Sunny to partly cloudy skies are expected Sunday, with a few showers possibly affecting the local area from time to time. The showers are in association with the passage of a weak tropical wave. Daytime high temperatures should range from the upper 80s and low 90s with a light to moderate breeze from the southeast.
Mariners can anticipate seas to four feet and winds to 10 knots. There is a moderate risk of rip currents along the eastern coastlines of St. Croix. During the latter part of the work week, hazardous marine and coastal conditions are expected due to swells generated by Hurricane Sam.
IN THE TROPICS
Sam remains a Category 4 hurricane with fluctuations in intensity likely during the next day or two. At 5 a.m. Sunday, the center was estimated near 13.8 degrees North, 49.7 degrees West or about 940 miles east-southeast of the northern Leeward Islands. Top winds are at 145 miles per hour. The hurricane is moving to the west-northwest at eight miles per hour, a motion that should continue Sunday, followed by a turn to the northwest on Monday. A track to the northwest is expected to continue through the middle of the week. Hurricane- force winds extend outward up to 30 miles from the center and tropical storm-force winds extend outward up to 90 miles from the center. There are no coastal watches or warnings in effect. Swells generated by Hurricane Sam are forecast to reach the Lesser Antilles early this week.
ANALYSIS — Sam remains a small but intense hurricane with a well-defined 10-mile-wide eye. NOAA aircraft are scheduled to investigate Sam later Sunday afternoon which should provide more insight into the structure and intensity of the hurricane. There is a compact inner core of deep showers and thunderstorms surrounding the center of circulation despite some overnight intrusion of dry air.
Sam is tracking to the west-northwest and a ridge to the north and east of the hurricane should steer it west-northwest to northwest over the next several days. By midweek, a trough will move off the east coast of the U.S., dig southward and erode the ridge. The southerly flow ahead of the trough should cause the hurricane to begin recurving, with a somewhat faster north-northwestward motion by Thursday.
The hurricane will likely experience some fluctuations in intensity over the next day or two. On one hand, Sam remains over warm waters and with little to no impacts from wind shear. However, on the other hand, some drier mid-level air in the surrounding environment may periodically enter the hurricane’s inner core. While some gradual weakening is forecast after Tuesday as southwesterly wind shear begins to increase, Sam should remain a major hurricane through the next five days.
PROJECTION — On the current forecast track, the center of the hurricane will make its closest point of approach to the Virgin Islands on Thursday morning when it passes approximately 400 miles northeast of St. Thomas. At that time, Sam is forecast to be a Category 3 hurricane with top winds of 125 miles per hour while moving to the northwest at 11-12 miles per hour.
ELSEWHERE IN THE TROPICS
A tropical wave is expected to move off the west coast of Africa on Monday. Environmental conditions are forecast to be conducive for gradual development thereafter, and a tropical depression could form by midweek while the system moves westward to west-northwestward at 10-15 miles per hour over the far eastern tropical Atlantic. There is a medium chance — 60 percent — of tropical weather system formation through five days.
A broad area of low pressure could form over the eastern or central tropical Atlantic early this week, to the west of the tropical wave that will be moving off the coast of Africa. Thereafter, environmental conditions could support some development of this disturbance while it moves westward at 5-10 miles per hour through the middle of the week. There is a low chance — 30 percent — of tropical weather system formation through five days.
Sunrise: 6:09 a.m.
Sunset: 6:12 p.m.
OBSERVATIONS AT THE 3D MANDAHL WEATHER STATION
Saturday’s high temperature: 88 degrees at 12:51 p.m.
Saturday’s low temperature: 78 degrees at 4:50 a.m.
Peak wind gust: 11 miles per hour
24-hour rainfall: 0.00 inches
Month rain: 4.03 inches
Year rain: 30.23 inches