will just keep the slight
chance of pcpn that the blended forecast has. Once the clippers
begin to move through, colder air will be allowed to pour into the
area and bring temps back to below normal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 556 PM CST TUE FEB 2 2016

Strong low pressure will continue to impact the central Illinois
terminal area through the period. Although the bulk of the
precipitation has ended locally, periods of IFR/MVFR conditions
and gusty winds are still anticipated. A period of unrestricted
CIGs & VSBYs will accompany the system`s dry slot later this
evening, but wrap around MVFR clouds will come back into the area
by late tonight. While a lull in the gusty winds is expected for
much of this evening, gusty southwest to west winds will return by
late tonight.


&&

.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until 2 AM CST Wednesday for ILZ027>031-
036>038-041>046-053>057.

Dense Fog Advisory until midnight CST tonight for ILZ040-047>052-
061.

&&

$$

UPDATE...BAK
SHORT TERM...07
LONG TERM...Auten
AVIATION...BAK


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