Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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644 FXUS63 KMQT 200835 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 435 AM EDT Thu Jun 20 2024 .KEY MESSAGES... -Better rain chances return tonight along with thunderstorms by Friday. -Keeping an eye on flooding concerns near Harvey along the Chocolay River and over the west due to the high recent rainfall amounts. - Moderate to heavy rain likely through first half of weekend. && .SHORT TERM /THROUGH TONIGHT/... Issued at 432 AM EDT Thu Jun 20 2024 Current water vapor imagery/surface analysis early this morning show a stationary frontal boundary draped across much of the Lower Midwest and eastern Great Lakes Region. Any showers and isolated rumbles of thunder associated with it overnight have now moved east of Upper Michigan with just a few lingering rain showers over the far south and east. Per time cross sections, will trend toward a dry forecast through much of the morning with a slight uptick in rain chances from the west across the southern half of the forecast area. Better rain chances will not arrive until tonight, though, as WAA overspreads the area ahead of the next approaching short wave. Meanwhile, expect temperatures at to slightly below normal today and tonight with highs generally topping off in the low to mid 70s (60s across Keweenaw) and lows in the upper 40s to mid 50s. We continue to keep an eye on flooding concerns along the Chocolay River near Harvey and also over the west where some places got rainfall in excess of 3 inches (some as much as 5 inches!). && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 347 AM EDT Thu Jun 20 2024 After a brief quiet period for Thursday, active weather returns to finish out the week. A warm front will be lifting through the Upper MIssissippi Valley into Friday as another shortwave ejects out of the Rockies. Warm advection precipitation should move into the western UP by mid-morning while the front stalls out somewhere across central or northern WI. Showers continue on and off throughout the day, most likely over the southwest and south-central UP, closer in proximity to the boundary. With a pretty decent cap developing in soundings, strong convection is not expected, but a few rumbles of thunder will not be ruled out. As the main upper trough moves out of the Plains later Friday, a surface low will deepen and lift northeastward along the boundary toward Upper Michigan by early Saturday. The moisture increase will be significant Friday night into Saturday with PWATs approaching 2 inches, so Saturday will likely be a washout for most with moderate to heavy rain. However, will note a trend among some of the guidance to keep the boundary (and heaviest rainfall) more to our south, across northern or central WI. Still, by the time this first round of rain winds down Saturday evening, much of the area will likely have picked up rainfall totals in excess of an inch (70-90% chance among ensemble guidance) with the Euro coming in even higher. Given recent heavy rains across portions of the U.P. this week ponding of water will and increase in stream flows will be the primary threats. As the low continues to move ENE through the area Saturday night, the cold front will push any remaining precipitation east of the area. While some drying will occur on Sunday, one more shortwave dropping down from the Canadian border could produce enough lift for a few additional showers on Sunday. However, will note that soundings are rather moisture-starved, so showers should be light. Moving into early next week, expect ridging and and warming as high pressure moves from the Plains through the Midwest. Then, a series of quickly-moving shortwaves and associated cold frontal passage will bring in additional chances for showers and storms Tuesday through the middle of next week, but timing differences persist among various model guidance this far out. With clouds and rain through the first half of the weekend, temperatures will be a little below normal before climbing back above normal early next week. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 120 AM EDT Thu Jun 20 2024 VFR conditions will continue across all of the TAF sites through the period. && .MARINE... Issued at 347 AM EDT Thu Jun 20 2024 Winds will be turning mainly over to the N to NE today, with a stretch of light winds expected today into early Saturday with surface ridging over Lake Superior. A surface low lifting through the Upper Lakes on Saturday will lead to northeasterly winds up to 20-25 knots over the western Lake during the day. Northwesterly winds behind the departing low should stay around or just below 20 knots on Sunday. Southwesterly winds will return early next week increasing to 20-25 knots ahead of another weak cold front by Tuesday afternoon. Moderate to heavy rain will be possible across the south half of the Lake from later Friday through Saturday which could lead to some dense fog development during that time. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TDUD LONG TERM...LC AVIATION...07 MARINE...LC