404 FXUS63 KDLH 070852 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 352 AM CDT Mon Oct 7 2019 .SHORT TERM...(Today through Tuesday) Issued at 352 AM CDT Mon Oct 7 2019 The main concerns for the short term focus on gusty winds today and Tuesday and temperatures. One last lobe of vorticity was located over northeast Minnesota, Lake Superior, and adjacent areas of northwest Ontario early this morning. A few lingering showers and a few clouds have hung on under the influence of the cyclonic flow aloft. Skies were mainly clear over central and north-central Minnesota and areas farther west. Look for clouds to decrease and showers to dissipate during the next few hours. Have left the Frost Advisory in place for now, but have become skeptical we’ll see frost develop. Temperatures are generally in the upper 30s to low 40s with light winds around 5 mph. Winds would have to subside for a few hours to decouple the boundary layer and allow temps to plummet. At this point I’m skeptical that will happen. As the boundary layer deepens once again this afternoon look for wind speeds and gusts to increase into the 5 to 10 mph and 10 to 15 mph range respectively. Temperatures will climb into the low 50s in the Arrowhead to the low 60s from the Brainerd Lakes east to around Hayward and Spooner. In the absence of a strong thermal inversion aloft, temps may overachieve with plenty of sunshine. Winds diminish tonight, but should remain around 5 mph. With warm air advection during the day continuing tonight and persistent light winds, have raised low temps a few degrees from previous forecast. Look for overnight lows around 40 degrees in the Sawtooth Mountains to the middle and upper 40s in central and north-central Minnesota. The flow aloft will back southwesterly on Tuesday which will increase the warm air advection over the region. Mixing won’t be as efficient as today due to a thermal inversion between 900 and 850 mb. Strong winds will be present in that layer which will mix down to the surface. Sustained surface winds will be from the south at 10 to 20 mph with gusts of 20 to 30 mph likely. Temperatures will climb into upper 50s in the Sawtooth Mountains to the middle 60s along the South Shore and areas inland from Lake Superior. .LONG TERM...(Tuesday night through Sunday) Issued at 352 AM CDT Mon Oct 7 2019 A late-week storm will bring widespread rainfall on the order of an inch or more Wednesday night through Friday, then a lingering chance for precipitation and much cooler temperatures through the weekend. There is a potential for accumulating snowfall, with the most likely scenario for much of the Northland being off and on light rain/snow showers Saturday and Sunday but limited (less than an inch) snowfall accumulations. Highs as cool as the upper 30s to near 40 over the weekend with low temperatures in the upper 20s to low 30s. Most of the region will fall below the freezing mark this weekend, including along the shores of Lake Superior. On the synoptic scale a mid/upper level longwave trough will deepen as it moves from the Rockies into the Great Plans Wednesday into Thursday, rapidly deepening and lifting north towards the Upper Midwest/Upper Great Lakes late-week with a resultant surface low deepening. This mature low then lingers over northern MN or northwest Ontario over the weekend before gradually exiting northward, keeping a persistent cool northwest flow across the Upper Midwest as well as lingering chances for precipitation. There is very high confidence in at least an inch of rainfall late-week through the weekend as well as high confidence in colder air arriving this weekend leading to highs in the 40s and lows in the upper 20s to near 30. Confidence in wintry precipitation over the weekend is high given the lingering wrap- around flow that is likely to be in place over the Northland, even if there remains some significant differences across guidance in the placement of the low over the weekend. The placement of the low will be critical in whether or not there is a dry slot across the Northland, which could mean the difference between non- accumulating light snow showers and the potential for a few inches of snowfall. It should be noted that at this point the majority of ensemble data across all models do not support the potential for much more than an inch of snowfall across the Northland, but several GFS Ensemble members have been consistent with stronger large-scale forcing Saturday morning which could lead to significant snowfall amounts. While it is perfectly normal to see accumulating snow in October - October days with snowfall amounts of an inch or more happen on average once every year - it is very rare to see more than a few inches of snowfall this time of year due to the comparatively longer days, higher sun angle, and lack of colder air at low levels. At International Falls there have only been six events with 2-day snowfall totals of four inches or greater during the month of October in the ~70 years of continuous snowfall records. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1217 AM CDT Mon Oct 7 2019 VFR through the forecast as high pressure builds into the area and skies clear out. Winds west-southwest around 5 to 10 knots Monday. && .MARINE... Issued at 352 AM CDT Mon Oct 7 2019 No hazardous marine conditions are expected through the next 48 hours. Southwest winds around 5 to 10 knots today into tonight, then stronger southerly winds around 10 to 15 knots Tuesday into Wednesday. These persistent southerly winds may lead to building waves along parts of the north shore, mainly north of Grand Marais, but wave heights are expected to remain below four feet and thus do not anticipate needing a Small Craft Advisory. Strong winds are likely across western Lake Superior late week into next weekend as a powerful low pressure system develops and lingers nears Lake Superior. && .PRELIMINARY POINT TEMPS/POPS... DLH 57 45 64 48 / 0 0 0 0 INL 57 46 65 48 / 0 0 0 0 BRD 61 46 66 51 / 0 0 0 0 HYR 59 44 65 49 / 0 0 0 0 ASX 59 44 67 49 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...Frost Advisory until 9 AM CDT this morning for MNZ010-011-018- 019-025-026-035-037. LS...None. && $$ SHORT TERM...Huyck LONG TERM...JJM AVIATION...JJM MARINE...JJM