Scientific Forecaster Discussion
fxpq60 pgum 250735
Area forecast discussion
National Weather Service tiyan GU
236 PM chst Thu may 25 2017
Marianas synopsis... east trade-winds and and a few showers prevail
over the marianas this afternoon.
no changes made to the forecast. Afternoon satellite and radar
imagery showed hardly any showers over the marianas. Satellite
water vapor imagery also shows little deep layer moisture over the
region. The precipitable water index decreased from 1.91 inches last
night to 1.57 this morning. Models show little change through
Saturday as a dry season weather pattern remains in place over the
local area. Expect only isolated showers at best to prevail through
Models suggest that there may be a period of mostly cloudy skies
Saturday night through next Monday as moisture increases slightly.
Despite the increase in moisture showers will remain isolated in
observations this afternoon from ritidian, tanapag, and ipan buoys
indicate combined sea heights around 2 to 4 feet.
An east trade-wind swell of 2 to 4 feet will persist through
Friday and generate surf of 4 to 6 feet on east facing reefs.
The surf on all other exposures will be 3 feet or less. Combined
seas and the east swell are predicted to increase slightly Friday
night. This increase is the result of slightly higher trade-winds
east of the marianas. These winds will increase the swell a little
which will briefly increase the raise seas and the east swell. This
increase will be minor and will last only through Monday as the
seas and swell will decrease Monday night.
trade-wind convergence continues to generate scattered showers
across eastern micronesia, mainly south of 7n. A very weak trade
disturbance moving through Kosrae has combined with the convergence
to enhance convection over Kosrae and will maintain scattered
showers over the state tonight. This disturbance will continue to
move westward over the next several days, but will remain to the
south of Pohnpei. The convergence band will maintain an unsettled
pattern over Kosrae through the first part of the weekend. Then
convergence will begin to lift further north Friday, bringing
increasing convection and cloud cover to Pohnpei for the weekend.
For Majuro, the eastern end of the convergence will be near enough
to bring a few more showers and cloud cover to the atoll Friday and
continuing into the the weekend. The convergence will move far
enough north by the end of the weekend to allow a drier pattern to
move into all three locations Sunday.
latest visible satellite data shows fairly dry conditions across
western micronesia this afternoon. By Saturday, a band of
convergence, currently over eastern micronesia, will drift into the
state, increasing convection and cloud cover for the weekend and
beginning of next week.
Yap looks to remain north of any organized weather pattern over the
next few days, hence a dry forecast through at least the beginning of
next week. For Koror, models show a fairly dry pattern continuing
there through Friday night. Then, an approaching disturbance from
eastern micronesia will bring an increase to both showers and cloud
cover for the weekend into the beginning of next week.