FLORIDA
STORMS
Hurricane Sam
LOCATED
625 MI S OF CAPE RACE NEWFOUNDLAND
WINDS
100 MPH
PRESSURE
964 MB
MOVING
NE AT 16 MPH
From the National Hurricane Center at 1100 AM AST Sun Oct 03 2021
Sam moving northeastward over the open north Atlantic.
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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 AM AST (1500 UTC), the eye of Hurricane Sam was located near latitude 37.7 North, longitude 54.6 West. Sam is moving toward the northeast near 16 mph (26 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 north Atlantic around 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 on Monday. Hurricane force winds extend outward up to 45 miles (75 km) from the center and tropical storm force winds extend outward up to 240 miles (390 km). The estimated minimum central pressure is 964 mb (28.47 inches).

At 1100 AM AST (1500 UTC), the eye of Hurricane Sam was located near latitude 37.7 North, longitude 54.6 West. Sam is moving toward the northeast near 16 mph (26 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 north Atlantic around 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 on Monday. Hurricane force winds extend outward up to 45 miles (75 km) from the center and tropical storm force winds extend outward up to 240 miles (390 km). The estimated minimum central pressure is 964 mb (28.47 inches).

Sam's cloud pattern remains quite symmetric for a hurricane moving into the higher latitudes. The eye has become more apparent in both visible and infrared satellite imagery over the past few hours. A very timely 1155 UTC GMI microwave image also reveals a well-defined inner eye that was surrounded by an outer ring of convection at a much larger radius. A blend of the T- and CI-numbers from the lastest subjective Dvorak classifications yields an initial intensity of 85 kt, this is also supported by earlier UW/CIMSS SATCON estimates.

The vertical shear over Sam is expected to remain low for the next 6-12 hours and only gradual weakening is anticipated while the system moves over gradually decreasing SSTs. Later tonight, Sam is expected to move over much cooler waters north of the north wall of the Gulf Stream and into an area of increasing southwesterly shear, which should result in continued weakening. However, a strong mid-tropospheric trough approaching Sam from the west on Monday is expected to result in a fairly quick transition of Sam to a large and powerful extratropical low. The low is forecast to gradually weaken over the far north Atlantic during the middle to latter portions of the week as the baroclinic forcing decreases. The latest NHC intensity forecast is similar to the previous advisory and is a blend of the various intensity aids during the early portion of the period, but leans toward the global model guidance during the post-tropical phase.

Sam is moving northeastward or 050/14 kt. The cyclone should continue to move northeastward in the flow between a strong subtropical ridge over the eastern Atlantic and mid-latitude trough over Atlantic Canada. As this trough approaches Sam from the west, a much faster northeastward motion is expected by Monday and Monday night. Around midweek, the post-tropical cyclone is forecast to slow down as it rotates around a large cut-off low over the north Atlantic. After that time, the low is forecast to resume a northeastward motion before it slows once again to the southwest of Iceland. Given the future complex interactions of the post-tropical low with the cut-off low and trough over the north Atlantic, the track guidance is in surprisingly good agreement, and the NHC forecast is near a blend of the ECMWF and GFS global models.

Sam's cloud pattern remains quite symmetric for a hurricane moving into the higher latitudes. The eye has become more apparent in both visible and infrared satellite imagery over the past few hours. A very timely 1155 UTC GMI microwave image also reveals a well-defined inner eye that was surrounded by an outer ring of convection at a much larger radius. A blend of the T- and CI-numbers from the lastest subjective Dvorak classifications yields an initial intensity of 85 kt, this is also supported by earlier UW/CIMSS SATCON estimates.

The vertical shear over Sam is expected to remain low for the next 6-12 hours and only gradual weakening is anticipated while the system moves over gradually decreasing SSTs. Later tonight, Sam is expected to move over much cooler waters north of the north wall of the Gulf Stream and into an area of increasing southwesterly shear, which should result in continued weakening. However, a strong mid-tropospheric trough approaching Sam from the west on Monday is expected to result in a fairly quick transition of Sam to a large and powerful extratropical low. The low is forecast to gradually weaken over the far north Atlantic during the middle to latter portions of the week as the baroclinic forcing decreases. The latest NHC intensity forecast is similar to the previous advisory and is a blend of the various intensity aids during the early portion of the period, but leans toward the global model guidance during the post-tropical phase.

Sam is moving northeastward or 050/14 kt. The cyclone should continue to move northeastward in the flow between a strong subtropical ridge over the eastern Atlantic and mid-latitude trough over Atlantic Canada. As this trough approaches Sam from the west, a much faster northeastward motion is expected by Monday and Monday night. Around midweek, the post-tropical cyclone is forecast to slow down as it rotates around a large cut-off low over the north Atlantic. After that time, the low is forecast to resume a northeastward motion before it slows once again to the southwest of Iceland. Given the future complex interactions of the post-tropical low with the cut-off low and trough over the north Atlantic, the track guidance is in surprisingly good agreement, and the NHC forecast is near a blend of the ECMWF and GFS global models.

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