At 11:00 am the center of Tropical Storm Bertha was estimated near latitude 14.0 north longitude 58.9 west, reports the BVI DDM. Bertha is moving toward the west-northwest near 21 mph and this general motion is expected to continue for the next couple of days. On the forecast track Bertha is expected to pass near or north of Barbados during the next several hours and move through the Central Lesser Antilles tonight and approach The Virgin Islands on Saturday.
Maximum sustained winds remain near 50 mph with higher gusts. No significant change in strength is forecast during the next 48 hours.
Tropical storm force winds extend outward up to 115 miles mainly to the north east of the centre.
The estimated minimum central pressure is 1008 mb.
HAZARDS AFFECTING LAND
Wind: Tropical storm conditions are possible in the warning area in the Virgin Islands on Saturday.
Rainfall: Bertha is expected to produce rainfall amounts of 1 to 3 inches with isolated amounts up to 6 inches across portions of the Leeward Islands and the Virgin Islands through Saturday night.
Jeff Masters of Weather Underground reports on Tropical Storm Bertha today: “With the atmosphere around Bertha quite dry, the storm will have to work hard to insulate itself from disruptive dry air incursions, and only slow intensification is likely through Saturday morning. I don’t see Bertha being stronger than a 55 mph tropical storm during this period. By Saturday afternoon, wind shear is forecast to fall to the moderate range, 10 – 15 knots, and this may allow Bertha to intensify as it moves over Puerto Rico.
“Passage over the high mountains of Puerto Rico may disrupt the storm some, counteracting the decrease in wind shear. If the system takes a more southwesterly track over the eastern Dominican Republic like the European model is suggesting, this would also disrupt Bertha. I don’t see Bertha being stronger than a 60 mph tropical storm as it affects Puerto RIco and the Dominican Republic. Two of our best intensity models, the GFDL and HWRF, predicted in their 06Z Friday runs that Bertha would have winds of about 40 mph as it passed over Puerto Rico on Saturday.”
The formation of Bertha on August 1 was right on schedule, according to climatology from 1966 – 2009: the Atlantic’s 2nd named storm has historically formed on August 1 during this period, Masters also reported.