Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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986 FXUS63 KMQT 220911 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 511 AM EDT Wed May 22 2024 .KEY MESSAGES... - A Wind Advisory is in effect today due to wind gusts up to 50 mph over the Keweenaw Peninsula and up to 45 mph along the remaining western Lake Superior shores of the UP. - Waves of 6 to 8 feet along the shores of Lake Michigan to cause high risks of rip currents today. - Another shortwave and low pressure system will bring another round of showers to Upper Mi late Friday into early Saturday. - There may be more opportunities for light showers next week although model uncertainty leads to low forecast confidence on timing/extent at this point. && .SHORT TERM /THROUGH TONIGHT/... Issued at 351 AM EDT Wed May 22 2024 GOES-16 Water Vapor imagery and radar returns show that behind a line of showers over the eastern UP, only isolated showers remain in an otherwise dry slot. RAP Analysis shows a 989mb low over the northwestern shores of Lake Superior progressing to the NNE. As the low and parent trough move into northwest Ontario today, an 850mb LLJ will be source of the most impactful weather over the UP today. By 20Z, the 00Z HREF shows 50 kts at 850mb over the Keweenaw with 35- 45 kt over the remainder of the west half of the UP. Mixing will allow for some of those winds to be transported to the surface in the form of wind gusts over the Keweenaw up to 50 mph and gusts across the rest of the west half of the UP to 35-45 mph. HREF and EPS guidance suggests only around 10% probability of wind gusts exceeding 58 mph over the Keweenaw, so the High Wind Watch is cancelled. The HREF does indicate some 30% probabilities along the western shores of the Keweenaw of 58 mph gusts, so coastal communities such as Freda, Eagle River, and Eagle Harbor could see a peak gust of that strength, but as far as widespread, sustained gusts are concerned, gusts up to 45 mph are the main concern. The Wind Advisory will continue for Gogebic and Ontonagon and will expand to cover northern Houghton County and Keweenaw County. For the remainder of the UP, gusts to 35 mph are expected today, which is still pretty gusty, but no products are expected to be issued, given the HREF has trended towards a more compact area of higher winds over the west. As the dry slot will continue to reside over the UP today, shower chances will be low, however, the HREF does show isolated to scattered showers supported by diurnal heating this afternoon, so some low-end (15-30 percent) PoPs are left in, but impacts from this should be minimal. For those willing to brave 55 degree water temperatures over Lake Michigan, waves of 6-8 feet over the nearshore waters of Schoolcraft County are leading to high chances of rip currents, prompting a Beach Hazard Statement. Tonight, as mixing becomes less efficient and the low pressure continues to lift north and away from the UP, winds fall off and the weather is mainly benign, with lows falling into the 40s. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 507 AM EDT Wed May 22 2024 The extended forecast begins Thursday into Thursday with mostly dry conditions under weak ridging. The weak ridging will then give way to the next shortwave emerging from the western CONUS trough which will lift through the Northern Plains and Upper Great Lakes west where a High Wind Watch and Wind Advisories were issued).s bringing another round of showers to the U.P. late Friday into early Saturday. While most of Saturday into Saturday night looks dry under weak high pressure, model uncertainty increases out to Sunday and beyond in the extended leading to lower forecast confidence although it looks like there will still be showery periods into next week. Beginning Thursday, the unusually strong storm system over western Lake Superior early this morning will gradually weaken late tonight into Thursday as it tracks ene from northern Ontario toward James Bay. Increasingly confluent flow ahead of the mid-level ridge building over the Northern Plains should lead to weak ridging/subsidence and mostly dry conditions across the area on Thursday. A few of the models hint at a subtle shortwave rotating thru the area in the afternoon from the storm system over James Bay, but any shower development from this weak wave should be sparse given dry low-levels depicted in fcst soundings. Overall, should be a nice day with highs across the interior mostly in the 70s with readings in the 60s along Lake Superior. By Friday, the focus shifts to the next shortwave emergieng from the western CONUS mid-level trough. As this shortwave lifts ne through the Plains