Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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056 FXUS63 KGRR 260249 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 1049 PM EDT Tue Jun 25 2024 .KEY MESSAGES... - Patchy fog with a chance of showers Wednesday morning/afternoon - High Pressure tracks through Thursday into early Friday - Thunderstorm chances increase Friday afternoon into Saturday && .UPDATE... Issued at 1049 PM EDT Tue Jun 25 2024 Dew points are rather elevated this evening with several sites in the lower 70s. That certainly supports the fog threat mentioned previously however extensive cloudiness related to the convection in IL has been streaming in from the southwest. These clouds could hamper the radiation fog risk but for now will maintain patchy fog in the forecast overnight. Also 20 percent pops for a few showers seem warranted near/south of I-94 in case any rain from the north side of the IL/IA activity should brush by. The earlier Beach Hazard Statement and Small Craft Advisory was allowed to expire at 8 pm with wind/wave conditions trending down. && .DISCUSSION... Issued at 301 PM EDT Tue Jun 25 2024 - Patchy fog with a chance of showers Wednesday morning/afternoon Strong westerly flow will continue through the rest of the day keeping wind gusts upwards of 30 mph. The strong flow will keep the area mixed before winds finally start to subside mid to late evening. Much of the area along and south of I 96 received an inch or more with areas along the lakeshore receiving several inches of rain. With drying in the mid levels, calm winds at the sfc, a strengthening sfc inversion and trapped low level moisture, patchy fog is expected along and south of I 96, especially along the lakeshore. Patchy dense fog in low lying regions is possible. Any fog will lift/dissipate by late morning. A weak trough will swing through tomorrow, late morning into the afternoon. There is a chance for storms with this system. This trough will bring with it a low level jet, though it is only around 30kts. MEAN CAPE values are below 1000 J/kg. Daytime highs are expected to only get into the low 80s. So while there is enough instability, shear and dynamics for storm formation, there shouldn`t be enough for severe. Skies should clear in the wake of the exiting trough mid to late afternoon tomorrow. - High Pressure tracks through Thursday into early Friday Models are in decent agreement in showing a larger Canadian high pressure system tracking east southeast through Lower Michigan during this timeframe. Stronger subsidence arrives as this system moves in Thursday leading to mainly clear skies. Warm advection the backside of the departing wave will support an increase the mid to upper level clouds especially as the ridge axis will be east of the area. We will feature slightly below normal temperatures for this period. - Thunderstorm chances increase Friday afternoon into Saturday An impressive surge of moisture is shown to arrive ahead of the next storm system Friday afternoon/evening. PWAT`s are shown to climb up to around 2 inches. This is well above normal. The upper level jet strengthens as a trough builds in from the west. This trough axis pivots east of the area by 18z Saturday. The instability axis shifts east of the area by 18z Saturday. As a result the bulk of the thunderstorm activity should be prior to 18z Saturday. As a result, while we will feature some shower/storm activity Saturday, we will feature falling POPs, especially in the afternoon. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 617 PM EDT Tue Jun 25 2024 MVFR conditions will continue this evening due to lingering low cloud cover. Patchy fog will develop during the early morning hours Wednesday as a result of partial clearing and lingering low level moisture from rain Tuesday morning. This will cause primarily MVFR conditions to continue until mid Wednesday morning when any lingering patchy fog and low cloud cover will dissipate. VFR conditions are forecast late Wednesday morning through the afternoon with west to northwest winds which will gust to near 20 kts at times. && .MARINE... Issued at 330 PM EDT Tue Jun 25 2024 Strong winds will continue in the wake of the exiting system and will keep winds and waves dangerous to small craft and swimmers into this evening. Rapidly changing lake fluctuations will also create rip currents that will be dangerous to swimmers. Expect patchy fog early Wednesday morning which will reduce visibilities into mid morning. There will be a chance for showers and perhaps an isolated thunderstorm late Wednesday morning/early afternoon. Another small craft advsy/ beach hazards statement may be needed due to strong winds in the wake of an exiting system late Wednesday into Thursday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...Meade DISCUSSION...MJS/Ceru AVIATION...Laurens MARINE...Ceru