Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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494 FXUS63 KMQT 081854 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 254 PM EDT Sat Jun 8 2024 .KEY MESSAGES... - A few stronger storms capable of small hail and gusty winds are possible this afternoon, mainly east-central. - Light rain showers are expected on Sunday with breezy north winds gusting up to 20-30 mph, especially over the eastern U.P. - High pressure brings a brief dry period for Sunday night through Tuesday. - Periods of showers and storms are expected mid to late next week. - Below normal temperatures are forecast through early next week, but a warming pattern will follow through next weekend. && .SHORT TERM /THROUGH TONIGHT/... Issued at 253 PM EDT Sat Jun 8 2024 Upper air pattern consists of an elongated 500 mb trough with several upper lows in it. The low of importance is one north northeast of Lake Superior which slowly moves to eastern Ontario by 12z Sun. As this happens, a cold front will move south through the area. Scattered showers and thunderstorms have popped up with this front and also lake breeze boundaries and more speckled showers are forming upstream in MN and western Lake Superior and are also headed this way. Will have some pops moving southeastward this afternoon along the cold front and then have some pops in with the next upstream shortwave that could affect the north and west early this evening. MUCAPE is about 500-1000 k/kg over most of the area with shear low for the most part, so could still see some small hail and gusty wind with some of these storms into this evening along the cold front. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 527 AM EDT Sat Jun 8 2024 The extended forecast period begins tonight with an elongated trough extending from Alberta to Quebec. This setup evolves into an omega shape by the start of the work week with positively tilted ridge over the Upper Mississippi Valley stuck between a trough over the Lower Great Lakes and another trough over Saskatchewan. As this pattern shifts east next week, the western trough passes over the UP later in the day Tuesday into Tuesday night. Meanwhile another trough over the Pacific Northwest is making landfall into British Columbia. This far western trough propagates east along the Canadian Prairie Provinces to the Upper Great Lakes for mid to late next week, sending two shortwaves over the area. Starting tonight, the oblong trough stretching across much of the US/Canada border begins to separate. Isentropic ascent and PVA will continue some light showers overnight, highest PoPs in the Keweenaw, north central, and eastern Upper MI. A few isolated storms are possible over south central before midnight, however no severe weather is expected as instability drops off as daytime heating ends and bulk shear diminishes below 30 kts per the 6/8 0Z HREF mean. Lows are expected in the mid to upper 40s. Chances for showers continue on Sunday as a cold front drops south of the UP. Cool north flow behind the front looks to keep temps below normal throughout the day in the 50s to mid 60s, warmest in south central Upper MI. That said, those along the eastern Lake Superior shores may never get out of the 40s all day. Northerly upslope flow with an uptick in moisture noted in the model soundings and PWATs increasing from around 0.7" to 0.9" will support mostly cloudy skies and light rain showers through the day. As high pressure begins to build in from the northwest, the UP dries out by the evening. A ~40 kt LLJ passing over the eastern CWA will help yield some breezy gusts up to 25-30 mph. Lows are forecast in the 40s, however upper 30s are possible in the interior east where drier air intrudes faster and we are able to clear out sooner. High pressure keeps the weather dry through Tuesday morning. Temps warm up from the weekend into the 60s under sunny skies on Monday. With increased mixing to around 900-800mb, higher mixing over the interior west, min RHs are expected in the mid 20s to mid 30s (drier away from the lakeshores and in the interior west). Gusts will be stronger over the east where RHs are not as low; this does flirt with borderline elevated wildfire conditions. The next round of showers and storms moves in from the west on Tuesday as a mid level trough moves east from Manitoba to Ontario. The shortwave rotating around it will support a sfc low tracking east along the international border from Manitoba to just north of Lake Superior into Tuesday night. The cold front tracking east with it will yield showers and possible storms into Tuesday night. While bulk shear is expected ~40kts, little CAPE leaves severe potential low (<10%). Shortwaves arriving mid to late next week leave potential for additional shower and storms, however with the current spread in timing among the guidance, opted to leave NBM PoPs as is for now. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 113 PM EDT Sat Jun 8 2024 Conditions will remain at VFR levels at all TAF sites until Sun morning when MVFR conditions move in. && .MARINE... Issued at 527 AM EDT Sat Jun 8 2024 West winds are expected to remain at or below 20 kts through Sunday morning. Winds increase to 20 to 25 kts, veering northwest, by Sunday afternoon over the east half of the lake as a LLJ passes overhead. There is a 40-60% chance for higher observing platforms over the eastern 3rd of the lake to see gusts approach 30 kts on Sunday. As high pressure builds in from the northwest into Monday, winds fall back below the 20 kt threshold. The next potential for winds to exceed 20 kts is Tuesday into Wednesday when a low pressure system tracks north of Lake Superior, but chances of winds exceeding 20 kts are low (<30%) given the stability over the lake. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...07 LONG TERM...Jablonski AVIATION...07 MARINE...Jablonski