and Upper Great Lakes increasing isentropic ascent, 850 mb theta advection and moderate q-vector convergence out ahead of the shortwave will lead to another round of rain showers spreading w- e across the fcst area late Friday into early Saturday. By late Saturday morning, ridging and associated subsidence builds in behind the shortwave leading to dry and seasonable temps for the rest of the day with highs mostly in the 60s with a few cooler mid 50s readings near Lake Superior. While models indicate weak ridging should hold on long enough to keep Sunday dry, there is plenty of model uncertainty with what will happen after that. The 00Z deterministic GFS and Canadian models maintain mostly dry conditions through the first half of next week suppressing a southern stream through Lower Great Lakes/Ohio Valley and keeping the Upper Great Lakes mostly dry. Meanwhile, the ECMWF the last couple of runs has trended toward a phased, deeper and farther north system tracking over the Straits by 12Z Mon and the latest 00Z run of the UKMET has also latched onto this idea. If this solution verifies it will potentially be a much more impactful system for the Upper Great Lakes into early next week with much of the U.P. receiving significant soaking rainfall and possibly heavy rainfall over the east half Sun night into Tue. Wraparound moisture in the deformation zone, comma head of the deepening e system would likely lead to the potentially heavy rainfall. This deeper solution would also lead to more wind impacts with gales likely over Lake Superior and windy conditions across much of the U.P. Needless to say, model trends will be watched closely in the coming days so stay tuned to possible forecast changes into early next week. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 132 AM EDT Wed May 22 2024 With TS now beyond all three TAF sites, -SHRA continues into the early morning hours, ending around 12Z. Throughout the late morning, ceiling heights will gradually improve, with all sites expecting VFR conditions by 18Z. Gusty SW winds are expected today, with the highest gusts up to 45 kt at CMX around 20Z, with gusts around 30 kt this afternoon at IWD and around 25 kt at SAW. A second round of - SHRA is possible at all 3 TAF sites in the late afternoon/early evening, but chances of precip are only around 30 percent, so SHRA is left out of the TAF at this time, but VCSH may be added in for later issuances. Precip and wind gusts fall off in the late portions of the TAF, though some LLWS may be present at SAW and CMX, but confidence is too low to include in the TAFs at this time. && .MARINE... Issued at 507 AM EDT Wed May 22 2024 East-northeast winds appear to be already shifting southwest over the western portion of Lake Superior early this morning as an unseasonably deep low pressure system now over the MN Arrowhead will continue to track north into Ontario today. Southwest gales can be expected across Lake Superior with high-end gales to 45 knots and maybe even a few storm force gusts to 50 knots expected over the west half into north central sections. East half sections will likely only see a brief period of southeast to south gales of 35 to 40 knots early this morning as a low-level jet continues to work across the area before winds subside blo gales late this morning into the afternoon. As the low gradually lifts north through Ontario and weakens, winds will drop blo gales for west and north central sections later this evening. The winds continue to diminish into Thursday afternoon, when light winds of 20 knots or less return to the area by evening. The period of light winds doesn`t last long over the western lake as northeast winds will begin to ramp up to 30 knots late Thu night into Friday in advance of another low pressure lifting from the Northern Plains towards Lake Winnipeg. Winds diminish to 15 to 25 knots over the west half of the lake and becoming southwest behind the low and the passage of its cold front late Friday night into Saturday. Behind this system, expect light winds of 20 knots or less across Lake Superior for the rest of this weekend as high pressure ridging moves over the area. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Wind Advisory until 10 PM EDT /9 PM CDT/ this evening for MIZ001>003-009. Beach Hazards Statement through this evening for MIZ014. Lake Superior... Gale Warning until 8 PM EDT /7 PM CDT/ this evening for LSZ162. Gale Warning until 8 PM EDT /7 PM CDT/ this evening for LSZ240- 241. Gale Warning until 11 PM EDT this evening for LSZ242>244-263- 264. Gale Warning until 11 AM EDT this morning for LSZ245>251- 265>267. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...Voss AVIATION...GS MARINE...Voss