663 
fxpq60 pgum 090754 aaa 
afdpq 


Area forecast discussion...updated 
National Weather Service tiyan GU 
554 PM chst Friday Jan 9 2009 


Synopsis...radar and satellite show isolated showers over the 
marianas this afternoon. A weak inverted trough could be seen to the 
northeast of Guam. 


&& 


Discussion... 
VAD wind profile had winds in the lower 20s through the day. 
GFS...UKMET...ECMWF and ngs all show wind speeds decreasing until 
Sunday. The wind speed decrease will be in response to a shearline 
approaching the local area. All the models have the shearline 
halting its advance over the northern marianas. The will winds 
decrease as the neutral point associated with the shearline moves 
across the marianas. Wind speeds increase fairly rapidly thereafter 
and become 15 to 20kts by late Monday. Did update winds from today 
through Wednesday 14/06z as the newer model data looked a bit better. 


Earlier forecast had a slight chance of showers for Saturday. 
Believe that the weak trough and associated showers...now northeast 
of Guam...will move mainly north of Saipan...but did not feel 
comfortable with just a slight chance with it in the vicinity. 
With this in mind changed slight chance to isolated for Saturday. 


Models do indicate a dry spell so left the slight chance in Saturday 
night through Tuesday. 


&& 


Marine... 
ww3 indicates a series of long period northerly swells moving across 
the marianas over the next few days. These swells will continue 
through the forecast period but are expected to decrease in height 
during the weekend only to rise by Monday. This higher swell height 
will persist until Wednesday before decreasing. This midweek lull 
will be temporary as another set of higher swells is expected by the 
end of the coming week. Surf calculation show that hazardous surf 
is possible Monday. 


&& 


Eastern micronesia... 
inter-tropical convergence zone runs from the international date line through Kosrae. Showers 
have weakened near Majuro since this afternoon but high clouds 
remain south and east of the forecast zone this evening. Near 
Kosrae...isolated trade-wind showers have already entered Kosrae 
coastal waters. More showers upstream are expected to reach Kosrae 
later tonight...will monitor this situation as it may require an 
update for increasing showers. Near Pohnpei...convection northwest of 
the surface trough has moved farther west of the coastal waters. 
Still...there are clouds obscuring most of Pohnpei this evening. 
Trade-showers east of 160e are expected to move over Pohnpei by late 
tonight into Saturday. 


Inter-tropical convergence zone is the main weather-maker and two main concerns are the durability 
and motion of the inter-tropical convergence zone between 3n and 8n. GFS keeps both Kosrae and 
Pohnpei under wet conditions with possible locally heavy showers 
during long term forecast periods. Majuro will remain north of the inter-tropical convergence zone. 
High pressure far north will aid in strengthening winds during the 
next 24 to 36 hours. Local winds over Marshall Islands including 
kwajalein and Majuro are expected to pick up speed to near 25 knots 
through Sunday night then back to 10 to 20 knots on Monday through 
Wednesday. 


&& 


Western micronesia... 
it was a gusty day on Chuuk with winds peaking at 22 knots this 
afternoon. It has been relatively dry across the region and it may 
be this way for the next couple of days on Koror and Yap as a 
surface ridge extends from 5n140e through south of Koror. Weather 
associated with the inter-tropical convergence zone is expected to move across Chuuk by Monday 
and Tuesday. 


A new north-northwest swell is expected to arrive on Koror and Yap by Sunday 
night. These swells will generate high surf heights from 10 to 12 
feet. Near Chuuk...trade-wind generated swells will first reach Chuuk 
by Tuesday before the arrival of a 5 feet north-northwest swell on Wednesday. It 
will be quite busy in this area but will continue to monitor 
different swells in the coming week. High surf advisory will be 
necessary for these events. 


&& 


Gum watches/warnings/advisories... 
GU...none. 
Marianas waters...none. 
&& 


$$ 


Ziobro/baqui 

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