Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Juan PR
259 PM AST Thursday Mar 13 2014
Synopsis...upper level ridge will remain as the main weather
feature across the region until Friday morning. A weak frontal
boundary will continue to move southeastward across the Atlantic
tonight. This feature will reach the local Atlantic waters while
dissipates Friday night and Saturday...inducing an increase in
moisture across the region. Strong upper ridge is then expected to
develop again early next week.
Discussion...a frontal boundary extending from a low pressure
center...over the northwest Atlantic...southwestward across the
Bahamas and Cuba...is expected to move rapidly southeastward across
the local Atlantic waters Friday night and Saturday. As this happens
the upper level ridge over the region will erode...inducing an
increase in moisture across the region during the weekend. The
frontal boundary is expected to dissipate over the region early next
week. Upper level ridge will then build again early next week
with a return to a general dry and stable weather pattern over the
local islands. Low level winds will continue mostly from the east
southeast tonight and Friday but will become from the northeast
late Friday and Saturday as the boundary approaches.
Aviation...brief periods of MVFR conditions with mountains
obscuration are possible across tjsj...tjps and tjmz until
13/21z. After that mostly VFR conditions expected across the
local flying area for the rest of the forecast period. Winds of 10
to 15 knots from the east to east southeast will continue from the
surface to 10k feet...becoming from the west and stronger aloft.
Marine...seas between 2-3 feet expected through Sat morning then
begin to build Sat afternoon in large north swells.
Preliminary point temps/pops...
sju 72 85 73 83 / 0 0 0 20
stt 74 84 75 85 / 10 10 0 10