AFDSJU Area Forecast Discussion National Weather Service San Juan PR 127 PM AST Tue Jan 6 2026 ...New SHORT TERM, AVIATION... .KEY MESSAGES... Issued at 119 PM AST Tue Jan 6 2026 * A few passing showers will continue to reach Puerto Rico and the Virgin Islands in the upcoming days, mostly in the morning and evening hours. The flooding threat is slim to none. * Temperatures will be seasonal, with lows in the low 60s for the high mountains in Puerto Rico, and the low 70s in coastal areas in both Puerto Rico and the Virgin Islands. * Life-threatening rip currents are expected late Wednesday and Thursday along the northwest to northeast beaches of PR, with a moderate to high risk for the north and east-facing beaches in the USVI. && .Short Term(This evening through Thursday)... Issued at 119 PM AST Tue Jan 6 2026 The morning was variable along the north and east of Puerto Rico and the Virgin Islands. Showers moved at times, affecting outdoor activities, but they were not strong enough to cause any flooding. Rainfall accumulations were minimal. Along southern Puerto Rico, skies were mostly sunny. Since early in the morning, mid-level water vapor imagery indicated that a drier and cooler air mass has moved over the northeastern Caribbean. At the low level, the TJSJ 06/12Z sounding did show precipitable water values of 1.49 inches,which is near normal for this time of year. Since then, values has gradually decreased to 1.2- 1.4 inches. Therefore, for the rest of Three King`s Day, weather conditions should improve, but under a northeasterly breeze, some showers may still stream along north and east Puerto Rico and also over the Virgin Islands. The high resolution models also show that showers are anticipated for the southwestern quadrant of Puerto Rico, with enough accumulation to cause ponding of water on low- lying areas. Aloft, a trough is crossing today, so isolated lightning cannot be ruled out with the afternoon activity. Then, for the middle of the workweek, a ridge will build in the mid levels, maintaining any available moisture close to the surface. Tomorrow, a surface trough will maintain the trade winds weak, coming out of the northeast below 10 knots. This trough will cross the region on Thursday, and winds will then shift from the east, but still weak. In terms of impacts, Wednesday and Thursday look similar. The morning and night hours will see brief rainfall interruptions along the east and north of Puerto Rico and the Virgin Islands. These showers will likely not cause flooding, but rather will be a nuisance for outdoor activities. The afternoons will see stronger showers along the southwest PR, with some ponding of water along roads and low-lying areas at best. In terms of temperatures, all indicators are near normal, meaning mild to cool lows at night, mostly in the 60s for the mountains, and the upper 60s to low 70s for coastal areas. Highs will still climb to the low and mid-80s each afternoon. && .Long Term(Friday through next Monday).../prev discussion/ Issued at 119 PM AST Tue Jan 6 2026 A surface high pressure moving from the western Atlantic into the central Atlantic will promote moderate to locally fresh east to northeasterly trades during the long term period. A weak induced surface trough northeast of the region will bring at times patches of low-level moisture over the islands, particularly on Friday and Saturday. During the second half of the forecast period, at the upper levels, a ridge over the southwestern Atlantic and a developing TUTT-low from the north central Atlantic will promote drier air aloft and more stable conditions in general. Therefore, showers that form through the period are not expected to produce heavy rainfall or grow into thunderstorms. These showers will be mainly driven by the increasing northeasterly trades, favoring an advective pattern at night, with showers moving at times across the USVI and along the east and north sections of PR. Shallow afternoon convection is expected over the Cordillera and the southern sections of PR, but the flood risk will remain low as rainfall accumulations are not expected to exceed an inch of rain per day. By early next week, global models now have the strong TUTT-low and induced surface trough a little farther away of the islands. This solution now suggest a drier weather trend than previously expected, with the GFS indicating a minimum in precipitable water content of 1.00-1.25 inches on Monday and Tuesday. && .AVIATION... (18Z TAFS) Issued at 119 PM AST Tue Jan 6 2026 Mainly VFR conditions expected to prevail through the forecast period. SHRA will continue to stream across the Atlantic and Caribbean waters, but impacts to operations, if any, should be limited. VCTS is expected for TJPS before 21z, with brief periods of reduced VIS and low ceilings possible. Winds are from the NE at 7-12 kts, gusting up to 20 knots. Winds will slow down after 22Z, before picking back up at 07/13-14Z. && .MARINE... Issued at 119 PM AST Tue Jan 6 2026/prev discussion/ Light to moderate northerly winds will continue today as a frontal boundary moves across the region. Showers and isolated thunderstorms are expected to continue through most of the morning hours. A long period northerly swell is expected to arrive on Wednesday, building seas up to 6 feet, particularly across the Atlantic waters and Caribbean Passages. A surface high pressure over the western Atlantic and weak induced surface troughs northeast of the region will promote moderate east to northeast trades for the rest of the period. && .BEACH FORECAST... Issued at 119 PM AST Tue Jan 6 2026/prev discussion/ A long period northerly swell will cause rough surf and life- threatening rip currents across the north-facing beaches of Puerto Rico, particularly on Wednesday. Elsewhere, the risk of rip currents will be moderate, except along the southern beaches of the islands where the risk will remain low throughout the week. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && $$