FLORIDA
STORMS
Hurricane Sam
LOCATED
460 MI SE OF CAPE RACE NEWFOUNDLAND
WINDS
100 MPH
PRESSURE
960 MB
MOVING
NE AT 32 MPH
From the National Hurricane Center at 1100 AM AST Mon Oct 04 2021
Sam moving quickly northeastward.
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 for the next day or so. 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 for the next day or so. 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 for the next day or so. 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 for the next day or so. 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 42.6 North, longitude 45.7 West. Sam is moving toward the northeast near 32 mph (52 km/h). A faster northeastward motion is expected through tonight. A slower east northeastward motion is forecast to begin on Tuesday and continue through midweek. Maximum sustained winds are near 100 mph (155 km/h) with higher gusts. Gradual weakening is forecast during the next few days, and Sam is expected to transition into a powerful post tropical cyclone over the north Atlantic tonight or early Tuesday. Hurricane force winds extend outward up to 60 miles (95 km) from the center and tropical storm force winds extend outward up to 275 miles (445 km). The estimated minimum central pressure is 960 mb (28.35 inches).

At 1100 AM AST (1500 UTC), the center of Hurricane Sam was located near latitude 42.6 North, longitude 45.7 West. Sam is moving toward the northeast near 32 mph (52 km/h). A faster northeastward motion is expected through tonight. A slower east northeastward motion is forecast to begin on Tuesday and continue through midweek. Maximum sustained winds are near 100 mph (155 km/h) with higher gusts. Gradual weakening is forecast during the next few days, and Sam is expected to transition into a powerful post tropical cyclone over the north Atlantic tonight or early Tuesday. Hurricane force winds extend outward up to 60 miles (95 km) from the center and tropical storm force winds extend outward up to 275 miles (445 km). The estimated minimum central pressure is 960 mb (28.35 inches).

Sam remains a formidable high-latitude hurricane this morning. An earlier 1102 UTC GMI microwave overpass continued to depict concentric eyewalls with a fairly well-defined inner-eye that was open over the southwestern quadrant. Although there has been a generally warming of the cloud tops in infrared satellite imagery, the eye remains apparent and the system is still fairly symmetric. A blend of the subjective Dvorak T- and CI-numbers from both SAB and TAFB yield an intensity of 85 kt, which is used as the initial intensity for this advisory.

Now that Sam has moved north of the north wall of the Gulf Stream it will be moving over progressively colder waters and into much higher vertical wind shear conditions by this evening, which should cause some gradual weakening. However, the interaction of the cyclone with a strong upper-level trough is likely to lead to the rapid transition of Sam into a powerful extratropical cyclone later this evening. The post-tropical cyclone is expected to maintain hurricane-force winds until late Tuesday. Gradual weakening should occur after that time as the baroclinic forcing decreases, and the system is forecast to spin down slowly over the north Atlantic later this week.

Sam continues to accelerate northeastward and is now moving at 045/28 kt. A faster northeastward motion is forecast through tonight as Sam moves within the strong southwesterly flow ahead of a mid-latitude trough. The post-tropical cyclone is forecast to slow down on Tuesday as it interacts with the trough/cut-off low. After that time, the system is forecast to turn east-northeastward, and then rotate cyclonically around the eastern flank of yet another cut-off low later in the week. The dynamical model guidance remains in generally good agreement on the overall track forecast scenario, albeit for some forward speed variations. The latest official forecast is similar to the previous advisory and lies near the TVCA multi-model consensus in deference to the aforementioned along-track differences.

Sam remains a formidable high-latitude hurricane this morning. An earlier 1102 UTC GMI microwave overpass continued to depict concentric eyewalls with a fairly well-defined inner-eye that was open over the southwestern quadrant. Although there has been a generally warming of the cloud tops in infrared satellite imagery, the eye remains apparent and the system is still fairly symmetric. A blend of the subjective Dvorak T- and CI-numbers from both SAB and TAFB yield an intensity of 85 kt, which is used as the initial intensity for this advisory.

Now that Sam has moved north of the north wall of the Gulf Stream it will be moving over progressively colder waters and into much higher vertical wind shear conditions by this evening, which should cause some gradual weakening. However, the interaction of the cyclone with a strong upper-level trough is likely to lead to the rapid transition of Sam into a powerful extratropical cyclone later this evening. The post-tropical cyclone is expected to maintain hurricane-force winds until late Tuesday. Gradual weakening should occur after that time as the baroclinic forcing decreases, and the system is forecast to spin down slowly over the north Atlantic later this week.

Sam continues to accelerate northeastward and is now moving at 045/28 kt. A faster northeastward motion is forecast through tonight as Sam moves within the strong southwesterly flow ahead of a mid-latitude trough. The post-tropical cyclone is forecast to slow down on Tuesday as it interacts with the trough/cut-off low. After that time, the system is forecast to turn east-northeastward, and then rotate cyclonically around the eastern flank of yet another cut-off low later in the week. The dynamical model guidance remains in generally good agreement on the overall track forecast scenario, albeit for some forward speed variations. The latest official forecast is similar to the previous advisory and lies near the TVCA multi-model consensus in deference to the aforementioned along-track differences.

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