Area Forecast Discussion
Issued by NWS San Juan, PR
Issued by NWS San Juan, PR
064 FXCA62 TJSJ 130854 AFDSJU Area Forecast Discussion National Weather Service San Juan PR 454 AM AST Tue Aug 13 2024 .SYNOPSIS... A Tropical Storm Warning remains in effect for Puerto Rico and the U.S. Virgin Islands. Tropical Storm Ernesto will approach the region late Tuesday, bringing strong gusty winds and heavy rainfall to the region. The areas most impacted will be the Virgin Islands, Vieques, Culebra, and eastern Puerto Rico. A significant risk of flooding is expected, with mudslides likely in areas of steep terrain. Marine and coastal conditions will start to deteriorate as early as Tuesday morning across the USVI and eastern waters of PR, then spread across the rest of the waters through Wednesday night or Thursday. && .SHORT TERM...Today through Thursday... The short-term forecast will be dominated by Tropical Storm Ernesto. A Tropical Storm Warning remains in effect for Puerto Rico and the U.S. Virgin Islands. At 200 AM AST, the center of Tropical Storm Ernesto was located near latitude 16.2 North, longitude 60.6 West, about 385 MI ESE of San Juan, Puerto Rico. Ernesto is moving toward the west near 24 mph. A westward to west-northwestward motion with some decrease in forward speed is expected during the next day or so. On the forecast track, Ernesto is expected to move near or over the U.S. Virgin Islands and Puerto Rico by this evening. Ernesto is then forecast to turn northward over the western Atlantic. As a result, later today through Thursday, a gradual increase in rainfall and winds will be observed as Tropical Storm Ernesto moves closer to the islands. Therefore, there is a high potential for flooding rains across the region. Tropical Storm Ernesto is expected to produce total rain accumulations of 4 to 6 inches over the U.S. Virgin Island with isolated higher amounts. For Puerto Rico, 3 to 6 inches of rainfall, with maximum amounts of 10 inches, is expected. Tropical force winds and higher wind gusts are expected to begin spreading over the Virgin Islands and Puerto Rico by this evening. A Coastal Flood Advisory have been issued for the eastern coast of Puerto Rico from San Juan to Guayama, including Vieques and Culebra, and the U.S. Virgin Islands as a storm surge will raise water levels by as much as 1 to 3 feet above ground level. Residents and visitors should continue to monitor the progress of this system and have their tropical emergency plans ready now. Please refer to the latest Tropical Cyclone Bulletin (TCPAT5) issued by National Hurricane Center and Hurricane Local Statements (HLSSJU) issued by WFO San Juan PR for updated information. .LONG TERM...Friday through Monday... The current forecast track has Tropical Storm Ernesto away from our region by Friday, about 650 miles, and it is forecast to be a Hurricane at that time. Weather conditions should improve in our local area and return to a more typical pattern. The latest Precipitable Water (PWAT) models suggest values returning to average values. High pressure across the Atlantic should promote southeasterly winds through Sunday, then shift from the east on Monday. At the upper levels, a TUTT will approach from the northeast, promoting favorable conditions aloft for daily showers. In general, local weather during the long term will be dominated by east-to-southeast winds, daytime heating, and local effects. Therefore, afternoon convective activity with showers and thunderstorms is expected across the interior and northwestern Puerto Rico. For the U.S. Virgin Islands, passing showers dragged by the winds will reach the islands mainly during the morning hours. Limited excessive rainfall risk will probably be present as ponding of water in roads and poorly drained areas is possible with shower activity, mainly on Friday. Warm conditions will return by Friday and last through the weekend, mainly across coastal and lower elevations. && .AVIATION... (06Z TAFS) At 200 AM AST (0600 UTC), the center of Tropical Storm Ernesto was located near latitude 16.2 North, longitude 60.6 West. Ernesto is moving west near 21 kts. On the forecast track, Ernesto is expected cross the Leeward Islands overnight and near or over the U.S. Virgin Islands and Puerto Rico by Tuesday evening. VFR conds expected at all terminals for most of the prd. However fqt passing SHRA/isold TSRA may impact USVI/TJSJ terminals 13/06Z-14Z. SFC wnds will be fm E-NE 8-12 kts but incrg 15-20 kts with hir gusts btw 25-30 kts accompanying SHRA/TSRA. SFC wnds will continue to increase to 15-18 kts and gusting to 30 kts or hir aft 13/14Z and accompanying rainbands from Ernesto when tropical force wind gusts will be possible. This activity will also promote MVFR/psbl IFR W/low VIS and CIG en route btw islands and psbl Mtn top obscr ovr E interior of PR til 13/14Z. && .MARINE... Tropical Storm Ernesto, located 385 miles ESE of San Juan, is expected to move into the local waters this evening into Wednesday as a tropical cyclone. However, marine conditions in our eastern Atlantic waters and the Anegada Passage could deteriorate as early as this morning. Further deterioration in marine and weather conditions is expected Wednesday through Thursday. && .BEACH FORECAST... Beach conditions will deteriorate as Tropical Storm Ernesto approaches the region. Large breaking waves are expected to impact the Virgin Islands and Puerto Rico from this evening into Thursday. High Surf Advisory and High Rip Current Statements are in effect from this evening through at least Wednesday afternoon and Thursday, respectively. && .HYDROLOGY... Tropical Storm Ernesto will bring rainfall accumulation of 4 to 8 inches for portions of the Virgin Islands, eastern and southern Puerto Rico, as well as the interior. The risk of flooding will be significant, with rapid river rises, and mudslides likely. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...Tropical Storm Warning for PRZ001>013. Coastal Flood Advisory from 6 PM this evening to 6 PM AST Wednesday for PRZ001>003-012-013. Flood Watch from this evening through Thursday morning for PRZ001>013. High Rip Current Risk from this evening through late Wednesday night for PRZ001>003-005-008. High Surf Advisory from 6 PM this evening to 6 PM AST Wednesday for PRZ001>003-005-008-012-013. High Rip Current Risk from Wednesday morning through late Wednesday night for PRZ010. High Rip Current Risk through late Wednesday night for PRZ012- 013. VI...Tropical Storm Warning for VIZ001-002. Coastal Flood Advisory from 6 PM this evening to 6 PM AST Wednesday for VIZ001-002. Flood Watch from this evening through Thursday morning for VIZ001-002. High Surf Advisory from 6 PM this evening to 6 PM AST Wednesday for VIZ001-002. High Rip Current Risk through late Wednesday night for VIZ001- 002. AM...Tropical Storm Warning for AMZ711-712-716-723-726-733-735-741- 742-745. && $$ SHORT TERM/AVIATION...RAM LONG TERM/IDSS....YZR UPPER AIR/SOCIAL MEDIA...RVT MARINE...CAM HLS...CAM/ERG