Area Forecast Discussion


782 
FXPQ60 PGUM 190853
AFDPQ 
Area Forecast Discussion
National Weather Service Tiyan GU
652 PM ChST Mon Feb 19 2018
.Marianas Synopsis...
Satellite shows a shear line near Anatahan and a trade-wind trough
well to the east-southeast of Guam, currently near Pohnpei. The
weather balloon from this morning indicates east-northeast winds
of 10 knots just off the ground increasing to 15 to 20 knots
around 2000 feet. The buoys reveal combined seas of 4 to 6 feet.
&&
.Discussion...
Fairly dry weather tonight as we are between the shear line to the
north and the tropical moisture to the south. Models bring the
shear line on through though, so for Tuesday the forecast has an
increase in the winds and isolated showers of moderate intensity.
For Wednesday we go back to light showers, then on Thursday that
trade-wind trough to the east-southeast could just brush us with
its northern edge. With broad support from GFS, ECMWF and NavGem,
went ahead and worded the Thursday forecast much like the Tuesday
forecast. Could be a little heavier, just went the same for now as
the previous grids broad brushed Thursday into a big long 
time range of fair weather from Wednesday into the next week. If 
it still looks beefier tonight or Tuesday, we have some time to 
adjust.
&&
.Marine...
Winds and seas are expected to build as the shear line marches
southward. They are expected to stay below small craft advisory
criteria, however it will not be much below. With only a small
margin for error, a small craft advisory could be needed on rather
short notice, so mariners should keep tabs on the latest marine
conditions, forecasts and advisories. Seas will then begin to
settle down again after Thursday.
&&
.Eastern Micronesia and Chuuk...
A broad trade-wind disturbance near Pohnpei will continue its 
westward journey across the region over the next few days. Expect wet
weather to continue near Pohnpei thru Tuesday and Chuuk thru 
Wednesday. Modest convergent southeast winds in the wake of this 
disturbance still can trigger a few showers and possible 
thunderstorms near Kosrae thru Tuesday. Farther east, strong trade-
wind convergence near the leading edge of a fresh surge will maintain
showery conditions near Majuro thru Tuesday. This same area is going
to impact Kosrae and Pohnpei Tuesday night and Wednesday, Chuuk 
Wednesday night and Thursday. Afterward, much drier fresh to strong
trades in the core of the surge should usher in fair weather to 
Majuro by midweek, and the rest of the locations toward the weekend.
Trade-wind swell and wind waves will build across the region starting
midweek. Meanwhile, a long-period northwest swell generated by strong
winds east of Japan will also arrive at the area by midweek. This
will cause seas and surf to rise and could become hazardous toward
the weekend.
&&
.Western Micronesia for Yap and Koror...
A very dry air mass above 800 mb will sustain pleasant weather for
both Yap and Koror thru Wednesday. Then a broad trade-wind 
disturbance currently near Pohnpei could affect far Western 
Micronesia by Wednesday night and Thursday.
Large trade-wind swell and wind waves are expected to arrive near 
midweek which could cause high surf and small craft advisory 
conditions near Koror and Yap. 
&&
.GUM WATCHES/WARNINGS/ADVISORIES...
GU...None.
Marianas Waters...None.
&&
$$
Stanko/Chan

782 
FXPQ60 PGUM 190853
AFDPQ 
Area Forecast Discussion
National Weather Service Tiyan GU
652 PM ChST Mon Feb 19 2018
.Marianas Synopsis...
Satellite shows a shear line near Anatahan and a trade-wind trough
well to the east-southeast of Guam, currently near Pohnpei. The
weather balloon from this morning indicates east-northeast winds
of 10 knots just off the ground increasing to 15 to 20 knots
around 2000 feet. The buoys reveal combined seas of 4 to 6 feet.
&&
.Discussion...
Fairly dry weather tonight as we are between the shear line to the
north and the tropical moisture to the south. Models bring the
shear line on through though, so for Tuesday the forecast has an
increase in the winds and isolated showers of moderate intensity.
For Wednesday we go back to light showers, then on Thursday that
trade-wind trough to the east-southeast could just brush us with
its northern edge. With broad support from GFS, ECMWF and NavGem,
went ahead and worded the Thursday forecast much like the Tuesday
forecast. Could be a little heavier, just went the same for now as
the previous grids broad brushed Thursday into a big long 
time range of fair weather from Wednesday into the next week. If 
it still looks beefier tonight or Tuesday, we have some time to 
adjust.
&&
.Marine...
Winds and seas are expected to build as the shear line marches
southward. They are expected to stay below small craft advisory
criteria, however it will not be much below. With only a small
margin for error, a small craft advisory could be needed on rather
short notice, so mariners should keep tabs on the latest marine
conditions, forecasts and advisories. Seas will then begin to
settle down again after Thursday.
&&
.Eastern Micronesia and Chuuk...
A broad trade-wind disturbance near Pohnpei will continue its 
westward journey across the region over the next few days. Expect wet
weather to continue near Pohnpei thru Tuesday and Chuuk thru 
Wednesday. Modest convergent southeast winds in the wake of this 
disturbance still can trigger a few showers and possible 
thunderstorms near Kosrae thru Tuesday. Farther east, strong trade-
wind convergence near the leading edge of a fresh surge will maintain
showery conditions near Majuro thru Tuesday. This same area is going
to impact Kosrae and Pohnpei Tuesday night and Wednesday, Chuuk 
Wednesday night and Thursday. Afterward, much drier fresh to strong
trades in the core of the surge should usher in fair weather to 
Majuro by midweek, and the rest of the locations toward the weekend.
Trade-wind swell and wind waves will build across the region starting
midweek. Meanwhile, a long-period northwest swell generated by strong
winds east of Japan will also arrive at the area by midweek. This
will cause seas and surf to rise and could become hazardous toward
the weekend.
&&
.Western Micronesia for Yap and Koror...
A very dry air mass above 800 mb will sustain pleasant weather for
both Yap and Koror thru Wednesday. Then a broad trade-wind 
disturbance currently near Pohnpei could affect far Western 
Micronesia by Wednesday night and Thursday.
Large trade-wind swell and wind waves are expected to arrive near 
midweek which could cause high surf and small craft advisory 
conditions near Koror and Yap. 
&&
.GUM WATCHES/WARNINGS/ADVISORIES...
GU...None.
Marianas Waters...None.
&&
$$
Stanko/Chan