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Marianas Update

The outer bands of Invest Area 94W will continue to affect us today, but will be departing the area earlier than previously thought as 94W continues to consolidate and also move away. This will allow winds and seas to relax a little and weather to dry out some starting tonight. Due in large part to drainage problems though, southern Guam will likely need a flood advisory today.

Tropical Systems

Invest Area 94W is now the subject of a Tropical Cyclone Formation Alert from the Joint Typhoon Warning Center. 94W is currently north of Koror Palau, and is expected to continue to consolidate and develop, but only at a moderate rate of speed. It will likely be away from Yap and Palau before becoming a warned tropical depression. For more information on 94W please see the TCFA from JTWC under WMO header WTPN21 PGTW.

Eastern Micronesia Update

Weather in Eastern Micronesia has not been quite as active as forecast. Reduced PoPs at Kosrae and Majuro, while leaving them mostly alone at Pohnpei.

Western Micronesia Update

Little change in Western Micronesia. Invest Area 94W is far enough north that only scattered showers in the Yap and Koror areas. Invest Area 94W is expected to gradually pull away as it consolidates and develops. It should be clear of Yap and Palau before it becomes a fully warned on Tropical Depression.

Prev discussion

/issued 651 PM ChST Tue Feb 3 2026/

Marianas Synopsis... Satellite imagery shows cloudy skies with scattered showers over the Marianas. Altimetry shows combined seas of 8 to 9 feet to the west and 7 to 8 feet to the east. Ipan buoy data shows heights of about 6 feet.

Discussion... There are several features interacting with each other over the Marianas. The first is Invest 94W, the outer band is producing cloudy skies. The second is a passing trough is moving into the region. And the third is the shear line over Pagan. With all three of these features interacting with each other, this will create an environment that could be supportive of showers building in over the next several hours, with some of these showers are anticipated to be heavy at time. However, the exact location, timing and intensity may be be delayed or shifted westward, this would lead to a more tame weather pattern overnight, and leading to a reduction in the risk for widespread showers and heavy rainfall. These features are expected to drift away from each other over the next 36 hours or so. A lull in showers is anticipated for the latter half of the week before another trough brings showers in to the region for the weekend. Once the weekend trough passes, model guidance suggests a bit of a drying out period for the upcoming week.

Marine/Surf... The high risk of rip currents statement was ended a bit early due to conditions improving quicker than originally anticipated. The trade swell is expected to continue to gradually fall to 4 to 6 feet over the next few days. The secondary north swell is expected to bounce between 3 and 4 feet through the rest of the week. Overall, combined seas of 6 to 8 feet are anticipated to fell to around 4 to 6 feet by as early as Sunday.

Tropical Systems... A broad but consolidating circulation known as Invest 94W is located near 9N135E, which is west of Yap and north of Palau. Joint Typhoon Warning Center (JTWC) has upgraded this system to medium, meaning that tropical cyclone development is likely but expected to occur beyond 24 hours. Invest 94W is continue to support and unsettle pattern across Yap and Palau over the next couple of days, but the risk for heavy rainfall and gusty winds should start to decline as the center of 94W continues to move westward through the Philippine Sea and towards the Philippines.

Eastern Micronesia... A fairly active Intertropical Convergence Zone (ITCZ) is expected to continue pummeling Pohnpei and Majuro tonight and Wednesday, and Kosrae tonight. As the leading edge of the ITCZ continues moving west, showers will move away toward central Micronesia to then continue to cycle over Majuro on Thursday night, while conditions improving elsewhere the ITCZ weakens downstream. In the meantime, Pohnpei and Kosrae are expected to see improving weather in the second half of the week, while another ITCZ pulse keeps Majuro wet through the weekend, before tapering down thereafter.

Combined seas of 7 to 10 feet near Pohnpei, and 6 to 9 feet near Kosrae and Majuro, are expected to taper down significantly in a few days as various swells and wind waves briefly diminish, to then pickup once again during the weekend. A combination of a significant easterly swell, northerly swell, and much higher wind waves, is still producing sea conditions hazardous to small craft at Pohnpei, so a Small Craft Advisory remains valid for Pohnpei waters tonight. As winds and primary swell taper a bit overnight, seas will drop below hazardous levels of 10 feet. Even so, elevated choppy seas will continue for much of the forecast period, before hazardous conditions return by the weekend.

Western Micronesia... An unsettle pattern continues to extend across the region. Invest 94W continues to drift westward and is currently located north of Palau near 9N135E. The strongest winds and heaviest showers and thunderstorms are be near and north of the center of 94W, where the system is pushing against the western extend of the shear line that been near the Marianas the last few days, while moderate to fresh winds extend over Yap and decreasing slightly to gentle to moderate over Palau. Yap Proper is currently in a pocket of slightly drier air which is causing showers to be more isolated in coverage, but expecting showers and thunderstorms to increase at Yap by midnight. Scattered showers and isolated thunderstorms extend across Palau with northerly winds expected to shift towards the west and then southwest overnight and into Wednesday morning. As 94W moves towards the Philippines, scattered showers and isolated thundestorms will continue around Palau and Yap over the next day or two, but the overall potential for showers and thunderstorms will shift westward, with models trending towards a drier overall pattern for Palau and Yap late this week and weekend. Seas are currently around 6 to 8 feet and will slowly decrease as Invest 94W drifts westward, following more toward 4 to 6 feet this weekend

At Chuuk, cloud cover is increasing as upper-level cloud cover is being advected westward from the heavier convection across Pohnpei, but showers are currently isolated around Chuuk. Model guidance shows the potential for showers gradually increasing late tonight into Wednesday as a surface trough, potentially developing a embedded circulation, shifts westward from near Pohnpei and Kosrae. Models show the potential for numerous locally heavy showers and gusty winds at Chuuk Wednesday night and Thursday, associated with the aforementioned trough, with the GFS showing an embedded circulation, while the ECMWF shows a more amplified trough passing through Chuuk. Convergent flow east of the trough then will help to support scattered showers around Chuuk through Friday, with a slight drying trend this weekend as drier air filters in from the north. Seas are currently around 6 to 7 feet, and may increase a foot or two Wednesay night and Thursday and the surface trough pushes through, before falling to 4 to 6 feet this weekend.

GUM WATCHES/WARNINGS/ADVISORIES

GU...None. MP...None. Marianas Waters...None.