Drought in Guam, June 1 to 30, 2020

Area Forecast Discussion
National Weather Service Tiyan GU
614 PM ChST Sun May 31 2020

.Marianas Synopsis...
Isolated showers and east trade-winds prevail across the Marianas
this afternoon. The trade-wind disturbance that brought wet weather
to portions of the area last night and this morning has moved west.

&&

.Discussion...
A few small changes made to the forecast. Satellite imagery from this
afternoon show the trade-wind disturbance west of the Marianas. Earlier
forecast had mostly cloudy skies for Guam and Rota tonight but satellite
imagery show that the clouds have decreased over the local area. Models
agree with decreasing the moisture and trimmed cloud cover and have
partly cloudy skies for all the islands in forecast for tonight.
Dry weather with partly cloudy skies and isolated showers are
expected through at least mid-week. An upper-level low was located
near 15N155E this afternoon. Models do show this upper-level low
moving slowly westward passing across the Marianas by Thursday.
A surface trough is also noted in the models passing just south of
Friday night and Saturday. The combination of these two weather
features will increase cloud cover and the chances for showers
Thursday through Saturday.

&&

.Marine...
Observations from Tanapag and Ipan buoys show seas between 2 and 5
feet and satellite altimetry agree. Models show seas remaining at
this height through Monday decreasing to 2 to 4 feet by Monday night.
Ipan buoy had a east swell while Tanapag had a northeast swell. Both
swells will generate a moderate rip current risk on east facing reefs
the next few days possibly becoming low the second half of the week.

&&

.Eastern Micronesia...
Moderate trade winds are present over eastern Micronesia, disturbed
by the presence of weak inverted troughs near Kosrae and Majuro. But
satellite imagery shows only moderately active convection, mainly
just northeast of Kosrae and just east of Majuro, with a large area
of dissipating convection in between. Over the next few days, areas
of showers are expected to form mainly south of the three forecast
locations. Kosrae can expect scattered showers and isolated
thunderstorms tonight, but after that only isolated showers or
thunderstorms are expected, as new convection forms further south
during the week. At Pohnpei, scattered showers are most likely
Tuesday and Tuesday night, but again the bulk of the activity is
forecast to remain to the south. Majuro looks fairly dry the next
few days, with the more significant weather remaining to the west.
By Thursday and Friday, the GFS shows a zone of convergence and
showers south of all three locations, but curving northwestward
across Chuuk.

&&

.Western Micronesia...
Very dry weather continues this afternoon across Palau and Yap with
gentle to moderate trade winds, but an upper-level disturbance most
evident at 500 mb is producing isolated showers and thunderstorms
across Chuuk. Over the next few days, fairly dry weather should
continue for Koror, but Yap should see isolated showers and
thunderstorms by Tuesday as a trough takes shape to the east and
moves west. GFS hints at scattered showers and thunderstorms around
Thursday and Friday, but the ECMWF is weaker with that, and so it is
too early to tell for now. Chuuk will continue with isolated showers
and thunderstorms the next couple of days, but by Wednesday, the
zone of convergence in eastern Micronesia should be extending in
from the southeast, with periods of scattered showers and isolated
thunder- storms Wed through Fri.

&&

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

Ziobro/Middlebrooke