Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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439 FXUS63 KMQT 141803 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 203 PM EDT Fri Jun 14 2024 .KEY MESSAGES... - Dry through Saturday before the return of showers and thunderstorms later in the weekend. - Warmer than normal next week with frequent chances for showers and storms. && .SHORT TERM /THROUGH TONIGHT/... Issued at 203 PM EDT Fri Jun 14 2024 GOES-16 visible imagery shows a fair-weather cu field away from Lake Superior across the UP, but otherwise clear skies are over the UP today. RAP analysis shows ridging over the Plains advancing towards the Upper Great Lakes, which the negative vorticity advection is supporting a near-1020mb high pressure over Lake Superior this afternoon. With the high pressure expected to linger over the region through at least Saturday morning, no precipitation is expected. While the main component of the wind is northerly, flow is weak enough that local influences and lake breezes are allowing for light and variable winds in some spots through this evening. Overnight, as the high shifts slightly, winds will gradually become more southerly, though should remain below 10 kt. Clear skies over the east will allow temperatures to fall to the low 40s per bias- corrected gridded MOS guidance, with some scattered skies over the west half keeping lows around 50. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 413 AM EDT Fri Jun 14 2024 Dry weather continues for most of Saturday with the midlevel ridge sliding over the area supporting surface high pressure centered over the Lower Great Lakes. However, another shortwave will be rippling out of the Plains, with a tightening pressure gradient resulting in increasing southerly winds for the afternoon. Expect wind gusts to around 20 mph for most of the UP, and as soundings at least across the eastern UP remain quite dry and well-mixed, we could be flirting with some fire weather concerns as RH drops below 40%. That said, cloud cover will be on the increase throughout the day ahead of the approaching wave. With strengthening theta-e advection into the evening on the nose of a developing 40-45kt LLJ, chances for showers and rumbles of thunder sneak into the western UP by early evening. PoPs increase overnight into Sunday morning as the shortwave moves across the UP and Lake Superior. Guidance is coming into agreement on the LLJ further increasing to as high as 50-60kts, so while the timing of the passing wave (early in the day Sunday) would be unfavorable for strong/severe surface-based convection, this impressive lift and elevated instability could still be supportive of stronger storms with gusty winds and small hail. Will note a potential for heavy rain as well, with PWATs exceeding 1.5in and soundings quite saturated. Temperatures, meanwhile, will be on the increase Sunday, in spite of the round of rainfall early in the day; expect highs ranging in the 70s in the eastern UP where rain may be lingering into the afternoon while the western UP climbs as high as the mid 80s. Warm and unsettled weather will continue into next week. Monday through midweek, the Great Lakes will be situated between high- amplitude ridging over the Eastern Seaboard and deep troughing over the Rockies. Persistent southerly flow into the area will continue to pump in a warm, moist airmass; look for highs Monday and Tuesday to range well into the 80s for most of the area and even nearer to 90F in the typically warmer southerly downsloping spots. With dewpoints well into the 60s, it is looking pretty muggy. Given this unstable airmass and our area situated on the perimeter of the ridge, passing weak waves will leave us with chances for showers and storms Monday and Tuesday. Winds should also become more elevated Tuesday as a midlevel shortwave ripples out of the Rockies with a surface low likewise closing off and heading into the Northern Plains, leading to a tightening pressure gradient over the area. Another strengthening LLJ may provide the lift needed for some additional convection Tuesday night into Wednesday while the surface low moves through Ontario. From midweek onward, temperatures trend more towards normal while the pattern governing the early part of the week breaks down. Look for hit and miss rain chances the rest of the period with sporadic shortwave activity amid generally zonal midlevel flow. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 133 PM EDT Fri Jun 14 2024 VFR conditions are expected at all sites throughout the duration of the 18Z TAF period as high pressure resides over the Upper Great Lakes. Winds are generally expected to be light and variable throughout the TAF period, but will become mainly southerly by tomorrow morning. && .MARINE... Issued at 413 AM EDT Fri Jun 14 2024 High pressure ridging over the Great Lakes will lead to tranquil conditions today and into the early part of the weekend. Winds come in at or below 10kts today, turning mainly out of the NE in western Lake Superior and eventually backing more WNW across the eastern half of the lake. Winds mainly out of the SE Saturday will be on the increase by the late afternoon, gusting up to 20 knots in the eastern half of the lake. Winds gusts to 20-25kts will be possible Sunday, then winds fall back below 20 kts Monday before increasing out of the SSE again Tuesday. Waves should generally be below 3ft for most of the period, but are expected to increase to around 3-4ft especially across the eastern half of the lake Sunday and Tuesday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...LC AVIATION...GS MARINE...LC