Area Forecast Discussion
Issued by NWS San Juan, PR
Issued by NWS San Juan, PR
060 FXCA62 TJSJ 300903 AFDSJU Area Forecast Discussion National Weather Service San Juan PR 503 AM AST Sun Jun 30 2024 .SYNOPSIS... Lingering moisture from a tropical wave combined with Saharan Dust will promote thunderstorm activity over western Puerto Rico during the afternoon hours. Hurricane Beryl is forecast to rapidly intensify today as it approaches the Caribbean waters. Marine and coastal conditions will start to gradually deteriorate across the Caribbean and local passages as Beryl approaches the area. Stay tuned for updates associated with this storm. && .SHORT TERM...Today through Tuesday... Scattered showers and isolated thunderstorms were noted across the local waters and over portions of the islands during the night. The Doppler radar estimated around half an inch of rain over Juncos and Las Piedras and around a quarter of an inch across St. Thomas and St. John. Minimum temperatures ranged from the upper 60s to mid-70s across the higher elevations and from the upper 70s to low 80s across coastal municipalities. Winds were up to 15 mph from the east, with gusts around 25 mph across coastal areas. For today, the lingering moisture from a tropical wave, combined with the influence of a Saharan Air Layer carrying moderate amounts of Saharan dust, will promote shower and thunderstorm activity, mainly across PR throughout the day, with drier conditions expected across the USVI. The hazy skies and low-level southeasterly winds will also contribute to hot temperatures across the islands, and a Heat Advisory (NPWSJU) is in effect for all coastal municipalities of PR and St. Croix. Maximum temperatures should reach the low 90s across the lower elevations, with general heat indices ranging between 106F and 112F. There haven`t been significant changes in the forecast track for Beryl, which is expected to pass about 200 miles south of the islands. However, weather conditions will quickly deteriorate between Monday afternoon and Tuesday as the outer bands from Tropical Cyclone Beryl bring showers and thunderstorms to the local area. Squally weather with strong gusty winds is possible across portions of the Caribbean waters, the US Virgin Islands, and eastern/southern Puerto Rico through Tuesday. .LONG TERM...Wednesday through Sunday... After the passage of Hurricane Beryl south of the local area, a drier airmass will quickly move over the islands. This drier airmass will promote stable conditions on Wednesday with limited shower activity. However, by Thursday onwards tropical activity is expected once again. The National Hurricane Center (NHC) is currently monitoring an area of low pressure located over the eastern Atlantic with a medium to high formation chance over the next 7 days. Latest model guidance suggest that this system will develop as a tropical storm or hurricane before reaching the Lesser Antilles. Nonetheless, this system should remain south of the islands and over the Caribbean waters. At this moment some of the potential indirect impacts associated to this low are: localized flooding, gusty winds, squally weather, and deteriorated marine and coastal conditions. It is too early at this moment to determine the amount of expected rain. Therefore, residents and visitors of Puerto Rico and the U.S. Virgin Islands may continue to monitor the progress of this system as it moves towards the Caribbean. A vast moisture field of this low will persist across the region once it departs on Saturday, promoting afternoon convective activity across the western portions of Puerto Rico. Following the system, more drier air and Saharan Dust particles will take over, enhancing stable and dry conditions for few days. Despite of the expected weather, high temperatures will remain between the upper 80s to low 90s across the islands with heat indices surpassing the mid 100s. && .AVIATION... (06Z TAFS) Mainly VFR conditions expected across all terminals. However, SHRA/TSRA expected to develop due to a departing tropical wave may cause tempo MVFR conds at TJSJ/TJBQ btw 30/16-22z. HZ due to Saharan dust expected but VSBY should remain P6SM. East winds at 12-16 kt with stronger gusts and sea breeze variations aft 30/14z. && .MARINE... A surface high pressure over the central Atlantic will promote moderate to locally fresh easterly winds over the next few days, bringing trade wind showers. Hurricane Beryl is forecast to strengthen as it approaches the Caribbean waters late Monday night into Tuesday, deteriorating marine and coastal conditions considerably for the Caribbean and local passages. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...Heat Advisory from 10 AM this morning to 5 PM AST this afternoon for PRZ001-002-005-008-010-012-013. VI...Heat Advisory from 10 AM this morning to 5 PM AST this afternoon for VIZ002. AM...None. && $$ SHORT TERM...DSR LONG TERM....GRS