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The National Weather Service in San Juan issued an urgent briefing at 11:00 AM AST on Thursday, highlighting the expected excessively wet and hazardous marine conditions for Puerto Rico and the U.S. Virgin Islands.
Forecasts indicate an influx of tropical moisture combined with favorable upper-level conditions that will result in showers and thunderstorms across the islands from Friday extending into the start of the following week. The heightened tropical conditions pose an elevated risk of flooding across both territories. Officials have hinted at the likelihood of issuing a flash flood watch by tomorrow.
Meteorologists have identified a surface trough from the east set to merge with moisture from post-Tropical cyclone Tammy, located well to the north. Additionally, a developing low off Colombia's coast is predicted to stretch northeastward, pulling significant moisture across the islands. This confluence of weather patterns will usher in heavy rains starting later on Friday, amplifying impacts over the weekend.
Outlook
From Wednesday to Friday of the upcoming week, the atmospheric conditions will remain highly saturated, amplifying the risk of hazardous weather in Puerto Rico and the U.S. Virgin Islands. Cumulative rainfall in southeast and east Puerto Rico could surpass 10-12 inches. The U.S. Virgin Islands, on the other hand, could witness upwards of 7 inches of rain by Wednesday.
Potential Risks and Impacts:
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Excessive Rain: Rainfall projections from now until early Tuesday hover between 3 to 8 inches. Wet conditions might persist from Wednesday to Friday.
- Where and When: Rain is expected daily across most regions, with southeast, interior, and eastern parts of Puerto Rico expected to bear the brunt. Heavy downpours are anticipated post-noon on Friday, extending throughout the weekend. Areas could experience 2 to 3 inches of rain daily, with the majority falling between Saturday night and Sunday.
- Impacts: The region could see widespread water ponding, urban flooding, and inundation of roads and streams. There is a significant concern for life-threatening flash floods and mudslides, especially in southern to eastern Puerto Rico. Several rivers may breach their banks.
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Marine Conditions: The Atlantic waters might see tumultuous seas ranging from 7-10 feet. Winds could reach speeds of 15 to 20 knots, with potential gusts surging up to 30 knots. Small Craft and High Surf Advisories will be active for these regions.
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Other Weather-Risk Hazards:
- Thunderstorms and Winds: The islands could experience isolated to scattered thunderstorms, characterized by frequent lightning and gusty winds.
- Rip Current and High Surf: A majority of the coasts, barring the southern sides of the islands, are under high rip current risk until Sunday. High Surf conditions with waves breaking at 10 feet or more are expected in some northern coastal regions from Friday through the weekend. Some areas have already reported waves of these magnitudes.
