Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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844 FXUS63 KMQT 060509 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 109 AM EDT Mon May 6 2024 .KEY MESSAGES... -Pleasant weather through Monday with dry conditions, little cloud cover, and seasonable temps. -Dry Monday, but fire concerns low given low winds and recent above normal precipitation. -Complex weather pattern with rain chances increasing on Tuesday and multiple passing low pressures keeping rain in the forecast through the end of the week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 239 PM EDT Sun May 5 2024 Confluent flow ahead of a mid-upper level ridge stationed over the Plains has resulted in building sfc high pressure and dry conditions across the Upper Great Lakes today. Other than fair weather cumulus clouds over the interior west and central, plenty of blue sky today. Under lake breeze circulations, temps have ranged from the 50s across the north to lower 60s south. Under clearing skies, light winds and fairly ideal radiational cooling conditions, went maybe a hair under the model blend guidance for min temps tonight. Generally expect mid 30s temps over the interior with upper 30s to lower 40s readings near the Great Lakes. Also, wouldn`t be shocked to see some patchy fog form over the interior as we radiate through crossover temperatures of 37-38F. && .LONG TERM /MONDAY THROUGH SUNDAY/... Issued at 403 PM EDT Sun May 5 2024 Ridging aloft continues to build overhead through Monday afternoon with surface high pressure shifting over to Lake Huron. Besides a FEW layer of fair weather cu, Monday is another dry, clear day. Soundings show a slightly shallower mixed layer relative to today, with mixed heights only up to around 5kft. RHs look to fall to the mid-20% range across much of the interior as a result. However, with mostly light winds below 10 mph gusting to 15 mph expected, along with prior rainfall, fire weather concerns should be fairly low. The wind direction may be locally variable around lake breezes, which CAMs resolve off of both lakes. Opposed to the ridging aloft on Monday is a deep, negatively tilted trough just on the lee side of the Rockies which becomes an anomalous closed low over the Dakotas late Monday. This stacked low will be stalled over the Dakotas Tuesday through Wednesday morning, but a shortwave rotating around the base of the low will be the focus for the weather pattern heading into the midweek. This shortwave will get jet support as it becomes coincident with a right- entrance region of a ~125 kt 300mb, giving enough synoptic support for showers over the UP beginning Tuesday morning in the west and overspreading the UP by the end of the day. Thunderstorm probability has decreased some as instability trends have been downward with the past 24 hours of ensemble guidance. Some more clarity will be provided by tomorrow afternoon as the CAMs begin to describe this time period, but the current forecast will only reflect a slight (~20%) chance of thunderstorms along the MI/WI state line and along Lake Michigan Tuesday. The pressure falls associated with the shower activity Tuesday will become a discrete surface low pressure by Wednesday morning and depart the region by the afternoon. As it does, the original closed low over the Dakotas will weaken from a peak strength of near 980mb Tuesday morning to near 1000mb by midday Wednesday as it slides southeast. As it does, it will phase with another weak lee cyclone off the Rockies, with ensembles tracking this new low generally around Lake Michigan and Illinois by overnight Wednesday into Thursday. Precip will be the forecast if the northern clusters verify, but the UP could be high and dry if a more southern solution materializes. By Friday, anomalous ridging over coastal British Columbia will be contrasted with anomalous troughing over the Lower Great Lakes, putting the UP in a northwesterly flow regime. Some deterministic and ensemble guidance suggests a clipper-type low late in the week into the weekend, keep PoPs in the forecast, though uncertainty is high in any specifics as the complex setup has a lot of variables to work out first. Confidence is increasing that this ridge will shift over the Great Lakes by the midweek of next week, warranting the CPC to favor below normal precipitation for the second half of May. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 109 AM EDT Mon May 6 2024 VFR conditions remain across the region the rest of today into this evening. Winds look to pick up from the southeast near the end of the TAF period as an area of low pressure slowly approaches from the Plains; we could (30% chance) begin seeing marginal LLWS near KIWD at the end of the TAF period. && .MARINE... Issued at 403 PM EDT Sun May 5 2024 With high pressure remaining over the Upper Great Lakes, winds are forecast to be below 20 kt through Monday night. Tuesday morning, approaching low pressure will force easterly and northeasterly winds to funnel over the western reaches of Lake Superior to 25 knots by noon Tuesday. Model guidance suggests around a 40% chance of a brief gale over far western Lake Superior Tuesday afternoon. However, with the majority of guidance sub-gale and the short duration of the highest winds, no Gale Watch is hoisted at this time. Winds across the rest of the western half of the lake increase to around 25 knots Tuesday evening, with a brief break in 20+ kt winds overnight into Wednesday. Periodic chances for winds in the 20-30 kt range dot the forecast through the rest of the week as multiple weak low pressure systems pass through the Upper Great Lakes region, but uncertainty increases with each passing system. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Voss LONG TERM...GS AVIATION...TAP MARINE...GS