Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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715 FXUS63 KMQT 182259 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 659 PM EDT Wed Sep 18 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 Thursday into Friday. Some stronger storms are possible in western Upper Michigan Thursday evening. && .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 raditional fog to develop in interior locations of Upper Michigan`s south-central and eastern locations. Upstream, vertically stacked low spining 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 /FRIDAY THROUGH WEDNESDAY/... Issued at 341 PM EDT Wed Sep 18 2024 The long term forecast starts off Thursday morning with patchy dense fog closer to Lake Michigan under a strong inversion and light southeast flow off the marine layer. This fog should burn off through the morning leading the way to a warm and dry afternoon. Fire weather concerns for tomorrow are minimal. RHs in the interior will only dip down into the mid 40s since better moisture advects into the UP as a surface low moves northeast into Manitoba. The aforementioned surface low sends a cool front across Upper Michigan late Thursday evening through Friday, finally providing us with slight relief from the summertime heat and much needed precipitation to fight the ongoing second fire season. Come late Thursday, the front will be approaching the far western UP where it could kick up a few thunderstorms, some possibly strong, before heading further east. Model soundings indicate elevated instability in excess of 1000 j/kg with bulk shear nearing 25-35 kts, therefore its worth mentioning the potential for a few strong thunderstorms before instability wanes with sunset. Unfortunately, overall precip amounts look to be on the lighter side with a range of only a tenth to a quarter of an inch of rain possible as the front passes by the UP through Friday. Pwat values push 1-1.5 inches, so a few fortunate folks could receive a heavier downpour in embedded thunderstorms. Brief ridging behind the departing shortwave action keeps things fairly quiet on Saturday. Looking into the late weekend and early workweek, model guidance begins to diverge on the timing and location of a few upcoming features that could bring more active weather to the UP. The first feature is a digging shortwave across central Canada Sunday into Monday, which ushers in a cold front and additional chances for rain. Behind this front, 850 temps in the single digits are possible, allowing us to finally tweak surface temperatures to near normal (60s and 40s) for this time of year. The second feature, a closed low currently diving south off the California Coast, will make its way into the Plains by the end of the weekend and approach the Upper Great Lakes Monday. The interaction of these features and any associated weather impacts will be targets of opportunity for upcoming forecast packages. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 658 PM EDT Wed Sep 18 2024 VFR conditions will prevail in this TAF period. && .MARINE... Issued at 341 PM EDT Wed Sep 18 2024 Light winds of generally 20 knots or less continue into Thursday before southeast to southerly winds pick up to 20 to 25 knots over the north central lake late Thursday into Friday morning ahead of an approaching cool front from the west. Showers and a few embedded thunderstorms are possible along the front, with a better chance of thunderstorms in the far western lake Thursday afternoon and evening. Winds die down below 20 knots Friday morning and remain so through the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JTP LONG TERM...BW AVIATION...07 MARINE...BW