Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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101 FXUS63 KMQT 061900 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 300 PM EDT Sat Jul 6 2024 .KEY MESSAGES... - Slight chance (~20%) for late afternoon showers and thunderstorms across interior western Upper MI today. -Sunday through Wednesday, daily chances of showers and thunderstorms, highest chances in the afternoons. Could see a couple of strong storms Sunday and maybe Monday (higher uncertainty). -Dry period begins Thursday, could be dry into next weekend. && .SHORT TERM /THROUGH TONIGHT/... Issued at 300 PM EDT Sat Jul 6 2024 Not much to talk about in the short term through tonight. Surface ridge axis extends from the Upper Midwest up into the Upper Great Lakes. Diurnally driven cu field has developed across the interior of the U.P. with light onshore flow along the Lakes shorelines. Fog per visible imagery over eastern Lake Superior has been shifting slowly eastward with time with the Luce county shorelines over to Whitefish point the only remaining areas experiencing fog/stratus. 12Z models have been consistent with previous runs showing enough destabilization by late afternoon/early evening for isolated shra/tsra activity mainly in the WI bordering counties. Will maintain slight chance pops until about 2-3Z there but most everybody will remain dry this evening. By late in the night, convection initiating this evening over MN along next shortwave moving into the Upper Mississippi Valley will be approaching northwest WI and far western Lake Superior. The U.P. will remain dry through 12Z with just an increase in mid/upper level clouds towards morning. Expect seasonable overnight lows mainly in the 50s. && .LONG TERM /TONIGHT THROUGH FRIDAY/... Issued at 325 AM EDT Sat Jul 6 2024 Ridging building over the West Coast of the U.S. early next week will allow weak shortwaves to cycle over us, bringing daily chances for rain showers and thunderstorms across our area for the afternoon to evening hours out to the middle of next week; we could see a couple strong sub-severe storms Sunday and maybe even Monday. However, moving into the second half of next week, as the high pressure ridge over the West Coast moves eastward into the Central and Eastern U.S., drier weather looks to move over us to end next week. Additional details follow below. Some isolated diurnal rain showers and thunderstorms end over the interior west this evening as the sun sets. While MUCAPEs are projected to be between 1000 to 1500 J/kg early this evening, with there being very little shearing in the atmosphere due to the departing weak sfc ridge overhead, only garden-variety pop-up showers and storms are expected. Moving into tonight, we could see some patchy fog develop across the interior areas as we look to be mostly clear until late tonight; expect the fog to burn away a couple of hours after dawn. However, as we approach dawn late tonight, expect clouds to roll in from our west as another shortwave low moving in from the Northern Plains encroaches our area. While this 1010mb low is nothing to write home about, it does look to bring in more showers and thunderstorms across the western half of the U.P. by late Sunday morning. CAMs show rain shower and thunderstorm coverage to be fairly scattered throughout the western half of the CWA Sunday, with convection dying out as it tries to enter into the eastern half due to subsidence remaining from the departing weak high pressure ridge. With over 1000 J/kg to work with in the atmosphere by Sunday afternoon and 0-6 km bulk shear being around 30 knots, we could see a couple strong thunderstorms bring sub-severe winds and hail across the western half late in the day. However, as we move into the evening to overnight hours Sunday night, expect the convection to weaken after the sunset, with showers and thunderstorms becoming isolated by the overnight hours. A second weak sfc shortwave lifting from the Central Plains fires up more rain showers and thunderstorms over our area Monday. Expect to see similar conditions to Sunday, with even a couple strong storms being possible late in the day (although there is greater uncertainty in the CAPE and bulk shear). However, once we get into the late night hours Monday night, expect the convection to die-out as the forcing weakens. More of the same is expected Tuesday and Wednesday as additional, weaker sfc shortwaves rotate through our area; expect the convection to be dependent on the diurnal heating through the daytime hours in order to fire during the afternoon and early evening hours across the U.P. before the convection dies out by the late night hours. As this occurs, expect the temperatures to generally be in the 70s, with a slight increase occurring between Tuesday and Wednesday. This increasing temperature trend continues into the last half of next week as the high pressure ridging that initially was building over the Western U.S. travels over the Central and Eastern U.S. by the latter half of the extended period. This high pressure ridging is expected to keep us dry from Thursday into next weekend. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 127 PM EDT Sat Jul 6 2024 Expect VFR and winds mostly under 10kt to prevail at IWD/CMX/SAW thru this fcst period. A few shra/possibly a tsra may develop across western Upper MI late aftn/early evening but should avoid the terminal sites. Shra and isolated tsra chance will increase again near Ironwood by the end of the TAF period. && .MARINE... Issued at 325 AM EDT Sat Jul 6 2024 Light winds of 20 knots or less continue this weekend through next week as weak shortwaves bring showers and storms along mainly the Lake Superior nearshores early this week before high pressure ridging brings dry and calm conditions over the lake late next week; while we may see a strong storm or two along the southern nearshores for wind and hail Sunday and maybe Monday (higher uncertainty), little, if any storms are expected over the open waters due to the subsidence caused by the Lakes. In addition, we could be seeing some patchy fog over the lake early this morning through today, mainly over the north central and eastern portions as weak sfc high pressure ridging moves through. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...MZ LONG TERM...TAP AVIATION...MZ MARINE...TAP