Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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040 FXUS63 KMQT 130915 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 515 AM EDT Thu Jun 13 2024 .KEY MESSAGES... - Gusty northwest winds are expected today along with additional chances for isolated showers and thunderstorms. There is a marginal risk (category 1/5) of severe weather for most of the UP, with the main threats being large hail in excess of an inch and damaging winds in excess of 60 mph. - Dry Friday and early Saturday before the return of showers and thunderstorms later in the weekend. - Warmer than normal temperatures frequent the forecast, with some areas approaching 90 for highs by next week. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 514 AM EDT Thu Jun 13 2024 RAP analysis shows a mid level trough over southern Manitoba with a weak low pressure trough at 1004 mb extending over Lake Superior and into the UP. A cold front drapes from western lake superior northeast into northern Ontario. Showers and lingering thunderstorms have almost made their way out of the UP, but dry weather is expected within the next hour as PVA diminishes and this sfc low pressure trough slowly moves east this morning. This dry period is only expected to be brief as mid level trough rotates east through northern Ontario, sending a stream of vorticity south across the UP today. As the sfc low pressure trough progresses east toward Quebec, it deepens and brings the cold front eastward across the UP through early this afternoon. CAMs do not have the greatest agreement on the timing of shower and storm activity today, but there does seem to be a consensus on two periods. The first one being a round progressing east across the UP with the cold front. The second period would be more PVA forced in the later part of the afternoon. The marginal risk for much of the UP seems appropriate for today as neither of these rounds is a home run. Bulk shear of ~50 kts will be sufficient for storms throughout the day, but the best instability (6/13 0z HREF mean SBCAPE to around 1000 J/kg) is expected in the earlier part of the afternoon ahead of mid level lapse rates increasing to near 7C/km. That said, some isolated stronger to severe storms are possible. If any severe storms are able to develop (5% chance), the main threats will be hail and winds. CAA and drier air behind the cold front will allow for some good mixing resulting in some gusty northwest winds. While the 6/13 0z HREF indicates only a 40-60% chance of wind gusts exceeding 30 mph, model soundings do indicate the potential for isolated gusts as high as 40 to even 50 mph. These gusts are not expected to be consistently high enough for an advisory, but it will still be a gusty day. Highs for the most part are expected in the 70s with the south central UP being warmer in the low to mid 80s. The other exception to highs in the 70s would be those near Lake Superior which may only see highs in the 60s. && .LONG TERM /THURSDAY THROUGH WEDNESDAY/... Issued at 335 PM EDT Wed Jun 12 2024 The active weather pattern across the CONUS continues through the long-term forecast. The main features of note at 500mb are a trough passing over Lake Superior Thursday and a deep cutoff low off the coast of the Baja California, which will be the cause of active weather over the weekend. Despite high pressure keeping a day of , the overall weather pattern through the long term is wetter than normal and warmer than normal, with some of the hottest temperatures of the year thus far forecast for Monday. Thursday, the aforementioned trough will pass over the area. 850mb cold advection and dry air behind the trough will allow for 20-30kt winds to mix down to the surface. EFI shift of tails has backed off somewhat but the Euro ensemble still calls for the potential of gusts up to 35 mph. These gusts will almost certainly (90+%) not be consistently high enough for an advisory but it will still be a gusty day. CAMs call for some diurnal showers supported by post- tropa clearing allowing for some radiational heating, but only isolated thunderstorms are expected. Highs look to be in the 70s for the most part except for the southern reaches of the UP reaching into the 80s and some of the near-Lake Superior communities only seeing highs in the 60s. Once showers move out of the UP entirely Thursday evening, dry weather will be over the UP through at least Saturday morning as ridging aloft builds in and supports a near-1020mb high pressure over the Upper Great Lakes. Friday will be a slightly cooler day with highs only in the 60s to low 70s, but highs recover to the mid 70s for Saturday. RHs look to fall into the 40s and 30s, but with very light winds, weather should be benign to end the work week and begin the weekend. Meanwhile, the deep cutoff low over the Pacific will deamplify and shift northeast through the Rockies. The GEFS shows a low pressure will develop in the Canadian Prairie, with the GEFS suggesting a central pressure potentially below 990mb and perhaps into the 970s mb over Manitoba by Sunday afternoon. With high pressure shifting to the east, predominantly southerly low level flow will allow Gulf moisture to surge north, as shown in the NAEFS vapor transport being at the 90th percentile of climatology along with PWATs of near 1.5 inches. As the weakening trough approaches the Upper Great Lakes and the cold front of the Canadian Low approaches, multiple lifting mechanisms for showers and thunderstorms will be present, with PoPs spreading west to east beginning Saturday PM. As the pattern is complex, details on the strength and timing of storms is tough to narrow down, so look for future forecast packages to gain clarity there, but with the available moisture to work with, ensembles do show about a 15% chance of daily precip totals to exceed an inch by Sunday. This is a little lower than the last 24 hours of guidance, but still enough to maintain some concern about weekend outdoor plans that would be ruined by a downpour. The gradual warmup continues into next week, with high 80s in the forecast for Monday, with widespread low to mid 90s in the 75th percentile of the NBM. PoPs remain in the rest of the long term forecast as ensembles show a continued chaotic pattern through mid- June. The general pattern looks to support ridging over the eastern CONUS with a persistent surface high off the East Coast, which should help create southerly to southwesterly flow to advect further Gulf moisture north. As a result, the CPC outlooks the 8-14 day period as being more likely to be warmer than normal and wetter than normal. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 115 AM EDT Thu Jun 13 2024 Lingering showers and thunderstorms near KSAW will continue pressing east after issuance, but expect improving conditions soon afterwards. In the wake of tonight`s storms, low level moisture will support MVFR ceilings at KCMX and potentially some fog. After the sun rises, expect improving ceilings to VFR at all sites and daytime mixing to support gusty conditions. Current forecast is for 25-30kt westerlies, but some guidance suggests mixing could support upwards of 40kts in some areas by afternoon Thursday. && .MARINE... Issued at 324 AM EDT Thu Jun 13 2024 Southwesterly winds will become west-northwesterly and increase behind a cold front later this morning with gusts of 20 to 25 knots. By Friday, winds will return to less than 20 knots with the return of high pressure where they will stay until early Sunday morning. At that point, the next cold front will bring southerly winds of 20 to 25 knots along with 4 to 5 foot waves along the US/Canada border on Lake Superior. In addition, thunderstorm chances will return to the forecast, but it is too early to determine severity. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Jablonski LONG TERM...GS AVIATION...JTP MARINE...TDUD