Hurricane Local Statement 4031, NWS Guam

Area Forecast Discussion
National Weather Service Tiyan GU
926 AM ChST Thu Oct 25 2018

.Marianas Synopsis...
Andersen Air Force Base Doppler weather radar shows the eye of Super
Typhoon Yutu (31W) to be near 15.6N and 144.4E. Yutu is still firmly
dominating weather in the Marianas coastal zones. As it continues to
move away, weather will gradually normalize. The VAD wind profile
shows southwest winds of 30 knots just off the surface which increase
to between 40 and 50 knots through the lowest 25 thousand feet of the
air. The buoys reveal a 3 foot east trade-wind swell and a 20 foot
southwest typhoon swell.

&&

.Discussion...
After Yutu exits the area, which could happen for all practical
purposes tonight, looks like we will return to standard wet season
TUTT enhanced weather, or mostly cloudy with isolated showers and
thunderstorms through Sunday. Monday it could settle down even more.

&&

.Marine...
Seas of 15 to 25 feet today will gradually setlle down. Starting
Sunday, seas will be 6 to 8 feet as winds settle down and turn toward
the southeast then eventually to the northeast.

&&

.Tropical systems...
Super Typhoon Yutu brought winds to Saipan and Tinian of high end
category 4 or a category 5. Satellite estimates of intensity were
up to 180 miles per hour. There will likely be an assessment, as no
wind instruments seem to have survived to tell how high the winds
got. Anecdotal evidence indicates it was worse than Soudelor, which
was expected when it began its rapid intensification. Yutu will
likely become the new yard stick by which future storms will be
judged.

&&

.Eastern Micronesia...
A weak circulation is centered near Kosrae near 6N165E and is causing
numerous showers and isolated thunderstorms just east of Kosrae.
Models show the disturbance moving WNW the next couple of days,
eventually opening up as a surface trough, the eastern extension of
the monsoon trough in the lee of Yutu. Wet weather will spread WNW,
staying just north of Pohnpei, but showers may become scattered at
times. Another trough will develop just north of Majuro over the
weekend, bringing unstable weather to the area then.

&&

.Western Micronesia...
Showers and thunderstorms persist at Chuuk, mainly in the western
waters. Upper-level winds are keeping the convection from proceeding
eastward for the time being. The upper winds will slacken later today
and allow the wet weather to push through and continue for the next
couple of days. Drier weather is expected early next week as winds
shift to south. Surf will remain hazardous through tonight, but is
expected to fall below hazardous levels Friday.

Yap and Koror remain just south of the monsoon trough axis, but as
Yutu moves farther into the Philippine Sea, the axis will lift north.
This will bring an increase in west winds and cloud cover. Models
still keep the bulk of showers to the east so have only kept isolated
showers and thunderstorms in the forecast for now. As long-period
northeast swell from Yutu approaches in the coming days, seas and
surf will increase. Hazardous surf is expected along north and east
reefs at Yap tonight and at Koror sometime Friday. Seas will also
become hazardous around Friday at both locations.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...Flash Flood Watch through late tonight for GUZ001>004.

     Tropical Storm Warning for GUZ001.

     Typhoon Warning for GUZ002>004.

Marianas Waters...Tropical Storm Warning for PMZ151.

     Typhoon Warning for PMZ152>154.

&&

Stanko/W. Aydlett