Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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092 FXUS63 KMQT 110820 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 420 AM EDT Tue Jun 11 2024 .KEY MESSAGES... - Chilly and dry again tonight with high pressure overhead. Frost is possible. - A couple rounds of showers and thunderstorms expected Tuesday afternoon through Thursday night. This will be accompanied by generally warmer than normal temperatures that continue into the weekend. - Strong and potentially severe storms look possible Wednesday afternoon and evening across the west half of Upper Michigan. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 420 AM EDT Tue Jun 11 2024 Currently it`s cool and quiet outside as mid level ridging moves over the Upper Great Lakes and high pressure settles southeast through the area. With only a few high clouds passing east over the UP ahead of the next system and a dry and chilly airmass overhead, radiative cooling has allowed for temps for much of the UP to drop into the 30s with low to mid 40s near the lakeshores. Temps will continue to settle a few more degrees yet before sunrise, letting more spots approach low to mid 30s. With the calm conditions, widespread frost is still expected away from the lakeshores. Moving on to the rest of today, the broad trough currently analyzed over Saskatchewan and Manitoba shifts east toward Ontario. The southern shortwave embedded in this trough rotates northeast from southern Manitoba to far northwestern Ontario through this period, supporting a similar northeastern track for the associated sfc low. This results in some weak PVA and isentropic ascent late morning into the afternoon over the west as the mid level ridge breaks down. The antecedent dry airmass from the high pressure likely will hold of showers until around noon in the far west, with showers progressing east across the UP through the afternoon ahead of the sfc low`s occluded front. Given the weak forcing and lack of instability/shear during the daytime hours (bulk shear peaking at ~30kts with MUCAPE below 250 J/kg), thunder should hold off until the evening hours. Mixing will result in some breezy southerly winds today with gusts up to 20-25 mph, strongest in the far west. Highs for the day are expected in the upper 60s to low 70s. && .LONG TERM /TUESDAY THROUGH MONDAY/... Issued at 319 PM EDT Mon Jun 10 2024 Overnight ridging will breakdown Tuesday as a shortwave and surface low press through Manitoba and into Ontario. By evening, an associated weakening cold/occluded front will press into the western UP. Ahead of the boundary by mid-late afternoon, showers with some embedded thunderstorms will press into western Upper Michigan, then continue east through the U.P. overnight as activity wanes. Guidance suggests instability will be limited (MLCAPE of 500 j/kg or less), so strong to severe storms are not expected. Daytime highs Tuesday should climb to near 70F while overnight lows Tuesday night only dip into the low 50s. Near-zonal flow with a couple embedded shortwaves will follow across the northern Tier into the Great Lakes. While these shortwaves progress close or through the Great Lakes, prevailing southerly low- level flow and warm air advection will support increased warming Wednesday and Thursday. This warm and moist airmass could support a couple rounds of showers and thunderstorms as these shortwaves press into the region Wednesday and Thursday. Beginning with a breakdown of Wednesday, a weak shortwave/PVA stream will move west to east through Lake Superior and Upper Michigan through the day. A 850mb LLJ to near 30-35kts alongside a jet exit region by afternoon may support large scale ascent and deep layer shear of 50-60kts. While the NAM is certainly an outlier with its 2-3k j/kg MLCAPE, the general consensus of 500-1000j/kg MLCAPE across the west half with the wind profile may support some strong or severe thunderstorms. It should be noted that the better forcing is expected to be south and west of the region, but steep mid-level lapse rates present in NAM, NAM3k, and GFS soundings suggest that if something does develop in our area, hail and stronger winds will be possible. Initial timing among the various deterministic systems suggest earliest onset would be in the afternoon in the west, but there`s a better signal for mid- late afternoon in the west, then increasing coverage in the evening U.P.-wide. By Thursday morning, another shortwave looks to press southeast through Lake Superior while a surface low lifts north through Ontario. There`s timing differences among the models as to when the trailing cold front will press through Upper Michigan, but the general consensus is that the front should clear the region by afternoon. Similarly to Wednesday, the strongest instability is out of our forecast area, but strong deep layer shear would be enough to support strong storms if they materialize ahead of the boundary. Post frontal dinural mixing may also support a gusty day on Thursday. Steeping low level lapse rates may be able to mix up into strong winds a loft. At the moment, current forecast is for 20-25 kts, but this may trend up in future forecasts. Another shortwave may follow Thursday night into early Friday, but confidence is low (<25%) at this point. Both Wednesday and Thursday, daytime highs may climb to the upper 70s or low 80s with overnight lows mostly in the 50s. Cooler airmass builds in for Friday which will support highs in the upper 60s to mid 70s. This is expected to be brief given guidance`s suggestion of a warming trend going for the weekend and into next week. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 125 AM EDT Tue Jun 11 2024 VFR prevails at all terminals for most of the forecast period. Apart from some stray high cirrus spilling into the area, skies are mostly clear across the UP. However, clouds thicken and lower into Tuesday with an approaching disturbance. This should bring in some scattered showers, and perhaps a rumble of thunder, from west to east during the afternoon and evening Tuesday. Some MVFR restrictions are possible. Otherwise, expect shifting winds this evening to turn to the south into Tuesday, with some gusts around 20kts possible especially at IWD. && .MARINE... Issued at 319 PM EDT Mon Jun 10 2024 High pressure over the region has supported winds mainly 20kts or lower across Lake Superior. A series of fronts will move through the lake Tuesday - late Thursday. Ahead of these fronts, southerly winds may support 20-25kt winds and showers and thunderstorms. Strongest storm potential will be Wednesday afternoon and evening across western Lake Superior. High pressure builds in on Friday, returning dry and calmer conditions with winds below 20kts to start of the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Frost Advisory until 8 AM EDT /7 AM CDT/ this morning for MIZ002>007-009>014-084-085. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Jablonski LONG TERM...JTP AVIATION...LC MARINE...JTP