Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
015 FXPQ50 PGUM 200752 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 552 PM ChST Sun Sep 20 2026 .Marianas Synopsis... Mostly cloudy skies with isolated showers and light to gentle winds prevail across the Marianas. Altimetry shows seas of 4 to 6 feet west of the waters. && .Discussion... Latest satellite and radar data show mostly cloudy skies with isolated showers across the region. increasing convection is seen east of the coastal waters and will approach the islands during the evening, ushering in increased showers and thunderstorms later this evening, near midnight. Overall, an unsettled pattern looks to continue across the Marianas through the next several days, with the islands seeing mostly POPs (Probability of Precipitation) in the 30 to 50 percent range through the week. Tinian and Saipan will see some brief periods of 20 percent POPs early in the week. Meanwhile, Guam and Rota will see periods of locally heavy showers Tuesday into Tuesday night as a weak disturbance drifts by south of Guam. && .Marine... Not much change in the marine forecast. A mix of swells from varying directions along with small wind waves will make for some choppy seas, though seas will slowly fall through the week from 4 to 6 feet down to around 3 to 4 feet later in the week. Winds will remain mostly light to gentle through the week. && .Eastern Micronesia... A weak, low pressure system is still located north of Kwajalein this evening with gentle to moderate westerlies across Pohnpei and Kosrae, becoming light to gentle upon reaching Majuro. Scattered showers and isolated thunderstorms will be possible at all forecast points tonight. A dryer trend will begin for Kosrae tomorrow and by Tuesday night for Pohnpei with only isolated showers expected. Gentle to moderate west winds will continue into Monday at Pohnpei and Kosrae with winds easing to light to gentle by Tuesday as the monsoon flow lifts northward. Southwest to west winds at Majuro may briefly increase to gentle to moderate tomorrow before dropping back down and becoming light and variable towards the end of the week. Combined seas of 4 to 6 feet will continue through early this week at all forecast points before possibly decreasing. && .Western Micronesia... A special weather statement has been issued for Yap State. Heavy showers and thunderstorms are expected through the middle of next week, and gusty winds at times near these heavy showers. For Palau, scattered showers and isolated thunderstorms will persist for the next few days. The monsoon pattern that is currently over Yap State is expected to move in to Palau around Wednesday. Showers are expected to be scattered through Thursday as the monsoon pattern moves into the Philippine Sea. Seas are expected to remain 3 to 5 feet with winds light to moderate. For Yap, there will be widespread locally heavy showers and isolated thunderstorms. Winds near these heavier showers may be gusty at times. Models indicate a potential circulation that may develop as the pattern moves westward. Showers may begin to wane as early as Wednesday. Rain totals are anticipated to be 1 to 2 inches a day. Seas are expected to be 5 to 6 feet through Wednesday before tapering down to 3 to 5 feet for the latter half of the week. For Chuuk, A surface trough interacting with some mid-level convergence is producing sporadic scattered showers around the coastal waters. These showers are anticipated to fill in and bring rain to the island through Tuesday. Once this trough move westwards, fairly benign weather conditions are expected to return for the remainder of the week. Seas are expected to be 4 to 6 feet through about Wednesday, then drop by a foot for the later half of the week. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Kleeschulte East Micronesia: Ogle West Micronesia: Bowsher