179 FXUS63 KAPX 110354 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1154 PM EDT Wed Oct 10 2018 .UPDATE... Issued at 949 PM EDT Wed Oct 10 2018 Widespread rain is pivoting ne-ward across northern MI, with a dry slot working into parts of nw lower, reducing precip coverage there. Some showers are found further west along the surface cold front, over far eastern WI and southern Lake MI. There are a few hundred j/kg of MuCape feeding that activity, thanks to differential temp advection. Have kept in a mention of isolated thunder for a few more hours, in deference to that, but there hasn't been thunder anywhere near us thus far. May drop thunder before midnight if that trend holds. Otherwise, the cold front moves w to e across the area over the next 6 hours, very firmly sending any trace of summer packing. Just sct showers expected post-frontal passage, as a surge in overlake instability is countered by a substantial drying trend. Temps will be in the mid 40s to around 50f by 8 am. && .NEAR TERM...(Through Tonight) Issued at 323 PM EDT Wed Oct 10 2018 ...Warm and muggy this evening, colder with lake effects Thursday... High Impact Weather Potential: Minor, with thunderstorms through tonight, increasingly gusty winds, and lake induced precipitation Thursday. Primary Forecast Concerns/Challenges: Potential for svr weather with thunderstorms through this evening, along with lake effects and pcpn type Thursday and Thursday night. Pattern Synopsis/Forecast...Active weather continues across the state during the next 24hours, as unseasonal warm and muggy conditions this evening trend toward below normal, as northwest flow lake effects dominate the weather Thursday. The storm system which has been organizing in the Plains since the weekend, will continue to lift up across Wisconsin this evening, before crossing ern Lake Superior Thursday morning. This system will exit the Great Lakes region into Quebec early Friday. At upper levels, a weak 500mb ridge over the mid Atlantic and eastern Great Lakes this evening, will push east while a broad 500mb trough (and colder mid lvl temps) settles over the Great Lakes and northern Plains through Friday. Some convection will linger over northern Michigan into the overnight hours as warm muggy air (sfc dew pts in the mid 60s) and limited instability (0-3km MuCape around 600 j/kg, 850/700mb lapse rates near 6 c/km) lingers in advance of the approaching storm system. 850/700mb qvectors show the best convergence with the system lingering across the Straits of Mackinac and eastern Upper tonight. Model soudnings show the deepest moisture and most unstable conditions diminishing across northern Michigan around 06z Thursday, which begins a transition to lake induced pcpn and clouds as winds trend northwest and 850mb colder pool settles into the region. 850mb temps quickly drop from +16c in advance of the storm system this evening, to -4c Thursday afternoon and to -6c early Friday morning, greatly increasing the over water instability with nrn lake water temps lingering around +15c. Model soudnings showing inversion heights deepening to around 5k feet Thursday aftn, while the freezing level drops to near 1k ft Thursday night for locations away from the warmer influences of the Great Lakes. Will mention mainly dry conditions across the eastern parts of the forcast area Thursday as high pressure and drier air settles into the region. However will mention lake induced pcpn and clouds in favored west-northwest flow lake belt areas of northwest Lower and east Upper Michigan Thursday and Thursday night. Will mention a few snow showers over the higher elevations of northwest Lower and east Upper Michigan Thursday night. && .SHORT TERM...(Thursday through Saturday) Issued at 323 PM EDT Wed Oct 10 2018 High Impact Weather Potential: Minimal. A 500 mb low treks eastward over Georgia Bay through Friday, and at the surface, a dirty high pushes through the Ohio Valley. Friday remains cool with west-northwest winds, continued cold air advection, and anomalously cold 850 temps near -5 C. Highs on Friday will be struggling to get out the the low 40s in many places. Normals for mid-October are in the high 50s, and after the recent warm stretch this airmass will definitely feel much colder. Delta Ts around 20 degrees over the lakes, along with some additional moisture trapped under the 4500 ft inversion keeps lake induced cloudiness in place through much of the area. Lake induced showers will be the most prevalent in northwest lower and near Whitefish bay in the picture through Friday. Some snow could mix in with the rain early Friday morning in higher terrain, but no accumulation should occur. Things dry out into the evening and overnight hours as the low level moisture scours out. .LONG TERM...(Saturday night through Wednesday) Issued at 323 PM EDT Wed Oct 10 2018 A shortwave ridge briefly builds into the Great Lakes Saturday, with a surface high moving slowly through the Ohio Valley, starts the day off dry. This is replaced by a shortwave heading from western Ontario toward the upper Great Lakes into Sunday. Rain moves back into the area as this system drags a cold front through Michigan into Sunday morning. The pattern becomes messy heading into next weeks with rounds of systems over the Great Lakes producing more wet weather and shots of cold air. Even through guidance is very inconsistent with the spatial/temporal details of each system, early next week looks quite wet. Highs remain in the low to mid 40s, about 10 degrees below normal. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1154 PM EDT Wed Oct 10 2018 Mainly MVFR. Some IFR at PLN Thursday. Some VFR at APN. Low pressure is in central upper MI, with a cold front (wind shift to sw) swinging across northern lower MI. The most expansive rain has departed, though showers will continue from time to time, especially downwind of Lake MI due to lake instability as much colder air pushes in. Cigs will broadly favor MVFR conditions, however APN should transition to VFR for a good portion of Thursday. PLN, meanwhile, may see periods of IFR cigs. Ongoing s winds will veer sw and then w tonight and Thursday, and will be quite gusty. && .MARINE... Issued at 323 PM EDT Wed Oct 10 2018 An extended period of strong gusty winds and chaotic waves on the Great Lakes into Friday as a well organized storm system lifts into the western Great Lakes, slowly pushes up across Lake Superior tonight, before exiting into Quebec Thursday afternoon. Strong southeast winds over Lake Superior and strong southwest winds over Lakes Huron and Michigan this evening, will remain gusty and trend northwest Thursday afternoon and evening. Winds will remain northwest and diminish across the northern Lakes Friday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...SMALL CRAFT ADVISORY until 5 AM EDT Friday for LHZ348-349. GALE WARNING from 4 AM to 8 PM EDT Thursday for LHZ345>347. LM...SMALL CRAFT ADVISORY from 2 PM Thursday to 11 AM EDT Friday for LMZ323-342-344>346. GALE WARNING until 2 PM EDT Thursday for LMZ323-341-342-344>346. SMALL CRAFT ADVISORY from 2 PM Thursday to 5 AM EDT Friday for LMZ341. LS...SMALL CRAFT ADVISORY until 5 AM EDT Friday for LSZ322. SMALL CRAFT ADVISORY from 5 AM Thursday to midnight EDT Thursday night for LSZ321. && $$ UPDATE...JZ NEAR TERM...SR SHORT TERM...STJ LONG TERM...STJ AVIATION...JZ MARINE...SR