


Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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894 FXUS63 KMQT 100748 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 348 AM EDT Thu Jul 10 2025 .KEY MESSAGES... - Chances for showers and thunderstorms return Friday and Saturday. Otherwise, a mostly dry end of week is expected. - Seasonable temperatures persist in the Upper Peninsula for the work week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 347 AM EDT Thu Jul 10 2025 GOES-East imagery shows a remarkably clear night over the UP, though high clouds upstream are advancing towards the region and are expected to reach the western UP and expand through the west half of the UP throughout the morning hours. Aloft, RAP analysis 500mb charts show the UP remaining upstream of a ridge axis centered over northern Ontario, but a prominent shortwave to the south of it is the cause of disturbed weather upstream (and thus explains the aforementioned high cloud cover). Besides a couple of CAMs showing the line of convection ongoing in Minnesota reaching the far western open waters of Lake Superior from 16-20Z today, model guidance consistently shows upstream convection either petering out entirely by the time it reaches the UP or skirting around the UP, primarily to the south. This is due to the high surface pressure upstream of the aforementioned ridge aloft, which the RAP analysis shows at 1016mb currently and the 00Z GEFS only shows modestly weakening throughout today. Sustained high pressure will help temperatures trend warmer today relative to yesterday, with high temps around the 80 degree mark expected. Once exception will be in the immediate vicinity of the Great Lakes, where CAMs show prominent lake breezes today, and the marine layer will help keep the shorelines in the mid to lower 70s for highs today. Expect tonight`s overnight lows to also trend warmer (around the 60 degree mark) especially as increasing cloud coverage decreases the efficiency of radiational cooling. Chances of precipitation tonight have trended downwards, but have left some slight chances (15-25 percent) of showers and thunderstorms along the state line to cover some of the faster solutions that still remain in the ensembles in bringing pre-warm frontal precipitation to the area Friday. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Issued at 225 PM EDT Wed Jul 9 2025 Beginning Friday, mid-upper ridge axis will lay through Upper Michigan, with a series of shortwaves embedded within split stream flow stream upstream over the Central and Northern Plains. Various placement of previous night MCVs are apparent in the different deterministic packages, which supports my initial uncertainty in the timing of the key features for Upper Michigan. Although 12z guidance appears to have produced a better consensus which overall looks to pull a warm front or the attendant surface low through the forecast area Friday afternoon or overnight. This while the mid- level shortwave to the west moves from the Dakotas into Minnesota/western Lake Superior. This main shortwave begins to take on a negative tilt, which might absorb the original low/shortwave. 6z and 12z guidance is unclear if this will actually take place overhead or downstream in northern Ontario. Regardless though, the cold front will help push the surface low through the region Saturday and Saturday night. While questions of the timing and location of the initial features exists, showers, potentially mixed with thunderstorms should be expected. Given the temporal clarity of the initial timing of precip, instability/shear may be present over the region, which could support stronger storms late Friday. DCAPE values suggest an isolated strong to severe wind threat, but model soundings show light background winds upwards of 25k ft, suggesting this potential is low (<25%). Guidance also suggests potential for mid-level lapse rates increasing to ~7C/km, which may be enough to support hail should a stronger updraft get going. Showers and storms will press through the region overnight while the cold front moves in from the west. Given the questions about phasing and the timing of the initial showers/storms, its unclear if precip will occur all day Saturday, or be mainly limited to the afternoon/evening hours ahead of the front. From there, another shortwave migrates through the region Sunday evening and overnight while surface high shifts from the Upper Midwest to the Lower Great Lakes. The high looks to keep the region mostly dry Sunday, but a line of showers may accompany the wave late Sunday night/Monday morning. A deep trough moving through the Canadian Prairies and a shortwave lifting northeast from the Central Plains will shift toward Upper Michigan on Monday. There are notable timing differences in the model suites regarding these and whether or not they`ll phase overhead next week. Right now the main window for precip associated with these features focuses on Tuesday to Wednesday. Daytime highs each day look to climb into the 70s to mid 80s and with overnight lows dipping into the 50s and 60s. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 135 AM EDT Thu Jul 10 2025 Primarily VFR conditions are expected at all TAF sites through the duration of the 6Z TAF period as high pressure holds over the Upper Great Lakes. The one exception to this is at SAW when some MVFR BR/FG development is anticipated early this morning. That said, guidance has slightly backed off on FG potential, so IFR vis or lower is less likely than the previous fcst package (now ~25% chance or less). Some MIFG is possible at IWD, but no vis restrictions are expected so mention was left out of the TAF for now. Otherwise calm winds this morning increase out of the S at IWD/SAW and E at CMX to around 6-8 kts for this afternoon. && .MARINE... Issued at 225 PM EDT Wed Jul 9 2025 Winds generally remain generally ~15 kts or less through the remainder of the work week as weak high pressure traverses the Great Lakes. However, a couple of disturbances move through the region Friday into the weekend. Thus, we can expect showers and thunderstorms to form from west to east across the lake from Friday through Saturday. In addition, we could see winds increase to around 15-20 knots from the southwest on Saturday, persisting into Sunday before falling back into Monday. Expect a brief reprieve from convection Sunday before additional storms potentially move in with a Clipper system next Sunday night through Monday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...GS LONG TERM...JTP AVIATION...Jablonski MARINE...LC