Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
464 FXPQ50 PGUM 121813 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 413 AM ChST Thu Jun 13 2024 .Marianas Synopsis... Satellite imagery is showing partly cloudy skies and isolated showers over the CNMI, with mostly cloudy skies and scattered showers over Guam. Increasing clouds and showers are approaching the Marianas from the east. Latest altimetry passes and Ritidian buoy are indicating seas of 3 to 5 feet. && .Discussion... Showers have become scattered over Guam and are expected to become scattered over the CNMI later this morning as a surface trough approaches the Marianas. Isolated thunderstorms are expected later today as moisture deepens. Models suggest scattered showers and isolated thunderstorms through tonight, with coverage expected to decrease on Friday as the trough shifts west. An upper-level low between the Marianas and Wake Island is slowly heading west toward the Marianas. As it moves into and to the west of the islands, upper-level winds should become more supportive for showers and thunderstorms. Friday night and Saturday look to be the best time frame for the unstable weather as a subtle surface trough passes through. For late weekend, shower and thunderstorm potential looks to decrease as surface and upper-level features push away from the region. && .Marine/Surf... Gentle to moderate trades will prevail into the weekend. Combined seas of 3 to 5 feet will slowly build to between 5 and 7 feet over the weekend as trade swell strengthens. Thunderstorms possible over the waters through Saturday and could bring some brief gusts of 20 to 25 knots. A moderate risk of rip currents is expected to continue along east facing reefs and expected to remain low along all other reefs. Surf is expected to increase about a foot over the weekend as the trade swell strengthens. This would bring a moderate risk of rip currents to north facing reefs. && .Eastern Micronesia and Chuuk... The Inter-Tropical Convergence Zone (ITCZ) is expected to intensify the next few days, bringing higher shower coverage across Chuuk, Pohnpei, Kosrae and Majuro coming into the weekend. By early next week, most of the convection is expected to shift westward, with seasonal trade showers expected in the first half of next week. Combined seas of 4 to 6 feet are expected to taper down by 1 to 2 feet near Pohnpei, Kosrae and Chuuk over the next few days as trade swell weakens. Meanwhile, seas of 5 to 8 feet near Majuro may drop by 2 to 3 feet by the weekend as both trade swell and wind waves decrease. && .Western Micronesia for Palau and Yap... A generally unsettled weather pattern remains to be expected for Palau and Yap through the weekend, as the waters south of Mindanao and northeastern fringes of Indonesia continue to simmer under the doldrums. Palau may see more intense showers and thunderstorms tonight and Friday due to higher likelihood of localized outflow boundaries forming. Meanwhile at Yap, on-and-off showers are expected for much of the forecast period. Combined seas of 2 to 4 feet are expected to last into early next week, with some localized upticks by a foot possible near outflow boundaries. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Slagle Micronesia: Montvila