240 
fxpq60 pgum 070750 
afdpq 


Area forecast discussion 
National Weather Service tiyan GU 
550 PM chst Tuesday Oct 7 2008 


Synopsis...the last wave of showers associated with the surface trough 
west of the islands has passed through the southern marianas this 
afternoon and the VAD wind profile shows significant drying above 
the boundary layer. Water vapor imagery indicates an upper level 
trough is slowly working its way westward...and is expected to 
impact local weather tonight with large scale subsidence aloft. 


&& 


Discussion...little change to previous forecast. Model guidance supports 
isolated showers the next few days with the next transitory 
feature projected to arrive around Friday night or Saturday. GFS 
and NOGAPS indicate the next trade wind disturbance Aka tropical 
wave in the Marshall Islands will amplify as it moves west near 
150e Friday then bring an increased chance of clouds and showers 
over the weekend. Still too far out to do more than maintain 
mostly cloudy skies in the extended forecast...should see 
scattered showers as well once timing is clear. 


&& 


Eastern micronesia...little change to the forecast on this side of 
micronesia. The inter-tropical convergence zone remains fairly active with near constant 
rain reported at most of the major islands. In addition...some 
gusty winds were reported at kwajalein. As stated earlier...model 
guidance does broad brush the area with low-level convergence and 
shower activity through most of the week before indicating 
slightly drier conditions by weekend. I found no reason to change 
with this scenario...for now. 




&& 


Western micronesia...forecast scenario for Palau and Yap remains 
unsettled during the next couple days as a trough of low pressure 
and possible circulation approaches and then moves quickly past 
the islands tonight and into the day Wednesday. At this time...the 
exact position of the circulation center is not certain and 
therefore wind forecast for the islands are highly dependent upon 
whether the circulation moves between Palau and Yap or closer or 
north of Yap. Models all have a weak circulation developing but 
are split on the exact position. In any case...the system is not 
that well developed...and it looks like it will move fairly 
quickly through the area before doing too much. Weather should 
show improvement by late Thursday or Friday while waiting for the 
next impulse to come in from the east sometime during the early 
part of next week. For now...have annotated the remarks to 
indicate possible heavy showers...and assumed increased flooding 
potential..for both Yap and Palau over the next 24 hours. 


Chuuk also looks like it will see several days of scattered showers 
as a weak trough axis hangs back over the islands and extends to 
east Pohnpei. Although nothing organized...models like pushing 
several impulses through as they pass along the trough axis westward 
from out of the marshals. 


&& 


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


$$ 


Mundell/Edson 

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