Area Forecast Discussion
Issued by NWS Chicago, IL

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS63 KLOT 192348

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
648 PM CDT Mon Mar 19 2018

127 PM CDT

Through Tuesday...

Breezy east-northeasterly winds are expected to continue through
the period as low pressure tracks eastward well south of the area
and high pressure remains dominate over Ontario tonight into
Tuesday. This northeasterly flow will transport a colder airmass
over the area for Tuesday resulting in cooler high temperatures
area-wide. High temperatures Tuesday are expected to be in the
low to mid 40s well inland, but likely only in the mid to upper
30s closer to the lake under partly cloudy skies. Conditions will
feel even cooler than these values, however, as winds continue to
gust up to 25 to 30 mph during the day.



214 PM CDT

Tuesday night through Monday...

Overview...Temperatures look to be slightly cooler to near normal
through the extended.  I have uncertainty about how the Friday
night/Saturday system will evolve, but most if not all of the
forecast area should see precip.

Cooler than normal conditions continue Tuesday night with moderating
temperatures Thursday as an upper level ridge begins to push east.
Quiet and near normal temperatures continue Friday under a broad
high pressure ridge.

The next low forms over the Southern Plains Friday night, and the
low weakens as it passes over the Mid Mississippi Valley Saturday
night.  An upper level wave passes over the region while the low
passes to our south, bringing precip to the region.  Guidance
differs on how far northeast the precip shield will reach, and I`m
expecting mainly rain Saturday.  There could be a period of heavier
rain Saturday evening before the forcing and precip shift east.  The
ECMWF suggests precip may linger into Sunday morning, while the GFS
has the system falling about quicker.



For the 00Z TAFs...

Gusty northeast winds generally expected through the TAF cycle,
though the gustiness could become less frequent overnight,
especially at the suburban airfields. Any slight decrease in
frequency of gustiness tonight should end tomorrow morning with
gusty northeast winds expected through the day Tuesday. Primarily
VFR conditions expected through the TAF cycle, though webcams do
show a few lake effect clouds blowing in off the lake. Not
expecting this cloudiness to become widespread enough to result in
CIGS, but will be something to watch overnight into Tuesday

- Izzi


214 PM CDT

Northeast times more due north or due east...will prevail
across Lake Michigan through the next seven days.

Speeds to 30 kt are expected as the lake finds itself between strong
high pressure to the north and passing low pressure well to the
south. Small Craft Criteria winds and waves will continue through
Tuesday  night. The highest wind and wave time in the Illinois and
Indiana nearshore looks to be tonight and Tuesday during the day.

Another low pressure is expected to move eastward across the middle
of the country, likely south of the lake, over the weekend weekend.
This again will strengthen east or northeast flow.



LM...Gale Warning...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-
     LMZ779 until 1 AM Tuesday.

     Small Craft Advisory...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...1 AM Tuesday to 9 AM Wednesday.




WWW.YOUTUBE.COM/NWSCHICAGO is the U.S. government's official web portal to all federal, state and local government web resources and services.