Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 klot 221948 
afdlot

Area forecast discussion
National Weather Service Chicago/Romeoville, Illinois
248 PM CDT Thu Aug 22 2019

Short term...
248 PM CDT

Through Friday night...

There are no weather concerns for most of the area through Friday
night. The only concern is at the beaches, where brisk
northeasterly winds are likely causing dangerous swimming
conditions due to high waves and strong currents. A beach hazards
statement is already in effect through 10am Friday and may need to
keep it going through later in the day, as winds are progged to
uptick again on Friday afternoon through early evening. Currently
not anticipating needing a Lakeshore flood advisory, as waves thus
far have topped out around 5 feet at the Wilmette buoy, but will
certainly monitor observations.

Outside of this, high pressure north of the Great Lakes with
ridging extending down to our area will gradually settle south,
keeping dry and comfortable conditions in place, with seasonably
cool nighttime temperatures. Skies going mostly clear tonight and
lighter northeast winds will support lows in the 50s outside of
Chicago and lower 60s in the city. Favored locations along and
west of the Fox Valley will likely dip into the lower 50s. On
Friday, the diurnal cu/strato-cu field inland may be a little
less pronounced than today. Slightly cooler thermal profiles will
yield highs in the mid to upper 70s inland and lower-mid 70s
Lakeside, with very low dew points for late August (lower-mid
50s). We should be able to shave a couple degrees off tonight's
lows for Friday night's lows as high pressure center draws closer.
This means a few of the favored cool spots may even drop to
48-49 degrees.

Castro

&&

Long term...
151 PM CDT

Saturday through Thursday...

Surface high pressure is expected to dominate across the Great
Lakes region through much of the upcoming weekend. Overall, this
is expected to result in pleasant (early autumn-like) weather
across the area. High temperatures are expected to be mainly in
the 70s, with overnight lows in the 50s Saturday night. Winds
will primarily be onshore, especially Saturday.

Early next week forecast guidance continues to be in good
agreement with a well defined mid/upper level trough digging over
the upper Midwest. With an associated surface frontal trough
likely to approach the area later Monday and Monday night, we will
have some decent chances for some showers and thunderstorms.
However, these chances should abate quickly during the day Tuesday
as the surface front shifts east-southeast of the area. This
looks to result in mainly dry and pleasant weather with seasonal
temperatures again for much of Tuesday and at least Wednesday.

Kjb

&&

Aviation...
for the 18z tafs...

There are no significant aviation concerns.

Main highlights over the next 24-30 hours:
* northeast winds gusting to 15-20 kt at times through this
afternoon at Ord, mdw and gyy. Sustained speeds 10-17 kt.
* Northeast winds 10-15 kt on Friday.

High pressure will influence the region through Friday, bringing
quiet weather conditions. With the high pressure centered north of
the Great Lakes today and over the northern Great Lakes on Friday,
expect steady northeast winds. There will be occasional gusts
through late this afternoon at Ord, mdw and gyy, with gusts likely
diminishing around sunset. Gusts may be less prevalent on Friday.
Scattered to broken lower VFR cigs this afternoon inland of Lake Michigan
should be mostly few-scattered VFR on Friday.

Castro

&&

Lot watches/warnings/advisories...
Illinois...beach hazards statement...ilz006-ilz014 until 10 am Friday.

In...beach hazards statement...inz001-inz002 until 10 am Friday.

Lm...Small Craft Advisory...nearshore waters
until 10 am Friday.

&&

$$

Visit US at http://weather.Gov/Chicago (all lowercase)

National Weather Service Glossary of Abbreviations