Area Forecast Discussion
Issued by NWS Chicago, IL

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885
FXUS63 KLOT 191125
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
525 AM CST Sun Nov 19 2017

.SHORT TERM...
121 AM CST

Through tonight...

After the soggy, windy, and cool autumn weather of the past few
days, we enter a fairly quiet and dry pattern as we head into the
Thanksgiving week. Sunday will begin on the cold side of the
temperature roller coaster in wake of yesterday`s system, one that
will continue to deepen across the northeast and bring this same
messy system to that region. Nighttime satellite across the
midwest depicts a still an area of stratus across much of
Wisconsin, northeast IL and northwest IN. Despite some breaking up
of the clouds, which Will gradually continue , the upper level
flow is still cyclonic, and thus the low clouds remain trapped
below a frontal inversion. As the morning continues, expect one
last upper wave to clear the area and the associated subsidence
will allow for better lower cloud clearing this afternoon. The
heart of the cold air behind this first front will shift through
the western Great lakes this morning, and with increasing higher
clouds today, highs will hold in the low to mid 30s.

Passing high clouds tonight but low level warm advection as winds
shift back to southwesterly as surface high pressure, overhead
this afternoon, will shift to the Ohio valley tonight. Therefore
temps will fallow back to the mid 20s in our colder areas. Highs
bounce back nicely Monday, with near 50 degree readings and
plentiful sun other than some cirrus.

KMD

&&

.LONG TERM...
121 AM CST

Monday through Saturday...

The general idea is high pressure will shift across
the Great Lakes, then shift off to the Ohio valley and mid
Atlantic regions with some regularity throughout the extended. A
series of clipper like systems will bring occasional wind, clouds
and cold spells, followed by warm ups as each high pressure
departs east. This will result in several up and down swings of
temperature. No one system is expected to bring any real
precipitation, even though occasionally Tuesday night, Wednesday
night, and toward Saturday a model will try to throw out some very
light QPF, so most of the week appears dry at this point. The
first front will lead to a little cooler day Tuesday, then a
repeat of today on Wednesday with highs only in the 30s, before
readings head back closer to normal Thanksgiving day and toward
week`s end before another colder shot next weekend, and maybe some
light precipitation mainly of the liquid form to accompany this
one.

KMD

&&

.AVIATION...
For the 12Z TAFs...

525 am...No forecast concerns this period. The back edge of high
mvfr based cigs around 3kft is moving across northwest IL and
should move east of the Chicago terminals by 15z at current speed.
Once these low clouds clear out...only high clouds expected for
the rest of the period. West/northwest winds 10-15kt with some
higher gusts will turn more westerly today. Speeds will diminish
under 10kts with sunset with wind directions turning more
southwest this evening. Speeds/gusts increase again Monday
morning. cms

&&

.MARINE...

156 am...Northwest gales have ended and will be canceling the
gale warning early. Northwest winds to 30 kts will slowly turn
westerly this afternoon as high pressure moves south of Lake
Michigan. Speeds may diminish further to 15-25kts tonight...
especially on the north end of the lake. Winds will turn to the
southwest Monday and are expected to increase to gales Monday
afternoon as strong low pressure moves across Ontario Monday
night. These gales will diminish Tuesday morning and shift to the
northwest as a cold front moves across the region. High pressure
will build across the plains Tuesday and then to the southern
lakes and Ohio Valley Wednesday into Thursday with westerly winds
for mid week. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...IN nearshore waters until 6 PM Sunday.

     Small Craft Advisory...IL nearshore waters until noon Sunday.

&&

$$

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