There are no coastal watches or warnings in effect.

SURF: Swells generated by Sam are forecast to reach the Lesser Antilles early this week. These swells could cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 1100 AM AST (1500 UTC), the center of Hurricane Sam was located near latitude 13.9 North, longitude 50.2 West. Sam is moving toward the west northwest near 8 mph. This general motion is expected to continue today, followed by a turn toward the northwest on Monday. Then, a northwestward motion is forecast to continue through midweek. Maximum sustained winds are near 145 mph (230 km/h) with higher gusts. Sam is a category 4 hurricane on the Saffir Simpson Hurricane Wind Scale. Some fluctuations in intensity are expected during the next day or so. Thereafter, some slow weakening is forecast. Hurricane force winds extend outward up to 30 miles (45 km) from the center and tropical storm force winds extend outward up to 90 miles (150 km). The estimated minimum central pressure is 943 mb (27.85 inches).

The satellite presentation of Hurricane Sam has been quite steady over the past 6 hours. Sam continues to have a well-defined, 12 n mi wide eye on visible and infrared satellite imagery this morning, with cloud tops colder than -70C completely surrounding the center. The latest subjective satellite intensity estimates from TAFB and SAB were both T-6.5/127 kt, while the objective estimate from ADT is near 122 kt. Based on these data, there is no reason to change the 125-kt initial intensity at this time, especially given that a NOAA Hurricane Hunter aircraft is scheduled for a late afternoon/early evening mission into Sam today.

Sam is moving toward the west-northwest, or 290/7 kt. A deep-layer subtropical ridge to the north and northeast of Sam should generally steer the hurricane west-northwestward to northwestward for the next several days. By midweek, an amplifying upper-level trough will move off the east coast of the U.S. and dig southward over the western Atlantic, which will erode the western extent of the steering ridge. The deep-layer southerly flow ahead of the trough should cause Sam to begin recurving, with a somewhat faster north-northwestward motion forecast by day 5. The latest NHC track forecast was adjusted a little to the left, or southwest of the previous official forecast, mainly at days 4 and 5, but not quite as far southwest as the model consensus aids.

The hurricane will likely experience some fluctuations in intensity during the next few days. Guidance, however, indicates that the chance of an eyewall replacement cycle during the next 36 hours is below climatology. Sam will remain over warm sea-surface temperatures and in a low wind shear environment for the next 3 days, with less than 10 kt of shear diagnosed by the SHIPS guidance. It is possible that Sam's slow forward motion during the next 2 to 3 days could cause some upwelling of cooler water, but this will probably not result in significant weakening. The official NHC intensity forecast lies on the high end of the guidance for the first 36-48 h of the forecast period. Thereafter, the NHC forecast is closer to the middle of the guidance envelope. Some gradual weakening is forecast later in the period as southwesterly vertical wind shear begins to increase, but Sam is still forecast to remain a major hurricane through the 5-day period.

The radii were expanded slightly by 5-10 n mi in the western semicircle from the previous advisory based on a 1155 UTC ASCAT-A pass.<

Sam has found a way to strengthen some more today. The ring of intense convection surrounding the 15-n-mi-diameter eye has expanded in size over the past several hours, while cloud tops colder than -70C still completely surround the center. An earlier GMI microwave overpass revealed very strong eyewall convection tightly wrapped around the small eye, a feature oftentimes seen with intense hurricanes. The latest Dvorak intensity estimates from TAFB and SAB remain T6.5/127 kt. However, the UW-CIMSS ADT estimate has recently increased to T6.6/130 kt. Based on the expansion of the ring of convection and a blend of these Dvorak estimates, the initial intensity is raised to 130 kt for this advisory. Sam remains compact, with winds of tropical storm force extending only 70 n mi from the center. A NOAA Hurricane Hunter aircraft is en route to investigate Sam and will provide more detailed intensity data.

It would not take much further expansion of the convection and cooling of the cloud tops over the inner-most core of Sam for it to become a rare Category 5 hurricane on the Saffir-Simpson hurricane wind scale. Although plausible given the ideal environmental conditions over the next couple of days, this strengthening is not explicitly forecast to occur. The only factors within the next 2-3 days that could cause Sam to weaken would be an eyewall replacement cycle or the upwelling of cooler waters due to the hurricane's relatively slow forward motion. By 72 h, vertical wind shear is forecast to increase, which should cause gradual weakening. However, given the current strength of Sam, the new forecast calls for it to remain a major hurricane throughout the 5-day forecast period. The latest NHC intensity forecast was increased by 5 kt through 60 h due to the change in the initial intensity and remains on the high end of the guidance through that time. At 72 h and beyond, the intensity forecast is near the HFIP corrected consensus approach (HCCA) model.

Sam has been wobbling a little north-northwestward and has slowed down over the past few hours, but the 12-h-average motion is about 305/06 kt. A subtropical ridge centered to the northeast of the hurricane should steer it northwestward for the next 3-4 days. By late Thursday, Sam is expected to reach the western periphery of the ridge and turn north-northwestward and begin to increase its forward speed as the cyclone starts to get caught up in the southerly flow between the ridge and an approaching mid-latitude trough. The various track model guidance is in better agreement today compared to yesterday, especially in the day 3-5 time frame. The latest NHC track forecast is little changed from the previous one, and lies near the various consensus track model solutions.