218 FXUS63 KLOT 110822 AFDLOT Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 322 AM CDT Thu Oct 11 2018 .SHORT TERM... 252 AM CDT Through tonight... The primary forecast concerns revolve around temperatures, especially the next couple of nights, which are likely to drop to near, or just below freezing across, at least portions of the area. Due to the likelihood for freezing conditions tonight across north central IL we have issued a freeze warning, which goes as far east as the Fox Valley. Elsewhere, with the exception of Porter County IN, a frost advisory has been issued for tonight. Surface low pressure will continue to deepen today as it moves over eastern Ontario and into western Quebec. Meanwhile, much colder air continues to stream in over the Midwest and Great Lakes Region in the wake of this departing low. Westerly winds have been gusty up around 35 mph through the night, and it appears that these gusty winds will continue into this afternoon before abating by early this evening. A large deck of MVFR stratus, indicative of the cold air advection regime across the region, will also continue to hang on across the area into this afternoon, before skies begin to gradually scatter later this afternoon. Temperatures today will remain quite cool, with highs likely only hovering around 50 degrees in most areas. These cold daytime highs today will then set the stage for a cold night across the area tonight. Surface high pressure is expected to build eastward today from the Dakotas to Iowa by tonight. With this being the case, it is likely that most areas will continue to experience a light 5 to 7 mph wind speed overnight. Typically, winds of this magnitude are not the best to support widespread frost development. However, in spite of this concern, due to the fact that surface temperatures are likely to fall to near freezing, we felt that it is worth issuing the respective frost and freeze headlines. KJB && .LONG TERM... 322 AM CDT Friday through Wednesday... Conditions during the period are expected to remain on the cool side, especially early in the period. There also looks to be a couple chances for some light precipitation, particularly on Friday and again late Sunday and Sunday night. The coldest day of this cool stretch looks to be Friday. With the heart of the cold surface high over the region, afternoon high temperatures are likely to remain in the 40s following the cold start Friday morning. It also appears that there will be a good amount of cloud cover, and possibly even some light precipitation, around on Friday in response to a decent mid-level short wave that will be shifting towards the area later in the day. At the this time it appears the best chances for any light precipitation will be over my southern CWA (south of I-80). The precipitation and cloud cover should begin to move out of the area Friday evening, so temperatures are likely to once again fall down around freezing. This may require another frost and or freeze headline. Slightly warmer conditions should allow temperatures to return to the 50s for the weekend. While Saturday looks dry across the area, it appears that there will be some increased chances for another round of light precipitation later Sunday into Sunday night. Another area of low pressure is forecast to move eastward across the Upper Great Lakes Sunday morning and this is likely to push another cold front over the area on Sunday. Some light rain will be possible with this frontal passage. There is also the potential for some continued precipitation over portions of the area Sunday night as forecast guidance suggests that a southern stream disturbance may result in some post cold frontal precipitation. The remainder of the period looks many dry and continued cool. However, temperatures should begin to moderate by the middle of next week. KJB && .AVIATION... For the 06Z TAFs... Dry conditions expected this forecast period, however, will continue to see MVFR ceilings this morning through midday/early afternoon. A slight rise in ceiling heights may occur this morning, but once again, think mainly MVFR ceilings. Expect skies to scatter later today, with clearer skies then anticipated this evening. West winds/gusts will persist this morning into this afternoon, but a diminishing trend will then occur this evening through the end of the forecast period. Rodriguez && .MARINE... 322 AM CDT Westerly winds continue to gust in the 30 to 35 kt range, so we will allow the gale to continue through mid morning. Some occasional gale force gusts have also been reported in the IN near shore waters. Overall, expect winds to gradually ease through the day, but will likely remain up around 25 kt for much of the day. Small craft conditions will continue through Friday morning, due to high waves. For this reason, we have extended the small craft advisory for the IN near shore waters through mid morning Friday. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Freeze Warning...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011- ILZ012...1 AM Friday to 9 AM Friday. Frost Advisory...ILZ006-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021- ILZ022-ILZ023-ILZ032-ILZ033-ILZ039...1 AM Friday to 9 AM Friday. IN...Frost Advisory...INZ001-INZ010-INZ011-INZ019...1 AM Friday to 9 AM Friday. LM...Gale Warning...Winthrop Harbor to Northerly Is. until 10 AM Thursday. Small Craft Advisory...Northerly Is. to Michigan City IN until 10 AM Friday. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO