816 
fxpq60 pgum 241933 
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Area forecast discussion 
National Weather Service tiyan GU 
533 am chst Friday Jul 25 2008 


Synopsis... 
infrared satellite loop showed dew point 09w well to the northwest of the 
marianas and an upper-level low centered near pagan. Scattered 
showers and isolated thunderstorms associated with this low were 
evident over the marianas on the latest WSR-88D loop. 


&& 


Discussion... 
aforementioned upper low triggered some shower activity this 
morning. Given the extent of convection...went ahead and appended 
scattered to the forecast through mid-morning. Activity should 
begin to taper after sunrise. Left the remainder of the forecast 
pretty much intact with mostly cloudy conditions through the 
weekend as favorable quadrant of upper low traverses region. 
Declined to include scattered in the forecast at this point given 
the relative inactivity associated with the low and the bearish 
GFS take on the system. However...will watch the low closely as 
these systems tend to become more active as they move further 
west. 


&& 


Eastern micronesia... 
a low latitude trade-wind surge is evident over Kosrae and portions 
of the Marshall Islands south of Majuro. This will bring scattered 
showers to Kosrae through tonight. Model guidance indicates the 
trade wind convergence zone will become well established across 
eastern micronesia Friday night. The zone will gradually creep 
northward reaching Kosrae Saturday night and Majuro on Sunday. On 
Monday the zone shifts farther north increasing the shower chances 
at Pohnpei and Majuro while reducing them at Kosrae. On Tuesday the 
convergence zone seems to sag south of Majuro but then moves north 
again on Wednesday. It may just end up that scattered showers 
continue in a low confidence scenario. Meanwhile Pohnpei is in a 
partial break in the convergence zone on Tuesday. This could be 
another low confidence scenario where scattered showers persist the 
entire time. 


Wave watch 3 does bring 6 foot seas into Pohnpei Saturday night. 
Wind waves appear to be a significant portion of this...with only a 
3 to 4 foot southeast swell. Therefore no hazardous surf is expected. 


Wave watch 3 brings 6 foot seas into Kosrae tonight. Again wind 
waves appear to be a significant portion. 4 foot southeast swell 
decays to 3 feet on Sunday. 2 foot south swell arrives Saturday but 
decays to 1 foot Monday. In the case of perfect constructive 
interference we might have a rouge surf of 8 foot...but this would 
be so rare as to not seem Worth mentioning. Especially so since the 
swell directions are 45 degrees apart. 


Likewise the 7 foot seas at Majuro are largely wind waves on the 
east facing reefs. High surf criteria are 12 feet here...so would 
not even expect this to be close. More 2 foot south swell which will 
have not much of an effect. Overall...these combined seas seem to 
have much more bark than bite. 


Western micronesia... 
light southeast flow will be replaced by easterly trade winds for 
Saturday night through Monday as a surface ridge shifts to the 
north. The GFS model shows isolated showers will prevail across 
western micronesia until Monday or Tuesday. The trade wind 
convergence zone is expected to become a little better organized at 
this time...also extending westward to reach Chuuk around Tuesday. 


Wave watch 3 does not indicate any combined seas above 5 feet for 
western micronesia at any time in the forecast period. 


&& 


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


$$ 


Lee/stanko 

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