Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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136 FXUS63 KMQT 111215 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 815 AM EDT Tue Jun 11 2024 .KEY MESSAGES... - A couple rounds of showers and thunderstorms expected this 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 /TONIGHT THROUGH MONDAY/... Issued at 541 AM EDT Tue Jun 11 2024 Convective activity will return for the first half of the extended period as temperatures return to more of a summer pattern. Immediately, ongoing showers will be possible this evening as a cold/occluded front continues its progression across Upper Michigan. And, with a little burst of instability, some rumbles of thunder can be expected into tonight, mainly west and central. But, with guidance suggesting MUCAPES struggling to get above 250 J/kg, storms will struggle to maintain much if any intensity after Wed 06Z. By Wed 09Z, almost all of the forecast area will be rain and thunderstorm free with a brief lull in activity before the next shortwaves enter the area. The first of two shortwaves is progged to enter Upper Michigan on Wednesday, advecting dewpoints in the mid to upper 50s and warm air (temps in the low to mid 80s) ahead of it. Despite the best instability being south and west of the UP, MLCAPE values could still reach the 500-1000j/kg range over the southwest UP. And, forcing in the exit region of a 50-70 kt mid-level jet combined with a surface cold front could be sufficient enough to generate some strong to severe thunderstorms mid to late afternoon (west) and over the remainder of the UP through the evening hours. Again, best 0-3 km storm-relative helicity will remain south and west of Upper Michigan. But, mid-level lapse rates in excess of 6 C/km over portions of Upper Michigan suggest that large hail could be a threat from any storms that do become severe. Thursday, the second of the two shortwaves will combine with a surface low propagating through the region to generate additional thunderstorm chances. Once again though, the best instability will remain out of Upper Michigan, but a few strong thunderstorms cannot be ruled out during the afternoon and evening hours with fropa of cold front. In the wake of the front though, wnw winds will become strong with gusts up to 25 to 30 kts. Further out, brief ridging will bring a break from the active pattern by Thursday night, continuing into the weekend. After a slightly cooler day Friday with highs in the 60s/70s, the warming trend will commence again for the second half of the extended period as highs reach the 80s again by Sunday and some of the warmest temperatures of the season by Monday with models hinting at upper 80s. A break down in that upper ridge, though, will be indicative of thunderstorm activity once again by late Saturday with additional chances through the end of the extended period with multiple waves. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 814 AM EDT Tue Jun 11 2024 VFR conditions will prevail at all terminals through at least this morning. An approaching system is expected to bring in some scattered showers and periods of MVFR cigs from west to east in the afternoon and evening hours; a few rumbles of thunder are possible this evening. Any lingering MVFR cigs this evening should clear out tonight as a drier airmass moves in later. Southerly winds today will be a bit breezy with gusts up to 25 kts possible at IWD; winds taper down this evening as they shift southwest. && .MARINE... Issued at 553 AM EDT Tue Jun 11 2024 Winds mainly 20kts and lower will persist across Lake Superior through tonight. But, as the high pressure is replaced by a series of disturbances, an uptick in southerly winds of 20 to 25 knots can be expected by Wednesday afternoon along with the potential for strong to severe thunderstorms through the evening hours of Wednesday. Southwesterly winds will continue at 20 to 25 knots with isolated gusts up to 30 knots through Thursday before finally relaxing on Friday with the return of high pressure. Additional shower and thunderstorm chances are expected Thursday, but strong to severe thunderstorms are not expected. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Jablonski LONG TERM...TDUD AVIATION...Jablonski MARINE...TDUD