Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxca62 tjsj 210858 
afdsju

Area forecast discussion
National Weather Service San Juan PR
458 am AST Tue Feb 21 2017

Synopsis...upper trof north of the area and associated weak
surface boundary will continue to move to the east and exit the
forecast area today. Ridge pattern will follow from the west and
drier fair weather is expected to prevail for the rest of the
week. Northerly winds will shift to the southeast on Thursday as
surface high moves north of the area.

&&

Discussion...scattered to numerous showers with isolated
thunderstorms over the Atlantic coastal waters moved across the
forecast area during the overnight. The heaviest showers remained
just north of the northern USVI. For the next few hours
additional showers are expected to move across the islands but
sunny skies are expected to return by the late morning hours.
Overnight temperatures were in the low to mid 60s across the
higher elevations to the low 70s across coastal areas.

Overall fair weather conditions are forecast to prevail for the
rest of the week as ridge pattern builds from the west and cap
inversion keep moisture below 800 mb. However, diurnally induced
afternoon showers cannot be ruled out each day and trade wind
showers should prevail across the northern and eastern coastal
areas through Thursday. Another upper trof and associated surface
boundary are forecast to move north of the area by late Sunday
enhancing shower activity once again.

&&

Aviation...scattered rain showers will affect the flying area thru 14z. As a
result, MVFR cigs are possible in passing rain showers across tjbq,tjsj and
tist. VFR conds are expected after 14z...with limited shower
activity over the region. West winds of 10-15 kt will continue below
fl150.

&&

Marine...small pulses of northerly swell are forecast to reach
the regional waters for the next few days. Swell is expected to
peak on Friday morning between 4-6 feet. There is a moderate risk
of rip currents along the northern beaches of the islands.
West to northwest winds between 10-15 knots will continue today as
weak frontal boundary moves across the local area.



&&

Preliminary point temps/pops...
sju 84 72 83 71 / 20 20 20 30
stt 82 74 82 72 / 50 20 20 30

&&

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

National Weather Service Glossary of Abbreviations