FLORIDA
STORMS
Hurricane Sam
LOCATED
520 MI S OF CAPE RACE NEWFOUNDLAND
WINDS
105 MPH
PRESSURE
957 MB
MOVING
NE AT 20 MPH
From the National Hurricane Center at 1100 PM AST Sun Oct 03 2021
Sam slightly re-strengthens over the Gulf stream.
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key messages
Alerts
hazards
summary
DISCUSSION

1. Swells generated by Sam will impact the northern Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, the eastern United States and Atlantic Canada for the next couple of days. 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, the Bahamas, Bermuda, the eastern United States and Atlantic Canada for the next couple of days. 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, the Bahamas, the eastern United States and Atlantic Canada for the next couple of days. 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, the Bahamas, the eastern United States and Atlantic Canada for the next couple of days. These swells could cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 1100 PM AST (0300 UTC), the eye of Hurricane Sam was located near latitude 39.3 North, longitude 51.2 West. Sam is moving toward the northeast near 20 mph (31 km/h). A northeastward motion at a faster forward speed is expected over the next couple of days. The cyclone is forecast to slow down over the far north Atlantic southwest of Iceland around midweek. Satellite images indicate that maximum sustained winds have increased to near 105 mph (165 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 by early Tuesday. Hurricane force winds extend outward up to 70 miles (110 km) from the center and tropical storm force winds extend outward up to 240 miles (390 km). The estimated minimum central pressure is 957 mb (28.26 inches).

At 1100 PM AST (0300 UTC), the eye of Hurricane Sam was located near latitude 39.3 North, longitude 51.2 West. Sam is moving toward the northeast near 20 mph (31 km/h). A northeastward motion at a faster forward speed is expected over the next couple of days. The cyclone is forecast to slow down over the far north Atlantic southwest of Iceland around midweek. Satellite images indicate that maximum sustained winds have increased to near 105 mph (165 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 by early Tuesday. Hurricane force winds extend outward up to 70 miles (110 km) from the center and tropical storm force winds extend outward up to 240 miles (390 km). The estimated minimum central pressure is 957 mb (28.26 inches).

Sam still had a surprise up its sleeve tonight, with its eye becoming warmer on satellite images along with a stronger eyewall. Microwave data from earlier today indicated that Sam has been undergoing a concentric eyewall cycle, and it appears that the inner eyewall has become better defined. Regardless, it is not every day you see a hurricane with that clear of an eye near 40N, and the intensity estimates the evening range from 90-100 kt. Given the concentric eyewalls, the initial wind speed is conservatively raised to 90 kt, but it could be higher.

High-resolution NOAA OISST data indicate that Sam is moving near a warm eddy along the north wall of the Gulf Stream. This favorable factor, in addition to low shear, should keep Sam's weakening to a minimum in the near term. Later on, although the shear increases rapidly and SSTs fall quickly, Sam is expected to transition into a powerful extratropical cyclone late Monday or early Tuesday due to a mid-latitude trough interaction well east of Newfoundland. This should cause extratropical Sam to maintain hurricane-force winds until early Wednesday. A slow weakening is expected thereafter as it slowly spins down as an occluded low. No significant changes were made to the previous forecast.

Sam is moving faster, now 050/17 kt. A northeastward motion and continued acceleration is forecast through Monday as the cyclone gets caught in southwesterly flow ahead of the mid-latitude trough. The tropical cyclone is expected to be the main surface low center as it merges with the trough in a couple days, hooking briefly to the left. Thereafter, the system should resume a northeastward motion and gradually turn northward and even westward at long range as it moves around another trough. Model guidance is close to the previous cycle, even with the loopy track, and the new NHC forecast is basically just an update of the last advisory.

Sam still had a surprise up its sleeve tonight, with its eye becoming warmer on satellite images along with a stronger eyewall. Microwave data from earlier today indicated that Sam has been undergoing a concentric eyewall cycle, and it appears that the inner eyewall has become better defined. Regardless, it is not every day you see a hurricane with that clear of an eye near 40N, and the intensity estimates the evening range from 90-100 kt. Given the concentric eyewalls, the initial wind speed is conservatively raised to 90 kt, but it could be higher.

High-resolution NOAA OISST data indicate that Sam is moving near a warm eddy along the north wall of the Gulf Stream. This favorable factor, in addition to low shear, should keep Sam's weakening to a minimum in the near term. Later on, although the shear increases rapidly and SSTs fall quickly, Sam is expected to transition into a powerful extratropical cyclone late Monday or early Tuesday due to a mid-latitude trough interaction well east of Newfoundland. This should cause extratropical Sam to maintain hurricane-force winds until early Wednesday. A slow weakening is expected thereafter as it slowly spins down as an occluded low. No significant changes were made to the previous forecast.

Sam is moving faster, now 050/17 kt. A northeastward motion and continued acceleration is forecast through Monday as the cyclone gets caught in southwesterly flow ahead of the mid-latitude trough. The tropical cyclone is expected to be the main surface low center as it merges with the trough in a couple days, hooking briefly to the left. Thereafter, the system should resume a northeastward motion and gradually turn northward and even westward at long range as it moves around another trough. Model guidance is close to the previous cycle, even with the loopy track, and the new NHC forecast is basically just an update of the last advisory.

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