FLORIDA
STORMS
Hurricane Sam
LOCATED
520 MI E OF CAPE RACE NEWFOUNDLAND
WINDS
90 MPH
PRESSURE
965 MB
MOVING
NE AT 36 MPH
From the National Hurricane Center at 900 PM GMT Mon Oct 04 2021
Sam racing northeastward over the north Atlantic.
TAP LINKS BELOW TO FOCUS
key messages
Alerts
hazards
summary
DISCUSSION

1. Swells generated by Sam will impact the northern Leeward Islands, the Greater Antilles, portions of the Bahamas, and southeastern Newfoundland through early Tuesday. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

1. Swells generated by Sam will impact the northern Leeward Islands, the Greater Antilles, portions of the Bahamas, and southeastern Newfoundland through early Tuesday. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

There are no coastal watches or warnings in effect.

There are no coastal watches or warnings in effect.

Key messages for Sam can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC, and on the web at hurricanes.gov/graphics_at3.shtml?key_messages.

SURF: Swells generated by Sam will impact the northern Leeward Islands, the Greater Antilles, portions of the Bahamas, and southeastern Newfoundland through early Tuesday. These swells could cause life threatening surf and rip current conditions. Please consult products from your local weather office.

Key messages for Sam can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC, and on the web at hurricanes.gov/graphics_at3.shtml?key_messages.

SURF: Swells generated by Sam will impact the northern Leeward Islands, the Greater Antilles, portions of the Bahamas, and southeastern Newfoundland through early Tuesday. These swells could cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 900 PM GMT (2100 UTC), the center of Hurricane Sam was located near latitude 45.1 North, longitude 42.5 West. Sam is moving toward the northeast near 36 mph (57 km/h). This general motion should continue tonight. A slower east northeastward motion is forecast to begin by late Tuesday, and a northeastward motion is expected Wednesday and Wednesday night. Maximum sustained winds are near 90 mph (150 km/h) with higher gusts. Although gradual weakening is forecast during the next few days, Sam is expected to transition into a powerful post tropical cyclone over the north Atlantic tonight. Hurricane force winds extend outward up to 80 miles (130 km) from the center and tropical storm force winds extend outward up to 275 miles (445 km). The estimated minimum central pressure is 965 mb (28.50 inches).

At 900 PM GMT (2100 UTC), the center of Hurricane Sam was located near latitude 45.1 North, longitude 42.5 West. Sam is moving toward the northeast near 36 mph (57 km/h). This general motion should continue tonight. A slower east northeastward motion is forecast to begin by late Tuesday, and a northeastward motion is expected Wednesday and Wednesday night. Maximum sustained winds are near 90 mph (150 km/h) with higher gusts. Although gradual weakening is forecast during the next few days, Sam is expected to transition into a powerful post tropical cyclone over the north Atlantic tonight. Hurricane force winds extend outward up to 80 miles (130 km) from the center and tropical storm force winds extend outward up to 275 miles (445 km). The estimated minimum central pressure is 965 mb (28.50 inches).

Sam's cloud pattern has finally begun to degrade as it moves over the cooler waters of the north Atlantic. The cloud tops have warmed and the eye is no longer discernible in infrared imagery, but banding features still remain well defined in all quadrants. Dvorak T- and CI-numbers from both SAB and TAFB have continued to decline and a blend of the latest subjective and objective estimates yields an initial intensity estimate of 80 kt for this advisory. Scatterometer data that arrived just after the release of the previous advisory showed that Sam's wind field has continued to expand and the latest radii estimates are based on those data.

Sam should gradually weaken this evening as it moves over progressively colder waters and into an area of strong southwesterly upper-level winds. However, an approaching mid-latitude trough should result in the system's quick transition into a powerful extratropical cyclone overnight. The post-tropical cyclone is forecast to maintain hurricane-force winds for until late Tuesday, but gradual weakening should occur after that time as the system occludes and baroclinic forcing decreases. It is not entirely clear as to whether Post-Tropical Sam will remain the dominant low (GFS solution) or if it will be absorbed by another extratropical low (ECMWF solution) later in the week. As a compromise, the new official forecast calls for absorbed by day 5 which is between the solutions from those typically reliable global models.

Sam is moving briskly northeastward or 035/31 kt. The cyclone is currently caught in strong southwesterly flow ahead of the aforementioned mid-latitude trough and a rapid northeastward motion is expected overnight. After that time, the post-tropical cyclone is forecast to slow down as it merges with the cut-off low. By late Tuesday, the post-tropical cyclone should turn east- northeastward before it rotates cyclonically around the eastern portion of another trough/cut off low over the north Atlantic. The latest NHC forecast is a blend of the GFS and ECMWF models and their respective ensemble means.

Sam's cloud pattern has finally begun to degrade as it moves over the cooler waters of the north Atlantic. The cloud tops have warmed and the eye is no longer discernible in infrared imagery, but banding features still remain well defined in all quadrants. Dvorak T- and CI-numbers from both SAB and TAFB have continued to decline and a blend of the latest subjective and objective estimates yields an initial intensity estimate of 80 kt for this advisory. Scatterometer data that arrived just after the release of the previous advisory showed that Sam's wind field has continued to expand and the latest radii estimates are based on those data.

Sam should gradually weaken this evening as it moves over progressively colder waters and into an area of strong southwesterly upper-level winds. However, an approaching mid-latitude trough should result in the system's quick transition into a powerful extratropical cyclone overnight. The post-tropical cyclone is forecast to maintain hurricane-force winds for until late Tuesday, but gradual weakening should occur after that time as the system occludes and baroclinic forcing decreases. It is not entirely clear as to whether Post-Tropical Sam will remain the dominant low (GFS solution) or if it will be absorbed by another extratropical low (ECMWF solution) later in the week. As a compromise, the new official forecast calls for absorbed by day 5 which is between the solutions from those typically reliable global models.

Sam is moving briskly northeastward or 035/31 kt. The cyclone is currently caught in strong southwesterly flow ahead of the aforementioned mid-latitude trough and a rapid northeastward motion is expected overnight. After that time, the post-tropical cyclone is forecast to slow down as it merges with the cut-off low. By late Tuesday, the post-tropical cyclone should turn east- northeastward before it rotates cyclonically around the eastern portion of another trough/cut off low over the north Atlantic. The latest NHC forecast is a blend of the GFS and ECMWF models and their respective ensemble means.

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