Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service San Juan PR
1136 am AST Monday Nov 24 2014

Update...passing showers affected the region from time to time.
Strong trade winds will continue to transport patches of low level
moisture across the region this afternoon. Forecast is on track
with ongoing weather situation.


Aviation...VFR conditions are expected to continue across all taf
sites rest of this afternoon. Vcsh will be around most taf
terminals through at least 24/22z.


Marine...bouy 41053 in San Juan was showing seas up to 7 feet.
Small craft advisories continues in effect for all coastal except
for the near shore waters of southwestern Puerto Rico.


Previous discussion... /issued 334 am AST Monday Nov 24 2014/

Synopsis...upper level ridge will begin to weaken tonight as an
upper level low over the central Atlantic retrogresses. Flat Ridge will
then establish next weekend.

Discussion...strong trade winds will transport shallow areas of
moisture today and tonight with the risk of showers mainly north
of the Cordillera and the Caribbean coastal waters. Some drying
is expected late Tuesday through Wednesday with a decrease in shower activity
expected due to upper level convergence between retrogressing
upper low from the central Atlantic and upper ridge to the west. Trade
winds will diminish rapidly Wednesday through Friday then strengthen again
next weekend as a new area of high pressure exits the Carolinas.
Occasional cloud clusters and light showers will affect eastern PR and
the coastal waters on Thanksgiving day with precipitation chances
increasing again next weekend due to strengthening trade winds.

Aviation...VFR conditions expected through the forecast period.
Passing -shra and vcsh likely across the leeward/USVI terminals and
eastern PR. Easterly winds will continue at 15-25 knots.

Marine...windy with seas 6-8 feet through Tuesday. Winds then diminish
rapidly Wednesday through Friday with seas improving rapidly. Winds strengthen
again next weekend to 20 knots with seas building 5-7 feet.


Preliminary point temps/pops...
sju 86 81 83 81 / 40 40 10 30
stt 82 81 82 81 / 30 30 10 30


Sju watches/warnings/advisories...
Coastal waters...Small Craft Advisory until 6 PM AST Wednesday for Anegada
Passage southward to 17n-Atlantic waters of Puerto Rico and
USVI from 10nm to 19.5n-Caribbean waters of Puerto Rico
from 10 nm to 17n-coastal waters of northern Puerto Rico
out 10 nm-coastal waters of northern USVI and Culebra out
10 nm-coastal waters of southern USVI Vieques and eastern
Puerto Rico out 10 nm-Mona Passage southward to 17n.

Small Craft Advisory until 6 am AST Tuesday for coastal waters
of southern Puerto Rico out 10 nm.

Small Craft Advisory until 6 PM AST Tuesday for coastal waters
of northwestern Puerto Rico out 10 nm.




National Weather Service Glossary of Abbreviations