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FXPQ60 PGUM 192021

Area Forecast Discussion
National Weather Service Tiyan GU
620 AM ChST Sat Jan 20 2018

.Marianas Synopsis...
Partly cloudy skies with moderate trade winds prevail across the
Marianas this morning. Only a few showers are evident over the
region on satellite and radar. Latest buoy data shows seas between
5 and 7 feet.


A few minor changes made to the inherited forecast. Latest time-
height products show very dry conditions across the Marianas over the
next week or so. Therefore, decided to lower POPs over the area to
slight chance of showers for today and isolated light showers 
through Monday. Otherwise, the only real forecast problem lies with 
the winds. Winds look to pick up to fresh by tonight and Sunday, with
breezy conditions likely for the same time period. This could 
continue on into the middle of next week.


Latest buoy data shows seas between 5 and 7 feet this morning with
periods of around 11 to 12 seconds. This shows the possibility that
surf could continue to marginally hit around 9 feet through Sunday on
east facing reefs, resulting in a high risk of rip currents. Surf
could briefly fall below 9 feet over the weekend, however, expect 
rip current risk to remain high through most of the weekend and 
early next week. Seas will begin to build Sunday night and Monday, 
resulting in the rip current risk possibly remaining high through 


.Eastern Micronesia and Chuuk...
A broad trade-wind disturbance can be seen near Pohnpei this morning.
Wet weather associated with this system will persist near Pohnpei
thru Sunday morning and Kosrae thru tonight. As this system steadily
pushes westward, it will also impact Chuuk with similar weather by
this evening. Farther east, a fresh trade-wind surge is approaching
the Date Line. Drier northeasterly trades within this surge should
prolong fair conditions near Majuro thru Sunday evening, spread them
to Kosrae and Pohnpei by Sunday afternoon and Chuuk early next week.
The leading edge of a trade-wind convergence zone is visible east of
the Date Line near 6N175W. This feature will put an end to the fair
trade-wind weather from east to west starting early next week.

Trade-wind swell and wind waves should continue to decline today 
which should allow surf on Kosrae to drop below hazardous levels by 
this evening. Due to the combination of longer period trade-wind 
swell and a King Tide cycle, minor coastal inundation remain possible
on Majuro thru Sunday night. A new set of trade-wind swell generated
by the surge might cause surf on Kosrae to reach hazardous levels
again early next week.


.Western Micronesia for Yap and Koror...
A surface trough related to a weak circulation south of Koror will 
gradually depart the area this afternoon and evening. In the wake of 
this trough, weak surface ridging building in from the east will 
provide a period of drier weather for Yap today and Koror this 
evening. Latest ASCAT and IR satellite imagery reveal two trade-wind
disturbances upstream, one west of Chuuk near 145E and another one
near Pohnpei. These disturbances will generate more showery weather
for Yap by late this evening and Koror by Sunday. After the passage
of these disturbances, a fair trade-wind pattern should return to far
western Micronesia toward midweek next week.


GU...High Rip Current Risk through Thursday afternoon for GUZ001>004.

     Fire Weather Watch through Monday evening for GUZ001.

Marianas Waters...None.

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