Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 260949

Area Forecast Discussion
National Weather Service San Juan PR
549 AM AST TUE JUL 26 2016

.SYNOPSIS...Tropical wave will continue to move across the
forecast area Today. Surface high pressure will continue across
the Atlantic waters. A drier mid level air mass with Saharan dust
will move over the islands on Wednesday and linger through
Thursday. An upper level trough will develop late Wednesday into
Thursday to the northeast of the islands and move westward quickly,
enhancing showers and thunderstorms on Thursday afternoon across
the mountain ranges of PR. Next tropical wave is expected on
Friday followed by another one on Sunday.


.DISCUSSION...Scattered to numerous showers and thunderstorms
affected the Atlantic and Caribbean waters during the overnight
hours. A couple of thunderstorms affected the northeastern quadrant
of Puerto Rico with frequent lightning observed just between
Culebra and Fajardo. The doppler radar estimated between 0.75 to
near 1 inch of rain from Rio Grande to Trujillo Alto. These
showers and thunderstorms will continue through the day as the
tropical wave exits the local area in the evening hours. For this
afternoon, thunderstorm development is expected mainly over the
interior and NW quadrant of PR. Urban and small stream flooding
is expected due to already saturated soils across these areas.

For Wednesday, dry mid level air with SAL will limit shower
development over the islands. A TUTT low is forecast to develop to
the northeast of the area and move quickly over Hispaniola to
enhance showers and thunderstorms on Thursday afternoon. Moisture
will increase once again on Friday as a weak tropical
wave/easterly perturbation moves over the islands. Saharan dust is expected
once again on Saturday and on Sunday another wave is forecast to
enter the eastern Caribbean.


.AVIATION...SHRA and TSRA associated with a tropical wave will
affect the flying area today. However...VFR conds will prevail
across most of the TAF sites, except in and around TJMZ and TJBQ
where mountain obscurations and brief MVFR conds are likely between
17Z-22Z. Low level winds prevail E at 10-20 kts with sea breeze
variations and gusty winds near the TSRA.


.MARINE...Seas are expected to remain below small craft advisory
criteria for the next several days. However, seas up to 6 feet and
east winds up to 20 knots are expected Today. Therefore, small
crafts should exercise caution across the Atlantic and Caribbean
waters. Thunderstorms are expected to continue through this
evening across the local waters. Periods of torrential rainfall,
frequent lightning and gusty winds are expected. Also, isolated
waterspouts can`t be ruled out.


SJU  90  82  90  80 /  60  30  30  40
STT  89  81  89  80 /  60  30  30  40


.SJU Watches/Warnings/Advisories...


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