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Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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095 FXUS63 KGRR 201110 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 710 AM EDT Sat Jul 20 2024 .KEY MESSAGES... - Humidity returns, chance of storms north Sunday - Quiet Weather through Monday, then rain chances return && .DISCUSSION... Issued at 328 AM EDT Sat Jul 20 2024 - Humidity returns, chance of storms north Sunday High pressure over the Great Lakes will begin to drift east today resulting in a southerly flow developing. Dewpoints will increase and so will the humidity. Highs around 80 and dewpoints around 60 are pretty typical of summer and that`s what we`ll have today, along with mostly sunny skies. Another mostly clear sky tonight will send temperatures down to around 60. The higher dewpoints may result in some patchy fog overnight. A deeper upper trough over James Bay will push a weak cold front south across Lower MI Sunday. The convergence along the frontal boundary coupled with the higher dewpoints and SBCAPE around 900 j/kg and LI`s around -6c may result in scattered convection developing over the northern half of the cwa Sunday afternoon. Given shear values less than 20 kts, no severe wx is expected. - Quiet Weather through Monday, then rain chances return Flow regime across the CONUS is dominated by northeast troughing and western upper high/ridging into next week. Surface anticyclone of Canadian origin persists over the weekend with low humidity and offers several days of drying sunshine. The next chance for rain comes by Tuesday as a shortwave trough diving southeast from Canada moves across the Great Lakes. Model soundings by Wednesday afternoon show some potential for strong storms with deep layer shear of 30 knots and sfc-based instability with over 1000 J/kg of CAPE...so we will continue to watch how this evolves. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 710 AM EDT Sat Jul 20 2024 VFR conditions will persist through Saturday night. Winds will be light and variable. && .MARINE... Issued at 328 AM EDT Sat Jul 20 2024 Light winds are expected due to high pressure overhead. Winds and waves will increase a tad late Sunday as a weak cold front moves south across the lake. At this time, waves should remain less than 2 feet. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno/04 AVIATION...Ostuno MARINE...04