638 FXUS63 KMQT 100947 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 547 AM EDT Wed Oct 10 2018 .SHORT TERM...(Today and tonight) Issued at 529 AM EDT WED OCT 10 2018 ...Moderate to heavy rain continues through this evening... Periods of moderate rain have lifted across Upper Michigan since Tue evening. The heaviest rain (1-1.25 inches) has occurred over far west and far east Upper Michigan. East getting a break currently but the regional radar loop indicates another batch of moderate to heavy rain will lift through next couple hours. 3 hour rainfall upstream with this activity mainly up to 0.50 but 1 hour rainfall has been up to 0.25 inch. Sfc low over northern IA is forecast to drift toward southeast MN by daybreak this morning then slowly lift to central Upper Michigan this evening. Main negative tilted shortwave trough will continue to pivot northward over the northern Plains today before shifting to northern Ontario tonight. Area of moderate to heavy showers that has lifted north overnight mainly supported by H85-H7 warm air advection and frontogenesis in right entrance of jet over Ontario. As forcing continues to lift north, may see rain become more scattered expect over far west. Deep moisture streaming ahead of the shortwave trough with PWATS near 1.50 inches or toward 225 pct of normal will support occasional showers/t-storms currently over southern WI and on into eastern IA/western IL and eastern MO expanding over especially central and east areas late morning through the aftn. Like idea offered up by GEM and HREF means of expanding these showers and t- storms over the east mid to late aftn as sfc-H85 theta-e ridge approaches from south-southwest. Could see locations such as ISQ and ERY picking up 1-2 inches of rain this aftn into the evening. Starting to look like the far south and far east may end up with the most rain from this whole event. Have kept the flood watch going though its possible it may be able to be dropped early over the far west once heavier rain moves through this morning. Will let dayshift make that call. Late today into this evening probably will be one more surge of heavier showers sweeping across west and central as the sfc low moves by and as stronger shortwave and elevated instability (SI/s less than 0) slides through. Expect the showers to taper off overnight central and east as the forcing and sfc low lift over eastern Lk Superior and to just north of SSM by 12z Thu. Some lake enhanced showers will begin to develop over the far west as colder air works in behind the exiting low. These showers will become more developed on Thu. Back to temps and winds briefly. Have lowered temps over west and north central with slower arrival of low/persistent northeast winds. Most areas in this part of U.P. will see temps remain in the low-mid 40s all day and there may be some fog at times. Temps over the south and east will be warmer, but trimmed these too as strong southerly flow never really fully arrives. Could also be some fog/drizzle off Lake Michigan that will hamper warming even as winds turn to the south. Temps tonight may actually try to warm along WI border as winds become WSW as low moves by to the north. Otherwise, temps will eventually fall off all areas into the mid 30s to lower 40s with cold air advection behind the low. East to northeast winds stay gusty across the Keweenaw today (seeing gusts to 30-35 mph. Certainly possible that these strong winds and saturated ground may make trees more prone to toppling, especially in locations exposed to the easterly wind direction. Lastly, the strong winds will build waves up on Lake Superior. Though northeast winds are mainly parallel to the west shore of Keweenaw down to Little Girls Point it is possible with waves of 10-14 feet there may be minor beach erosion. Too marginal for lakeshore flood advisory, but did mention in HWO. .LONG TERM...(Thursday through Tuesday) Issued at 419 AM EDT WED OCT 10 2018 Thru the upcoming weekend, a mean ridge will remain over the Gulf of AK, extending n thru AK and far nw Canada at times. Operational medium range guidance and ensemble means point toward some broadening and slight progression of the ridge during next week. This will force a mean Rockies to central N America trof to drift e to eastern N America as next week progresses. In the end, this will lead to a drier pattern (a trend to blo normal pcpn amounts) taking hold across the Upper Lakes next week under developing nw flow. In the meantime, the pattern will continue to provide frequent opportunities of pcpn. Current amplified western CONUS trof/eastern CONUS ridge configuration will support mdt/hvy pcpn amounts thru today until the main shortwave currently lifting out across the Plains shifts thru the Upper Lakes tonight/early Thu. Thereafter, periodic pcpn events associated with a series of shortwaves progressing thru the mean trof will be much lighter for the remainder of this 7 day fcst. As for temps, solidly blo normal temps will prevail late week thru much of next week as mean troffing gradually shifts e, placing the Upper Lakes under chilly nw flow. Trends from the last 24hrs of operational medium range models/ensembles suggest the ridge drifting into western N America and the downstream trof over eastern N America may be a bit more amplified than suggested 24hrs ago. This would support cooler conditions, blo normal temps, persisting thru all of next week, though there still should be a tendency for some moderation at the end of the week. Beginning Thu, sfc low pressure will be over ne Lake Superior at 12z and will track to near James Bay by late aftn. Will be blustery and turning colder in the wake of the low under steady caa which drops 850mb temps from -4C w/2C e at 12z to -5 to -7C across the board by 00z. As a result, temps over the higher terrain of the w and n central will likely not get out of the 30s during the daylight hrs while temps e and s central fall to the lwr 40s. Under cyclonic flow, caa and deep moisture to 12-15kft, lake enhanced showers will already be ongoing into western Upper MI under wnw flow to start the day and will expand quickly eastward. With wetbulb zero heights falling blo 700ft, expect some shsn along with the shra over the w. May see some graupel as well, typical of earlier season lake effect. Pres rises are not particularly notable and will already be over the fcst area during the morning, so not really expecting an isallobaric enhancement to the post-frontal winds Thu. Given potential mixed layer winds, may see some 35-40mph gusts over the Keweenaw and along the lake from around Munising eastward. So, at this point, not anticipating that a wind advy will be needed Thu. Deeper moisture doesn't begin to depart until later Thu night/Fri morning. With 850mb temps of -6 to -8C and Lake Superior water temps running mostly 6-8C and locally up to 10C or so, wnw/nw flow sct lake effect showers will continue Thu night, and ptype will transition to just snow as wetbulb zero heights fall blo 700ft, except in areas exposed to the moderating influence of a long fetch across the lake. In those locations, expect a mix. Some light accumulations of snow (inch or less) will probably occur, mainly over the higher terrain. A weak shortwave passes on Fri, but fcst soundings show no real response in moisture depth. Nonetheless, the weak forcing overtop adequate instability over the lake (850mb temps around -7C) should continue to support some light w to nw flow lake effect showers on Fri. Will be another chilly day with w and n central not getting out of the 30s. Low to mid 40s expected elsewhere. A few lake effect showers may linger into Fri night, but drying air mass and the start of waa ahead of the next shortwave dropping into the Dakotas should spell an end to any pcpn. There is slight improvement in medium range guidance with regard to shortwave timing and amplitude early next week. A slightly faster trend is noted with the first shortwave arriving this weekend. While most of the area should still remain dry on Sat, waa/isentropic ascent ahead of the first wave may bring some -shra into the western fcst area in the aftn. Sat will be a warmer day though still blo normal. High temps will be in the 40s. Isold to sct -shra will acccompany the shortwave across the area Sat night with a trailing stronger shortwave arriving Sun. Given 850mb temps of -4C or lower, could see a short period of decent lake enhanced pcpn as this wave passes. If boundary layer is cold enough during the day, some minor wet snow accumulation would occur over the w. LES with a mix closer to shore will then follow into Sun night under 850mb temps falling toward -8C. At least one more shortwave will move across the area in the Mon-Wed time frame, probably on Tue, bringing an increase in sct shra. Otherwise, air mass will likely be cold enough for much of this time to support some isold/sct lake effect -shra/-shsn. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 141 AM EDT WED OCT 10 2018 Conditions are expected to deteriorate again overnight as abundant low level moisture north of a frontal boundary and low pressure system will support mainly LIFR conditions through the forecast period along with periods of rain. There may be brief periods where conditions drop below minimums at KSAW but any periods should be brief during intervals between areas of rain. Gusty northeast winds will also persist as the low approaches but diminish and become light at KSAW as the low center moves into Upper Michigan Wednesday evening. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 545 AM EDT WED OCT 10 2018 Winds have ramped up quickly as low pressure is lifting north across Iowa. DISW3 and ROAM4 are already from the northeast over 40 kts for gusts with DISW3 now reaching storms with 49 kt gust in last hour. Have upgraded far west to Storm Warning as occasional storm force winds continue into this aftn as the low slowly lifts toward Upper Michigan. Rest of western and north central Lake Superior will see high-end gales into this evening. Winds shift to west-northwest late tonight into Thu morning as the low exits to east of Lake Superior. Looks like another gale for mainly east half of Lake Superior on Thu/Thu evening so we went with a gale watch. Winds will likely remain elevated late Thu night into Fri morning, before the pressure gradient slackens over the region. Winds will diminish to 20 kts or less Fri into Mon, though there may be a brief increase of west winds to 25-30 kts on Sun in wake of a low pressure trough. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Flood Watch through this evening for MIZ001>006-009>013-084. Lake Superior... Gale Watch from Thursday morning through Thursday evening for LSZ266-267. Gale Warning until 5 PM EDT this afternoon for LSZ266. Storm Warning until 5 PM EDT /4 PM CDT/ this afternoon for LSZ162. Gale Warning from 5 PM EDT /4 PM CDT/ this afternoon to 1 AM EDT /midnight CDT/ Thursday for LSZ162. Gale Warning until 1 AM EDT Thursday for LSZ263-264. Gale Watch from Thursday morning through Thursday evening for LSZ265. Lake Michigan... None. && $$ SHORT TERM...JLA LONG TERM...Rolfson AVIATION...JLB MARINE...JLA