Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
206 FXPQ50 PGUM 240817 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 617 PM ChST Fri May 24 2024 .Marianas Synopsis... Cloudy skies with numerous showers are seen across Guam, with partly cloudy skies and isolated showers across the CNMI. Gentle to moderate trade winds prevail across the Marianas. Altimetry shows seas between 5 and 7 feet, with 4 to 6 feet east of the waters. && .Discussion... A weak trough moving through the Marianas this afternoon, interacting with weak convergence to the south of Guam. This interaction brought scattered to numerous showers to Guam and Rota through the afternoon. Numerous showers will remain over Guam, becoming isolated early in the evening. Thereafter, expect a dry pattern to return to the islands, with little rainfall expected through the middle of next week. && .Marine... Combined seas of 5 to 7 feet tonight will subside a bit overnight, becoming 4 to 6 feet by Saturday morning. Seas look to remain in the 4 to 6 foot range, along with gentle to moderate trade winds, through the middle of next week. && .Fire weather... Guam Airport measured a wetting rain today, with 0.81 inch of rain at 4:00 PM. Higher rainfall amounts were seen around the island, mainly over southern Guam, where rainfall in excess of 1 to 1.5 inches are likely to have occurred. Andersen AFB saw 0.90 inch by 4:00 pm as well. This rainfall will help mitigate the fire danger in the short term, though dry conditions look to return for the next several days. Latest model run shows total additional rainfall of only 0.50 to 0.75 inch over the next 7 to 10 days. && .Eastern Micronesia... A broad trade-wind trough between Kosrae and Pohnpei is currently producing scattered showers around Kosrae, and should bring scattered showers to Pohnpei later tonight. Trade convergence behind the trough is producing scattered showers and isolated thunderstorms around Majuro and extending northward to around 10N, which should bring some needed rain to Wotje, which has been experiencing extremely dry weather so far this year. Further east, beyond the Date Line, the Inter-Tropical Convergence Zone (ITCZ) is looking well developed on satellite. Models support low-end scattered showers across the region this weekend as the broad trough and convergence continue to push through the region, with the greatest potential for showers expected around Monday and Tuesday as the the ITCZ extends westward into the region early next week. Winds are expected to be gentle to moderate this weekend and into the middle of next week. Combined seas are expected to be between 5 and 7 feet, dominated by a east to northeast swell. && .Western Micronesia... Invest 93W has continued to move west-northwest into the Philippine Sea and is now west of 130E and out of WFO Guam`s Area of Responsibility (AOR). Palau and Yap State remain in the convergent flow east of 93W, where the MIMIC TPW satellite product shows precipitable water (PWATs) around 2.70 to 3.00 inches, which continue to support showers and thunderstorms across these islands tonight and into the weekend, which will bring some much needed rain to Yap State. The overall potential for showers will decrease across Palau and Yap this weekend as 93W starts to lift northward, dragging the convergent flow and moisture with it, potentially allowing for a period of isolated showers around Monday as a weak ridge briefly builds in. Then a transition back into the trade-wind pattern, with passing trade-wind troughs, will bring periods of scattered showers back to Yap and Palau around the middle of next week. Over at Chuuk State, some drier air (PWATs around 2 to 2.15 inches) is pushing into Chuuk Lagoon, where showers are now fairly isolated, but remain scattered in the western half of the State. This drier weather looks to be short lived, as the trough near Pohnpei and Kosrae will move into Chuuk by Sunday. Then, as the ITCZ builds across eastern Micronesia, the western edge is expected to push into Chuuk early next week. Yap and Palau buoys indicate seas are around 5 feet, and altimetry shows seas around 4 to 6 feet across western Micronesia. Some stronger gusts are still possible in heavier showers around Palau and Yap, but overall winds are gentle to moderate and from the east to southeast around Palau and Yap and mainly east across Chuuk. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Kleeschulte Micronesia: Schank