159
FXPQ50 PGUM 211949
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
549 AM ChST Wed May 22 2024

.Marianas Synopsis...
Satellite imagery showing mostly cloudy skies and scattered showers
for Guam this morning, with partly cloudy skies and isolated showers
for the CNMI. Latest altimetry data is indicating seas of 6 to 8
feet to the west and east of the coastal waters.

&&

.Discussion...
Scattered showers this morning over Guam will become isolated this
afternoon as the trade disturbance shifts west. Another trade
disturbance will drift across the southern Marianas Thursday night
into Friday. Scattered showers back for Guam, along with isolated
thunderstorms, as models suggest deeper mid-level moisture and
enhanced convergence creeping north. Showers look to remain isolated
for the CNMI.

&&

.Marine/Surf...
A surge in trade winds and an elevated trade swell continue to move
through the region. Winds will be moderate to fresh through tomorrow,
with occasional strong gusts today, and combined seas of 6 to 8 feet
expected. Winds may approach Small Craft criteria of 22kt through
this afternoon, but for now look to remain just below thresholds.
Winds and seas diminish by tomorrow evening. Scattered showers will
be possible in the Guam waters today, and more scattered showers with
isolated thunderstorms will be possible Thursday night into Friday
for the Guam waters.

A high risk for rip currents will persist through this afternoon
along east facing reefs, with a moderate risk from tonight onward. A
moderate risk for rip currents continues along north facing reefs. A
low risk continues for south and west facing reefs. Surf looks to
lower further through the end of the week as the trade swell
continues to diminish, with the rip risk possibly becoming low on
north facing reefs

&&

.Fire Weather...
0.11" of rain fell yesterday at the Guam airport, allowing the
KBDI to rise 577, well into the high category. Scattered showers
expected this morning and again Thursday night into Friday, with
a wetting rain possible. Gusty winds expected through this evening,
but with the elevated clouds and moisture, the fire threat looks
to remain below Red Flag criteria.

&&

.Tropical Systems...
The broad and weak circulation, 93W, southeast of Palau near 5N138E
remains the tropical feature of interest. It is currently rated as a
LOW for development potential by the JTWC, meaning TC development is
unlikely within the next 24 hours. Satellite imagery shows an exposed
low-level circulation center with deep convection displaced to the
east. West of the center, clusters of showers and thunderstorms are
developing amid a swath of drier air feeding in from the west, as
noted in recent MIMIC TPW imagery. Deterministic and ensemble model
guidance largely keeps 93W as a broad circulation with a large center
of weak winds as it passes near Palau through tomorrow. The most
likely effects from 93W to the Palau and Yap areas will be the
heavier shower and stronger easterly wind gust potential as 93W heads
WNW. Once 93W heads into the PI Sea, models show a slow organization
of the circulation with GFS still being more aggressive in the 5-10
day time frame, as has been the case for quite some time. Residents
of Yap State and the Republic of Palau should continue to monitor
forecasts for any changes in expected conditions.

&&

.Eastern Micronesia...
Currently, Majuro and Kosrae are in fair weather. However for Majuro
cumulus are seen on satellite imagery. This is the anticipated
Inter-Tropical Convergence Zone (ITCZ). So far, the ITCZ looks to be
lack luster with only a few cells that can produce heavier showers.
An embedded trough that reaches down to southeast of Makin Atoll,
this trough will pass over much of the islands and atolls below 10
north of RMI and eventually Kosrae.

Pohnpei currently has some shallow cumulus clouds that are filling
in. These region is where the trade winds are converging and causing
some stronger convection near Pohnpei`s waters. Most of the
convection with this trough has stayed north, however, this is
expected to change over today and tonight. These showers are not
expected to remain for very long, maybe 24-hours or so.

Gentle to moderate trade winds and trade-wind swell continues across
the region. Seas near Kosrae are anticipated to be around 4 to 6
feet and 3 to 6 feet near Majuro, around 6 feet to the west of
Pohnpei.

&&

.Western Micronesia...
Chuuk can expect to see some spotty but short-lived showers today.
Then, the convergence region that is currently over Pohnpei will be
moving over Chuuk, this will be the next opportunity for Chuuk to get
more showers.

For Yap and Palau, Invest 93W will remain the main concerns for these
islands. Showers are expected to build to numerous over the next day
or two. These showers maybe heavy at times and winds will be stronger
near the stronger cells. Showers are expected to be the strongest on
the north and eastern sides. 93W is not expected to become a tropical
cyclone before it passes these islands. Once 93W passes, regular
trade-wind troughs are anticipated to push through the region. At
this time, the showers associated with these troughs are fairly weak
with maybe a one bolt wonder.

Winds will be mainly moderate for Yap and Chuuk and gentle to
moderate for Palau through the week. Fresh to strong gusts are
possible near heavier showers for Yap and Palau Wed-Thu, due to the
passage of 93W. Seas are 4 to 5 feet near Yap and Palau, 4 to 6
around Chuuk.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...High Rip Current Risk through Wednesday afternoon for GUZ001.

MP...High Rip Current Risk through Wednesday afternoon for MPZ001>003.

Marianas Waters...None.

&&

$$

Marianas: Slagle
Tropical: Slagle/Aydlett
Micronesia: Bowsher