Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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042 FXUS63 KMQT 222258 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 658 PM EDT Sat Jun 22 2024 .KEY MESSAGES... - Today`s rain will continue for central and eastern Upper Michigan, before a lull moves in this evening. Another wave of rain expected to move into the west this evening, then progress into the eastern U.P. tonight. - Additional rainfall amounts of half to one inch possible this afternoon in the east. Tonight up to half inch of additional rain possible west and a quarter inch east. - A few thunderstorms are possible (~30%) on Sunday, mainly in the west half; no severe weather is expected. Some patchy fog may develop overnight into Monday. - Dry during the day Monday, but ~15% chance of strong to severe thunderstorms overnight in the west. && .SHORT TERM /THROUGH TONIGHT/... Issued at 131 PM EDT Sat Jun 22 2024 Current GOES 16 Water Vapor and IR imagery, coupled with current radar data, show this morning`s precip shield spread across the central and eastern Upper Michigan. Across western Upper Michigan, radar returns are becoming spotty with some breakage in the cloud cover noted in northern WI south of the Apostles. In the east, rain showers, with some embedded moderate to heavy rain showers are currently being observed. MRMS estimates for rainfall, so far, in this event are estimated ~0.25 inches or less far west and Keweenaw, widespread 0.5 to 2 inches central, and up to ~0.5 inches in the east. As we progress through the remainder of the afternoon, expect another 0.5 to 1 inch of rain in the east while the western lull spreads into the interior west/central. A canopy of overcast skies have blanketed the region today, which has limited daytime heating. So far, highs have only climbed into the mid-upper 50s to low 60s across the region. Current mesoanalysis places a warm front over southern Wisconsin eastward into lower Michigan, with a surface low over central Wisconsin and a second low trailing over Iowa. Over western Minnesota, a shortwave pressing eastward will force both eastward, enabling the central Wisconsin low to deepen and press east across Lake Michigan and to near the Straits/Lake Huron by Sunday 12z while the Iowa low drags across southern WI along the frontal boundary. Additional forcing between these 3 features will support another wave of rain into the west this evening, which spreads east along the low`s northern flank as the low transits the Great Lakes. CAMS are a little mixed on shower coverage in this wave, but appear to consistently suggest lighter rain then we received through the day today so far. Recent HREF and NBM runs validates this with probabilities of >0.5 inches at 60% or less. General consensus among the packages suggest an additional 0.5 inches would be most likely across the west while the east half sees up to another 0.25 inches tonight. Expect patchy fog to develop overnight as we cool into the low 50s to upper 40s west and mid-upper 50s east. && .LONG TERM /SUNDAY THROUGH SATURDAY/... Issued at 425 PM EDT Sat Jun 22 2024 Starting Sunday, the sfc low centered near Lake Huron will be departing east toward southern Quebec while weak sfc high pressure builds in behind it. Bulk shear ~25-35 kts with mean SBCAPE ~500-750 J/kg will be supportive of some isolated showers and thunderstorms as a shortwave trough pivots south over the UP; no severe weather is expected. CAMs are very hit and miss with location and exact timing of any showers/storms, but the main area to focus on is the west half of the UP. This is reflected by a region of 20-30% PoPs traversing southwest across the western UP through the day. As high pressure continues to build in from the northwest over the western Great Lakes, dry weather returns in the evening. Highs on Sunday are expected in the mainly in the low to mid 70s, temps then settle into the upper 40s to mid 50s Sunday night with some patchy fog possibly developing overnight into Monday. On Monday we stay quiet and dry as high pressure shifts east- southeast over the Great Lakes and mid level ridging builds in. Some lake breezes are possible in the afternoon, otherwise no noteworthy weather is expected. Highs are expected in the mid 70s to low 80s. Meanwhile, a trough will be progressing east through the Canadian Prairie, deepening the sfc low beneath to around 990 mb and increasing southerly WAA and moisture advection; PWATs increase to around 1.7". Monday night into Tuesday the mid level trough over Manitoba moves east through northern Ontario. The associated sfc low moves east with it, moving through far northern Ontario, James Bay, and into Quebec by Tuesday evening. This sfc low well to the north drapes a cold front south into the midwest that moves through the area Monday night supporting showers and storms aided by isentropic ascent. The 6/22 12Z LREF mean SBCAPE builds up to around 750-1250 J/kg Monday night with mid level lapse rates around 7-7.5 C/km and 35-40 kts of bulk shear. The environment will be supportive of strong to severe storms with hail and winds being the main threats. Model soundings indicate a decent cap ahead of the cold front and the nighttime arrival will be limiting factors. Also, stronger large-scale ascent with the tough will remain north of the international border. Regardless, the SPC slight risk (15%) for the far west seems appropriate given the set up. Will continue to monitor this risk with future forecast packages. Showers and storms continue east across the UP through the rest of the day Tuesday with dry weather returning Tuesday evening. Tuesday is expected to be the warmest day of the week with highs in the upper 70s to upper 80s. A dry period holds through Thursday. Uncertainty rapidly increases into next weekend, so opted to leave NBM PoPs as is. The general consensus is to bring a trough over the northwestern U.S. on Thursday to the Upper Great Lakes yielding a few embedded shortwaves and multiple chances for showers and storms. At the sfc, a low pressure system likely will eject off the rockies Thursday night/ Friday, continuing northeast into the Midwest/Great Lakes for the weekend. && .AVIATION /00Z TAFS THROUGH 00Z MONDAY/... Issued at 657 PM EDT Sat Jun 22 2024 Rain and low ceilings will continue into tonight across Upper Michigan, impacting primarily KIWD and KSAW with IFR and VLIFR conditions. KCMX is north of the main precip shield and should remain MVFR into this evening. After rain ends west to east, another wave of showers, will move into western Upper Michigan. This will impact KIWD/KSAW and maybe KCMX with continued low ceilings. Expect KSAW/KIWD to remain LIFR or IFR for a majority of the night due to low ceilings and fog/mist. CMX will go VFR later tonight and SAW will be VFR on Sun morning. && .MARINE... Issued at 425 PM EDT Sat Jun 22 2024 A deepening low pressure system will gradually lift through the Great Lakes through tonight, exiting into Ontario Sunday morning. During this period, northwest winds back north this evening then west to northwest on Sunday mainly remaining below 20 kts. High pressure ridging then passes over Lake Superior Sunday night and Monday, letting winds fall down to around 15 kts or lower through that period. South winds increase to around 20 kts Monday night ahead of a passing cold front. South west winds behind the front are expected around 20-25 kts. Winds taper off Tuesday night into Wednesday, remaining around 15 kts through the late part of next week. Some isolated thunderstorms are possible Sunday afternoon and evening across the west. Strong to severe storms are possible in the west Monday night into Tuesday with the passing cold front. Waves will be strongest between Isle Royale and the Keweenaw Peninsula Tuesday afternoon and evening (4-6 feet). && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Dense Fog Advisory until 8 AM EDT /7 AM CDT/ Sunday for LSZ240. Dense Fog Advisory from 2 AM EDT /1 AM CDT/ to 8 AM EDT /7 AM CDT/ Sunday for LSZ241. Lake Michigan... None. && $$ SHORT TERM...JTP LONG TERM...Jablonski AVIATION...07 MARINE...Jablonski