Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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071 FXUS63 KAPX 161900 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 300 PM EDT Sun Jun 16 2024 .KEY MESSAGES... - Chances for additional showers and thunderstorms tonight. - High heat and humidity Monday through much of the work week. - Periodic chances of showers and storms this week. && .SHORT TERM /THROUGH MONDAY/... Issued at 256 PM EDT Sun Jun 16 2024 Pattern Synopsis/Pattern Forecast: Warm, moist advection continues across the Great Lakes early this afternoon, driven by maturing southwest flow between expanding southeast Conus centered subtropical ridging and broad troughing digging into the Intermountain West. Subtle shortwave troughs racing northeast within this deep layer southwest flow kicking off pockets of showers and thunderstorms across the western Great Lakes. Subtropical ridge/heat dome will continue to expand with time through early this week, delivering a shot of true summertime heat into the Great Lakes region. Primary Forecast Concerns/Challenges: Initial focus centers on shower/storm potential, especially through tonight. Attention quicky turns to one of heat Monday. Details: Just one downright tricky (and thus low confidence) forecast with regards to convection tonight. Plume of enhanced lapse rates and attendant corridor of elevated instability set to fold across at least the north half of the area tonight, with a well defined mesoscale convective driven vorticity lobe expected to pass across southern Michigan. Moisture profiles only become more impressive with time, with precipitable water values expected to exceed 1.5 inches. Per the northern Michigan usual, uncertainty centers on a trigger mechanism to utilize this convective potential. Unfortunately, that is where all the unanswered questions remain. Definitely not seeing any large scale forcing mechanisms to utilize this potential...with best low/mid level convergence on nose of low level jet looking to remain off to our northeast, best mid/upper level jet support remaining off to our west/northwest, and forcing from that MCV remaining off to our south. As previously mentioned, suppose sustained moisture advection north of the partially modified outflow boundary from current shower activity may be that trigger. Again, where exactly that boundary locks in place and just how much activity forms along and north of it remains a source of high uncertainty. If convection does indeed materialize, moisture rich profiles definitely supports some rather high intensity rainfall rates, with any training of convection supporting some locally heavy rainfall totals. Not completely out of the question for an isolated severe storm, although lack of more defined wind fields through the vertical argues otherwise. Focus for Monday quickly becomes one of heat. Access to traditional heat reserved for the south is fully realized, with thermal profiles continuing to support widespread highs nearing/exceeding 90 degrees across much of northern lower Michigan...with just slightly cooler readings north of the big bridge and near those big bodies of water. While not terrible excessive, low level moisture profiles support dewpoints remaining in the 60s...only adding to how warm it will feel. Still have some concern with convective debris clouds, along with the potential for additional moist convection to fire during the afternoon...especially across northeast lower Michigan (where mixed layer cape in excess of 1k J/kg and enhanced low level convergence will reside). Still expecting it to be unpleasantly warm for most, and perhaps dangerously so for those working outdoors or those with no access to home cooling. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 256 PM EDT Sun Jun 16 2024 Pattern Synopsis/Pattern Forecast: Strong upper level high pressure will be centered along the eastern seaboard over the next several days. Northern stream troughing will attempt to knock down heights across the western Great Lakes later in the week into next weekend. Details: Strong upper level ridging will be centered along the east coast over the next several days. This ridge will extend westward into the Great Lakes for a majority of the period. This will result in hot and humid conditions through much of the work week. Heat indexes will approach heat advisory criteria at times (100 degrees/3 hours), especially across our southern counties. The area could see occasional "cooling" thunderstorms develop either in the form of convective systems possibly moving around the periphery of the ridge or daytime heating/lake breeze induced. Whether or not this occurs will be difficult to ascertain this far in advance unfortunately so pops will stay in the chance category. As we head deeper into the work week, northern stream energy will attempt to knock down the ridge but guidance varies on the extent/timing of this possibility. Highs of well into the 80s to the mid 90s (mainly south) are likely through mid-week with highs of at least the upper 70s to upper 80s likely later in the week. Perhaps more noticeable cooling will arrive for next weekend. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 121 PM EDT Sun Jun 16 2024 Other than perhaps some MVFR cigs spreading across KCIU late tonight/early Monday morning, expecting VFR conditions to persist under some passing mid and upper level clouds. A few light showers will fall out of this cloud deck this afternoon, but with minimal impacts. Will need to watch for isolated to scattered convective development tonight, any of which could bring brief heavy rain and gusty winds. Confidence is much too low to include a specific mention of this in the forecast. Overspreading of low level jet tonight will produce wind shear. Gusty southeast to south surface winds this afternoon expected to decrease in speed tonight. && .APX WATCHES/WARNINGS/ADVISORIES... MI...Air Quality Alert from midnight tonight to midnight EDT Monday night for MIZ020-025-026-031. MARINE...Small Craft Advisory until 2 AM EDT Monday for LHZ346-348-349. Small Craft Advisory until 2 AM EDT Monday for LMZ344>346. Small Craft Advisory until 10 PM EDT this evening for LMZ323- 341-342. && $$ SHORT TERM...MSB LONG TERM...AJS AVIATION...MSB