622 
fxpq60 pgum 230752 
afdpq 


Area forecast discussion 
National Weather Service tiyan GU 
552 PM chst Monday Nov 23 2009 


Synopsis...fresh to strong trade winds and combined seas 9 to 10 
feet are the result of a strong pressure gradient between tropical 
depression 26w embedded in the monsoon trough west of Chuuk and a 
moderate ridge of high pressure north of the marianas. Satellite 
imagery shows cloud bands associated with 26w within 200 miles or 
so southwest of the islands...which radar is picking up as well. 
&& 


Discussion...the most significant change to the forecast was to 
place the entire marianas under a Small Craft Advisory and high 
surf advisory until the tropical cyclone is forecast to move away 
from the marianas. Winds at Guam and Saipan are regularly gusting 
to around 25 knots...and the Quikscat indicates marine winds are 20 
to 25 knots. With winds and seas only expected to increase as dew point 26w 
approaches the southern marianas its a good reason to have a small 
craft and high surf advisories out due to the hazardous conditions. 
There is good agreement between the various model forecasts for dew point 
26w. So expect the cyclone to move northwest and intensify after an 
initial period of slow movement while embedded in a monsoon trough. 
&& 


Marine...combined effect of NE trade swell...wind waves and swell 
generated by the tropical depression will allow seas to build to 
around 11-12 feet by Wednesday and Thursday. Winds and seas will 
be hazardous for small craft and beach-goers the next 3-4 days. 
&& 


&& 


Eastern micronesia... 
a trade disturbance over the Marshalls will provide Majuro with 
scattered showers through mid-week. Although little shower activity 
occurred today...models reinvigorate convection tonight along a weak 
trough axis. A weak embedded circulation within the monsoon trough 
will pass to the north of Pohnpei tonight. Convection associated 
with this feature has been limited and models show even less 
activity through tomorrow as ridging builds over the area ahead of 
the next disturbance currently over the Marshalls. 


&& 


Western micronesia... 
convection has continuously regenerated over Chuuk today with 
constant rainfall through much of the day. The slow movement and 
simultaneous intensification of 26w will promote more convection to 
fire over the area through tomorrow. Showers should taper off 
beginning Tuesday night as 26w moves further northwest. Models are 
in fair agreement on a developing monsoon tail associated with 26w 
as it passes between Yap and Guam. Scattered showers should develop 
late Tuesday into Wednesday over Koror but remain south of Yap until 
the weekend. 


Fresh to strong southerly winds associated with 26w continue to 
produce hazardous seas and surf along south and west facing 
exposures on Chuuk. Therefore...continued high surf advisory through 
Tuesday night...especially considering the slow movement of 26w. 


&& 


Gum watches/warnings/advisories... 
GU...high surf advisory until 10 am chst Friday for guz001>004. 


Marianas waters...Small Craft Advisory until 9 PM chst Thursday 
for pmz151>154. 


&& 


$$ 


Mundell/Williams 

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