Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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305 FXUS63 KDLH 081123 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 623 AM CDT Mon Jul 8 2024 .KEY MESSAGES... - Several more days of afternoon/early evening pop up showers and thunderstorms expected Monday and Tuesday before drier conditions become more prevalent mid week. - Steadily warming temperatures through the week and into the weekend. Above normal low and high temperatures expected leading to increased heat risk. - High water persists across the Rainy River Basin and a Flood Advisory is in effect, now until Friday. See Hydro discussion for more details. && .DISCUSSION... Issued at 401 AM CDT Mon Jul 8 2024 A calm and quiet early morning has developed across the Northland with patches of fog becoming steadily more widespread. Expect areas of widespread thin fog and some patches of dense fog by the time the sun is coming up, but this should burn off fairly quickly through the morning hours. Upper level troughiness persists over the Upper Mississippi Valley and northern Great Lakes today, which will allow yet another blossoming of afternoon convection. We remain in a moist environment with precipitable water values still over 1 inch and with fairly light upper level winds which may lead to slow storm motions and give anyone under todays showers and storms a good little downpour. Rainfall should largely be a couple tenths of an inch or less but a couple locally higher bullseyes are possible. The best upper level support and a little shear (maybe 15-20kts bulk shear) will be over portions of NW WI, where the best potential for a stronger storm is with some gusty winds and small hail. No severe storms are expected. With the loss of daytime heating and the upper level vort max moving eastward, expect shower/storm coverage to once again dissipate quickly through the evening hours. Another round of some patchy fog could be possible overnight into Tuesday morning. Our upper level trough will be hard to shake and continues into Tuesday, which will, you guessed it, make for another shot at afternoon showers and non-severe thunderstorms! Another little vort max comes spinning down through the afternoon and evening which could help force an isolated stronger storm once again. With this northwesterly flow however, some smoke from Canadian wildfires (originating from northern British Columbia and Alberta) could start to make its way across the Northland. Higher concentrations are currently modeled to stay aloft and further north, but some lighter concentrations could make it to the surface, especially with an assist from afternoon thunderstorms mixing the lower atmosphere. MPCA currently forecasts much of NE MN to increase to moderate AQI (still below the "unhealthy for sensitive groups" category however) through today into Tuesday, and is being closely monitored for the potential to higher AQIs. WI DNR has NW WI outlooked in Good AQI, but those forecasts will be updated later today. A couple more scattered showers could be possible Wednesday, but into Thursday we should be looking at some upper level ridging bringing a fairly precipitation free day. Some more weak disturbances are possible into the weekend, but no major storms are expected at this time. WAA will be picking up into the weekend, with some of the warmest temperatures of the summer so far moving in. Widespread temperatures in the mid to high 80s are likely and some temperatures nearing 90F could be possible. Current HeatRisk shows much of the area in a 2 out of 4 level late this week and into the weekend - this level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. This is further emphasized by overnight lows warming as well, largely staying in the 60s overnight. These above normal temperatures may continue through mid to late month, per latest CPC graphics. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 623 AM CDT Mon Jul 8 2024 Patchy MVFR to IFR fog across much of the area this morning, affecting just about every terminal except DLH. Fog is not too far off, so kept at least MVFR vis in for DLH through the next couple hours. Visibilities should steadily improve over the next hour or two becoming VFR quickly. Expecting another round of afternoon showers and thunderstorms today. Coverage will be scattered but could bring a quick reduction in vis and ceilings if a storm comes right over a terminal. Should see coverage in these showers greatly diminish through this evening with conditions returning to clear and VFR. Another round of some patchy fog possible overnight into Tuesday morning. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 401 AM CDT Mon Jul 8 2024 Largely calm conditions expected to persist. Patchy dense fog is likely this morning, but should burn off quickly through the morning hours. Some afternoon showers and thunderstorms could lead to brief gusty winds today and tomorrow. Southwesterly winds 5-10 knots today through midday Tuesday, then winds become 5-10 knots out of the north to northeast through Thursday. With temperatures steadily warming on the mainland into the 80s by mid to late week, these northeast winds could be slightly enhanced in the afternoon by a lake breeze circulation but gusts over 15knots are currently not expected. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .HYDROLOGY... Issued at 401 AM CDT Mon Jul 8 2024 A Flood Advisory continues across portions of the Rainy River Basin, extending as far east as Lac La Croix and as far west as the Rainy Lake outlet. This advisory has been extended through Friday, but as headwaters level begin to crest, may be trimmed in its areal extent through the week. Lingering high water from rains in June continue across the Rainy River Basin. Far headwaters gauges on the Kawishiwi River, Basswood River, and Lake Vermilion have crested and are slowly but surely coming down, but remain elevated (Lake Vermilion still a foot above its pre-rain level). The Vermilion River continues to fall once again, falling at a rate of a couple inches each day, and the River Flood Warning may be able to be canceled in the next day or two should these recessions continue. This has allowed the lake level increases on Crane Lake to slow considerably, with less than an inch of rise in the last 24 hours. Lac La Croix levels are beginning to show signs of cresting, as rises in the last day have been less than an inch as well (around 2cm), after some much faster rates of rise earlier this month. All this high water continues to lead to steady rises on downstream lakes, notably Namakan/Kabetogama (Nam/Kab) lakes where minor flooding continues, and on Rainy Lake where levels are high but no flooding is ongoing, per latest reports and webcams. Per the latest IJC water level bulletin, dam operators are working to maximize outflow through the basin. However, the sheer volume of water moving through will still result in additional rises on these lakes. As water levels upstream crest and begin to come down, rates of rise on Nam/Kab should begin to slow and eventually crest, and levels continue. We`ve already seen the rates of rise begin to demonstrate signs of slowing. From July 1 to 3rd, Nam/Kab Lakes were rising at 2- 2.5" per day, but have slowed to 1-1.5"/day over the weekend. General guidance suggests peak levels on Nam/Kab could be possible this week, but that is uncertain. As is usual for this basin, water will move slowly and recessions will happen at glacial speeds. Additional rainfall may cause brief rises in tributaries and extend the period of high water in core lakes. Boaters should expect high water, potentially hidden underwater hazards (including submerged docks), and strong currents in constricted areas. Generally light winds are expected, except for possible brief erratic gusts out of thunderstorms, so wave heights should remain fairly minimal. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...Dense Fog Advisory until 10 AM CDT this morning for LSZ121- 140>148-150. && $$ DISCUSSION...Levens AVIATION...Levens MARINE...Levens HYDROLOGY...Levens