Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 181944

Area Forecast Discussion
National Weather Service San Juan PR
344 PM AST Mon Dec 18 2017

.SYNOPSIS...Mid and upper level ridge will prevail over the local
area through the workweek. ENE to NE winds expected for the next
few days as a SFC high pressure remains to the NW of the local
area. Upper trough to approach the local area this weekend,
possibly causing unsettled weather.


.SHORT TERM...Today through Thursday...

Seasonable temperatures are expected for the next few days as we
stay under an ENE to NE wind flow. Therefore expect high temps in
the low to mid 80s across the lower elevations and in the 70s
across the higher elevations. Near normal moisture is also
expected and the ridge in the mid and upper levels will promote
mainly fair weather with passing showers across the northern and
eastern sections of PR as well as around the USVI.

.LONG TERM...Friday through Tuesday...

The mid to upper level ridge that has brought somewhat fair
weather with an occasional isolated shower will weaken ahead of a
cold front that will move into the north Atlantic waters. The
front will push an upper level trough near the forecast area on
Friday. Friday will be a transition day from quiet weather to a
more unsettled pattern due to an increase in tropical moisture
across Puerto Rico and the U.S. Virgin Islands. The GFS and ECMWF
models are indicating that this active pattern will remain through
Christmas due to an tutt low that might cut off near Puerto Rico
and the U.S. Virgin Islands. At this time it`s something to keep
an eye on over the next several days.


.AVIATION...Mainly VFR conditions will prevail across all the
terminals through the forecast period. However, brief passing trade
wind showers could affect at times the northern and eastern PR
terminals as well as the USVI/Leeward terminals. Winds will continue
from the northeast at 10-15 kts.


.MARINE...Seas will be up to 6 feet this evening and ENE to NE
winds up to 20 knots. There is a high risk of rip currents for the
northern beaches of PR until 6 AM Tuesday, and for Culebra island
until 6 PM this evening.


SJU  77  85  77  83 /  40  40  50  30
STT  79  86  76  83 /  40  40  50  30


PR...High Rip Current Risk through late tonight for North Central-
     Northeast-Northwest-San Juan and Vicinity-Southeast-Western

     High Rip Current Risk until 6 PM AST this evening for Culebra.



LONG TERM....99 is the U.S. government's official web portal to all federal, state and local government web resources and services.