210
FXPQ50 PGUM 060802
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
602 PM ChST Mon May 6 2024

.Marianas Synopsis...
Partly cloudy skies with spotty showers and gentle to moderate trade
winds prevail across the Marianas this evening. Altimetry shows seas
between 3 and 6 feet.

&&

.Discussion...
No big changes made to the previous forecast. Latest model guidance
shows a dry pattern continuing across the Marianas for the next
several days. Around Thursday, disagreement emerges between the
different models. The latest model runs show a Near-Equatorial Trough
(NET), currently near the equator to around 4N from 130E to south of
Weno, Chuuk near 151E, drifting northward over the next several days.
Along the trough, several weak circulations are popping up, then
decaying, as the trough drifts north. The latest GFS and GFS Ensemble
show one of these circulations developing into a significant Tropical
Cyclone (TC) as it moves through to the south of Guam. This could
bring increasing showers and thunderstorms to the Marianas later this
week. Confidence in this happening, however, is fairly low as the
other models and ensembles show only weak circulations moving along
the NET. This could bring a few thunderstorms to the Marianas late in
the week into the weekend, especially for Guam and Rota. Based on
the low confidence in the development of a TC, maintained a slight
chance of thunderstorms for the Marianas from Thursday through the
beginning of next week.

&&

.Marine...
Gentle to moderate trade winds will continue into the weekend.
Combined seas of 4 to 6 feet tonight look to build a bit to around
the 5 to 7 foot range Tuesday into early Wednesday morning as a
northeasterly swell that is now affecting the Marianas slowly builds
to between 4 and 6 feet. This swell will be fairly short-lived and is
expected to begin to subside Wednesday morning. The northeast swell
and the east swell will maintain a moderate risk of rip currents
along north and east facing reefs the next couple of days. As the
northeast swell diminishes Wednesday into Thursday, surf will also
subside, allowing the rip current risk to drop to low along north
facing reefs by the weekend. Due to the trade swell continuing and
slightly building for the weekend, expect the rip risk to remain
moderate along east facing reefs through the weekend.

&&

.Tropical systems...
An active pattern is seen on satellite over western Micronesia,
south of Yap and Palau. A NET is evident on the latest ASCAT
analysis, extending eastward from near 5N130E to a weak circulation,
Joint Typhoon Warning Center (JTWC) Invest 91W, centered near
4N136E. The NET continues eastward through a second circulation,
JTWC Invest 90W, centered near 4N142E. The latest GFS and GFS
Ensemble show one of these circulations developing into a significant
Tropical Cyclone (TC) as it moves through to the south of Guam,
toward Yap and Palau. Confidence in this happening, however, is
fairly low at this time as the other models and ensembles show only
weak circulations moving along the NET. This area will be monitored
closely over the next few days for any possible development.

&&

.Eastern Micronesia...
Trade-wind convergence and a few trade-wind troughs are producing
scattered showers and isolated thunderstorms across the region during
the day. Model analysis during the day continues to show trade-wind
convergence and troughs will remain mostly south of Majuro through
at least Friday, and generate scattered showers and isolated
thunderstorms for Kosrae and Pohnpei. Both the deterministic GFS and
ECMWF and ensemble GFS agree that the trade-wind convergence will
lift northward with a slight uptick in showers and thunderstorms at
Majuro.

Moderate to fresh trades are expected through at least Tuesday at
Kosrae, and through Thursday at Majuro. Otherwise, combined seas of 5
to 7 feet and gentle to moderate trades are expected at Majuro,
Kosrae, and Pohnpei.

&&

.Western Micronesia...
ASCAT and satellite analysis this afternoon show a couple of embedded
weak circulations along the Near-Equatorial Trough (NET) that is
located over the far southern portion of the Republic of Palau.
Models continue to show the NET being pulled northward with the weak
circulations closer to Palau, increasing shower and thunderstorm
activity through the week at Palau and Yap. For more information on
the circulations along the NET, please see the Tropical systems
section above. For Chuuk, a trade-wind trough currently between
Pohnpei and Chuuk will push over Weno on Tuesday, generating chances
for scattered showers and isolated thunderstorms. Afterwards, both
GFS and ECMWF, with various timing and placement issues, show the
NET lifting northward with impinging trade-wind troughs generating
enough convergence for scattered showers and thunderstorms through
early next week.

Gentle to moderate trades and combined seas of 4 to 6 are expected
at Chuuk, Yap, and Palau through early this weekend.

&&

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

$$

Marianas: Kleeschulte
Micronesia: Kelly