Drought in Guam, January 1 to 31, 2023

Area Forecast Discussion
National Weather Service Tiyan GU
601 PM ChST Sat Dec 31 2022

.Marianas Synopsis...
Satellite and radar imagery showed isolated showers over the
Marianas this afternoon.

&&

.Discussion...
A few small changes made to the forecast. Radar imagery showed
only a few showers over the area this afternoon. A decaying shear
line over the area continues to generate clouds over the Marianas.
Models show that enough low-level convergence and moisture
remains that scattered showers are possible after midnight tonight
over the local area.

New Year's day will see drier air returning and showers remaining
isolated. Showers will remain isolated through Monday night.

A trade-wind disturbance will bring more chances for showers and
thunderstorms Tuesday and Tuesday night. Another trade-wind
disturbance will bring more showers Thursday night.

High pressure passing to the north will keep the pressure
gradient higher over the area through the forecast. This will keep
winds elevated through much of the forecast. Expect breezy
conditions at times the next few days.

&&

.Marine/Surf...
Ritidian and Tanapag buoys showed sea heights between 8 to 10
feet. Models show seas of 8 to 10 feet tonight persisting through
Tuesday. Winds will remain elevated, 15 to 25 knots, through
Wednesday. With the seas and/or winds this high conditions will be
hazardous to small craft. Both buoys also showed a north swell
and a east-northeast swell. Both of these swells will persist
through the forecast.

The east-northeast swell is high enough to produce surf of 7 to 9
feet on east facing reefs and a high rip current risk through
Tuesday night.

&&

.Eastern Micronesia...
A weak Inter-Tropical Convergence Zone (ITCZ) meanders eastward
from western Micronesia to south of Pohnpei, across Kosrae then
south of Majuro to beyond the Date Line near 5N. Although the ITCZ
is weak right now, it looks to strengthen over the next few days
as weak trade-wind troughs traverse the boundary. The ITCZ looks
to waver north and south over the coming days with POPs
(Probability Of Precipitation) undulating in response. Pohnpei
will see low-end scattered showers tonight as a weak trough moves
through the state, with POPs dropping to around 20 percent for New
Years Day. Then, the ITCZ will drift a bit farther north,
bringing increased POPs to Pohnpei. Meanwhile, the ITCZ looks to
remain close to Kosrae through the period, with 30 to 50 percent
POPs expected through the middle of next week. As with Pohnpei,
Majuro also looks to remain north of the ITCZ through Tuesday.
this is when the first of a series of troughs will move through,
bringing increased convection to all three locations by midweek
next week, with showers likely at times from Wednesday into next
weekend.

Seas look to remain around 6 to 8 feet across the region over the
next several days. A northeast swell of 4 to 6 feet tonight will
maintain surf of 8 feet along east facing reefs of Kosrae today,
with the swell building around a foot by Sunday, resulting in surf
of 7 to 9 feet. Surf looks to remain at around 7 to 9 feet
through at least the middle of next week at Kosrae. Moderate to
fresh trade winds look to continue across the region through the
middle of next week as well. Although not in the forecast at this
time, winds could increase to above 22 knots, early next week in
response to another building high pressure system moving through
to the north of the Marianas.

&&

.Western Micronesia...
The western end of a weak ITCZ is seen across Chuuk, along with a
trough extending northeast from a buffer centered near the
equator at around 145E. These two features will maintain scattered
showers and isolated thunderstorms across Weno through tonight.
The trough then moves off to the west as the ITCZ drops back
south, bringing lower POPs, around 20 percent, to Chuuk for the
next few days. Then, around Wednesday night, the ITCZ will drift
northward and interact with a surface trough approaching from
eastern Micronesia. Latest guidance shows the ITCZ wavering north
and south near Chuuk for the latter half of next week, resulting
in undulating POPs Thursday night into next weekend.

For Yap and Palau, the shear line is basically dissipated, with
the main feature now being the Near-Equatorial Trough (NET) south
of both Palau and Yap State. Latest surface analysis shows the NET
has drifted a bit farther north. Another significant feature that
looks to affect Yap in the short term is a trough, currently near
Chuuk, that will move into Yap proper by New Years morning. As
the NET and this trough approach closer to both Yap and Palau,
POPs look to increase accordingly. Yap will see the increase first
as the trough approaches from Chuuk. Due to the proximity of the
NET, Palau looks to get the majority of the activity, with
numerous showers possible Monday as the other surface trough
approaches from Yap.

Combined seas of 6 to 8 feet are expected for the next few days
for Yap and Chuuk, with 5 to 7 feet for Palau. Latest guidance
indicates that and increasing northeast swell will then approach
the region, with seas reaching as high as 9 feet for all 3
locations early to midweek next week. The ECMWF-Wave shows seas up
to 10 feet north of all 3 points around the same time frame.
Though not expected at this time, seas could reach as high as 10
feet, Small Craft Advisory levels. Mainly moderate winds will
continue through Monday for Palau and Chuuk, becoming moderate to
fresh Monday night. Winds will remain moderate to fresh for Yap
through the forecast period.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...Beach Hazards Statement through Sunday afternoon for GUZ001.

     High Rip Current Risk through Wednesday afternoon for GUZ001.

MP...Beach Hazards Statement through Sunday afternoon for MPZ001>003.

     High Rip Current Risk through Wednesday afternoon for MPZ001>003.

Marianas Waters...Small Craft Advisory until 6 PM ChST Wednesday for
	 PMZ151>154.

&&

Marianas: Ziobro
Micronesia: Kleeschulte