Peotone Weather
National Weather Service Forecast for: Peotone IL
Issued by: National Weather Service Chicago, IL
Updated: 11:15 pm CST Dec 14, 2018

Peotone, IL
 
Overnight

Overnight: Widespread dense fog.  Otherwise, cloudy, with a low around 34. Northeast wind around 10 mph.
Dense Fog

Saturday

Saturday: Widespread dense fog, mainly before 9am.  Otherwise, cloudy, then gradually becoming mostly sunny, with a high near 44. Northeast wind around 10 mph, with gusts as high as 20 mph.
Dense Fog
then Mostly
Sunny
Saturday
Night
Saturday Night: Partly cloudy, with a low around 27. North wind 5 to 10 mph.
Partly Cloudy

Sunday

Sunday: Sunny, with a high near 46. North northwest wind 5 to 10 mph becoming west in the morning.
Sunny

Sunday
Night
Sunday Night: Mostly clear, with a low around 26. West northwest wind around 10 mph.
Mostly Clear

Monday

Monday: Sunny, with a high near 37.
Sunny

Monday
Night
Monday Night: Mostly clear, with a low around 24.
Mostly Clear

Tuesday

Tuesday: Sunny, with a high near 40.
Sunny

Tuesday
Night
Tuesday Night: Partly cloudy, with a low around 28.
Partly Cloudy

Lo 34 °F Hi 44 °F Lo 27 °F Hi 46 °F Lo 26 °F Hi 37 °F Lo 24 °F Hi 40 °F Lo 28 °F

Hazardous Weather Outlook
Dense Fog Advisory
 

Overnight
 
Widespread dense fog. Otherwise, cloudy, with a low around 34. Northeast wind around 10 mph.
Saturday
 
Widespread dense fog, mainly before 9am. Otherwise, cloudy, then gradually becoming mostly sunny, with a high near 44. Northeast wind around 10 mph, with gusts as high as 20 mph.
Saturday Night
 
Partly cloudy, with a low around 27. North wind 5 to 10 mph.
Sunday
 
Sunny, with a high near 46. North northwest wind 5 to 10 mph becoming west in the morning.
Sunday Night
 
Mostly clear, with a low around 26. West northwest wind around 10 mph.
Monday
 
Sunny, with a high near 37.
Monday Night
 
Mostly clear, with a low around 24.
Tuesday
 
Sunny, with a high near 40.
Tuesday Night
 
Partly cloudy, with a low around 28.
Wednesday
 
Partly sunny, with a high near 44.
Wednesday Night
 
Rain and snow likely. Mostly cloudy, with a low around 35.
Thursday
 
A chance of rain and snow. Mostly cloudy, with a high near 42.
Thursday Night
 
Mostly cloudy, with a low around 29.
Friday
 
Mostly sunny, with a high near 38.

 

Forecast from NOAA-NWS for Peotone IL.

000
FXUS63 KLOT 150524
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1124 PM CST Fri Dec 14 2018

.UPDATE...
854 PM CST

Had updated late this afternoon to issue a dense fog advisory for
the entire forecast area. Latest update is to extend end time for
all counties to 10 AM Saturday morning.

Shallow, moist boundary layer and relatively light winds have
allowed fog to develop or thicken across the area since this
afternoon. Visibility has improved a little in many areas south
and southeast of Chicago, though expectation is that there will be
some deterioration again overnight. West and northwest of the
city, visibility has been significantly lower, with obs of 1/8 to
1/4 of a mile fairly common. Higher clouds have moved out of these
areas, and some erosion of low stratus has been noted. However,
would expect radiative cooling to redevelop fog and low stratus in
these areas. Timing of an improving trend is of very low
confidence later tonight. Much of the available guidance depicts
quick/significant improvement after midnight, with forecast
soundings depicting lowering of the subsidence inversion into the
shallow saturated boundary layer. Just how shallow this layer is
can be seen in the 00Z DVN RAOB. With guidance generally doing a
poor job with the fog/stratus up to this point, elected to carry
the fog advisory into mid-morning Saturday. Headline can be
cancelled early if need be.

With loss of the higher clouds, temps have fallen into the mid and
upper 20s across north central IL this evening. This has resulted
in some frost/ice deposition on roads in some spots. Some slick
or slippery spots are therefore likely into early Saturday,
primarily northwest of the I-55 corridor in northern IL.

Updated text/digital forecasts and fog advisory available.

Ratzer

&&

.SHORT TERM...
242 PM CST

Through Saturday Night...

Main concern for the short term forecast period will be the timing
of clearing low clouds and patchy fog across the region.

