Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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641 FXUS63 KAPX 250138 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 938 PM EDT Mon Jun 24 2024 .KEY MESSAGES... - Watching the potential for some strong thunderstorms later tonight into Tuesday. - Additional chances of active weather return this weekend. && .UPDATE... Issued at 938 PM EDT Mon Jun 24 2024 Quiet wx here at the moment, as surface high pressure pushes east across Lake Erie and Georgian Bay. But in the wake of this ridge, warm advection is getting underway. A mid-cloud band and some weak radar returns are noted near ISQ-Munising. Spotty deep convection is over southern WI, and in far northern MN. We await additional convective development between these two areas, with impressive instability/shear but with a cap that is still hindering initiation. Most CAMs are insistent on deep convection triggering in parts of central MN into western WI, then growing upscale into an MCS that targets Lake MI and lower MI. This occurs as warm advection upstream further strengthens, enough so to overcome the cap and sustain convection. CAM guidance remains wet for us very late tonight into Tue morning, and the going forecast has been tweaked but still reflects that. A particularly popular solution is to bring a warm advection wing of SHRA/TSRA into western areas after 2 am, followed closely by a bow echo heading into nw lower MI after 4 am. The latter should be in a weakening state in this scenario; we will not be as unstable as further west. But we are eventually on the nose of the low-level jet by about 09Z/5am, which supports MuCape values somewhat in excess of 1k j/kg working into our far sw areas. The above scenario poses a severe wind threat to our area, in particular in nw lower MI. SPC was enough of a believer to expand the Day 1 Slight risk into more of nw lower MI, including TVC and CAD. This is all dependent on convection developing, and fast, upstream. Though this forecast absolutely has bust potential, the threat of svr wx (damaging winds in particular) overnight has increased. && .SHORT TERM /THROUGH TUESDAY/... Issued at 307 PM EDT Mon Jun 24 2024 Pattern Synopsis/Pattern Forecast: Mid/upper level ridge in the process of building east across the area early this afternoon as its surface reflection pushes off into the northern Ohio Valley. Attendant dry air and deep layer subsidence resulting in one downright pleasant early summer day across the Northwoods, with sun-filled skies and temperatures recovering up to near normal levels in the 70s and lower 80s. Rather rapid changes set to take place overnight into Tuesday as shortwave trough, currently racing east across the southern lands of Canada and northern Montana, pushes into the western Great Lakes by morning. Surge of pre-system warm, moist advection and eventual passage of cold front set to bring a round of showers and thunderstorms into the region later tonight. Primary Forecast Concerns/Challenges: Late night into Tuesday shower/storm evolution and severe weather potential. Details: Pleasant evening expected with just some increasing clouds with time. Unfortunately, uncertainty ramps up significantly as we head into the overnight. Strong moisture advection on nose of organizing and intensifying low level jet and attendant rapidly increasing upstream instability axis will drive the organization and intensification of showers and thunderstorms to our west. What happens thereafter remains the unanswered question. If convective allowing guidance`s placement/evolution of low level jet and folding instability gradient is realized, then shower/storm evolution should trend southeast, with most organized and intense activity sliding into southwest lower Michigan later tonight...leaving more "generic" and more scattered activity to impact our area. Pattern recognition of these type of systems strongly supports this idea. However, if forced convergence on nose of low level jet is displaced just a bit further north, then upstream more organized and intense activity has a much better chance to impact at least parts of our area later tonight into early Tuesday. Will definitely need to monitor, as increasing deep layer shear through the depth of the convective layer would support a least a low end severe wind threat...as well as some marginal severe size hail. Latest SPC convective outlook continues to highlight this potential, placing nearly all of northern Michigan into a marginal risk for severe weather. What happens tonight/early Tuesday morning will significantly dictate what transpires later Tuesday. Actual cold front set to cut west to east across our area during the morning and early afternoon, with that timing at least theoretically supporting the potential for additional destabilization...especially across northeast lower Michigan (if skies can at least partially clear). However, primary instability axis will remain well south of us, and any pre-frontal convergence axis (from morning showers/storms) may drive best convergence south and east of our area before actual front arrives. Very possible late Tuesday morning and afternoon are completely devoid of any activity, with showers and storms remaining east and south of our area. Again...if storms can develop, isolated severe potential will continue given brisk wind fields through the vertical. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Issued at 307 PM EDT Mon Jun 24 2024 PATTERN SYNOPSIS/FORECAST: Longwave troughing will continue chances of active weather before a ridge of high pressure builds overhead promoting quieter weather by mid-week. Low pressure tracks along the northern U.S and Canadian border, and eventually to Lake Superior for Friday/Saturday, bringing back the next chances for showers/ thunderstorms. Temperatures will increase throughout the week then decrease for the weekend as active weather is expected to return. PRIMARY FORECAST CONCERNS: - Precipitation Chances: A shortwave trough will slide across the Great Lakes Region Wednesday bringing increasing cloud cover through the day. Some guidance hints that some light showers could be possible later in the day Wednesday, but confidence is low. Attention then turns to a longwave trough and its associated low pressure will track towards the Great Lakes Region Friday/Saturday bringing active weather back to the forecast area. It`s still too early to message specific impacts, but guidance suggests that it`s likely active weather will return for this weekend- Stay tuned! && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 757 PM EDT Mon Jun 24 2024 A round of thunderstorms is expected to impact the area after 08Z, pushing quickly se across the area. Brief but significant restrictions along with gusty winds will be possible, with the best chance at MBL and TVC. Some lower cigs will linger for several hours after precip chances, with gradual improvement on Tuesday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...JZ SHORT TERM...MSB LONG TERM...NSC AVIATION...JZ