436
FXPQ50 PGUM 120612
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
412 PM ChST Wed Feb 12 2025

.Marianas Synopsis...
Fair weather cumulus and moderate to fresh northeast trades prevail
across the region this afternoon. Buoys indicate seas are around 9
feet.

&&

.Discussion...
A dry trade-wind pattern continues across the region. No significant
features are expected to bring notable rain chances over the next
several days. This is expected to affect severe drought conditions
in Tinian and Saipan and abnormally dry conditions for Guam and Rota,
as well as fire danger across the Marianas.

&&

.Marine/Surf...
Small Craft and High Surf Advisories remain in effect through
Thursday afternoon, along with a high risk of rip currents along
west, north and east facing reefs. Long-period north swell, combined
seas of 7 to 10 feet, and moderate to fresh winds with strong gusts
will continue through Thursday, creating hazardous conditions for
mariners. Significant long-period north swell continues to drive
larger surf along west, north, and east facing reefs, creating
hazards  Pulses of long- period north swell continues to move over
the region the next several days, however a decrease in overall swell
heights are expected to generate seas below hazardous levels, near 5
to 7 feet this weekend. Surf could diminish by about a foot or two
each day on Thursday and Friday, allowing the risk of rip currents to
return to moderate levels by Friday.

&&

.Fire weather...
Guam has been without a wetting rain (greater than or equal to 0.20
inches) since February 4th. Several spot fires have already
occurred in the southern mountains, and the KBDI is in the high
category at 587 and climbing. Low afternoon humidites and winds of
15 and 20 mph with stronger gusts, especially in the mountains, are
expected to continue over the next day or so. Looking at possible Red
flag conditions by Saturday for Guam. Although Tinian and Saipan had
a few days of wetting rains in the last week, the ensuing dry trade-
wind pattern will continue to put stress on ongoing drought
conditions there as well.

&&

.Eastern Micronesia...
ASCAT analysis indicates an area of disturbed weather is centered
just NNW of Kosrae and NE of Pohnpei at 7.5N162.5E; embedded in a
slow westward moving surface trough. Another area of disturbed
weather associated with the ITCZ is causing numerous showers over
the southern Marshall Islands and the Tarawa area, and eastward to
beyond the Date Line. Both of these features will be the weather
producers for Eastern Micronesia through the next few days.

Meanwhile, High Surf advisory remains in effect for Pohnpei and
Kosrae. The persistent long-period north swell will be re-enforced
at times on Thursday through Friday with surf up to 10 feet along
the north facing reefs. Surf at Majuro is still not expected to reach
the higher criteria of 12 feet.

&&

.Western Micronesia...
A decaying shear line stretches east-northeast from Ulithi and Fais
to just north of Gaferut, before curving more to the northeast. This
is easily seen in the various satellite imagery, especially the
visible and MIMIC water vapor. What also jumps out of you in the
imagery and model data is another fragmented/weakening shear line
entering the northern-most portions of the CNMI, with a third such
feature north of 20N, but settling south as well. The models have
these features well-portrayed in their solutions, with each decaying
shear line advecting drier air into all of Western Micronesia with
each successive passage. This will lead to decreasing rainfall
potential as we head into the weekend and to start early next week.

The exception to this will be a disturbance north of Kosrae/east of
Pohnpei that looks to pass through Chuuk sometime in the Friday
through Saturday time frame, getting some of its moisture pulled
north then northeast towards Guam as the current northern CNMI shear
line waggles south in a slightly faster pace than a quasi-stationary
front. We`ll need to watch for any nocturnal flareups that could
give this feature a little more of a "nudge" in its southward
journey.

What`s left of this disturbance moisture-wise will then make its in-
roads into west Central Yap State and Yap early next week, before
stalling near or slightly north of Palau. With this progression of
shear lines expected, Palau will have the best shot of seeing
scattered showers due to better moisture quality and surface
convergence (albeit weak convergence) throughout the forecast period,
with Yap and Chuuk having the best potential when the shear
lines/increased moisture/surface convergence is in its best
juxtaposition.

As for seas and surf, the latest altimetry pass wasn`t sufficient to
sway us one way or the other, regarding canceling the headlines
early or not. Given no close pass to the three forecast points,
maintaining the current headlines to "error on the side" of caution
was optimal given the situation.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...High Rip Current Risk through Thursday afternoon for GUZ001.

     High Surf Advisory until 4 PM ChST Thursday for GUZ001.

MP...High Rip Current Risk through Thursday afternoon for MPZ001>003.

     High Surf Advisory until 4 PM ChST Thursday for MPZ001>003.

Marianas Waters...Small Craft Advisory until 4 PM ChST Thursday for PMZ151>154.

&&

$$

Marianas: Montvilla/Cruz
East Micronesia: Simpson
West Micronesia: Doll