Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
504 FXPQ50 PGUM 241948 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 548 AM ChST Sat May 25 2024 .Marianas Synopsis... A trade-wind trough that produced large amounts of rainfall yesterday has moved west of the Marianas this morning, although patchy clouds remain over the region. Local airports report gentle trade winds and combined seas are running 4 to 6 feet. && .Discussion... After a passing trade-wind trough produced surprisingly large amounts of rainfall for Guam and Rota yesterday, we again are expecting fair weather to prevail over the Marianas for the next few days, with a relatively dry trade-wind flow through the coming week. && .Marine/Surf... Model guidance indicates gentle to moderate trade winds and combined seas of 4 to 6 feet thru the next few days. There will be a moderate risk of rip currents along east facing reefs, and a low risk of rip currents along south, west and north facing reefs. && .Fire weather... The heavy rainfall yesterday at Guam airport totaled 1.88 inches, and the KBDI is way down at 432 today. The rainfall was surprisingly widespread yesterday, when only scattered to isolated showers were at first expected. The risk of fast spreading wildfires is now low. && .Eastern Micronesia... Convergence behind a trade-wind trough is producing scattered showers and isolated thunderstorms around Majuro. A broad trough between Kosrae and Pohnpei is producing scattered showers and isolated thunderstorms. West of the International Date Line, scattered showers and isolated thunderstorms are seen along the Inter-Tropical Convergence Zone. Latest model guidance shows an ITCZ building westward through the weekend with convergence and broad troughing pushing through the region with scattered showers and isolated thunderstorms. Both the ECMWF and GFS show the ITCZ building westward through early next week with increasing shower and thunderstorm chances at Kosrae and Pohnpei Gentle to moderate trades and combined seas of 5 to 7 feet are expected through at least Wednesday at Majuro, Kosrae, and Pohnpei. && .Western Micronesia... Yap and Palau remain in the broad convergence flow of JTWC 93W with scattered showers and isolated thunderstorms seen over the islands during the overnight hours. Model guidance shows 93W will continue to lift northward with scattered showers expected to taper off by sometime Sunday, as a weak ridge moves over the region Monday. For Chuuk, model guidance shows an ITCZ building west to Chuuk through at least Tuesday with scattered showers and isolated thunderstorms before the ITCZ dissipates and gives way to a trade-wind pattern. Both ensemble and deterministic model guidance then shows a trade- wind pattern setting up over Yap and Palau early next week. Models then show a ridge building into the area with isolated showers expected at Palau, Yap, and Chuuk through the latter part of the week. Gentle to moderate trades and combined seas of 4 to 6 feet are expected at Chuuk, Yap, and Palau through around the middle of next week. Some stronger gusts are possible with showers around Palau and Yap through at least today as 93W continues to push north and away from the region. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Simpson Micronesia: Kelly