Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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780 FXUS63 KMQT 222313 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 713 PM EDT Sun Sep 22 2024 .KEY MESSAGES... - High swim risk through this evening for the Lake Superior beaches of Marquette and Alger counties. - Other than a low chance (15-30%) of showers Tuesday into Wednesday southeast and east, dry weather is expected this upcoming week with a trend toward much above normal temps again late in the week. - Patchy frost is possible (~20%) for typical cold spots of interior western Upper Michigan both Monday and Tuesday mornings. - Supportive setup for typical fall radiative patchy fog (~25%) each morning next week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 217 PM EDT Sun Sep 22 2024 Water vapor imagery shows a well-pronounced midlevel shortwave moving through northern Ontario, while at the surface, the associated cold front is already through most of Upper Michigan. Rain showers lingering in the far eastern UP should come to an end by the evening. Skies are largely clearing behind the front with ridging extending out from the Plains. Still, with cool NW flow (around 4C at 850mb) over the 15-18C waters of Lake Superior, some lake clouds are apparent over the northwest and north-central UP. Soundings really begin to dry out at lower levels into the evening, however, so we may be able to see some more clearing while flow turns more anti-cyclonic. Meanwhile, NW winds remain elevated, with gusts up to 20mph common across the area. Higher gusts to 20-30mph will remain possible across the Keweenaw through the afternoon. Where skies are clearing out, temperatures have been able to climb up into the lower to mid 60s, but to the east, we may struggle to get out of the 50s this afternoon. Temperatures quickly fall back into the 40s across most of the UP under clear skies tonight, and with a pretty sharp inversion present among some of the model soundings, patchy fog will be possible. As temperatures dip further into the 30s in the typically cooler locations throughout the interior-western UP, some patchy frost may also develop. However, if lake clouds can be more persistent than expected, temperatures may come in a couple degrees warmer. && .LONG TERM /MONDAY THROUGH SUNDAY/... Issued at 420 PM EDT Sun Sep 22 2024 Beginning Monday, the mid-level trough over the area today will shift east tonight as weak shortwave ridging and an associated weak sfc ridge build in from the west ensuring dry conditions and partly cloudy to mostly sunny skies. With a ne-e mostly onshore flow and 850 mb temps of 6-8C lingering over the area through much of the day, expect max temps in the lower to mid 60s. Monday night through the mid portion of next week, the trough over the Dakotas dives southeast toward the Lower Mississippi Valley which helps ejects a shortwave northeastward from the Mid Mississippi Valley/Central Plains. This shortwave and its associated sfc low are expected to track northeast through Lower MI and the Central Great Lakes late Tuesday into Wednesday. While a few models suggest some light showers associated with this system may scrape the southeast and eastern portions of the UP Tuesday into Wednesday, accumulations will be very light as the better forcing remains se of the CWA. Otherwise, highs on Tuesday and Wednesday should trend above normal from the mid 60s to mid 70s, warmest Wednesday. Monday night could be another cool night with lows in the upper 30s to upper 40s with maybe some patchy frost possible again for the interior west cool spots. Model soundings show a more impressive inversion Monday night compared to tonight, so there is more radiation fog potential Monday night. The amplified mid level ridge over the western CONUS shifts east toward the Great Lakes late week into the weekend as models show a Rex block developing over the central CONUS including the Upper Great Lakes region. Models indicate an amplified 588-590 dam 5H ridge dominating the Upper Great Lakes/Upper Midwest region getting undercut by the closed low over the Southern Plains/Lower Mississippi Valley. There are some model discrepancies on how the closed low to the south interacts with the forecast tropical system lifting out the Gulf of Mexico later in the week and whether any moisture from that tropical system can reach north to bring any rain chances into the Upper Great Lakes next weekend. That said, the stronger ridging moving over the Upper Great Lakes region will favor continued dry weather for the late week through probably much of next weekend with a trend toward well above normal temps. Expect highs Thu-Sat reaching into the mid to upper 70s across much of the area and wouldn`t be a bit surprised to a few lower 80s possible over the western interior. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 713 PM EDT Sun Sep 22 2024 VFR conditions are expected to prevail in this TAF period thanks to dry air across the area. There is a slight chance for some patchy fog development tonight at KIWD/KSAW, but guidance continues to limit its coverage and confidence remains low. && .MARINE... Issued at 420 PM EDT Sun Sep 22 2024 Northwest winds gradually fall below 20 kts from west to east across the lake this afternoon through this evening, veering north tonight. Although a low pressure system tracks through Lower MI and the Central Great Lakes late Tuesday into Wednesday, winds are expected to remain below 20 kts through the remainder of the forecast. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement until 10 PM EDT this evening for MIZ005-006. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...LC LONG TERM...Voss AVIATION...JTP MARINE...Voss