530 FXUS63 KMQT 091918 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 318 PM EDT Tue Oct 9 2018 .SHORT TERM...(Today and tonight) Issued at 522 AM EDT TUE OCT 9 2018 ...Periods of heavy rain could result in flooding... SW flow between broad trough over western CONUS and strong high just off east coast is pumping the unusually high moisture into the Upper Great Lakes. PWAT at GRB 00z was 1.73 or a whopping 279 pct of normal for this time of year. Deep moisture advection and low-level warm air advection along and ahead of sfc-H925 trough (now as far north as scntrl Upper Michigan) continues to drive the show thus far with multiple clusters of showers/t-storms extending from Upper Michigan sw all the way to the Big Bend area of TX. The extensive coverage of the moderate to heavy rain across the central CONUS is rather impressive. Initial wave of heavier rain moved across central Upper Michigan last night and dropped rainfall amounts up to 1.00 inch, heaviest near Lake Michigan. Next batch of showers/t-storms over central Upper Michigan through about daybreak is riding along and north of strongest H925 warm advection and edge of MLCAPE gradient. Decent rainfall with 0.61 inch/1 hour at IMT as convection moved through. Since this heavy rain will affect areas that saw heavier rain on Mon evening (northern Menominee, Delta and Alger counties) expanded flood watch into those areas earlier this morning. May be a bit of a lull behind this activity but regional radar indicates another batch of at least moderate showers already pushing into central WI. Looks to be quite a soggy morning for central Upper Michigan. Attn later today is on area of showers/t-storms currently lifting across western MO extending down into OK/TX. These showers are more along stronger sfc wave of low pressure over TX that will be lifting across Neb/IA this evening and reaches southeast MN by 12z Wed. Strong large scale lift is expected to spread across the Upper Great Lakes this evening and overnight ahead of negative tilted upper level trough lifting across the central Plains. Large scale q-vector convergence will combine with stronger sfc-H85 convergence ahead of the low/warm front to bring a period of showers/t-storms with very heavy rain. Expect widespread heavy rain as this background forcing will be supplemented by another surge of H925 warm air advection and strong low-level moisture transport into the Upper Great Lakes. PWATS tonight forecast to be at least if not higher than values seen currently, so probably above 300 pct of normal. Wow! Rainfall rates may be intense as area will also be on northern edge of MUCAPE leading to larger areas of convection. Overall, type of regime that is occurring in TX and OK this morning could very well be ongoing over Upper Great Lakes tonight. Preferred to lean on heavier qpf from GEM as it is initializing upstream activity better this morning. Some locations over especially the west half of Upper Michigan may see rainfall totals just tonight of 1 to 2 inches. This will boost event totals to near 3 inches with more rain to come on Wed. No need to change the going flood watch as it covers this situation appropriately. Other issue tonight will be strong/gusty east winds on the Keweenaw. May see gusts to around 30 mph. Temps today and tonight will stay mainly in the low-mid 40s northwest and north central as they remain on cool side of sfc boundary. Fog at times for these areas as well. Temps over the far south and east currently in the 50s to near 60F should stay steady much of the day before falling off late as northerly winds increase to the north of the approaching sfc low. .LONG TERM...(Thursday through Tuesday) Issued at 317 PM EDT TUE OCT 9 2018 As the main system continues to exit the region Thursday into Friday, lingering upper-level energy and cooler air working in behind the system will allow for lingering lake-effect precipitation Thursday. It does appear Thursday morning will start off with some deeper moisture and cold enough temperatures aloft to support some snow flakes mixing in with lingering rain, before transitioning over towards lingering drizzle. Thursday evening into Friday, cold air advection will strengthen and allow for lingering drizzle to switch over to light lake effect snow showers primarily inland from the Great Lakes across the northwest to west wind snow belts. Right now it doesn't appear that the magnitude of the cold air advection and resulting lake-induced stability will be strong enough to support much in the way of accumulating snow. On Friday into Saturday, low- level flow will back west to southwest and 850mb temperatures will warm; therefore, expect any lingering lake effect precipitation to weaken if not diminish, for what appears to be a dry afternoon/evening across much of the area. Saturday through early next week, we will remain in an active pattern with numerous shortwaves tracking across the region late Saturday through Monday, and another system progged to arrive towards the middle of next week. Saturday looks to be the warmest day within the extended as the warm noise lifts northeast across the Upper Peninsula ahead of the leading shortwave, otherwise temperatures look to remain 10 to 15 degrees below normal for this time of year with afternoon highs only climbing into the 40s. As these systems move through the region, periodic chances for rain are expected across the Upper Peninsula late Saturday through early/middle next week, especially near Lake Superior. Behind the exiting systems, depending on how strong the cold air advection is we could see linger chances for lake effect rain/snow showers, with snow showers especially likely during the overnight hours inland from the Great Lakes. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 111 PM EDT TUE OCT 9 2018 Poor aviation conditions will persist over the next 24 hours as a system lifts northeast across the Upper Great Lakes tonight through Wednesday. IFR to LIFR ceilings are expected to persist with visibilities likely varying between MVFR during light rain to LIFR as heavier rain moves in tonight through the early to mid morning hours. Right now it appears the longest period of lower visibilities is expected across KIWD/KCMX, due to a persistent moderate to heavy band of rain. Very slim thunder chances are possible at KSAW Wednesday morning, but were not high enough to include mentions within the TAFs at this time. Outside of the poor ceiling and visibilities, northeast winds will increases and become gusty across all TAF sites tonight through Wednesday morning. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 305 PM EDT TUE OCT 9 2018 Winds will pick up substantially tonight into tomorrow, with the western half of Lake Superior seeing the highest winds tonight, followed by the east half on Thursday. This is due to the approach and passage of a deepening low pressure system that will be crossing the Upper Great Lakes. These periods of increased winds through tomorrow evening have been highlighted in a Gale Warning, with an additional warning possible for the east half on Thursday. Sustained winds out of the NE tonight will start out in the 20-30 knot range, then increase to near/above 34 knots for the western half tomorrow. Gusts will approach 45 knots, with brief, localized gusts exceeding storm force possible. Greater than gale force gusts will persist into tomorrow night, with the focus shifting to the eastern half by Thursday, as mentioned. As the low passes across, expect the winds to swing around to out of the NW by Thursday. Winds will likely remain elevated into early Friday, before the pressure gradient slackens over the region. Look for less than 20 knot winds to prevail through the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Flood Watch through Wednesday evening for MIZ001>006-009>013-084. Lake Superior... Gale Warning from 5 AM to 5 PM EDT Wednesday for LSZ266. Gale Warning from 8 PM EDT /7 PM CDT/ this evening to 1 AM EDT /midnight CDT/ Thursday for LSZ162-263-264. Lake Michigan... None. && $$ SHORT TERM...JLA LONG TERM...Ritzman AVIATION...Ritzman MARINE...lg