As of early this afternoon, all pcpn has pushed well east of the
area, but widespread stratus and patchy fog has been very slow to
clear out.  latest satellite imagery indicates a clearing area over
far nern IL as well as the sharp back edge of the stratus deck
eroding from northwest to southeast.  Based on latest satellite
trends, expect that the Rockford area should clear out shortly
before 00z.  There is some uncertainty as to whether the clearing
area over far nern IL will reach the Chicago area first or whether
the general erosion of the cloud deck from the northwest will reach
that area first.  Regardless, the short range guidance has been
quite poor in handling the stratus and fog, and have been relying
more on satellite trends to try to time the clearing.  However, the
general trend should be that skies should clear out through the late
afternoon and into the evening hours as high pressure spreads
across the Middle/Upper Mississippi Valley and across nrn IL/IN and
the Lower Great Lakes regions.  As the high pressure builds across
the region overnight tonight, there is the chance for some fog
redevelopment.  However, any fog redevelopment will be dependent on
whether winds will diminish enough to allow for adequate radiative
cooling under the clearing skies, which could help develop some
shallow ground fog for the early morning hours.  Otherwise, the
remainder of the short term forecast period will be dry, with much
more sunshine than has been seen in recent days.  Since the high
pressure building over the region is a continental polar air mass
and not an arctic air mass, temperatures will remain somewhat
moderate, with lows tonight ranging from the upper 20s over the
Rockford area to the middle 30s over the far sern portions of the
CWA.  Under ample sunshine highs Saturday will be in the lower to
middle 40s and lows Saturday night should be a bit lower, generally
ranging from the lower 20s over the nwrn locations to the upper 20s
over the sern portions of the CWA.  The Chicago Area Urban Heat
Island area should see lows only drop to arnd 30 F.

&&

.LONG TERM...
259 PM CST

Sunday through Friday...

At 12Z Sunday morning, there is a low pressure system centered over
Canada with the trough axis lined up with the CWA. A region of high
pressure begins building over the Rockies. Winds will be out of the
northwest during the morning, then will become westerly before
returning to northwest flow. Temperatures should be fairly mild
for the time of year, with mid to upper 40s likely. By 00Z
Monday, the high pressure begins building into the Central Great
Plains.

Overnight Sunday into Monday, the high pressure region weakens and
elongates. The high pressure region remains west of the area by 12Z
Monday. This should continue to support wind directions out of
the WNW given the placement of the high pressure system.
Temperatures could get into the mid- to- upper 30s. By 00Z
Tuesday, the high pressure center should be over the CWA and should
gradually shift east-southeast of the region into Tuesday night.
Temperatures are again likely to get into the upper 30s, and
winds should be light throughout the day on Tuesday.

By 12Z Wednesday morning, the next low pressure system to impact the
area sets up over Saskatchewan. The low pressure system moves across
the Northern Great Plains during the day Wednesday. With southwest
winds expected ahead of this feature, mild temperatures into the
low-to-mid 40s again appear possible. By 06Z Thursday, the low is
by the MN/MI/Canadian border. Both the GFS and the ECMWF indicate
the potential for precipitation to fall as mainly rain ahead of
the front descending from the trough overnight Wednesday into
Thursday afternoon. It should be cloudy throughout the day on
Thursday with temperatures in the upper 30s to low 40s. By
Thursday night, the low is set up mostly over the Great Lakes
region and moving off to the northeast.

The next low pressure system sets up over Saskatchewan/Manitoba by
12Z on Friday. There is still some uncertainty with how this system
will play out and the timing of it. The GFS and ECMWF show a region
of intense vorticity that is just west of the low, and the low
appears to be positively tilted. During the day Friday, there is
some weak ridging over the CWA as it is between the two low pressure
systems. Temperatures are expected to get into the upper 30s. There
is another system with northwest flow aloft that could spread
precipitation into the Northern Great Plains. The precipitation
could reach portions of the CWA Friday night into Saturday.
However, at this time range, the uncertainties are too high for
specifics.

With the current model runs of the GFS and ECMWF, the weather
pattern after next week appears to bring cooler temperatures and
possibly more active weather.

Swaney/KB

&&

.AVIATION...
For the 06Z TAFs...

Primary forecast concern and challenge remains cigs/vis through
the period.

Some clearing has occurred from southeast WI into north central IL
late this evening. Guidance continues to suggest this clearing
will sag south through the early morning hours but confidence is
low. Widespread dense fog remains across northwest IL with another
ribbon through arr/dpa/pwk. Its possible that some of this dense
fog could move into ord at times overnight. In addition...the
dense fog at rfd/dpa and other areas may begin to improve
overnight. While dense fog is possible further southeast at
mdw/gyy...it appears unlikely. Given the uncertainty...changes can
be expected with later forecasts/updates.

Clearing/scattering/lifting trends Saturday morning are all
dependent on trends overnight. Added a lower cig for a few hours
late Saturday morning and maintained the clearing in the afternoon
but its possible some fog/low clouds may persist through the day.
Fog and low cigs appear likely again Saturday night into Sunday
morning but very low confidence for now. cms/bmd

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Dense Fog Advisory...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
     ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
     ILZ023-ILZ032-ILZ033-ILZ039 until 10 AM Saturday.

IN...Dense Fog Advisory...INZ001-INZ002-INZ010-INZ011-INZ019 until 10
     AM Saturday.

LM...Dense Fog Advisory...nearshore waters
     until 10 AM Saturday.

&&

$$

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