Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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401 FXUS63 KDLH 082010 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 310 PM CDT Mon Jul 8 2024 .KEY MESSAGES... - Afternoon showers and storms once again will dissipate shortly after sunset. No severe weather is expected but some brief heavy downpours with pea sized hail is possible. - Patchy dense fog will be possible in the morning once again with visibilities dropping to less than 1/2 mile. - Similar conditions for tomorrow with storms firing off in the afternoon once again. Smokey skies aloft will also enter due to Canadian Wildfires. - Temperatures trends for this weekend look warm with highs climbing into the 90s. A Heat Advisory may be needed for the Brainerd Lakes Region. && .DISCUSSION... Issued at 307 PM CDT Mon Jul 8 2024 Current Conditions/Today: Broad upper level troughing persists across the Upper Midwest this afternoon. Satellite reveals blossoming cu fields with radar indicating thunderstorm cells filling in across the Arrowhead and NW WI. Like we have seen for the past several days these storms are largely diurnally driven and will be scattered in nature. Lack of upper level flow will lend itself to no severe storms. Instability is somewhat notable with MLCAPEs of 1000 J/kg. This should be enough to generate some pea sized hail at times but lack of storm tilt this afternoon will lead to shallow storms collapsing on themselves. The only other concern with these storms is some minor flooding. Surface streamlines highlight a corridor of good convergence south of Sawyer where training storms have been ongoing. Depending on how this line shifts it may impact our CWA. Storm activity quickly diminishes after sunset and overnight could see some patchy fog develop once again. High res guidance suggests a 40-60% chance of fog reducing visibility to less then a half a mile. Tomorrow: Rinse and repeat of the previous day. Upper level trough with cyclonic flow aloft paired with the summer sun and PWATs of over an inch will lead to pop up thunderstorms in the afternoon. The same convective parameter space still applies. Negligible shear but modest instability producing scattered storms some capable of small hail and brief heavy downpours. Activity wanes after sunset and some patchy fog in the morning can`t be ruled out. Smoke/Tuesday: Wildfire smoke from Canadian fire in northern British Columbia and Alberta may slide through the Northland over the next several days. The HRRR smoke model keeps the majority of the smoke aloft with a few pockets mixing down to the surface at times. The higher concentrations aloft look to move in Tuesday. Afternoon rain showers could help pull some of this concentration to the surface. Currently the MPCA has the northern MN highlighted in a "high end" moderate for AQI. No Air Quality Alerts at this time. Midweek into the weekend: Wednesday could see some additional diurnally driven storms in the afternoon once again. Upper level ridging starts to push in from the west Thursday with dry air pushing in from Canada. Thursday will be a precipitation free day with highs starting to climb into the upper 80s. This warming trend continues into the weekends with highs climbing into the 90s for portions of the Northland. Min T`s for the weekend won`t offer too much in heat relief either with lows staying into the 60s. A Heat Advisory may be needed for the weekend, most likely in the Brainerd Lakes Region. There may be a return of severe weather this weekend as well with the CSU probabilities starting to move into the Northland. However, there still remains a fair bit of disagreement among the 12Z suite of guidance. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1223 PM CDT Mon Jul 8 2024 Diurnally driven cumulus clouds are starting to show growth this afternoon on satellite with some storm initiation over NW WI. It is another similar set up as the previous day with pop up storms scouring the Northland with activity waning after sunset. No severe weather expected put some brief heavy downpours with small hail will be possible. Some patchy fog will also be envelope the Northland tomorrow morning with 30-50% chance of LIFR visibilities. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 307 PM CDT Mon Jul 8 2024 Light winds through the forecast period. Main item of note is the diurnally driven thunderstorms that have popped up this afternoon. This activity will wane after sunset and no severe weather is expected. Expect additional round of thunderstorms to populate in the afternoon for Tuesday and Wednesday. 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...None. && $$ DISCUSSION...Britt AVIATION...Britt MARINE...Britt HYDROLOGY...Levens