Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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048 FXUS63 KMQT 292009 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 409 PM EDT Wed May 29 2024 .KEY MESSAGES... - Widespread frost expected tonight across much of the UP away from the shores of the Great Lakes. Localized hard freezes can`t be ruled out but is not expected to be widespread. - Below normal temperatures through tonight, then warming up through early next week. - A more unsettled pattern returns on Friday, continuing into next week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 230 PM EDT Wed May 29 2024 GOES Visible imagery shows a near-perfectly clear sky over the UP today with fair weather cu staying to the south and west of the UP. This is caused by a RAP-analyzed 1025mb high pressure centered over west-central Lake Superior this afternoon, supported by ridging aloft over the Great Plains. High temps this afternoon in response to the clear skies will climb into the 60s for much of the interior UP, though lingering northerly wind gusts will keep the Lake Superior shores in the 50s. Overnight, clear skies will continue. With a well-mixed airmass that has already seen RHs falling into the 20s, radiational cooling is expected to be quite efficient. However, various rules of thumb point to temperatures only reaching around freezing or just above freezing, with MOS guidance trending warmer with recent model runs. Forecast lows overnight are now forecast to be as low as 30F as a result, though it would not be a surprise for the typical cold spots in valleys and other low-lying areas to have hard freezes. While hard freezes will be limited to localized areas, frost should be widespread in the early morning areas for all of the UP away from the shores of the Great Lakes. && .LONG TERM /THURSDAY THROUGH WEDNESDAY/... Issued at 409 PM EDT Wed May 29 2024 The quiet and dry period ends on Friday as a cold front moves into the west. This is followed by precip chances for the weekend into early next week as we track out shortwaves into the Upper Great Lakes. Temperatures warm through the early part of next week as ridging shifts toward the Atlantic coast and WAA increases. Starting on Thursday, high pressure continues to shift southeast over the Great Lakes Basin as mid level ridging builds in. This results in more mixing and dry conditions similar to today. While mixing is not expected to be as high (mixing to around 4-6kft), highs are expected to be warmer in the upper 60s to mid 70s in the interior with cooler 60s by the Great Lakes lakeshores. This brings min RHs in the interior into the 20s, higher near the lakeshores (30- 40%). Light southerly winds are forecast save for some east winds in the Keweenaw and the varying wind directions near Lake Superior as a lake breeze pushes in off the lake during the afternoon. The warm and dry conditions flirt with borderline elevated wildfire criteria with winds being the limiting factor as gusts are mainly expected below 15 mph. Skies stay mostly clear Thursday night with lows in the low 40s to low 50s, warmer in north central and western Upper MI where there is southerly downslope flow. A weak cold front associated with a sfc low over northern Saskatchewan moves into the western UP on Friday. This brings in a band of showers over the west on Friday, but not much eastward progression is expected as the front weakens and stays relatively stationary. Chances for thunderstorms on Friday remain low (>15%) with minimal instability (high-end of MUCAPE guidance around 100-200 J/kg), lower bulk shear (25-30 kts), and a weakening frontal boundary. Where precip holds off and skies remain clearer over the east on Friday, mixing could result in borderline wildfire conditions with gusts to 20 mph and minimum RHs back into the 20s. Chances for showers increase Friday night into Saturday as a shortwave lifts northeast from Iowa through the Upper Great Lakes and isentropic ascent increases. This will be quickly followed up by another shortwave tracking east from the Northern Plains Friday night through Lake Superior Saturday into Saturday evening. Better chances for thunderstorms accompany the secondary shortwave on Saturday when there is better instability and shear. A brief dry period is expected to follow into Sunday as we warm into the upper 60s to upper 70s. The rather active weather pattern continues into early next week with an additional shortwave expected to pass over Lake Superior and Upper Michigan on Monday ahead of a deeper trough for mid next week. That said, accumulations are not expected to be high as 5/29 0z LREF probabilities of at least 0.25" of QPF in a 24 hour period stay below 50%. With spread in the guidance among timing and track of the shortwaves, opted to leave NBM PoPs as is. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 125 PM EDT Wed May 29 2024 Under high pressure, VFR will prevail at all TAF sites with SKC conditions and P6SM vis through 12Z Thursday. Winds may be variable, but they will be mainly 5 knots or below through the TAF period with the exception of gusty conditions currently at SAW and IWD. && .MARINE... Issued at 409 PM EDT Wed May 29 2024 High pressure slowly shifts southeast over the Great Lakes Basin into this weekend. This leaves light and variable winds mainly below 15 kts through Thursday morning. Winds become easterly Thursday morning, veering south Thursday evening. South winds then increase to 10-20 kts through Friday as a weak low level jet passes overhead. With probabilities of winds exceeding 22 knots below 20% through this weekend, winds are expected to mainly remain below 20 knots into the early part of next week with no major systems in the vicinity of Lake Superior. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Frost Advisory from 2 AM EDT /1 AM CDT/ to 10 AM EDT /9 AM CDT/ Thursday for MIZ002-004>007-009>014-084-085. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...Jablonski AVIATION...GS MARINE...Jablonski