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000
FXPQ50 PGUM 180640
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
440 PM ChST Thu Apr 18 2024

.Marianas Synopsis...
Mostly clear skies with only spotty light showers are evident on
satellite imagery across the Marianas. Mostly gentle winds prevail
across the region, with occasional fresh gusts at Guam Airport.
Altimetry shows seas between 5 and 7 feet.

&&

.Discussion...
The very dry pattern looks to continue across the Marianas through
the middle of next week. Time/Height products show a shallow moisture
layer, around 5000 feet and only reaching as high as 7000 feet at
times. Therefore, showers look less likely over the weekend than the
previous forecast. Based on satellite, Time/Height and CIMMS MIMIC
Precipitable Water products, expect cloud cover to remain mostly
clear to partly cloudy through the middle of next week. The
approaching shear line is also decaying rapidly and looks to be
minimal by the time it reaches the Marianas, and it looks unlikely
that it will push south of Pagan.

&&

.Marine...
Fairly benign marine conditions are expected to continue through the
weekend. Combined seas are currently between 5 and 7 feet and is
composed of a northeast to east trade-wind swell and a small north
swell. Seas look to subside slightly to between 4 and 6 feet by
Friday as the small north swell decreases further. Seas look to
continue at this level through Tuesday next week. As the north swell
continues to diminish, the rip current risk looks to drop to low
along north facing reefs over the weekend. Mostly gentle winds
tonight are expected to become gentle to moderate by the weekend and
continue through the beginning of next week.

&&

.Fire weather...
Dry conditions will continue to plague Guam over the next several
days. Guam Airport reported no rainfall yesterday and only a trace
the previous 2 days. The KBDI continues to climb and now stands at
707, which is in the very high category due to the lighter winds. The
only factor keeping Guam out of a Fire Weather Watch or Red Flag
Warning is the winds, since winds are not expected to reach over 15
mph for the next several days. Regardless, with the extremely dry
fuels, low RHs and lack of rainfall, open burning is highly
discouraged as any fires could spread easily.

&&

.Eastern Micronesia including Chuuk...
Active pattern across the region for most the period. The convergent
band strengthens as a surge in trade winds pushes south. A well
defined Inter-Tropical Convergence Zone (ITCZ) is expected to develop
and straddle across Chuuk, Pohnpei and Kosrae, while settling south
of Majuro. Multiple trade troughs and surges will traverse through
the convergent zone as well. Showers look to become numerous and
heavy at times from Chuuk to Kosrae. The convergence looks to
strengthen and lift north over Majuro by late weekend and showers
look to become numerous and heavy at times as well. Next week, the
convergence across the region becomes a little less defined, but with
multiple trade troughs and surges passing through the region, expect
the Probability of Precipitation (POPs) to remain in the 40 to 50
percent range and possibly bumping up to likely (60-70 percent) at
times.

Marine conditions look to remain fairly uneventful through the
weekend. Gentle to moderate trade winds are expected at Chuuk,
Pohnpei and Kosrae, with moderate to fresh winds at Majuro. Combined
seas of 4 to 7 feet will be the primary height for Chuuk, Pohnpei
and Kosrae. Seas of 6 to 8 feet are expected at Majuro.

&&

.Western Micronesia for Yap and Palau...
A Near-Equatorial Trough (NET) remains south of Yap and Palau. A
broad, weak disturbance within the NET is slowly drifting towards the
west, staying south of Yap and Palau. Showers continue to be spotty
for Yap, but numerous showers for Palau with the increased
convergence along the northern periphery of the NET and disturbance.
Satellite and model trends are showing a trade trough/surge pushing
away from Chuuk towards Yap. Enough moisture may also be pulled far
enough north that showers could become scattered for Yap later Friday
night into Saturday. As the NET and disturbance push west this
weekend, the trade flow increases in its wake. With multiple trade
troughs passing through, expect P0Ps in the 30 to 40 percent range
for most of next week. In addition, model guidance suggesting the NET
redeveloping late week and creeping north towards Palau and Yap,
with increased trade convergence and shower potential.

Gentle to moderate winds expected to become moderate with fresh gusts
by late this weekend into early next week as the trade flow increases.
Combined seas will generally be in the 4 to 6 foot range through
early next week, then decreasing by about a foot or two by late next
week. A longer-period northeast swell will continue to push through
the region through Friday night. While swell height is small,
around 3 to 4 feet, will see increased surf along north and east
facing reefs, but below hazardous levels.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...None.
MP...None.
Marianas Waters...None.

&&

$$

Marianas: Kleeschulte
Micronesia: Slagle