AFDSJU Area Forecast Discussion National Weather Service San Juan PR 427 AM AST Sat Jan 10 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 420 AM AST Sat Jan 10 2026 * Moderate rip current risk continues: A moderate risk of life- threatening rip currents persists along Atlantic-facing beaches of Puerto Rico and Culebra, as well as the north- and east- facing beaches of St. Croix. By Sunday, this risk expands to western Puerto Rico and the northern U.S. Virgin Islands. Hazardous swimming conditions are possible at exposed beaches, especially near coastal structures. * Passing showers with limited flooding risk: A typical trade- wind pattern will bring brief morning showers to windward areas, followed by isolated to locally scattered afternoon showers mainly across the interior, and southwestern Puerto Rico. Localized flooding is possible, particularly across the southwestern quadrant, but widespread flooding is not expected. * Near to slightly above-normal seasonal temperatures: Overnight temperatures will remain slightly below normal across Puerto Rico and the U.S. Virgin Islands, while daytime high temperatures stay near to slighly-above typical values for this time of year. && .Short Term(Today through Monday)... Issued at 420 AM AST Sat Jan 10 2026 Overnight, isolated to scattered showers moved across portions of northern and eastern Puerto Rico. Doppler radar estimated rainfall accumulations of 1.00 to 1.50 inches in northern areas, with the highest totals concentrated along the coast between Arecibo and Barceloneta. The U.S. Virgin Islands experienced frequent passing showers, though these resulted in minimal accumulations. Minimum temperatures ranged from the upper 60s to low 70s across lower elevations, while higher terrain in Puerto Rico saw cooler temperatures in the upper 50s and low 60s. Light to moderate northeasterly winds prevailed across the islands throughout the night. A strong surface high-pressure system migrating from the western to the central Atlantic will maintain a moderate northeasterly wind flow through at least Sunday afternoon. Winds are then expected to shift from the east by Monday as the high pressure settles over the central Atlantic. Weather conditions will remain influenced by this system, promoting generally drier and more stable conditions across the region. During this period, passing morning showers will continue along the windward coasts, followed by localized afternoon activity over central, southwestern, and south-central Puerto Rico driven by daytime heating, sea breeze convergence, and local effects. Precipitable water values will remain near seasonal norms, ranging from 1.25 to 1.50 inches. Consequently, the flooding risk for today remains limited, primarily affecting the southwestern quadrant of Puerto Rico during the afternoon. By late Sunday into Monday, a mid-to-upper-level low and its associated surface trough will gradually increase moisture levels, leading to more frequent shower activity across the area. Temperatures at the 925 mb level will stay near climatological normals through Monday, with maximum temperatures reaching the low to mid-80s in lower elevations and the mid to upper 70s across higher terrain. Pleasant overnight temperatures will persist, particularly across the mountains of Puerto Rico. && .Long Term(Tuesday through Saturday)... Issued at 420 AM AST Sat Jan 10 2026 A deep-layer mid-to-upper-level trough will continue moving eastward and away from the Lesser Antilles from Tuesday onward. At the same time, a mid-to-upper-level ridge builds over the Northeast Caribbean. At the surface, an abnormally strong Azores High will persist over the North Atlantic. This pattern will keep frontal boundaries exiting the eastern seaboard well north of Puerto Rico and the US Virgin Islands, limiting any direct frontal influence over the local area through at least the end of the upcoming workweek. Then, ECMWF and GFS indicated a frontal boundary approaching the region. If it gets close enough, it could promote increased available moisture and the potential for an unstable wet pattern around Friday and next Saturday. Under this configuration, the prevailing weather will be dominated by a typical trade-wind (advective) pattern. This will favor occasional periods of passing showers, mainly affecting windward locations of Puerto Rico and the US Virgin Islands, including the eastern and northeastern coastal areas. These showers are expected to be brief, with limited rainfall accumulation. As the mid-to upper-level ridge strengthens, atmospheric stability is expected to increase. This will result in reduced afternoon convection over western Puerto Rico, compared to more unsettled patterns. Any afternoon showers that do develop are expected to be isolated and short-lived. Ensemble model guidance indicates that temperatures over the long term will range from near-normal to slightly above-normal across Puerto Rico and the US Virgin Islands. && .AVIATION... (06Z TAFS) Issued at 420 AM AST Sat Jan 10 2026 Mainly VFR conds are expected to prevail across all terminals during the forecast period. VCSH/SHRA are expected this morning at TJSJ/TJBQ/TIST/TISX aft 10/13Z as trade wind showers continues to move inland from the local waters. Locally induced SHRA over central, south-central and southwestern PR, may cause brief MVFR cigs at TJPS btw 10/17Z-22Z. ENE winds btw 08-15 kt with sea breeze variations and higher gusts expected aft 10/13z. && .MARINE... Issued at 420 AM AST Sat Jan 10 2026 A surface high pressure migrating eastward across the western Atlantic, in conjunction with a weak induced surface trough currently northeast of the region, will continue to maintain moderate east to northeast winds across the local waters through the middle of next week. Additionally, a small long-period northerly swell will continue to slowly subside through this afternoon across the Atlantic Waters and Caribbean Passages. && .BEACH FORECAST... Issued at 420 AM AST Sat Jan 10 2026 There is a moderate risk of rip currents. This risk is associated with persistent trade winds and lingering northerly swell energy, which can enhance currents, particularly along Atlantic-facing beaches in northern and eastern Puerto Rico, as well as on exposed beaches of St. Thomas, St. John, and the north and east shores of St. Croix. Under a moderate rip current risk, life-threatening rip currents are possible, especially near jetties, groins, reefs, and piers, where water flow can be locally intensified. Even experienced swimmers may have difficulty returning to shore if caught in a rip current. The risk will remain moderate, especially on north and east- facing beaches, due to the influence of easterly winds and the arrival of pulses of moderate-period easterly and northerly swells next week. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && $$