Dust Devil in Guam, March 20, 2024

Area Forecast Discussion
National Weather Service Tiyan GU
729 AM ChST Wed Mar 20 2024

.Marianas Synopsis...
Gentle to moderate northeast trades, partly cloudy skies, and
isolated showers prevail across the region this morning. Tanapag
buoy shows seas are around 5 to 6 feet.

&&

.Discussion...
No major changes were made to the forecast. Quiet conditions are
anticipated through the remainder of the week, then winds and shower
potentials increase in response to a shear line descending into the
region from the northwest. A tropical disturbance well to the south
near eastern Yap State is expected to shift northward slightly and
interact with the shear line feature over the weekend, potentially
leading to more unsettled weather for the southern portions of the
Marianas, namely Guam and Rota.

&&

.Marine/Surf...
Gentle to moderate trade winds and combined seas of 4 to 6 feet will
prevail for the next couple days. Seas begin to increase starting
Thursday as northerly swell builds into the region and a descending
shear line brings a quick rise in northeast swell. In addition,
winds that could bring near-gale force gusts by the weekend, creating
hazardous conditions for small craft. There will be a moderate risk
for rip currents along west, north, and east facing reefs for the
next few days. Surf will remain below hazardous levels through
Thursday, but will begin to increase across north facing reefs
Thursday night.

&&

.Fire weather...
No rain fell yesterday at the airport, allowing the KDBI to increase
to 656, which remains in the high category. A wetting rain does not
look probable over the next several days and minimum relative
humidities have been low (below 60 percent), so concern for fire
weather heightens, especially with the onset of stronger winds by the
weekend. Look for issuances of a Fire Weather Watch or Red Flag
Warning in the coming days.

&&

.Eastern Micronesia and Chuuk...
Little has changed in the forecast overnight. Buckling in the trade-
wind pattern as it encounters a broad trough extending from a Near-
Equatorial Trough (NET) to the west, will continue to induce
diminishing winds and on-and-off showers across Pohnpei and Kosrae
the next few days. In addition, a convergence zone forming along the
northern periphery of the aforementioned NET will continue to bring
increasing shower coverage and some thunderstorms to Chuuk over the
next several days, before tapering down during the weekend. Majuro is
expected to see much more pleasant weather through at least the
weekend, with a further drying in the localized moisture column to
allow mostly clear skies to ensue tonight.

Combined seas of 5 to 7 feet are expected across most of the region
through midweek, then pulses of north and northwest swell generated
by systems over the far north Pacific are expected to arrive and
persist into next week. However, a stronger pulse of northwest to
north swell will enter the region by this weekend, with seas back up
to 7 to 9 feet or higher.

&&

.Western Micronesia for Palau and Yap...
The Near-Equatorial Trough (NET) remains the primary weather feature
affecting Palau and Yap for much of the forecast period. Showery
conditions are observed over Palau this morning, but are expected to
dissipate quickly late morning, as the moderate to deep convection
observed to the southeast of the main island enter a quiet phase.
This can be attributed to an injection in much-drier air from the
northeast, that is already bringing dry conditions upstream, with
mostly clear skies expected at Yap tonight. Unsettled weather is
expected to return to the far western Micronesia during the weekend,
as a descending shear line interacts with the convergence zone
induced by the NET and the westward-propagating disturbance embedded
within the NET.

The Ngaraard/Babeldaob buoy shows seas ranging between 5 and 7 feet
today; waves mainly from the NNE and some from the east. Wave models
indicate that combined seas will build later this week, along with a
long-period north swell arriving by about Friday. Combined seas could
reach 7 to 10 feet this weekend and a Small Craft Advisory may be
needed by then, especially for Yap.

&&

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

Marianas: Cruz
Micronesia: Montvila