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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KLOT 021744
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1144 AM CST Tue Mar 2 2021

.SHORT TERM...
216 AM CST

Through Wednesday...

After yesterday`s blustery and colder conditions, we`ll turn a bit
milder today as southwesterly winds return with surface ridging
departing to our east. Increased low-level flow at the northern
flanks of the departing ridge will support the development of
gusty winds later this morning and afternoon, perhaps towards
30-35 mph across northern Illinois, easing somewhat with southward
extent.

Otherwise, the only item of note during the short term
forecast is the potential for a lake-enhanced cold front to
approach or even move through a portion of the region on
Wednesday. Questions remain, however, regarding the exact timing
of the associated north and northeast wind shift, as well as the
magnitude of low-level moisture present in the post-frontal
airmass. A good portion of our available hires guidance is now
suggesting quick saturation of the low-levels will take place
through Wednesday morning and afternoon with this boundary surging
down the lake and into northwest Indiana and northeast Illinois
by early afternoon. Have trended temperatures in this area down a
bit, while still holding onto low to even mid 50 degree highs
into north-central Illinois where any frontal passage should hold
off until after peak heating. The ECMWF remains pretty much
cloud-free through Wednesday afternoon, allowing temperatures
even near our lakeside locales to rise well into the upper 40s and
lower 50s. A decent bust potential exists as a result, but
electing to side a bit more with climatology here, while not
totally biting on the coldest advertised solutions yet.

Carlaw

&&

.LONG TERM...
216 AM CST

Wednesday night through Monday...

Surface high pressure is forecast to dominate across much of the
western Great Lakes Thursday and Friday. This will continue to
support onshore winds with cooler temperatures over northeastern
IL and northwestern IN both days. Expect lakeshore temperatures to
top out mainly in the 30s, with inland areas reaching into the
40s. Thursday could also end up featuring more clouds than
currently advertised, which could further knock high temperatures
down a bit farther inland.

Saturday will start our transition into a warmer pattern as
southwesterly return flow re-develops. High temperatures will
commensurately increase each day into early next week, with
widespread mid and upper 50s becoming more of a possibility by
Monday and Tuesday. We`re currently advertising precipitation-free
conditions through the end of the official forecast period, but
the weather pattern does look to trend more active, especially by
the middle and end of next week.

Carlaw

&&

.AVIATION...
-- Changed Discussion --
For the 18Z TAFs...

Quiet weather expected this afternoon with the only notable
feature of interest being the breezy southwesterly winds. As these
winds ease this evening there will be a marginal threat for LLWS
tonight as winds a couple thousand feet off the surface increase
into the 40-45 kt range. The best potential for this looks to be
on the 03z-09z timeframe.

A cold front will then shift southward across the area early
Wednesday morning, resulting in a northerly wind shift across the
area. While winds should remain light in the wake of this initial
front, conditions across the Chicago area terminals could turn a
bit more breezy from the northeast during the mid to late
afternoon hours as a lake breeze pushes inland.

KJB
-- End Changed Discussion --

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
IL...None.
IN...None.
LM...Small Craft Advisory...Winthrop Harbor to Gary IN until 9 PM
     Tuesday.
-- End Changed Discussion --

&&

$$

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