Marine Weather and Tides
12/16/2019 NOAA is having trouble with requests that include wind gusts. I am posting graphs without wind gusts until it gets fixed.
10/9/2019 Updated the Marine Zones.
9/4/2019 Fixed the weather maps due to NOAA moving them.
7/25/2019 New feature in the Airports section gives a link to 5 minute updates for data reports.
|Sunrise 6:42AM||Sunset 6:21PM||Wednesday February 19, 2020 4:01 AM AST (08:01 UTC)||Moonrise 3:54AM||Moonset 2:52PM||Illumination 20%|
7 Day Forecast for Marine Location Near Su�rez, PRHourly EDIT Help
Area Discussion for - San Juan, PR  (on/off)  Help NOTE: mouseover dotted underlined text for definition
FXCA62 TJSJ 190257 CCA AFDSJU
Area Forecast Discussion . CORRECTED National Weather Service San Juan PR 1057 PM AST Tue Feb 18 2020
UPDATE. No change to the inherited short term forecast package and reasoning at this time. Recent GFS model guidance initialized fairly well and continued to suggest occasional surges of trade wind moisture during the overnight and early morning hours, carried by the brisk easterly trades. Brief wind gusts between 25 to 30 mph accompanied some of the passing showers as they moved across the coastal waters and brushed portions of the islands from time to time.
AVIATION. Prevailing VFR at all terminals but TEMPO MVFR psbl AT TJSJ/TISX/TIST/TNCM/TKPK til at least 19/06Z due to SHRA/-SHRA and low cig. Isold-Sct shra ovr regional waters btwn islands til 19/14Z SCT ocnl BKN lyrs nr FL025. FL050 . FL080 durg prd. Sfc wnds fm E 10-15 kts with brief wnd gust mainly with passing SHRA.
MARINE. No change to previous marine discussion. Choppy and hazardous seas will continue overnight and through the end of the work week. Recent data from surrounding buoys continued to suggest moderate to fresh easterlies of 15 to 20 knots with occasionally higher gusts between 25 to 30 knots.
PREV DISCUSSION. /issued 509 PM AST Tue Feb 18 2020/
SYNOPSIS . A series of surface high pressures across the North Atlantic will continue to result in brisk easterly trade winds through at least Thursday. Patches of low-level moisture embedded within the easterly trade wind flow will move across the area from time to time to result in passing showers. However, given the unfavorable conditions aloft, significant rainfall activity is not expected.
SHORT TERM . Tonight through Thursday .
Overall, a fairly benign weather pattern is expected to prevail across the area through the short-term period. Aloft, the region will be located on the western side of a trough over the far western tropical Atlantic and on the eastern side of a ridge building over the western and central Caribbean. This will provide subsidence aloft, limiting the development of significant showers.
At lower-levels, high pressure over the far northeast Atlantic and another high pressure moving over the north-central Atlantic will maintain the local pressure gradient tight. Therefore, brisk easterly trade winds between 15 and 25 mph with higher gusts are expected, especially from the mid-morning through the afternoon hours. These easterly trade winds will also drive patches of low- level moisture into the region from time to time, resulting in brief light to moderate showers, especially across portions of eastern Puerto Rico and the USVI. Some afternoon showers are possible across western Puerto Rico due to local and diurnal effects. Given the unfavorable conditions aloft and the fast low-level flow that will keep these showers moving fast, only minor rainfall accumulations are expected.
LONG TERM . Friday through Tuesday .
PREV DISCUSSION . /issued 529 AM AST Tue Feb 18 2020/
At mid and upper levels a vigorous trough with northeast- southwest orientation across the western tropical Atlantic will pull away on Friday leaving northwest flow over the area. On Saturday a weak trough at upper levels will pass through the area, then on Sunday a strong long wave trough will pass north of the area over the Atlantic waters at both mid and upper levels. As this trough at upper levels moves east, northwest flow will resume.
At lower levels the passage of a weak trough on Friday and the approach of a cold front from the northwest will cause low level winds to become light and in places variable. Low moisture levels on Friday will bring mostly sunny conditions with some above normal temperatures over the islands. Low level moisture is patchy and wind patterns are too light to predict over the weekend which will lead to scattered showers of a local nature, generally over higher terrain. During this period persistent showers in weak and variable flow dominated by land and sea breezes could lead to localized urban and small stream flooding. On Monday and Tuesday moisture increases and the chance of showers improves, but very moist conditions are localized and transitory, making shower activity erratic. Winds at lower levels gradually become easterly again, but remain light so interior Puerto Rico is the most likely to see showers in sea breeze convergence with only scattered showers elsewhere.
AVIATION . VFR conditions will continue with easterly winds at 10 to 20 kt with higher gusts, especially in and near the passing SHRA. Passing SHRA will affect the terminals at times. JMZ/JPS will observe afternoon SHRA through 18/23z. Similar weather pattern will continue through the forecast period.
MARINE . The combination of a weak northerly swell and fresh easterly trade winds of up to 20 kts will result in choppy and hazardous seas of up to 7-8 feet across most of the regional waters through at least Thursday. Therefore, small craft advisories are in effect for most of the regional waters. There is also a high risk of rip currents for the northern facing beaches of Puerto Rico and Culebra as well as Cramer Park Beach in Saint Croix.
PRELIMINARY POINT TEMPS/POPS. SJU 74 84 74 84 / 50 30 50 30 STT 74 84 74 84 / 50 20 50 30
SJU WATCHES/WARNINGS/ADVISORIES. PR . High Rip Current Risk through Wednesday afternoon for Culebra- Northeast-San Juan and Vicinity-Southeast.
High Rip Current Risk through late Wednesday night for North Central-Northwest.
VI . High Rip Current Risk through Wednesday afternoon for St Croix.
AM . Small Craft Advisory until 8 PM AST Thursday for Anegada Passage Southward to 17N-Caribbean Waters of Puerto Rico from 10 NM to 17N-Mona Passage Southward to 17N.
Small Craft Advisory until 8 PM AST Wednesday for Coastal Waters of Northwestern Puerto Rico out 10 NM-Coastal Waters of Northern Puerto Rico out 10 NM.
Small Craft Advisory until 8 PM AST Friday for Atlantic Waters of Puerto Rico and USVI from 10 NM to 19.5N.
Small Craft Advisory until 2 AM AST Friday for Coastal Waters of Northern USVI and Culebra out 10 NM-Coastal Waters of Southern USVI Vieques and Eastern Puerto Rico out 10 NM.
SHORT TERM . RAM LONG TERM . GL PUBLIC DESK . TW
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