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Area forecast discussion 
National Weather Service San Juan PR
950 PM AST Wednesday Jul 30 2014

Update...isolated showers will continue to move across the local
waters...with a slight increase after midnight. Some showers will
move over land and mainly affect the eastern portions of Puerto
Rico and the USVI.



&&

Aviation...VFR conds will prevail at all taf sites through the forecast
prd. However overnight and early morning isolated-scattered rain showers/-shra may
bring brief MVFR ceilings across the coastal waters by the way eastern PR and the
northern leewards from 31/04z-31/12z with vcsh near tjsj...tjnr...tisx and
tist. On Thursday...passing rain showers from 31/17-31/22z west/brief MVFR ceilings
possible due isolated-scattered rain showers/isolated thunderstorms and rain mainly across the ctrl interior
and northwestern sections of PR affecting tjbq and tjmz...vcsh possible
at tjsj. General wind below fl150 from southeast at 5-15 kts during prd. No other
sig operational weather impact at this time.



&&

Marine...seas up to 4 feet and winds up to 17 knots are expected
to continue across the coastal waters through Friday. Conditions
will quickly deteriorate on Saturday as a strong tropical wave
moves across the local waters between late Saturday through
Sunday. Mariners are urged to monitor the development of this
tropical system as reach the local waters.



&&

Previous discussion... /issued 300 PM AST Wednesday Jul 30 2014/

Synopsis...upper level trough north of the area will linger next
several days close to the local area. A surface trough will move
across the region Thursday into Friday. A very strong tropical
wave...located this afternoon near 1300 miles southeast of Puerto
Rico is forecast to move west northwest and will approach the
local area Saturday night into Sunday.

Discussion...showers and thunderstorms developed this afternoon
over the western interior section of Puerto Rico. Rainfall
accumulation of between 1 to 2 inches were observed with this
activity. This activity was primarily associated with the
combination of an upper level trough and daytime heating.

For tomorrow...a surface trough will move across the local
region...bringing with it an increase in showers and possible
thunderstorms over the local region. As this surface trough
interacts with the upper level trough to our north...some
localized urban flooding can be expected tomorrow afternoon.

A strong tropical wave...located near 1300 miles southeast of
Puerto Rico this afternoon...is forecast to move west northwest
and will approach the local area Saturday night into Sunday. This
tropical wave still have the potential to become a tropical
depression during the next couple of days. The expected impacts
over the weekend for the local islands are still uncertain.
However at this time...model guidance seem to agree a bit more
with one another and has this system passing very close to the
northern USVI. This scenario would give northeastern PR and the
northern USVI some much needed rain. However...confidence is low
in this forecast as we are still unsure of when will cyclogenesis
will occur and how it will evolve over the next several days. Stay tuned.

Aviation...VFR conds will prevail at all taf sites through the forecast
period with vcsh...excpt for brief MVFR ceilings possible due isolated-scattered
rain showers/thunderstorms and rain across the central interior and northwestern sections of
PR...ending around 30/21z. East-southeast winds 10-15 kts with isolated higher
gusts near storms.

Marine...seas up to 5 feet and winds up to 17 knots are expected
to continue across the coastal waters through Thursday.

&&

Preliminary point temps/pops...
sju 77 88 77 87 / 20 20 30 30
stt 78 89 78 89 / 30 30 30 30

&&

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

$$

09/10

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