Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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452 FXUS63 KMQT 100838 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 438 AM EDT Fri May 10 2024 .KEY MESSAGES... - Showers move in from the west this afternoon, mainly after 2 PM EDT, progressing eastward into tonight. There is a slight chance for thunderstorms in the far western U.P. and along the WI/MI state line. - Dry conditions are expected ahead of the showers with minimum RHs in the 20s to low 30s. That being said, there are no major wildfire concerns with light winds and showers on the way. - Chances for thunderstorms return on Sunday. There is a low (2%) chance for some marginally severe hail and wind. - Dry weather returns for the early part of the next work week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 436 AM EDT Fri May 10 2024 The rest of tonight will stay quiet with cooler than normal temps. RAP analysis shows a 1015mb high pressure over the UP, Lake Superior and the eastern half of northern Ontario. A positively tilted and somewhat compressed mid level ridge is analyzed over MN and northern Ontario with a shortwave over the far eastern portion of Lake Superior. Nighttime microphysics is already showing this shortwave forcing some mid level clouds over the water and far eastern UP, this looks to continue as the shortwave drops south the rest of the night, however significant cloud cover is not expected as model soundings only show a thin layer of moisture available around the 7kft level. This subsidence and mostly clear skies will allow for good radiative cooling, especially over the west. Lows are expected into the mid 20s to upper 30s, warmer near the lakeshores and coolest in the interior west; I would not be surprised if a few spots dip into the low 20s before sunrise. Moving on to the daytime, a shortwave currently over Manitoba dives southeast into Upper MI and WI mid to late afternoon. Mixing ahead of the showers is expected to result in lower RHs into the mid 20s to low 30s. Even though min RHs are below critical thresholds, there are no major fire weather concerns as highs for the day are expected in the 50s to mid 60s (cooler near the lakeshores), winds are expected to remain light (mainly below 15 mph), and precip is on the way. CAMs are really picking up on the lake breezes expected already late this morning into the early afternoon off both lakes, stronger in the east. This should help RHs recover a bit and result in some variable winds, especially in the east where the two breezes interact. Some convective cloud development is likely over the east. Even though the CAMs reflectivity shows some isolated showers developing along these two colliding lake breeze boundaries, confidence in any shower development off the Lake breezes is low as available moisture ahead of the cold front is lacking. If any precip is able to develop, some sprinkles would be the high end scenario. PVA and the associated clipper system`s cold front bring showers into the far west mainly after 2 PM EDT. As the pair of forcing mechanisms move east over the UP, showers move east with it. Low and mid level lapse rates ~7-8C/km and bulk shear is around 40-45 kts along the passing frontal boundary which would be supportive of storms. That being said, energy is lacking: the 5/10 0z HREF mean MUCAPE is around 100j/kg with individual models plotting up to 200- 400j/kg on the high end. Putting this all together, there is a slight chance for thunderstorms over the far western UP and along the WI/MI state line late this afternoon into the evening hours, but severe weather is not expected. Chances for showers continue east across the UP tonight, but thunderstorm chances end this evening as loss of daytime heating diminishes any lingering instability. As the front departs from the UP, precip looks to be primarily driven by PVA with some support from northerly upslope flow. This means the best chances for showers tonight are expected over the north central and eastern UP. Overall accumulations through tonight are a trace to 0.15"; a few spots may see up to 0.25" with thunderstorm development. Lows tonight are expected in the upper 30s to mid 40s. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 347 AM EDT Fri May 10 2024 Rain showers end across the area Saturday as a small high-pressure ridge moves through the area from the northwest to the southeast. However, more rainfall returns late Saturday night into Sunday as a second shortwave drops across the area; while the chance is low (2%), some marginally severe wind and hail is plausible, particularly over the south central Sunday afternoon. While high pressure ridging brings dry weather back over Upper Michigan during the first half of the next work week, additional rain chances look to return for the latter portion of next week to end the extended period. Expect above normal temperatures and precipitation amounts to continue through the extended period and next weekend. Additional details follow below. The shortwave low originally from far northern Manitoba gets pushed out of the Upper Great Lakes Saturday as shortwave ridging moves through from the northwest to southeast throughout the day. As this occurs, the light rain showers associated with the low end across the U.P. from west to east, with skies becoming mostly sunny across the region by the late afternoon hours. With cooler air aloft remaining over the area Saturday, expect temperatures to be around or slightly below average, with highs getting into the 50s to low 60s in the south central. The reprieve from the rainfall looks to be a fairly quick one though, as another shortwave low dropping down from the Northwest Territories brings showers and thunderstorms back across the area late Saturday night through Sunday; with cloud cover increasing Saturday night, expect low temperatures to be in the mid 30s in the interior east to mid 40s in the west. However, with warm air advection increasing across the area Sunday, expect the high temperatures to be in the 60s, with the mid 70s being seen in the interior west near the Wisconsin border. As the shortwave`s cold front goes through Upper Michigan during the afternoon hours, there is a low (2%) chance that we could see some severe weather as MUCAPEs approach 1000 J/kg and 0-6 km bulk shear is around 30 knots. With the NAM model soundings showing SBCAPE in the south central by the afternoon hours, we could see marginally severe hail and wind, particularly over the south central; we will have to see if the chances for severe weather increase as we approach this weekend. Otherwise, outside of possibly some locally heavy rainfall in a few of the cells, expect light rainfall amounts across most of the area late Saturday night through Sunday. Dry weather returns by next Monday and remains for the first half of the work week as high pressure ridging moves overtop us. While we could see min RHs approach 30% Monday through Wednesday, with fairly light winds and around normal temperatures predicted, no elevated fire weather concerns are expected at this time. Rainfall looks to return late next week as a troughing pattern moving through the Central CONUS brings a shortwave pattern back across the area. Model guidance seems to be pushing the timing back on the return of the precipitation; while the NBM brings rain chances back over us Wednesday afternoon, it seems like the latest deterministic runs in the differing medium range model guidance suites hold the rain off until late Wednesday night/Thursday. Therefore, I wouldn`t be surprised if the rain chances get pushed back in subsequent NBM runs (and thus our extended forecast). The rain chances look to continue to the end of the period. Beyond the end of the period, the CPC has a slightly higher chance of above normal temperatures and above normal precipitation in the 6-10 day period; in the 8-14 day period, there is an equal chance for above, near normal, and below normal temperatures whereas there is still a higher chance for above normal precipitation in the 8-14 day range. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 126 AM EDT Fri May 10 2024 VFR conditions are expected to prevail at the terminals through much of Friday. A low pressure trough moving through the area will bring some isolated to scattered rain showers and MVFR cigs to the terminals late Friday into Friday evening. Light winds will become light northwest to north behind the trough. && .MARINE... Issued at 347 AM EDT Fri May 10 2024 Light winds of generally 20 knots or less dominate the period as stable conditions prevent the mixing of higher wind speeds down to the water`s surface. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Jablonski LONG TERM...TAP AVIATION...Voss MARINE...TAP