Hurricane Season runs from June 1-November 30
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000 FXCA62 TJSJ 232017 AFDSJU Area Forecast Discussion National Weather Service San Juan PR 417 PM AST Tue Apr 23 2024 .SYNOPSIS... The surface trough will continue to impact the local islands, bringing periods of showers and thunderstorms. The wet weather pattern will persist through the end of the workweek, but drier conditions are anticipated late in the weekend and early next week. && .SHORT TERM...Tonight through Thursday... Overall, a mixture of sunny to hazy skies and partly cloudy to rainy weather conditions prevailed across Puerto Rico and the U.S. Virgin Islands today. In the morning, mostly calm weather conditions prevailed across the islands, with some showers developing over northeastern Puerto Rico and the U.S. Virgin Islands. By the afternoon hours, showers started to form along the interior municipalities of Puerto Rico and spread almost across the entire island. Around 1:30 PM AST, a funnel cloud formed particularly in the municipalities of Bayamon. The emergency managers and the general public from Bayamon sent us pictures and videos, and they reported that it did not reach the ground and therefore, did not caused any damage to life or property at the time of the report. Nonetheless, National Weather Service employees are on their way to the area to do a storm survey and analyze the area. We encourage people to stay updated for any changes regarding the upgrade of this weather feature if considered necessary. Temperatures- wise, they remained in the mid to upper 80s along the coastal areas, while over the higher elevations, they stayed in the 70s to low 80s. With the axis of the surface trough forecast to linger across the region combining with the approach of a mid-level short-wave trough and surface frontal boundary from the west, a wet pattern will continue through the rest of the workweek with unsettled conditions that will bring persistent rainfall and possible thunderstorms at times. Steep 850-700 mb lapse rates and precipitable water content will remain within the range of 1.9 to above 2.0 inches for most of the period, which will enhance the chance of convective development each afternoon. With winds becoming more easterly on Thursday, the strongest activity will be seen across western Puerto Rico during the afternoon hours. USGS river sensors still indicate that most rivers over the eastern half of Puerto Rico are exceeding the 75th percentile, with half of them surpassing the 90th percentile or well above normal. Soil saturation is also high, increasing the potential for excess runoff and landslides in steep terrain. Therefore, the flood risk over Puerto Rico will remain elevated for the rest of the short-term forecast, as any additional rainfall could exacerbate these factors. For the rest of the area, a limited to elevated flooding risk will persist. Suspended Saharan dust particulates will be present, strengthening on Thursday, promoting hazy skies in areas with limited shower activity. && .LONG TERM...Friday through Tuesday... //from previous discussion// As a shortwave trough digs into the western Caribbean, high clouds are expected to get established over Puerto Rico and over the Virgin Islands. At the surge, a high pressure over the central Atlantic drives the trade winds from the east at speeds below 15 knots. Moisture from a surface trough/old frontal boundary will linger into the region, maintaining that pattern of showers reaching the region at times. The moisture will finally be pushed south of the islands late on Friday and early Saturday, as a high pressure exits the eastern coast of the United States. This feature will push a drier air mass into the islands, with precipitable water values falling to near normal values on Saturday, and below normal all the way into Tuesday. Winds will be from the northeast all this period, with a more northerly component at times. It will be brisk too, with speeds at 15 to 20 mph, and stronger gusts. In reality, is not going to be completely dry, since some showers will still develop over the Atlantic, reaching the USVI and northeastern PR at times, and some showers will still develop in the afternoon over southwestern Puerto Rico. However, they will not be as widespread or strong as the one being experienced lately. && .AVIATION... (18Z TAFs) SHRA/TSRA could lead to MVFR conditions at TJBQ/TJSJ thru 23/22z. VFR conds should prevail thru the rest of the period. HZ due to Saharan dust but VSBY should remain P6SM. Low-level winds will continue SE/SSE at 8-12 kt, bcmg light and variable overnight. && .MARINE... A surface trough crossing the islands will yield winds from the east tonight. Showers and thunderstorms will continue to affect the local waters for the next few days. A small northwesterly swell will arrive late Wednesday and Thursday. Another surface trough will strengthen east winds by Wednesday, before becoming northeast on Saturday under the influence of a surface high pressure over the western Atlantic. && .BEACH FORECAST... Breaking waves of around 3 feet will maintain the risk of rip currents generally low to moderate. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && $$ SHORT TERM...MMC/RC LONG TERM....ER AVIATION...DS MARINE...RC BEACH FORECAST...MMC
