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FXPQ60 PGUM 231922

Area Forecast Discussion
National Weather Service Tiyan GU
520 AM ChST Mon Jul 24 2017

.Marianas Synopsis...
Light to gentle southeast to south winds with mostly cloudy skies
prevail across the Marianas this morning. PGUA WSR-88D data shows
isolated showers across the region. Latest buoy readings show 
seas between 2 and 4 feet.


No changes made to the inherited forecast. Isolated thunderstorms
remain in the forecast for today and tonight. Models indicate 
that the ridging between the tropical systems to the north and the
monsoon trough to the south will remain over the region through 
next weekend. This will promote partly cloudy skies and only a few
showers for the next week. Southeast to south winds will gradually
shift to the southwest over the next few days.


A small southwest swell will arrive the next few days, but with 
Typhoon Noru expected to remain to the north for the remainder of 
the week, a building north to northeast swell is anticipated to 
move into the Marianas, becoming the dominant swell around 
midweek. If Noru continues to develop over the next few days, the 
north swell could build sufficiently to bring high surf conditions
to the islands by the end of the week, especially for Tinian and 


.Eastern Micronesia...
A robust trade-wind disturbance coupled with upper-level divergence 
is producing showery weather over the Marshall Islands and some of 
the far northern islands, and for Kosrae today through tonight at 
least. Slightly drier mid levels should provide mild weather for 
Pohnpei and Chuuk thru today, at least. As the disturbance moves 
west over the next few days, showery conditions will spread toward 
Pohnpei and Chuuk. Decreasing trade winds near midweek should allow 
conditions to improve from east to west across the region. Another 
trade disturbance currently upstream near 163W could move into 
Eastern Micronesia later this week.

Surf conditions will need to be monitored carefully at Majuro. The 
astronomical high tide or King Tide cycle will affect the Marshall 
Islands for the next few days, and there are east-southeast swell 
and wind waves up to 6 or 7 feet. Surf along south shores will be 
higher than average and splashing waves could occur along coastal 
roads and near the airport.


.Western Micronesia...
There are High Surf and Small Craft Advisory head-lines for both 
Koror and Yap. A monsoonal circulation, Invest Area 99W, remains 
northwest of Koror near 11N131E with a monsoon trough stretched 
across Yap to southwest of Chuuk. Heavier showers are developing 
southeast to south of Koror, otherwise extensive cloudiness with 
patchy showers and thunderstorms are over Yap State and the Republic 
of Palau. Model guidance indicates increasing southwest winds and 
waves across Palau toward Yap, along with periods of showers, today 
thru Tuesday. Invest 99W should eventually move farther north into 
the Philippine Sea, and its influence over the area should diminish 
by Wednesday. After midweek, a surface ridge and milder weather is 


Marianas Waters...None.

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