Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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377 FXUS63 KMQT 240733 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 333 AM EDT Fri May 24 2024 .KEY MESSAGES... - Another shortwave and low pressure system will bring a round of showers and a slight chance (around 20% chance) for some thunder to Upper MI late Friday into early Saturday. - There will be more opportunities for rain next week although model uncertainty leads to low forecast confidence on timing/extent. && .SHORT TERM /THROUGH TONIGHT/... Issued at 344 PM EDT Thu May 23 2024 Current RAP analysis shows the mid level low along the southern end of James bay with it`s associated 995 mb low pressure center still over James bay, but just northwest of the mid level low. With weak sfc high pressure at around 1012 mb building over the CWA, mostly sunny skies have been the predominant sky conditions for much of the UP this afternoon. This has allowed for temps to warm up into the 60s for much of the UP; onshore flow has kept cooler temps along Lake Michigan between Manistique and the Mackinac Bridge as well as near Lake Superior. The sunny skies have also helped mixing yield a breezy day with west to northwest gusts up to 20-30 mph, strongest in the Keweenaw. Winds will gradually diminish into this evening as high pressure continues to build in. Some diurnal cumulus has developed over the southern UP and will continue to increase this afternoon with the support of a mid level shortwave moving east through northern WI. Afternoon highs are expected to peak in the mid 50s to mid 60s near Lake Superior, 60s along Lake Michigan east of Manistique, and upper 60s to mid 70s elsewhere. Some slight chances for showers return to the forecast along the WI/MI state line with the best chances for showers in Menominee County late this afternoon where there is better instability (5/23 12Z HREF mean MUCAPE up to 250 j/kg in south central). Accumulations will likely be only a few hundreths at best, but showers moving through Menominee county could bring up to 0.1" to 0.2" of rain on the high end if the NAM Nest solution is favored. As daytime heating ends and high pressure continues to build in tonight, skies will mostly clear out helping temps settle slightly cooler than normal into the upper 30s to upper 40s. While mostly clear skies are expected with dry weather, cloud cover increases late into Friday ahead of the next low pressure system. This approaching low will also turn light winds northerly then eventually easterly by Friday morning. && .LONG TERM /TONIGHT THROUGH THURSDAY/... Issued at 333 AM EDT Fri May 24 2024 Upper air pattern consists of a deep 500 mb trough on the west coast, a negatively tilted shortwave and closed 500 mb low in the upper Mississippi Valley 00z Sat. This shortwave heads northeast into the upper Great Lakes 12z Sat and across Ontario on Sat night. Upper troughing then remains over the area into 12z Mon as more energy comes out of the west coast trough and keeps troughing over the area. A wave of pcpn will come in tonight and move out late tonight into Sat morning with dry weather moving in for most of Saturday before the next system moves in for Sun. There are some pops that could make it into the far west by Sat evening and have slights in there to cover it. Otherwise, did not make too many changes to the going forecast. In the extended, the GFS and ECMWF and Canadian all show a 500 mb trough in the Great Lakes region 12z Mon which moves to the lower Great Lakes region 12z Tue. Ridging then moves into the northern plains 12z Wed and into Thu. Upper troughing then moves into the northern plains 12z Fri. Temperatures look to be near normal for this forecast period. Only prolonged dry period looks to be Wed for now. With troughing, does look unsettled. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 120 AM EDT Fri May 24 2024 Dry air mass associated with sfc high pres ridge drifting across the area overnight will allow VFR to continue at IWD/CMX/SAW. Winds will also be light, mostly under 5kt. During the day today, low pres lifting across the Northern Plains will swing an occluded front to the ne. That front will cross Upper MI tonight. Although some shra well ahead of the front may push into the w half of Upper MI mid and late aftn, the main area of shra and isold tsra will hold off until early evening. So, fcst only reflects vcsh at IWD this aftn. Expect -shra/MVFR cigs to arrive at IWD around 22z, spreading to CMX/SAW during the evening hrs. IFR will be possible at CMX/SAW near the end of the fcst period under increasing low-level moisture and upsloping winds. E to SE winds will increase during the day, becoming gusty to around 25kt at IWD, to around 30kt at CMX, and to around 20kt at SAW. LLWS is also a possibility this aftn and evening, but guidance is lacking in agreement on strength of low-level jet shifting over the area. && .MARINE... Issued at 333 AM EDT Fri May 24 2024 East winds will begin to ramp up to 20 to 30 knots today in advance of another low pressure lifting from the Northern Plains towards Lake Winnipeg. Northeast gales to 35 knots will continue across the far western part of the lake today. Winds over the west half becoming southwest behind the low and the passage of its cold front late tonight into Saturday and generally stay in the 15 to 25 knot range. Winds decrease late Saturday behind the exiting system, then expect light winds of 20 knots or less across Lake Superior for the rest of this weekend as a high pressure ridge builds over the area. Looking ahead to early next week, another system moving out of the Plains will head towards the Great Lakes. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning from 11 AM EDT /10 AM CDT/ this morning to 8 PM EDT /7 PM CDT/ this evening for LSZ162. Lake Michigan... None. && $$ SHORT TERM...Jablonski LONG TERM...07 AVIATION...Rolfson MARINE...07