463 FXUS63 KMQT 301148 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 748 AM EDT Mon Sep 30 2019 .SHORT TERM...(Today and tonight) Issued at 526 AM EDT MON SEP 30 2019 WV imagery and RAP analysis indicated a mid/upper level trough over the western CONUS and a ridge over the southeast resulting in sw flow from the central Plains to the northern Great Lakes. At the surface, s to se flow was increasing between a 997 low pres over south central South Dakota and a ridge from Quebec into New England. A 30-40 knots 850 jet and associated 300k-310k isentorpic lift suppported a large are of shra/tsra with some heavy rain from northern MN into nw WI. Although the heavier rain remained south of Upper Michigan moderate rain with some embedded thunder was spreading into the west. Today, expect the stronger tsra and higher rainfall amounts to remain west of Upper Michigan in line with the focus of the low level jet and higher MUCAPE values into the 1k-2k J/Kg range. However, portions of the west may see some rainfall amounts into the 1.00-1.50 range as PWAT values climb well above normal to around 1.5 inches. Otherwise, the strong WAA and moisture advection pattern will support shra and a few tsra spreading across the rest of Upper Michigan this morning with a diminishing trend this afternoon as the pcpn moves off to the northeast. The clouds may thin enough so that WAA will help push temps into the lower 70s west. and mid to upper 60s over the east. Tonight, as the low moves from nrn MN into northern Ontario, it will drag a cold front through Upper Michigan. Although mid level forcing will be weak, low level conv near the front may still be enough to support sct shra/tsra by late evening into the overnight. With fprecast CAPE values still in the 1000-1500 and 0-6km shear values of 35-45 knots, some strong storms may be possible. However, the greater chance for severe storms may remain to the south near the higher instability. .LONG TERM...(Tuesday through Sunday) Issued at 349 AM EDT MON SEP 30 2019 This period starts off with an exiting wave and associated low pressure system continuing to lift out of the Great Lakes region NE towards James Bay. The cold front from this system will remain just to our south, stalled out with a ridge of high pressure controlling the SE CONUS. This sfc trough and thermal boundary will become the focal point for an axis of heavy precipitation through the middle of the work week. Although clouds will stay around, Wednesday afternoon looks to be dry at the moment for the UP, with models beginning to converge on another wave of precipitation moving in late Wednesday night into Thursday morning. High pressure pushes in from the west quickly for Friday morning, which should keep things dry into Saturday. Models suggest another chance for precipitation Saturday night into Sunday as another low pressure system passes just to the north through Canada. Look for another high pressure system to be over the Northern Plains to start the week next Monday. Starting off on Tuesday, low pressure continues to move NE into Quebec. A trough extending SW from the low and a passing cold front are expected to cross Upper Michigan early in the day before stalling out across mid to southern Wisconsin thanks in part to a ridge of high pressure across the SE CONUS. Early in the morning on Tuesday, ahead of the cold front, around 500 J/kg of CAPE will be across south-central UP, so have included a small chance of thunder in the forecast to account for that. Overall, models suggest a broad area of Q-vector conv across the CWA, with a good consensus of PWATs up near 1.5 inches across the southern UP with around an inch throughout the northern portions. Sounding profiles north of a line from IMT to ESC suggest an elevated layer of dry air after the fropa. Have tried to keep PoPs in line with this idea, keeping some likelys in southern Menominee County, decreasing into chance rather quickly into Dickinson and Delta Counties. NBM may keep too much PoPs across northern Upper Michigan Tuesday night into Wednesday morning, but with that axis remaining just to our south, felt fine leaving slight chances. Generally, the best chances Tuesday into Wednesday morning will stay across the southern most portions of Upper Michigan. Upper Michigan should see a brief dry period Wednesday afternoon before the large trough that is currently over the western CONUS finally progresses eastward, reaching the Northern Plains on Wednesday afternoon. This shortwave will eject across the Upper Great Lakes region, bringing a good amount of PVA and q-vector conv with it. There won't be any chance for moisture return prior to the arrival of this wave with PWAT values on the order of 0.50 to 0.75 inches. With a high pressure system following right behind, this should be a bit more of a progressive system with the best chances between 06 and 15Z Thursday. Behind this shortwave, 850 temps fall between -2 and -4C with winds becoming NW. Have left residual PoPs downwind of Lake Superior to account for lake-effect rain. A ridge of high pressure moves into the region quickly behind the Thursday shortwave bringing some return SW flow. This switch should cut off any residual lake-effect rain, clouds, mist, etc. by Friday morning. There is a decent chance for some frost Thursday night into Friday morning with low temperatures expected right around freezing in the western interior portions of Upper Michigan. Expect a drier air mass to move into the region with this high pressure system with dew points into the 30s. Skies will begin to clear through Friday, leading to some clearing Friday night along with another chance at frost for Friday night. On Saturday, WAA ahead of the next shortwave will moderate temps back into the mid to upper 50s, but will also be accompanied by another chance at rain. Fairly decent agreement among the GFS/EC/GEM in terms of timing, but quite the different outcomes in terms of QPF. Current guidance shows rain moving in after 00Z Sunday, progressing quickly across Upper Michigan, and drying out by Sunday afternoon. For now have left chance PoPs through the duration of Sunday to account for shifting model guidance. Look for high pressure to move into the region Monday afternoon, bringing some drier conditions to start the next week. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) Issued at 748 AM EDT MON SEP 30 2019 Expect IFR to ocnl LIFR cigs this morning with rain and thunderstorms and an influx of low level moisture ahead of a warm front. As the rain diminishes, some improvement to MVFR should develop at KIWD and KCMX. However, KSAW is more likely to remain IFR into the afternoon. As a cold front moves through tonight, additional sct shra and possibly a few ts will develop with VCSH mentioned. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 526 AM EDT MON SEP 30 2019 A strong low pressure system will move toward northwest Ontario supporting SE winds in the 20-30 knot range into this afternoon over eastern Lake Superior, highest downwind from Whitefish Bay. Winds will diminish back to 10-20 knots later today but will again increase to 20-30 knots late tonight into Tuesday from the w to Winds will generally drop to 20 knots or less for Wednesday into Thursday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...JAW AVIATION...JLB MARINE...JLB