Marianas Synopsis
Partly cloudy skies with isolated showers and gentle to moderate trade winds prevail across the Marianas. Tropical Storm Champi, currently east of the Marianas, continues its trek toward the islands.
Discussion
The big story, TS Champi. Champi continues to slowly strengthen east of Guam as it moves west. The latest forecast track brings Champi over northern Guam Sunday morning, with tropical storm force winds arriving before midnight Saturday. Therefore, a Typhoon Warning was issued for Guam and Rota, with a Tropical Storm Warning issued for Tinian and Saipan, with a Typhoon Watch continuing in case Champi makes a turn to the north. The forecast for tonight and Saturday maintains the current drier pattern. However, that will change drastically as Champi approaches. Tropical storm force winds, increasing heavy showers and thunderstorms will move into the region Saturday evening. By Sunday morning, we can expect at least category 2 typhoon force winds at Guam, category 1 at Rota and strong tropical storm winds at Tinian and Saipan. Winds and convection will continue over the islands through Sunday night, with tropical storm conditions possibly ending Sunday night, after midnight. After Champi exits the region, a dry pattern looks to move into the region around Monday and continuing through the end of the week. Residents of the Marianas should make sure that they are prepared for typhoon force sustained winds of up to 105 mph. Stay safe and follow our forecasts for any updates as they occur.
Marine
Marine and surf conditions will deteriorate rapidly, beginning Saturday evening as TS Champi approaches. A Typhoon Warning is in effect for Guam and Rota waters, with a Tropical Storm Warning now in effect and Typhoon Watch remaining in effect for Tinian and Saipan. Combined seas will remain at or below 7 feet through Saturday morning, then begin to build as a large east swell from Champi enters the waters. As Champi moves through the waters, seas could reach as high as 35 feet near the center of Champi, depending on how much Champi strengthens. Seas will be lowest for Tinian and Saipan waters, but still reach around 19 feet as Champi moves through. The large seas produced by Champi are expected to produce dangerous/deadly surf and rip currents, as well as coastal flooding, with inundation of 5 feet or more near the eye of Champi, and as high as 1 to 3 feet at Tinian and Saipan. Surf could reach as high as 26 feet at Guam and 19 feet at Tinian and Saipan. Rota can expect around 20 feet. Seas could remain hazardous through Monday, after Champi departs the region.
Tropical Systems
As of 700 PM ChST, the center of Tropical Storm Champi (29W) was located near 12N152E, which is about 510 miles east-southeast of Guam. It was moving west at 13 mph, with maximum sustained winds having increased to 60 mph near the center. Champi is expected to make a slight turn toward the west-northwest with a slight increase in forward speed through Saturday. This general forecast track will take Champi close to, or over, Guam Sunday morning. Champi is expected to go through a period of rapid intensification over the next 24 hours, becoming a typhoon by Saturday and strengthening further thereafter. Winds and rain will come in rapidly, with winds becoming dangerous and life threatening very soon after onset. Do not let a false sense of normalcy now dictate your actions tomorrow; prepare NOW!
For more information, please refer to the bulletins issued by the Joint Typhoon Warning Center under WMO header WTPN32 PGTW, and by the National Weather Service in Tiyan, Guam under WMO header WTPQ32 PGUM.
Eastern Micronesia
Tropical Storm Champi continues to move away from the region, which will allow showers to become isolated at Pohnpei Saturday night. Kosrae will mainly see isolated showers as well through the weekend, before increasing next week. However, at Majuro, the monsoon trough is lingering just to the north, with a another tropical circulation east of the Date Line poised to move into the region early next week. This will keep scattered showers going through the forecast period there.
As Champi moves away, winds and seas will slowly decrease. Seas will return to the 4 to 6 foot range at Pohnpei and Kosrae, remaining at these values for Majuro.
Western Micronesia
The main forecast challenges were maximum wind gusts at Chuuk, and swell direction and height for Yap and Palau as current TS Champi passes north of there. For now, kept wind gusts to 30 knots at Chuuk but mentioned a few higher gusts could occur, but with some uncertainty as to when during the next 24 hours Champi begins its RI (Rapid Intensification) cycle. Therefore a special weather statement remains in place along with a Small Craft Advisory for hazardous seas. will be elevated Then at Yap, focus was placed on trying to refine swell heights and directions, while introducing them at Palau Tuesday.
Otherwise, look for isolated shower coverage at Palau and Yap to continue, becoming isolated at Chuuk by the end of the weekend. Gentle to fresh winds are expected at Chuuk, decreasing as we head into next week, while increasing at Yap during the same time. Palau will remain in the light to gentle range.
Gum Watches/Warnings/Advisories
GU...Flood Watch through Sunday afternoon for GUZ001.
Typhoon Warning for GUZ001.
Coastal Flood Watch from Saturday afternoon through late Sunday night for GUZ001.
High Surf Warning from 5 PM Saturday to 4 AM ChST Monday for GUZ001.
MP...Flood Watch through Sunday afternoon for MPZ001>003.
Typhoon Warning for MPZ001.
Coastal Flood Watch from Saturday afternoon through late Sunday night for MPZ001>003.
High Surf Warning from 5 PM Saturday to 4 AM ChST Monday for MPZ001>003.
Tropical Storm Warning for MPZ002-003.
Typhoon Watch for MPZ002-003.
Marianas Waters...Typhoon Warning for PMZ151-152.
Tropical Storm Warning for PMZ153-154.
Typhoon Watch for PMZ153-154.
Marianas: Kleeschulte East/West Micronesia: Doll Tropical: Montvila/Mesa DSS: Mesa