Area Forecast Discussion
Issued by NWS
FXPQ60 PGUM 290636
Area Forecast Discussion
National Weather Service Tiyan GU
324 PM ChST Thu Sep 29 2016
TD Chaba has moved well west of the Marianas, but satellite shows
outflow boundaries ejecting from Chaba`s eastern flank, triggering
scattered showers across the Marianas this evening. South winds
have diminished to around 15 kt, and combined seas are at 5-7 ft.
Expect scattered showers through the evening, but as Chaba gets
farther away, they should lose steam after midnight, and it`ll be
back to isolated showers and thunderstorms in line with GFS.
Adjusted the timing of next episode of scattered showers to a day
sooner--Sun-Mon night rather than Mon-Tue night, as GFS and ECMWF
both bring the next disturbance faster than before. Accordingly,
period of just isolated showers moved forward to Fri night to Sat
night when mid-levels are driest.
Boosted wave heights a foot for tonight and Friday in line with
Ritidian buoy. Also refreshed winds from the GFS through next the
next 8 days, mainly to be in line with the next disturbance
getting in a little faster as noted above. Seas will diminish
steadily and should settle to near 4 feet for the first half of
next week, when rip risk should be low.
The slow-moving surface trough is still causing showers and a few
thunderstorms in patchy areas over the northwest Marshall Islands,
along with much of Kosrae and Pohnpei States. Showers were also
moving into Chuuk State this afternoon. Models indicate the trough
will edge westward in the coming days, and cause deteriorating
weather conditions for Chuuk State much of this weekend. Drier
weather will spread slowly from east to west behind the trough,
but another surface trough arriving from the east will bring
increased clouds and showers to the region early next week.
Benign sea conditions are expected at Majuro the next several days.
However, PACIOOS Wave Run-Up Forecast shows slightly higher seas
through this weekend with the New Moon phase. Water levels will be
high during high tides through October 3rd, but inundation is not
expected at this time as combined seas will be between 3 and 5 feet.
Majuro/Kalo Buoy shows combined seas around 3 feet.
Reasoning for the Chuuk forecast is included in the Eastern
Micronesia section above.
Tropical Depression Chaba will be moving west across the Philippine
Sea well to the north of Yap during the next day or two. Monsoon
southwest winds will develop and cause showers and thunderstorms to
increase for Yap and Koror the next couple of days at least. Also,
model guidance indicates that a disturbance in eastern Micronesia
will move farther westward and cause unstable weather for Yap State
and Palau by Monday or Tuesday.
The sea and surf conditions will need to be monitored in the coming
days, especilly is Chaba intensifies or slows down enough to push
larger swell waves toward far western Microneeisa.