Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
755 FXPQ50 PGUM 041902 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 502 AM ChST Sun May 5 2024 .Marianas Synopsis... Partly cloudy skies reign over the Marianas with the worst of is near Saipan. Altimetry shows combined seas of 3 to 5 feet to the far west. Winds are out of the east and are gentle. && .Discussion... The forecast was largely unchanged, a few trade-wind trough will pass through the region. The first few troughs are expected to be fairly weak with not much increase of chance of showers. The major chance in the forecast was the more robust trough later in the week. The latest model run suggest that the the thunderstorm potential was a tad over zealous, so thunderstorms were dropped for the over night forecast. && .Marine... A north and easterly swells are reigning over the region. Over the next few days, models suggest that the northern swell will increase. The most noticeable effect is the risk of rip currents along north facing reefs will increase to moderate. Surf is expected to remain below the 9 foot mark on north facing reefs and the 12 foot mark along east facing reefs. Seas are expected to build through mid week then gradually fall through the rest of the week. Winds are expected to gentle to moderate throughout the week. && .Eastern Micronesia and Chuuk... Trade-wind convergence is causing cloudiness and patchy showers mainly between 1N and 7N across the region this morning. Satellite shows most of the showers and thunderstorms over Kosrae State and Southern Pohnpei State, and a few showers near Butaritari. ASCAT Analysis indicates a weak circulation at about 1.5N161E; embedded in a Near-Equatorial Trough (NET) that extends much farther westward past southern Chuuk State. Majuro remains on the drier side so far, while Kosrae has been low-end scattered. A weak trough has crossed the Date Line and is moving towards the southern Marshall Islands. Thunderstorms are still expected to remain isolated across the region due to the lack of strong divergent flow aloft. Repeat: The northern islands of the RMI, such as Wotje, and islands north of 7N are dry and are expected to remain dry thru the weekend and the middle of next week. Perhaps, as the convergent trade flow starts to lift north next week, some of these islands may start to see some scattered showers, although models vary greatly on potential rainfall amounts for the northern islands over the next 10 days, with some like the Canadian Ensemble showing about 1.30 inches, with the ECMWF being the most aggressive at about 4.3 inches, while the GFS sits roughly in the middle. Moderate to occasional fresh trade winds and combined seas of 5 to 7 feet and perhaps up to 8 feet in the northern Marshall Islands are expected most of this week. && .Western Micronesia for Yap and Palau... Satellite loops show an area of showers and thunderstorms nearly stationary to the southeast of Koror; mainly between 7N and 3N from 135E to 140E. ASCAT Analysis indicates a Near-Equatorial Trough (NET) meanders westward from well south of Chuuk along 1N to 3N past far southern Palau to beyond 130E. A slight chance of thunderstorms was introduced for Koror today just based on the proximity of thunderstorms to their southeast. Yap remains in a dry trade-wind flow. Models indicate unstable weather will continue over southern Palau and southeast Yap State, and more showers are expected to develop at times this week, and possibly moving northward enough to hopefully give the Yap and Ulithi areas a few showers. Winds over the ocean are expected to be moderate from the northeast to east with combined seas around 4 to 6 feet for the next several days. Models show a north swell entering the region by midweek and that may cause elevated surf along the north shores. $$ .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Bowsher Micronesia: Simpson