626 FXUS63 KMKX 191420 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 920 AM CDT Thu Aug 19 2021 .UPDATE... (Issued 920 AM CDT Thu Aug 19 2021) Fog continues to improve this morning and should be largely gone within the next hour. After this, expect another round of late morning and afternoon cumulus, with an isolated shower or storm possible along and west of the lake breeze. In all, the forecast looks on track for the remainder of the day. DDV && .SHORT TERM... (Issued 245 AM CDT Thu Aug 19 2021) Today through Friday: Main concern is early morning fog trends. Seeing pockets of dense fog. This fog appears to be forming in river valleys and low lying areas. These pockets of dense fog should improve through mid morning. Overall weak pressure gradient once again will allow for a lake breeze to form. Like yesterday we could see isolated showers pop up here and there with the lake boundary being the primary focusing mechanism. Any of that activity should dissipate this evening with yet another setup for some fog. The surface high still will be providing a light wind regime across the area with the better return flow setting up to our west. By Friday we get into more of a south or southeast flow with the pressure gradient tightening up. This is largely due to the high retreating and our next weather maker drawing closer. && .LONG TERM... (Issued 245 AM CDT Thu Aug 19 2021) Friday night through Saturday: A trough will approach from the northern Plains. This feature is proggd to take on a negative tilt and shift more to the north of the area on Saturday. With further warmth/moisture advection Friday night we could see some shra/tsra develop in this pattern and with the mid level flow becoming more cyclonic. We will see an southward extension of the energy passing to our north along with the surface/850 cold front swinging through on Saturday. May be able to speed up the pops further eastward as system is showing a swifter pace to it. In fact, progs show the axis of mid level energy shifting east of the area for Saturday afternoon. Some indications the lower level front may linger some showers/storm chances a bit longer. Have trimmed back some pops for Saturday evening. Saturday night through Sunday: After the fropa a ridge of high pressure works into the area this period. A period of cold air advection with a low level thermal trough sets up but briefly. All in all Sunday looks like the better day of the weekend. Sunday night through Wednesday: Getting into early next week the combo of the proximity of lower level baroclinic zone and mid level ripples in the flow may result in more than one round of thunderstorms affecting southern WI. One wave rides through Sunday night into early Monday. The next wave could affect the area later Tuesday into Tuesday night. High pressure will push a building in from Canada into the U.P towards midweek will push a frontal system through the area. As the high continues to build in the precip should gradually wind down with drier, cooler and less humid weather returning as the low level wind flow turns more northeast. && .AVIATION... (Issued 920 AM CDT Thu Aug 19 2021) Lingering fog should clear out within the next hour. Late morning and afternoon cumulus around 4 kft is likely again today. May see an isolated shower or storm along and west of the lake breeze today, but most places will stay dry. High pressure will still linger tonight, so may see another round of fog. DDV && .MARINE... (Issued 245 AM CDT Thu Aug 19 2021) High pressure centered over Lake Michigan will gradually weaken and push eastward the next couple days in advance of approaching low pressure. Winds will remain on the light side through Friday and will be variable at times. Southerly winds will pick up a bit Saturday ahead of the low, with breezy northwest to north winds behind the low Saturday night into Sunday. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Dense Fog Advisory...LMZ643-LMZ644 until 10 AM Thursday. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSMilwaukee www.twitter.com/NWSMilwaukee www.youtube.com/NWSMilwaukee