Sat Feb 17 Meteorology for Chicago

[Brett Crapser]

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1152 AM CST Sat Feb 17 2024

KEY MESSAGES...

- Windy and cold today with wind chills in the single digits to
teens and wind gusts to 35 mph

- A return to above-normal temperatures next week with 40s and
50s back in the forecast

&&

DISCUSSION...
Issued at 320 AM CST Sat Feb 17 2024

Through Friday:

Mostly clear skies sit overhead early this morning which, in this
cold advection regime, has allowed for temperatures to cool into the
lower and middle teens as of around 3 AM. Winds all night have had
no issue regularly mixing into a 20-25 kt 925 mb jet. This breeze is
making conditions feel like anywhere between -5 and +5 F. Highs are
only forecast to reach near 30 degrees or so with our far south
likely to stay a few degrees cooler courtesy of the fresh snowpack
from yesterday. Low level winds are anticipated to relax some after
dawn but will build again during the afternoon and evening
eventually reaching upwards of 50 kt late this evening at 925 mb.
We`re looking at 25-35 mph gusts for the better part of the
afternoon and especially the evening. This will keep wind chills
down in the teens at best for our Saturday.

Following the passage of a broad upper trough today, a warming
pattern will kick off beginning tomorrow. Highs will be back in the
40s tomorrow, again with mostly sunny skies. 50s are looking likely
for some as early as Tuesday and for most of the area on Wednesday.
Otherwise, our weather during the first half of next week will be
rather uneventful. There is an amplified little mid level shortwave
that`s progged to cut across the region late Monday into Tuesday.
Models agree though that our profile will be too dry to stir up any
precip though. A second, less-impressive wave is slated for Tuesday
night and Wednesday. However, this time we may see sufficient low
level moisture in place for a few light showers to develop.

Our best, though still marginal, precip potential over the next week
is on Thursday and Thursday night. A trough will drop into the
region from the north and drag a system of rain and snow across the
Great Lakes. With the storm`s center expected to track to our north
and east and the quasi-zonal orientation of the low-mid level wave,
that puts us in an unfavorable spot to see much in the way of
forcing. The NBM draped slight (20%) rain and snow chances
across the area and that seemed appropriate for the forecast.
This system also looks to reintroduce some cooler conditions to
the area for the latter part of next week.

Doom

&&

AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 1139 AM CST Sat Feb 17 2024

Main Concern:

- Gusty west and southwest winds, strongest this evening

Breezy west (250-280 deg) winds will strengthen later this
afternoon from a 230-250 deg direction. Gusts are expected to
peak in the 30-35 kt range this evening, with some upside
potential per forecast soundings. ORD and MDW likely have a
higher chance of observing any gusts >35 kt in the mid to late
evening since they usually stay better mixed than outlying
terminals. Winds will then gradually ease overnight. Much of
Sunday will be breezy but not as windy as this evening with
direction returning back to westerly. Gusts in the 20-25 kt
range should end by the mid afternoon as the direction becomes
west-northwest. VFR conditions will prevail through the period.

Castro

&&

MARINE...
Issued at 320 PM CST Fri Feb 16 2024

NW winds being a bit gustier early this morning than previously
thought prompted us to issue a short-lived Small Craft Advisory
for the Illinois nearshore zones through 6 AM. A second Small
Craft Advisory remains on deck for this afternoon once winds
pick back up following a lull after sunrise. On the Indiana
side, a Small Craft Advisory remains in effect all day today
for a combination of wind and waves. This is before a Gale
Warning goes into effect for all of southern Lake Michigan at
00Z. Winds over the lake should subside to below gales by
daybreak Sunday and will continue to steadily stair-step down
through the morning.

Doom

&&

LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 6 PM CST this evening for the IL
nearshore waters.

Gale Warning from 6 PM this evening to 4 AM CST Sunday for the
IL and IN nearshore waters.

Small Craft Advisory until 6 PM CST this evening for the IN
nearshore waters.

&&

$$