Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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637 FXUS63 KAPX 180237 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1037 PM EDT Mon Jun 17 2024 .KEY MESSAGES... - Very hot, humid conditions expected to continue through the middle of the week. - Chances for showers/storms at times this week into the weekend. && .UPDATE... Issued at 1023 PM EDT Mon Jun 17 2024 Very spotty convection impacted parts of the area earlier this evening, but most areas remained rain free. A potent decaying outflow boundary from upstream convection raced into the area late this afternoon/early this evening, eventually lying west/east and stalling out in the vicinity of the M-72 corridor. While the surface pressure pattern would support mainly southwesterly flow overnight, remnant boundaries from earlier convection and/or lake breezes have winds more variable at the moment. Despite nocturnal surface stabilization, lapse rates aloft will remain quite steep through the night. Main concern is if any disturbances can initiate nocturnal convection. Most model guidance suggest the bulk of the precipitation will remain west of the area overnight where the low-level wind fields are stronger. However, can`t rule out something spotty occurring, especially in eastern Upper and far northern Lower Mi. Also need to keep an eye on the MCV moving east-northeast across central Wisconsin at the moment which should impact the northern portion of the forecast area before daybreak. Going forecast was in pretty good shape. Only minor tweaks were needed, mainly to PoP trends. && .SHORT TERM /THROUGH TUESDAY/... Issued at 310 PM EDT Mon Jun 17 2024 True summer airmass has made its presence felt across northern Michigan, courtesy of sustained deep layer southwest flow between expanding east coast sub-tropical ridge and broad troughing slicing east across the Intermountain West. A classic long-wave configuration to drive heat north, and temperatures are responding accordingly, with most areas pushing well into the 80 early this afternoon...with even a few locations in the lower 90s. Tap to Gulf of Mexico moisture also becoming increasingly established, as evident by dewpoint temperatures remaining in the 60s and lower 70s (this despite increased afternoon mixing). Combination of this heat and humidity has help produce quite a bit of low level instability, with SPC mesoanalysis displaying over 2K Joules/kg of mixed layer cape across much of the Northwoods. Despite this, a lack of a well defined trigger to make use of this instability has prevented much shower and storm generation...with primary focus remaining to our west within zone of max deep layer moisture convergence and better jet dynamics on ridge/trough interface. Not a terrible amount of change expected as we head through tonight and Tuesday, with deep southwest flow directed right into the Great Lakes region. This sets the stage for more uncomfortable warmth tonight and Tuesday, along with additional low chances for showers and storms at times. Primary Forecast Concerns/Challenges: Temperature trends and addressing any shower/storm concerns. Details: Warm and muggy tonight, with lows only falling into the upper 60s (perhaps not out of the low 70s) for much of northern lower Michigan. Readings will be a bit cooler for those areas north of the Straits. Anyones guess with regards to shower/storm potential tonight. Large scale deep layer forcing is most definitely lacking. Simple breadth of sustained moisture advection and any passing impulses/decaying outflow boundaries from previous convection may be able to pull the trigger on the development of a few showers and storms. Definitely feel most of the area and much of the time will remain a dry one. Lack of any organized shear should preclude any severe threat, but if storms do form, they will be capable of brief heavy rainfall rates given such a moisture rich environment (precipitable water values remain over an inch). Surge of even better Gulf moisture arrives Tuesday, with this plume of deeper moisture already well displayed rotating north in current water vapor imagery. Simple extrapolation supports this deeper moisture spreading directly overhead during the day Tuesday. This will serve to likely keep actual temperatures from reaching their full potential (based of column thermal progs) and at least help increase the odds for a few showers and storms...especially during the afternoon hours. Again, a definite lack of a well defined trigger for more organized storm potential, but any subtle forcing should be enough to support some moist convection. Nothing widespread anticipated, with most areas again likely remaining dry. Brief periods of intense rain and marginally gusty winds will be the primary concern with any storm activity. While no doubt it will remain uncomfortable warm given combination of highs in the upper 80s to lower 90s and that increasing moisture, simply not seeing enough evidence for dangerously hot conditions to require any type of heat related headline. Will continue to hit these uncomfortably warm conditions in our latest messaging/graphics and hazardous weather products. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Issued at 310 PM EDT Mon Jun 17 2024 Strong upper level ridging centered across the East Coast through mid-week will edge into the Atlantic later this week into this weekend. This setup will likely allow northern stream troughing to approach the region from the north. In the meantime, very hot and humid conditions will continue into at least Wednesday. Not quite as hot but still rather humid conditions likely continue for a few days after that. Since it looks like northern Michigan will be located in the battle ground between the strong ridge and the trough, shower and thunderstorm coverage will likely increase through the week, especially as we head into the weekend. Highs of well into the 80s to the mid 90s Wednesday will be replaced by the upper 70s north to the mid 80s south Thursday through Saturday. Further cooling with highs in the 70s to near 80 are then penciled in for Sunday and Monday. Uncomfortably warm lows Tuesday night in the upper 60s to mid 70s will be replaced by the mid 50s north to the mid 60s south for much of the remainder of the long term. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1019 PM EDT Mon Jun 17 2024 VFR condtions expected more often than not through the 06Z TAF valid time. While showers/storms can`t be ruled out which may reduce conditions below VFR, expected coverage and confidence in timing is too low to include in the terminals at this time. South to southwest winds will prevail through the period, with mainly diurnal increases in speed. && .APX WATCHES/WARNINGS/ADVISORIES... MI...Air Quality Alert until midnight EDT tonight for MIZ020-025- 026-031. MARINE...None. && $$ UPDATE...PBB SHORT TERM...MSB LONG TERM...AJS AVIATION...PBB