Hurricane Season runs from June 1-November 30
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Area Forecast Discussion (AFD)
043 FXCA62 TJSJ 201703 AFDSJU Area Forecast Discussion National Weather Service San Juan PR 103 PM AST Wed May 20 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST, FIRE WEATHER... .KEY MESSAGES... Issued at 1215 PM AST Wed May 20 2026 * Breezy conditions across the local islands will continue to bring fast moving showers, resulting in a limited to elevated flooding risk. Additionally, gusty winds may blow around unsecured items. * Under the prevailing east-southeasterly flow, heat indices will remain between 100 and 105F. This will primarily affect heat- sensitive individuals, especially those outdoors without adequate cooling or hydration. * The breezy conditions will continue to promote moderate rip current risk across most coastal areas. * Regarding the marine conditions expect choppy to rough seas at times. Small Craft Advisories remain in effect through at least Thursday afternoon for the offshore Atlantic waters. * Across the U.S. Virgin Islands, the main hazards continue to be heat indices around 100F and a moderate risk of rip currents, particularly for Saint Croix. && .Short Term(This evening through Friday)... Issued at 1215 PM AST Wed May 20 2026 Variably cloudy skies prevailed across the islands today, with frequent showers observed over the surrounding waters and eastern coastal areas of Puerto Rico. Localized afternoon convection in western Puerto Rico will remain possible until sunset. East-southeasterly winds of 15 to 20 mph continued throughout the day, while coastal temperatures ranged from the upper 80s to low 90s. Latest guidance suggests that 250 mb heights will gradually rise as a mid- to upper-level trough over the western tropical Atlantic weakens and shifts further west. At lower levels, surface high pressure anchored over the north-central Atlantic will promote fresh to locally strong east-southeasterly winds. In fact, 925 mb winds are expected to persist near 20 knots, which is near or above the climatological normal for this time of year. Moisture will remain mostly confined below 700 mb, with precipitable water values staying near seasonal normals through Friday, followed by a sharp increase in available moisture. Maximum temperatures are expected to range from the low to mid-80s in higher elevations to the upper 80s and low 90s along coastal areas. Temperatures at the 925 mb level are forecast to peak on Thursday and Friday, making them the warmest days of the forecast cycle. Limited dust concentrations will also continue. Under this evolving pattern, passing showers will continue over eastern Puerto Rico and the outlying islands, with locally induced afternoon convection developing over western Puerto Rico Thursday and Friday. Breezy conditions will drive fast-moving showers and a limited risk of localized flooding, while gusty winds may affect unsecured items. Finally, heat indices between 100 and 105F will primarily impact heat-sensitive individuals and those outdoors without proper hydration. && .Long Term(Saturday through next Tuesday)... Issued at 1215 PM AST Wed May 20 2026 No major changes were introduced to the long-term forecast. As mentioned in the previous discussion, a broad surface high pressure will linger over the Western Atlantic through most of the period, promoting E-ESE winds and resulting in breezy to locally windy conditions across the CWA. Instability should gradually increase Saturday onwards, as an upper-level trough extending into the tropics may shift eastward and linger north of the CWA. According to the latest model guidance, moisture content will increase as well, with PWAT values approaching near-normal levels (up to 2.0 inches). Additionally, the latest Grand Ensemble shows members tending to wetter conditions for the first part of next workweek (difference around 0.2 - 0.3 inches), increasing confidence. Under the influence of the trough, mid-level temperatures may become slightly cooler than normal (near -9 degrees Celsius), while winds aloft may become stronger and allow ventilation. Additionally, the latest Galvez- Davison Index (GDI) solutions dont rule out the potential for isolated to scattered thunderstorms across the islands each day, becoming frequent Monday onward during afternoon into night hours. Hence, windward sections of the islands can expect passing showers moving each day, while afternoon showers and thunderstorms will likely concentrate over western/northwestern Puerto Rico. Due to strengthening winds, showers should remain progressive, with rainfall accumulations likely to result in ponding of water over roadways and poorly drained areas, including minor flooding. Nevertheless, urban and small streams flooding cannot be ruled out over the aforementioned areas. As mentioned in the previous discussion, warmer than normal temperatures and abundant moisture content will increase the likelihood of heat indices exceeding 100 degrees Fahrenheit. Although a limited risk is expected across low elevations and urban areas of the islands, individuals sensitive to heat must take necessary precautions, such as remaining hydrated and avoiding long sun exposure. && .AVIATION... (18Z TAFS) Issued at 1215 PM AST Wed May 20 2026 VFR conditions across all TAF sites. Winds will bring occasional rounds of -SHRA/SHRA around windward terminals thru 20/23Z, SHRA/+SHRA and VCTS, will develop across the interior and NW resulting in brief MVFR conds over TJBQ. Each day, expect breezy to locally windy E to ESE winds at 15-20 kts with higher gusts and sea breeze var, decreasing after 23Z. && .MARINE... Issued at 1215 PM AST Wed May 20 2026 Marine conditions will remain somewhat hazardous through the next several days as strong high pressure over the Atlantic continues to support moderate to fresh easterly winds across the regional waters. Winds will occasionally reach locally strong levels, resulting in choppy to rough seas at times. Small Craft Advisories remain in effect through at least Thursday afternoon for the offshore Atlantic waters. In addition, isolated afternoon and early evening thunderstorms may develop each day across the western coastal waters of Puerto Rico, producing locally higher winds and seas near storms. && .BEACH FORECAST... Issued at 1215 PM AST Wed May 20 2026 Moderate rip current risk conditions are expected to persist across most local beaches through much of the week and into the upcoming weekend due to persistent breezy conditions and ongoing wind-driven seas. The highest risk will continue to be along north and east- facing beaches. Beachgoers should exercise caution, avoid swimming alone, and remain near lifeguard-protected beaches whenever possible, as life-threatening rip currents can develop even under moderate risk conditions. && .FIRE WEATHER... Issued at 1215 PM AST Wed May 20 2026 Increased moisture could prevent RH values from decreasing below threshold values for prolonged periods; however, rainfall should again remain limited across the southern plains, allowing relative humidity to drop to critical fire weather thresholds in the region. Additionally, sustained winds of 15 to around 20 mph, with higher gusts, combined with elevated KBDI values, will favor the rapid spread of wildfires across the southern coastal plains. The low 7-day percent of normal rainfall will also persist across the southeastern coastal plains. Fire management partners are once again urged to remain vigilant. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...Small Craft Advisory until 6 PM AST Thursday for AMZ711. && $$ SHORT TERM...OMS LONG TERM...MNG AVIATION/MARINE/BEACH FORECAST/FIRE WEATHER...MMC
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