Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 160513
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1113 PM CST Sun Jan 15 2017

.UPDATE...
Issued at 848 PM CST Sun Jan 15 2017

The band of light rain and sleet that pushed across the area late
this afternoon into this evening continues to track northeast out
of the area with one more additional area of light rain.
Temperatures have held around the freezing mark or slightly above
that as the rain moved through so no significant icing problems
were seen. Once this last area of light rain moves through it
appears we will see mainly some spotty light rain/drizzle and some
patchy fog for the rest of the night with the possibility for a
little freezing rain or drizzle along and especially north of the
I-74 corridor. Overnight temperatures are expected to remain
nearly steady, especially across the north with steady or slowly
rising temperatures across the south late tonight as the next
storm system starts to push towards our area on Monday bringing
rain to the forecast area along with mild temperatures. With the
lingering chance for some freezing rain or drizzle overnight,
there will be no changes made to the current Winter Weather
Advisory across the north. We should have the update out by
915 pm.

&&

.SHORT TERM...(This evening through Monday)
ISSUED AT 307 PM CST Sun Jan 15 2017

Will continue the winter weather advisory from Fulton, Tazewell and
McLean counties northward tonight into Monday morning for light
icing up to a tenth inch possible along with some sleet. Latest
model runs are warming surface temps a bit quicker late tonight into
Monday morning, so the winter weather advisory might be able to end
sooner.

An area of light rain was along and south of a Macomb to Lincoln to
Terre Haute line at mid afternoon, with the northern fringe of
precipitation mixed with some light freezing rain and sleet. Surface
temperatures were mostly just above freezing over CWA, expect still
30-32F from Galesburg to Jacksonville west where mixed light
precipitation occurring. 1030 mb high pressure over the southern
great lakes was keeping northeast CWA from Lincoln ne dry so far
today with overcast mid level clouds around 10k ft. Light
precipitation was from overrunning of a warm front just south of TN
into central Texas to 1006 mb surface low pressure in sw Texas.
Aloft a 555 dm 500 mb low was spinning just east of El Paso Texas.

Hi resolution models like the HRRR and ARW (to a lesser extent with
the RAP model) lift the light precipitation ne across rest of
central IL late this afternoon and this evening. Then more
precipitation develops later tonight over western CWA and then
spreads ne across rest of area on Monday. Continued small chances of
thunderstorms late Monday afternoon sw of Springfield. The thermal
profiles still support best chances of light freezing rain north of
I-72 this evening, shifting nw of a Rushville to Bloomington line by
sunrise Monday, and nw of a Galesubrg to Henry line by 9 am Monday,
as temps rise above freezing. Lows tonight range from around 30F
over northern CWA where winter wx advisory is posted, to the mid 30s
from I-70 southeast and may be nearly steady or even rise slightly
later tonight. Milder highs Monday range from low to mid 40s over
northern CWA, to the low to mid 50s in southeast IL with southeast
winds 8-15 mph.

.LONG TERM...(Monday night through Sunday)
ISSUED AT 307 PM CST Sun Jan 15 2017

The upper low currently over western TX will eject northeastward
across the southern Plains reaching NW Missouri by Monday evening.
As it does so, warm moist southerly flow ahead of the low will
result in instability characterized by MUCAPE values around 200
J/kg, which should allow for isolated thunderstorms...continuing
after midnight east of I-55. Moderate rain amounts around 1/2 inch
to 1 inch should accompany this portions of the storm as the surface
low moves through northern IL. Low temperatures should only reach
around 50 near the Indiana border to the upper 30s in Galesburg as
the cold front sweeps across the state late in the night. As
temperatures remain above freezing and saturation depth decrease
dramatically behind the upper wave, precipitation type should remain
all rain with a loss of ice aloft. A bit cooler Tuesday with some
lingering drizzle/light rain toward the northeast, with highs
ranging from near 40 in Galesburg to above 50 in Lawrenceville.

Fair weather mid week as high pressure shifts east across the
central U.S. with highs in the mid 40s to lower 50s and lows upper
20s to mid 30s.

Pattern transitions to a longwave trough over the west and ridge
over the east for late in the week and next weekend. The result will
be a series of waves ejecting out of the southwestern U.S. toward
the Midwest. Although timing and track uncertainties remain, this
should bring mild temperatures with periodic chances for rain Friday
through the weekend. Current model consensus places a chance for
precipitation Friday and Sunday as indicated in afternoon forecast
package, however there will undoubtedly be refinements in the timing
and track of these systems in the upcoming days. As highs/lows
likely to be in the 50s/40s through this time, all rain expected at
this point.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1102 PM CST Sun Jan 15 2017

Cigs and Vsbys will deteriorate at all sites to LIFR with some
tempo VLIFR conditions in fog in the 08z to 12z time frame which
should last through at least 18z. A warm front will approach the
area by later in the day and that may bring cigs to IFR as rain
overspreads the area. Look for the poor cigs and vsbys (IFR to
LIFR) to hold into the evening along with occasional rain. Surface
winds will be light east to southeast tonight and then pick up
a bit from an east to southeast direction on Monday with speeds
in the 10 to 15 kt range during the afternoon and evening.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST Monday for ILZ027>031-
036>038.

Dense Fog Advisory until noon CST Monday for ILZ049>052-061-062-
066>068-071>073.

&&

$$

UPDATE...Smith
SHORT TERM...07
LONG TERM...37
AVIATION...Smith


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