Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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002 FXUS63 KDLH 252007 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 307 PM CDT Tue Jun 25 2024 .KEY MESSAGES... - Mainly dry today, with some scattered showers and a couple embedded thunderstorms in the Borderlands this evening into tonight and other portions of the Northland (20% chance) tonight. - Isolated showers lingering Wednesday morning. - Larger area of low pressure moves through the region late this week, with some heavy rainfall/flooding potential. Some strong to severe storm potential on Friday, ahead of the cold front, as well. - Another active period of weather for early next week. There are some hints of additional heavy rainfall and severe potential next Monday and Tuesday, although details are still a bit fuzzy. && .DISCUSSION... Issued at 306 PM CDT Tue Jun 25 2024 Rest of Today - Tonight: Mostly sunny to partly cloudy weather and quiet weather continues through this afternoon as a brief area of high pressure sits in the region, allowing afternoon high temperatures to top out in the upper 70s to mid 80s with decreasing dewpoints and gusty west to northwest winds. We will begin to see increasing cloud cover later this afternoon and evening as another cold front approaches from our north in association with low pressure over northern Quebec. Shortwave energy moving through the Northland in conjunction with the southward advancing cold front will kick off scattered shower activity this evening in far Northern MN, with this shower activity sagging southeast into NE MN tonight into early Wednesday. Short-term models also show some shower activity clipping the Brainerd Lakes into east-central MN tonight. Can`t rule out a rumble of thunder or two tonight, mainly across far northern MN, but no severe weather will occur given very little in the way of instability. Precipitation amounts will be light, on the order of 0.1-0.25" across far Northern MN, and less than 0.10" elsewhere. Wednesday: A few of these showers/storms linger through Wednesday morning, but on a much more isolated basis. High pressure builds into the area late under northwest flow aloft, bringing clearing skies later in the day into at least Wednesday night. Temperatures will be more mild in the mid-60s to mid-70s. Thursday - Saturday: Surface high pressure begins to depart to our east on Thursday, as a feed of Gulf moisture begins to advect north into the Upper Midwest, raising PWATs into the 1.5-1.8" range (90+ percentile of late June sounding climatology) Thursday night into Friday. A stronger upper-level trough moving east across the northern U.S. Rockies and northern High Plains Thursday night through Friday will kick off a deepening surface low pressure over the northern High Plains, with the low passing through the Northland Friday afternoon-evening. Showers and thunderstorms start in the Northland Thursday evening/night in association with the warm front ahead of the approaching low. Current indications are for the warm front to set up somewhere near or just north of the International Border, but the location will still likely waiver a bit as this system approaches, and could be a focus for moderate to heavy rainfall given high PWATs. Additionally, there is a window of time Friday afternoon and evening in the warm sector ahead of the cold front with this system where potentially 1000-2000 J/kg of MUCAPE combined with 0-6km shear of 40-50 knots could provide the focus for strong to severe thunderstorm potential along with moderate to heavy rainfall associated with the thunderstorms. However, it should be noted that this severe potential will be contingent on how long earlier day convection lingers, as well as the strongest upper-level forcing being located farther west than the best instability. In addition to the severe potential, one other thing we will be continuing to watch closely is the heavy rain and flooding potential due to the very wet soils and elevated streamflows across much of the Northland. The main shortwave trough slides through the Northland on Saturday, leading to lingering showers to start the weekend before conditions briefly dry out late Saturday into Sunday as surface high pressure moves through the Upper Midwest again. Sunday - Next Wednesday: The high pressure settling in briefly for Sunday will be accompanied by high temperatures around the 70 degree mark for most of the Northland. Things look to change as we head into Monday. As a result of an increasing mid-level jet through this period, a series of mid-level shortwave troughs look to impact the area resulting in yet another active pattern for our region. That being said, there is increasing potential for severe weather with the CSU Machine Learning probabilities highlighting both the Monday and Tuesday timeframe for severe weather potential. SPC convective outlook discussions for Monday and Tuesday corroborate this. In addition, Gulf moisture will be pulled up from the Gulf of Mexico. The GFS IVT shows this well with a strong return of moisture being advected into the area in the July 1st and July 2nd timeframe (next Monday and Tuesday). It is too early to determine exactly where this setup plays out. However, when looking at the CSU Machine learning Probabilities for excessive rainfall, our region is highlighted once again. This is certainly something to keep an eye on as moist soils are already saturated and rivers are still running high. It wouldn`t take much more rainfall to exacerbate the ongoing flooding across the area. However, this is still several days out so the forecast can and likely will change as this early next week timeframe approaches. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1244 PM CDT Tue Jun 25 2024 VFR and dry conditions through this evening with gusty daytime westerly winds gusting to 20 to 25 knots before turning light and veering northwesterly tonight. Clouds will increase this evening and tonight, with ceilings gradually lowering to MVFR late tonight into Wednesday morning as some scattered showers move into the Northland. Can`t rule out some brief IFR at KHIB/KDLH late tonight into early Wednesday morning, but chances are only 30-40% so left ceilings as MVFR for now. Shower chances are low (20-30%), and have VCSH mention for most terminals aside from a brief -SHRA at KINL and dry conditions for KHYR. There may be an isolated thunderstorm across far northern Minnesota (10% chance). Winds turn northerly Wednesday morning, with some gusts up to 15 knots during the mid to late morning. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 306 PM CDT Tue Jun 25 2024 Westerly winds of 10-15 knots with gusts to 20 to 25 knots will continue through very late this afternoon before winds veer to northeasterly this evening and weaken to less than 15 knots, with lingering conditions hazardous to small craft until early this evening. Small Craft Advisories are in effect. Winds briefly increase early to mid-Wednesday morning with gusts to 20 knots mainly in the head of the Lake and around the South Shore before turning light the remainder of the day into Wednesday night as high pressure moves in. Winds turn south to easterly on Thursday on the back side of the high pressure, with gusts up to around 15 knots during the afternoon. Isolated showers and perhaps a thunderstorm for tonight into mid-Wednesday morning. No severe weather is expected. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...Small Craft Advisory until 8 PM CDT this evening for LSZ121- 140>148-150. && $$ DISCUSSION...Rothstein/CJM AVIATION...Rothstein MARINE...Rothstein