Tropical Weather Outlook
NWS National Hurricane Center Miami FL 800 PM EDT Thu Oct 4 2018 For the North Atlantic…Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Tropical Storm Leslie, located over the central Atlantic Ocean.
1. Surface observations and satellite data indicate that an area of low pressure is located near Cabo Gracias a Dios on the eastern border of Honduras and Nicaragua. This system is accompanied by an extensive area of disturbed weather extending from Central America eastward through Hispaniola. Upper-level winds are not currently favorable for tropical cyclone formation, but environmental conditions are forecast to become less hostile and a tropical depression could form by late this weekend or early next week in the northwestern Caribbean Sea or the southern Gulf of Mexico as the system moves slowly northwestward. Regardless of tropical cyclone formation, this disturbance will continue to bring torrential rains primarily to portions of Central America and the Yucatan peninsula during the next few days.
* Formation chance through 48 hours…low…near 10 percent.
* Formation chance through 5 days…medium…50 percent.
CARIBBEAN SEA… A large cyclonic gyre, defined by a broad area of low pressure, covers a portion of Central America and the western Caribbean Sea. Within this gyre, a surface trough is analyzed from 20N80W to a 1007 mb low near 15N83W to 11N84W. Satellite imagery shows scattered moderate to isolated strong convection across the central Caribbean between 69W-80W. Some slow development of this system is possible this weekend or early next week as the system drifts northwestward across the northwestern Caribbean and the southern Gulf of Mexico. A mid to upper level trough extending over the Bahamas and Greater Antilles will help advect moisture northwestward over the next several days. As a result, heavy rainfall is likely to spread over portions of Hispaniola, Jamaica, Cuba, the Yucatan Peninsula and Central America Friday through early next week.
ECMWF MODEL
GFS MODEL
CMC- CANADIAN MODEL
TROPICAL STORM LESLIE
BULLETIN 11:00pm advisory
Tropical Storm Leslie Advisory Number 35 NWS National Hurricane Center Miami FL AL132018 1100 PM AST Thu Oct 04 2018 …LESLIE REMAINS A LARGE CYCLONE… SUMMARY OF 1100 PM AST…0300 UTC…INFORMATION LOCATION…34.9N 57.6W ABOUT 450 MI…725 KM ENE OF BERMUDA MAXIMUM SUSTAINED WINDS…65 MPH…100 KM/H PRESENT MOVEMENT…N OR 350 DEGREES AT 12 MPH…19 KM/H MINIMUM CENTRAL PRESSURE…984 MB…29.06 INCHES WATCHES AND WARNINGS —————There are no coastal watches or warnings in effect.
DISCUSSION AND OUTLOOK —At 1100 PM AST (0300 UTC), the center of Tropical Storm Leslie was located near latitude 34.9 North, longitude 57.6 West. Leslie is moving toward the north near 12 mph (19 km/h), and this motion is expected to continue through Friday with a decrease in forward speed. Leslie should turn eastward or east-southeastward over the weekend. Maximum sustained winds are near 65 mph (100 km/h) with higher gusts. Little change in strength is forecast during the next 2 to 3 days. Leslie is a large cyclone and the tropical-storm-force winds extend outward up to 290 miles (465 km) from the center. The estimated minimum central pressure is 984 mb (29.06 inches).
HAZARDS AFFECTING LAND —SURF: Large swells generated by Leslie will continue to affect portions of the southeastern coast of the United States, Bermuda, and the Bahamas during the next few days. Swells are expected to increase near the coasts of New England and Atlantic Canada by the end of the week. Please consult products from your local weather office as these conditions could cause life-threatening surf and rip currents.
Tropical Storm Leslie Discussion Number 35
NWS National Hurricane Center Miami FL AL132018 1100 PM AST Thu Oct 04 2018 Leslie lacks an inner core and now consists of a vigorous large circulation with small outer bands of shallow to moderate convection. Satellite intensity estimates have continued to yield a lower intensity, and the winds have been reduced to 55 kt in this advisory based on a recent ASCAT pass. The shear does not appear to be a problem for Leslie, and the cyclone is forecast to be moving over SSTs which appear to not be cool enough to result in significant weakening. In fact, the average of the intensity guidance suggests that Leslie basically will be a 50-kt cyclone through the forecast period and so does the NHC forecast. Leslie is moving northward or 350 degrees at 10 kt steered by the southerly flow on the western edge of the subtropical ridge. In about 24 to 36 hours, the storm will encounter the mid-latitude westerlies, and this flow pattern will force Leslie to make a sharp turn to the east and even to the east-southeast with no change in forward speed.
Track guidance is in extremely good agreement with this solution for the next 3 to 4 days. After that time, the models vary significantly in speed, but since the cyclone will be embedded in the westerlies, the NHC forecast maintains the eastward progression of Leslie as indicated in the previous forecast. Large swells generated by Leslie are expected to continue during the next few days across the southeastern coast of the United States, Bermuda, the Bahamas, and the Greater and Lesser Antilles. These swells will also begin to increase near the coasts of New England and Atlantic Canada on Friday. Please consult products from your local weather office as these conditions could cause life- threatening surf and rip currents.
