496
FXPQ50 PGUM 040708
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
508 PM ChST Thu Jul 4 2024

.Marianas Synopsis...
Satellite shows showers and isolated thunderstorms over large areas
toward the west and southwest of Guam, between the Marianas and Yap,
while upstream eastward only isolated showers area seen. Ritidian
buoy showed combined seas around 4 feet, but seas could be a little
higher toward the east and northeast. Surface winds are gentle to
moderate over the region this afternoon.

&&

.Discussion...
The upper-level trough that supports deep convection and development
of thunderstorms has drifted a little farther away toward the west
today, but there is still just the possibility of thunderstorms near
or just west of Guam and Rota overnight. Otherwise, models indicate
a more seasonal type of moist flow developing over the Marianas next
week. Also, unstable weather continues over Eastern Micronesia, and
there will likely be disturbances passing by Guam just to our south
in the coming days.

&&

.Marine/Surf...
Gentle to moderate trade winds and combined seas of 3 to 5 feet will
continue. There will be a moderate risk of rip currents along east
facing reefs of the Marianas through the middle of next week, and a
low risk along the other reefs. There will be a moderate risk of
lightning tonight, mainly near Guam and Rota. A more general risk of
lightning is possible starting Sunday. Weather conditions could
become a little more unstable next week.

&&

.Eastern Micronesia...
Satellite imagery shows numerous showers and isolated thunderstorms
ongoing for Majuro and are approaching Kosrae. Widespread showers are
expected across Kosrae tonight with numerous showers possible at
Majuro. Current upper level observations align with the GFS showing a
TUTT to the north of eastern Micronesia and an upper jet on the
southern edge of the TUTT extending down to Majuro. The combination
of the upper jet and upper divergence across eastern Micronesia has
led to numerous to widespread showers and isolated storms today. This
looks to persist into the night as the GFS digs the jet southward,
farther into eastern Micronesia. The trade-wind trough that is the
surface trigger for the storms will move west tomorrow while the
upper jet and TUTT shift eastward. This will lead to quieter
conditions for Majuro and Kosrae as we head into the weekend. The
bulk of the showers and storms should move towards Pohnpei on Friday
and Friday night before shifting west of eastern Micronesia on
Saturday. Much of the weekend appears relatively quiet for the region
before an increase in precipitation coverage is anticipated early
next week.

Seas are generally in the 3 to 5 feet range but should build into
the 4 to 6 feet range this weekend into next week. A Small Craft
Advisory is in effect for Majuro until 6 PM this afternoon for
convectively induced gusty winds.

&&

.Western Micronesia...
Satellite imagery shows scattered showers and isolated thunderstorms
across Yap and Palau this afternoon. This is mostly associated with
the TUTT that is moving westward to the north of western Micronesia,
and the interaction with a couple of trade-wind troughs that have a
weak circulation embedded to the west of Palau. These features are
expected to shift westward and conditions appear to quiet down at the
synoptic scale heading into the weekend. There does appear to be
some potential for island convection for Yap, Palau, and Chuuk with
light winds up to 500 mb through the weekend. Showers and storm
coverage looks to increase for Chuuk early next week as a trough
moves in from eastern Micronesia.

&&

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

$$

Marianas: Simpson
Micronesia: Williams