textproduct: San Juan

SYNOPSIS

A weak Saharan Air Layer with minor dust concentrations continues across the area today. The remnants of an old front north of the region will continue to bring on and off showers for the next couple of days. Temperatures will cool down a little by the end of the week and early next week. Hazardous seas across the Atlantic waters and life-threatening rip currents are expected late in the weekend due to the arrival of a northerly swell.

LONG TERM...Sunday through Thursday

The latest model guidance indicates a dry and cooler weather pattern for most of the long-term period. However, shallow moisture content associated with the passage of a cold front during the weekend is expected to linger over the islands on Sunday. As the front passes over the area, isolated to scattered showers are likely, primarily affecting the northeastern municipalities of Puerto Rico and the U.S. Virgin Islands during the morning. In the afternoon hours, shower activity is anticipated in the southern and southwestern sections of Puerto Rico.

A surface high pressure over the western Atlantic responsible of pushing the front across the area, and a broad surface low developing in the central Atlantic, will promote moderate winds from the north-northeast through midweek. As these systems strengthen over the waters, cooler and drier air will move into the area, resulting in lower temperatures during the overnight hours. A decrease in precipitable water content is forecasted from Monday onwards, with values around 1.25-1.45 inches, just below climatology. Consequently, limited shower activity and stable weather conditions are expected for the New Year's festivities. However, cooler air under northerly winds may bring occasional passing showers along portions of north- northeastern Puerto Rico and the USVI during the nighttime.

AVIATION

(06Z TAFS)

Mainly VFR conds are expected at all terminals with VCSH thru fcst period. SHRA anticipated at JSJ and possible TSRA at JBQ btw 17-22z that may cause brief MVFR conds. East winds at 5-12 kts will prevail today, shifting from the NNE by late Friday.

MARINE

A building surface high pressure over the Western Atlantic will yield gentle to moderate east to northeast winds. Increasing winds and a northerly swell from a surface low over the central Atlantic arriving this weekend will deteriorate seas once again, and Small Craft Advisory conditions are expected across the Atlantic waters. In the meantime, patches of moisture carried by the winds will lead to passing showers across the waters, with possible isolated thunderstorms over the western waters of Puerto Rico during the afternoons.

BEACH FORECAST

A moderate risk of rip currents is expected to prevail across most north and east facing beaches of Puerto Rico, and across most beaches of the U.S. Virgin Islands through early Saturday. Life- threatening rip currents are expected once again across the north facing beaches of Puerto Rico from Fajardo to Rincon, and Culebra on Sunday and early next week due to a long period northerly swell. A low risk of rip currents is expected across the southern protected beaches of Puerto Rico.

SJU WATCHES/WARNINGS/ADVISORIES

PR...None. VI...None. AM...None.