Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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325 FXUS63 KMQT 190716 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 316 AM EDT Thu Sep 19 2024 .KEY MESSAGES... - Extended stretch of well above normal temperatures continues through at least Saturday with highs mainly in the upper 70s and 80s. - A cold front brings scattered showers and a few thunderstorms late today into Friday. Some stronger storms are possible in western Upper Michigan early this evening. - Temperatures around normal are expected to return for next week. && .SHORT TERM /THROUGH TODAY/... Issued at 122 PM EDT Wed Sep 18 2024 Another warm and dry day over Upper Michigan has developed. This, after morning temps in the 40s and 50s, and fog, some dense, across portions of central and eastern Upper Michigan. So far, temps have warmed into the 70s to low 80s, with the warmest spots being the southerly wind downsloping locations near Lake Superior. Effective mixing into a very dry airmass aloft has enabled dewpoints to fall into the upper 40s to 50s in the driest interior locations, which with the heat, is supporting RH values in the 30s and 40s in many locations. Thankfully, winds have been mostly light, which is limiting fire weather potential. As we progress through the remainder of the afternoon and tonight, expecting some additional warming before the heat wanes. Still expecting widespread low to mid 80s everywhere away from Lake Michigan`s influence where 70s will dominate. RH will respond as well and will support continued near and/or isolated elevated fire weather concerns into the evening. Overnight lows will again dip into the 40s and 50s. Also expecting another round of radiational fog to develop in interior locations of Upper Michigan`s south-central and eastern locations. Upstream, vertically stacked low spinning over North Dakota will lift northeast into Canada. An associated cold front will march east into western Minnesota overnight. Ahead of the front, theta-e ridge with a plume of robust instability will support showers and thunderstorms overnight. Its possible that some of these showers/storms may continue into western Lake Superior by morning. && .LONG TERM /TONIGHT THROUGH WEDNESDAY/... Issued at 315 AM EDT Thu Sep 19 2024 Some active weather starts off the extended forecast tonight as a cool front pushes in from the west, bringing with it showers and thunderstorms over Upper Michigan. With MUCAPE between 1k to 2k J/kg and 0-6 km bulk shear being around 25 to 35 knots, we could see a few strong thunderstorms over the western U.P. this evening a couple of hours after the sunset, with namely strong winds and large hail being the main threats. However, as the front and precipitation travel eastward with time tonight, the convection looks to outrun the better CAPE and shearing, causing the strong storm threat to end around midnight over the central U.P.. While rainfall amounts from the front won`t be all that impressive (mainly between 0.10 and 0.30 inches), we could see a few isolated spots, mainly over the west and central, that could see some localized soaking rainfalls as the heaviest downpours move over them (PWATs will be around 1.50 inches). In addition to the rainfall, we could also see some record warm low temperatures tonight as the antecedent warm air along with the cloud cover will work to keep lows from reaching the 50s. The showers and storms continue over the east half Friday as convection redevelops behind the initial line. While not expected, there is a small, outside chance (2% or less) that we could see a strong storm or two over the central and east, even though the conditions are not as ideal as what they will be over the far west this evening. Expect slightly cooler temperatures too on Friday, with highs only being in the 70s. The rainfall associated with the front looks to get out of here by Saturday morning as weak ridging moves overhead. More dry weather and well above normal temperatures return Saturday as weak, localized ridging looks to keep precipitation and cloud cover away. Expect to see high temperatures return into the upper 70s to low 80s once again Saturday, meaning that some spots in the U.P. may flirt with tying or breaking their daily max temperature record. However, as a cold front from our north and west phases with a shortwave low lifting from the Plains through the U.P. Saturday night and Sunday, we could see showers return to the area. Currently, the expectation is that the rainfall from this will be fairly light. Temperatures will return to around normal next week behind this cold front, with highs generally being in the 60s and lows in the 50s to mid 40s later in the week. We may see additional rainfall over mainly the central and east around next Tuesday as a low lifts from the Southern Rockies into the Upper Midwest. However, model agreement is still shaky at this time, so confidence in this occurring is still pretty low (30-40% chance). Behind this low, expect surface ridging to return to the Great Lakes region by the latter half of next week. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 127 AM EDT Thu Sep 19 2024 VFR conditions will prevail in this TAF period. && .MARINE... Issued at 315 AM EDT Thu Sep 19 2024 Light winds of 20 knots or less today give way to southeast to southerly winds of 20 to 25 knots over the central lake this evening as a cool front slowly trudges from west to east today through Friday. This front will bring some showers and storms across the lake, with some storms possibly being strong to severe over the west (the main threats being strong, erratic winds and large, damaging hail). As the front moves eastwards with time, expect the severe threat to diminish, particularly by around midnight tonight EDT. While winds generally decrease to 20 knots or less across Lake Superior by Friday morning, the showers and storms continue along the front through Friday night. Weak ridging over the area keeps winds light Saturday before a cold front passes through Saturday night and Sunday from the west. Currently, we could see northwesterly winds gust to 20 to 25 knots behind the cold front over the western half of the lake late Saturday night and Sunday. In addition, expect to see some showers and a few thunderstorms with the front`s passage Saturday night through Sunday, although the convection isn`t a guarantee as some models do keep the lake rain- free (50 to 60% chance of occurrence). Another low lifting from the Southern Rockies may lift into the Upper Great Lakes around the Tuesday time period too and bring stronger winds and thunderstorms back across the lake, but uncertainty on this occurring is higher (around 30 to 40% chance of occurrence). && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JTP LONG TERM...TAP AVIATION...07 MARINE...TAP