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FXPQ50 PGUM 121928 CCA
AFDGUM

Area Forecast Discussion...CORRECTED
National Weather Service Tiyan GU
528 AM ChST Sun Jul 13 2025

.Marianas Update...
Only minor changes to the Marianas forecast this morning. The showers
for tonight are being taken down to isolated, as it looks like that
break will be appearing a little earlier, that`s the main one.
Satellite imagery shows that is already beginning to happen.

&&

.Marine...

Corrected a typo in the Marine paragraph

A moderate risk of rip currents along east facing reefs will start
slipping away Monday, and be gone by Tuesday night. In its place, a
moderate risk of rip currents along west facing reefs, and possibly
also along south facing reefs, will arise. Seas and winds will still
be well below advisory criteria though.

&&

.Aviation...
Koror, Yap, Pohnpei and Kosrae (in the afternoon) will be the most
likely places for IFR ceilings or visibilities today. MVFR conditions
will be possible for Guam and the CNMI. High winds and/or crosswinds
are not expected to be an issue in Micronesia today, although there
were a few occurrences at Kwajalein yesterday evening.

&&

.Tropical Systems...
Tropical Storm 06W has begun to move slowly eastward. Look for a
change more to the north as time goes on today. The weak circulation
that was not too far from Yap has evidently become weaker and is now
impossible to make out on ASCAT. We will maintain it for tonight and
see if it`s more visible on the afternoon pass.

&&

.Eastern Micronesia...
Satellite shows an active Intertropical Convergence Zone (ITCZ),
generating a band of deep convection shifting closer to southern
waters of Majuro and another area of showers developing across much
of Pohnpei State. Cloud cover is less dense over Kosrae this
morning, although still seeing some scattered showers in the area.

The main changes were to issue a Small Craft Advisory (SCA) for
Majuro for moderate to strong winds through this afternoon and to
extend the High Surf Advisory (HSA) for east-facing reefs of Kosrae
to this afternoon as well. The GFS shows stronger winds along an
embedded trough in the ITCZ, possibly producing 30 kt gusts, although
GFS places this gust potential south of Majuro waters. GFS also
advertises the potential of SCA winds for Kosrae with the passage of
the aforementioned trough late tonight. For now, bumped up winds to
moderate to fresh in the forecast, up to 20 kt. Based on satellite
trends, increased showers to numerous locally heavy near Pohnpei
this  based on satellite trends, but still expecting a decrease to
scattered this afternoon. Also increased PoPs at Majuro for ITCZ
showers building in late morning and to Kosrae tonight. Trade swell
is slow to subside at Kosrae, but may see surf along east- facing
reefs subside below 8 feet this afternoon.

Buoy and altimetry data reveal combined seas of 5 to 7 feet across
the region and up to 8 feet near Majuro.

&&

.Western Micronesia...
In this developing monsoon pattern, unsettled weather continues
across Palau and Yap. Meanwhile, Chuuk`s weather is impacted by a
broad disturbance at the leading edge of the ITCZ. Only changes to
the forecasts were to try and time numerous, locally heavy showers
over the next 24 hours. Satellite shows overcast skies and locally
heavy showers over Palau and lightning just east of coastal waters.
Deeper convection southeast of Chuuk will try to build back in this
morning, but overall convection is expected to decrease in the
afternoon. Yap is currently northeast of the bulk of convection, but
model trends indicate and increase in showers late tonight.

Buoy and altimetry data indicate combined seas around 3 to 5 feet
near Palau and Yap, and 4 to 6 feet at Chuuk. Seas may see an
increase near Palau and Yap mid to late week in response to an
increase in southwest swell and wind waves. Sea heights will see a
very slight decrease for Chuuk early next week with an easing of
trade swell.

&&

.Prev discussion... /issued 424 PM ChST Sat Jul 12 2025/

Marianas Synopsis...
Mostly cloudy skies reign over the Marianas today. 0.5 inches of rain
has fallen since midnight at the airport. Winds have been light with
gusts to moderate. Altimetry shows combined seas of 3 to 5 feet,
while the buoys 4 to 6 feet.

Discussion...
A wet and unsettled pattern is expected to continue for the weekend
and the latter half of next week, with a short lull around Monday and
Tuesday. TS 06W, located near the northern border of the AOR is
pulling the trade winds into itself. This is causing a convergence
zone over the Marianas and producing showers and thunderstorms. This
zone will remain over the Marianas through the weekend. Then a short
24 to 36 hour lull in showers is anticipated due to TS 06W moving
further away and the incoming monsoon trough building in. As the week
progresses, models suggest that the eastern section will be forced
northward. This northward trend is what will bring showers to the
Marianas for the latter part of next week.

Marine...
Overall, fairly benign seas are expected for the Marianas. The surf
is expected to be the highest along east facing reefs with a moderate
risk of rip currents. On all other reefs, surf is expected to remain
below 4 feet and the risk of rip currents will be low. Later next
week, the monsoon flow may produce a southwest swell which could
bring the surf up and possibly increase the risk of rip currents to
moderate.

Tropical Systems...
A tropical disturbance remains southwest of Guam this afternoon.
There is not a well defined circulation center, however, based on
curvature shown in the visible satellite data, it is loosely located
near 12N140E. Not much is expected from 94W over the next couple of
days as it drifts west. Model guidance is in pretty good agreement
that 94W will see little to no development over the next few days.

Eastern Micronesia...
The Inter-Tropical Convergence Zone (ITCZ) remains the primary
player for eastern Micronesia. The ITCZ remains active, with
scattered to numerous showers and isolated thunderstorms seen across
the region. The majority of the convection is currently seen north
of Majuro and south of Pohnpei associated with weak trade-wind
troughs moving through and interacting with the ITCZ. This will
continue to be the case for the next few days. A more robust trough
looks to move into Kosrae Sunday night and Pohnpei Monday, bringing
and extended period of numerous showers and isolated thunderstorms
to both locations. Kosrae can expect the increase in coverage Sunday
night through Monday night, with Pohnpei seeing the increase Monday
and Monday night. The ITCZ looks to break down early next week,
allowing POPs (Probability of Precipitation) to drop to around 20
percent Tuesday and Wednesday for Kosrae and Majuro and Wednesday for
Pohnpei. Latest guidance indicates another burst in activity along
the ITCZ by the end of next week.

No major changes to the marine forecast. Mostly gentle to moderate
winds are expected at Pohnpei and Kosrae, with occasional fresh winds
possible early next week. For Majuro, moderate to fresh winds will
become gentle to moderate late in the weekend. At Pohnpei and Kosrae,
combined seas of 5 to 7 feet tonight will subside over the weekend,
dropping to 3 to 5 feet Sunday night. For Majuro, combined seas of 6
to 8 feet will slowly subside over the next few days, becoming 4 to 6
feet by Tuesday evening.

Western Micronesia...
Palau and Yap:
Similar to what`s been talked about the past few days, a
southwesterly monsoon flow looks to develop in the next few days
across the region. MIMIC PWATs are already in the 2.5 to 3 inch
range with deep moisture saturation (surface to 50K feet), making for
efficient rain-producers. Thus, some heavy rain concerns will
potentially develop. For now, we increased shower coverage to
numerous/likely for periods of time, especially at Yap as they`ll be
better juxtapositioned for stronger surface winds and lift. Much of
the upcoming week looks like "a wet one".

Chuuk:
A series of subtle trade wind troughs within the ITCZ will also allow
persistent deep moisture transport with periods of increased lift.
Here too, periods of numerous showers/likely probabilities will
continue much of the week, with scattered shower coverage expected in
between.

&&

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

$$

Marianas: Stanko
East/West Micronesia: Cruz