Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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426 FXUS63 KMQT 261746 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 146 PM EDT Wed Jun 26 2024 .KEY MESSAGES... -Pattern remains active, especially from late week into early next week, with yet more rounds of showers and storms && .SHORT TERM /THROUGH TONIGHT/... Issued at 314 AM EDT Wed Jun 26 2024 GOES-16 water vapor imagery shows a region of unsettled clouds over northwestern Ontario moving southeast collocated with a RAP- analyzed 500mb trough. As the surface high pressure ended up weaker and further south than previous global model runs had forecast, this has lead to increased chances that the shortwave can overcome the dry air and cause some light showers over the UP later this morning. Per the HREF, these showers will mostly be limited to north of a line from Ontonagon to Marquette. These showers should end by 18Z, and by the time the dust settles, HREF mean QPF over the Keweenaw is around 0.1 inch with 0.01 inch to 0.1 inch of rain for the remainder of the areas that see rainfall. Skies gradually clear behind the shortwave and winds become northerly, setting up a north-south gradient for high temperatures today, with highs in the mid to upper 50s along Lake Superior to highs in the mid to upper 60s along Lake Michigan and the interior west. The clear skies overnight should allow temperatures to underperform relative to most guidance. This forecast will reflect values close to the NBM 10th percentile, with lows in the upper 30s for the interior and 40s along the lakeshores. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 252 AM EDT Wed Jun 26 2024 The pattern will remain fairly active and progressive through the extended fcst period as a couple of Pacific-based shortwave troughs traverse the northern tier of the CONUS and bring more rounds of showers and t-storms to the Upper Great Lakes mainly in the Friday- Saturday night and Monday night into Wednesday time periods. Starting Thursday, a weak high pressure ridge persists across the region into much of Thu night as dry weather prevails. Weak pressure gradient and light winds will result in lake breezes during the day on Thursday. Expect highs generally in the lower 70s, except a touch cooler in the mid to upper 60s near the Great Lakes shores. Look for lows Thu night in the lower to mid 50s, except for some cooler upper 40s readings over the eastern interior. Friday and Saturday, a mid-level trough/closed low just off the Pacific Northwest coast as noted on satellite imagery early this morning will move onshore later this morning. This trough will support cyclogenesis in the lee of the Northern Rockies Thursday night with the sfc low ejecting east into the Dakotas and along the international border/northern MN Friday and into the Upper Great Lakes on Saturday. WAA/isentropic ascent and theta-e advection ahead of the low will support showers and thunderstorms spreading into Upper Mi on Friday. The initial shortwave embedded within the mid- level trough will move into the region Saturday while pushing a cold front through the area Friday night into Saturday. Increased instability noted ahead and along the cold front should increase chances for thunder as it passes through the area at this time. A second shortwave moving through the trough axis will send a secondary cold front across the area late Sat into early Sun perhaps triggering some isolated to scattered light showers along with a burst of gustier nw-n winds and colder temps. High pressure building in quickly behind the front will result in drier, albeit cooler conditions Sunday afternoon into Monday. Models then advertise another mid-level trough moving in off the West Coast which again will promote lee-side cyclogenesis over the Northern Rockies early next week. The associated sfc low is fcst to lift northeast through the Northern Rockies into Manitoba and northern Ontario Mon night into Tuesday as it propels a cold front across the Upper Great Lakes on Tuesday. Ahead of and along this front another round of showers/t-storms is expected next Mon night into Tuesday. The passage of another shortwave and secondary cold front from this system could bring more light showers into the area on Wednesday. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 145 PM EDT Wed Jun 26 2024 A stratus deck, IFR cigs, that developed during the morning at IWD/CMX/SAW has lifted to MVFR recently. Expect MVFR cigs to gradually lift to VFR BKN clouds at 3500ft over the next 2-4hrs at all terminals. VFR will then continue for the remainder of the fcst period. && .MARINE... Issued at 252 AM EDT Wed Jun 26 2024 Winds have switched northerly early this morning at 15-20 kts behind a cold front dropping south across the lake but will taper off below 15 kts during the day today. With high pressure over the lake through Thursday, winds are expected to mainly remain below 20 kts. A weakening low pressure tracking through the Upper Great Lakes early this weekend will allow for s-se gusts 20-25 kt Friday over mainly the east half ahead of the front and then nw gusts 20-25 kt behind the cold frontal passage on Saturday before building high pressure returns Sunday and ushers in lighter winds into Monday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...Voss AVIATION...Rolfson MARINE...Voss