Weather

048 
fxca62 tjsj 292033 
afdsju 


Area forecast discussion 
National Weather Service San Juan PR 
433 PM AST Friday Aug 29 2008 


Discussion...Tropical Storm Hanna continues to move west-northwest around 8 
knots this afternoon...under SW shear induced from persistent upper 
low to our north. Spiral bands of showers and thunderstorms in S 
semicircle of Hanna have been increasing across the local Atlantic 
waters and sinking S into the northern Virgin Islands. A broad 
zone of convergent low level flow across the Lesser Antilles and into 
this southeast quadrant of Hanna is expected to produce very active weather 
across the leewards islands and adjacent waters tonight and 
Saturday and shift west-northwest across the local area through Sunday 
morning. Impacts would likely be felt strongest across the Virgin 
Islands and adjacent waters in the form of rainfall...with NE and 
east Puerto Rico also likely to be affected. GFS is finally getting a 
handle on this situation and maintaining this moisture across the 
area through early Sunday...but was not available for preparation 
of this forecast package. I had used the NAM for this package as 
it had seemed to have a much better handle on this scenario from 
the onset. 24 hour rainfall totals of one to three inches are 
likely through Sunday morning...with very isolated areas in excess 
of 5 inches possible...but these may occur exclusively over water. 
Should some of these bands become stationary across portions of 
the local islands...then these higher rain values are possible. 


Weather is not expected to improve greatly on Sunday...as another 
convergent band of low level moisture associated with the next 
approaching tropical wave will move into the area from the NE for 
scattered diurnal convection. However...this moisture will be 
overladen with sal...and conditions are expected to be 
moderately unstable. This next tropical wave is expected to drift 
into the area on Tuesday. 


&& 


Marine...buoy 41043 showing NE swell of 9 feet at 11 seconds this 
afternoon with combined seas 10-11 feet. This swell energy to move 
into the local Atlantic waters tonight through Saturday. Have had to 
manually adjust wwiii guidance for graphical forecasts as I expect 
local offshore Atlantic seas to reach 6 feet late tonight through 
Saturday morning. S semi Circle of Hanna moving across local Atlantic 
at this time and winds will back with time as Hanna moves northwest over the next 
48 hours. Winds and seas to briefly diminish sun-Monday in advance of 
next wave and associated Ely wind swell. 


&& 


Preliminary point temps/pops... 
sju 89 78 93 78 / 50 50 70 20 
stt 88 79 88 79 / 50 50 50 50 


&& 


Sju watches/warnings/advisories... 
PR...none. 
Vi...none. 
&& 


$$ 


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