####018004068#### AXPQ20 PGUM 270218 TWDPQ Tropical Weather Discussion National Weather Service Tiyan GU Issued by National Weather Service Honolulu HI 1218 PM ChST Sat May 27 2023 Tropical Weather Discussion for the Western North Pacific between the Equator and 25N from 130E to 180. The following information is based on recent satellite imagery/data, weather observations, radar, and meteorological analysis. ...SIGNIFICANT/SPECIAL FEATURES... TROPICAL CYCLONES... Super Typhoon Mawar (02W), still packing maximum winds of 165 mph, continues its motion to the west-northwest and at a fairly rapid pace of 20 mph. The nearly 30 mile wide eye is well depicted in IR satellite imagery but visible imagery shows an abundance of low-level clouds. Overnight 91 GHz SSMIS data portrays a complete circular band of intense convection, a testament to the torrential rains and violent typhoon-force winds that extend out to about 120 miles. Tropical storm force winds and bands of heavy showers and thunderstorms extend farther from the center, out to about 220 miles. For more information on STY Mawar, please refer to bulletins from the Joint Typhoon Warning Center under WMO header WTPN31 PGTW and from the National Weather Service under WMO header WTPQ31 PGUM. TROPICAL AND MONSOON DISTURBANCES... A wet southwesterly monsoon flow persists across Palau and Yap well south of STY Mawar. Abundant fast-moving showers and thunderstorms are seen, mostly to the north of 6N and sweeping as far east as 142E. Overnight scatterometry indicates 20-25 kt winds in the vicinity of the main islands of Palau with various observations around Palau indicating 30-40 kt wind gusts. These winds, and northerly swell from STY Mawar, are helping to produce seas of around 10 ft across the region. Well west-southwest of Chuuk, in the interface between the westerly monsoon flow from Yap and Palau and easterly trade flow from Chuuk State, showers and thunderstorms are developing within the low-level convergent flow. Satellite analysis depicts a clockwise-turning point-convergence area centered near 1N145E. ...OTHER WEATHER SYSTEMS... TRADE-WIND TROUGHS... Showers and thunderstorms are found across the Marshall Islands ahead of an eastward-moving surface trough aligned north-south along 174E. showers extend ENE-ward to near 12N180. TUTT... A tropical upper-tropospheric trough extends southwestward from a TUTT cell near 23N178E to north of Pohnpei at 10N156E. Dry, subsident flow north of the trough axis is leading to benign weather consisting of only low-level cumulus, including across Wake Island. To the south of the trough axis, divergent flow aloft is aiding convection associated with the trade-wind trough to stream upper-level cirrus northeastward to the east of Wake Island. ...DISCUSSION... STY Mawar will continue WNW the next few days, slowing in forward motion Sunday and Monday before it begins a northward turn somewhere near 120E, east of Luzon and Taiwan. Mawar will slowly continue to weaken, but will remain a powerful typhoon for another several days. Its presence in the Philippine Sea will continue to send out large long-period swell across western Micronesia and the Marianas. The convection well west-southwest of Chuuk will diminish over the weekend as regional surface winds reorient into a surface trough near or just west of Chuuk. Low-level convergent flow will continue to foster showers and thunderstorms near and north of 5N, occasionally extending across Chuuk. The trade-wind trough across the RMI will gradually diminish later this weekend with regional convection occasionally becoming more reflective of ITCZ-type of convection infused with sporadic upper- level westerly support before the TUTT retreats farther to the north. Convection will occasionally support some sporadic wind gusts to around 25 kt between Pohnpei and the RMI. $$ Aydlett/HFOtest