Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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117 FXUS63 KMQT 111726 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 126 PM 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 TODAY/... Issued at 126 PM EDT Tue Jun 11 2024 A line of showers has progressed west to east through Minnesota and into western Lake Superior today. Dry air, apparent on GOES Water Vapor imagery, has resulted in a gradual diminishing trend to this line as its moved closer. Cloud cover has also expanded across western and central Upper Michigan, resulting in highs only in the low 60s interior west. Elsewhere, enough sunshine was observed to allow warming into the mid-upper 60s, except near Lake Michigan, which has been moderated by southerly flow off the bay and lake. These spots have barely climbed into the low 60s. As we progress through the remainder of the afternoon and overnight tonight, a weakening occluded front will continue pressing eastward, spreading cloud cover and light rain east across Upper Michigan. Only light accumulations are expected given the antecedent dry air. A rumble of thunder or two can`t be ruled out. Further upstream in northwestern Minnesota, increasing instability this afternoon may result in showers and thunderstorms developing and pressing east/southeast ahead of another shortwave rotating around a mid- level low in Manitoba. This may support another round of brief showers, perhaps a thunderstorm, late this evening in the Keweenaw/west and after midnight in the east before clearing skies spread overhead. Significant additional heating isn`t expected today, so expect highs mostly in the 60s to near 70F in some spots. Overnight lows should dip into the 50s, maybe high 40s in the interior west if we`re able to clear out earlier then expected. && .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 /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 126 PM EDT Tue Jun 11 2024 Cloud bases will gradually lower this afternoon as a weakening occluded front brings showers west to east through the evening hours. Some thunderstorms will be possible, mainly at KIWD, but confidence is low (<25%). MVFR ceilings may be achieved as well, particularly at KIWD this afternoon and KCMX this evening. Expect clearing skies overnight. Winds will prevail out of the south then southwest tonight. Guidance is still keen gusty conditions at KIWD this afternoon. However, no gusts have been observed there or upstream. While still possible, I`ve removed it from this TAF given the probability appears to be low (<25%). Mist/fog may develop overnight at KCMX and KSAW before lifting after sunrise. && .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...JTP LONG TERM...TDUD AVIATION...JTP MARINE...TDUD