FLORIDA
STORMS
Hurricane Sam
LOCATED
700 MI E OF THE NORTHERN LEEWARD ISLANDS
WINDS
120 MPH
PRESSURE
957 MB
MOVING
NW AT 9 MPH
From the National Hurricane Center at 500 PM AST Mon Sep 27 2021
Sam beginning to regroup after weakening.
TAP LINKS BELOW TO FOCUS
key messages
Alerts
hazards
summary
DISCUSSION

1. Large swells generated by Sam are affecting the Leeward Islands and will spread to portions of the Virgin Islands, Puerto Rico, Hispaniola, the Bahamas, and Bermuda by Thursday or Friday. Significant swells will likely reach the east coast of the United States and Atlantic Canada by the weekend. These swells will likely cause life-threatening surf and rip current conditions, and beachgoers and other interests along these coasts are urged to follow the advice of lifeguards and local officials through the upcoming weekend.

1. Large swells generated by Sam are affecting the Leeward Islands and will spread to portions of the Virgin Islands, Puerto Rico, Hispaniola, the Bahamas, and Bermuda by Thursday or Friday. Significant swells will likely reach the east coast of the United States and Atlantic Canada by the weekend. These swells will likely cause life-threatening surf and rip current conditions, and beachgoers and other interests along these coasts are urged to follow the advice of lifeguards and local officials through the upcoming weekend.

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.

SURF: Swells generated by Sam will impact the Lesser Antilles for the next several days. Swells are expected to reach Bermuda and the Bahamas mid to late week, and then spread to the United States east coast late this week. 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.

SURF: Swells generated by Sam will impact the Lesser Antilles for the next several days. Swells are expected to reach Bermuda and the Bahamas mid to late week, and then spread to the United States east coast late this week. These swells could cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 500 PM AST (2100 UTC), the center of Hurricane Sam was located near latitude 16.3 North, longitude 52.7 West. Sam is moving toward the northwest near 9 mph (15 km/h), and this motion is expected to continue for the next few days, with an increase in forward speed beginning on Thursday. A turn to the north is expected by Friday. On the forecast track, Sam will pass well to the northeast of the northern Leeward Islands Wednesday and Thursday. An Air Force Reserve Hurricane Hunter aircraft indicates that the maximum sustained winds are near 120 mph (195 km/h) with higher gusts. Sam is a category 3 hurricane on the Saffir Simpson Hurricane Wind Scale. Some strengthening is expected through tonight. Thereafter, fluctuations in intensity are possible through Thursday. Hurricane force winds extend outward up to 30 miles (45 km) from the center and tropical storm force winds extend outward up to 105 miles (165 km). The minimum central pressure measured by the aircraft is 957 mb (28.26 inches).

At 500 PM AST (2100 UTC), the center of Hurricane Sam was located near latitude 16.3 North, longitude 52.7 West. Sam is moving toward the northwest near 9 mph (15 km/h), and this motion is expected to continue for the next few days, with an increase in forward speed beginning on Thursday. A turn to the north is expected by Friday. On the forecast track, Sam will pass well to the northeast of the northern Leeward Islands Wednesday and Thursday. An Air Force Reserve Hurricane Hunter aircraft indicates that the maximum sustained winds are near 120 mph (195 km/h) with higher gusts. Sam is a category 3 hurricane on the Saffir Simpson Hurricane Wind Scale. Some strengthening is expected through tonight. Thereafter, fluctuations in intensity are possible through Thursday. Hurricane force winds extend outward up to 30 miles (45 km) from the center and tropical storm force winds extend outward up to 105 miles (165 km). The minimum central pressure measured by the aircraft is 957 mb (28.26 inches).

Sam's weakening trend ended earlier today, with the intensity likely bottoming out between the issuance of the previous advisory and now. Over the past few hours, microwave data and satellite imagery indicate that the inner core and eyewall of the hurricane are making a comeback. There is now a clear eye in visible imagery, convective cloud tops colder than -65 degrees C wrap completely around the center, and the convective mass is becoming more circular once again. An Air Force Reserve Hurricane Hunter aircraft currently investigating Sam indicates the central pressure has dropped to 957 mb, with peak 700-mb flight-level winds of 106 kt, SFMR values of 100 kt, and dropsonde surface winds of 102 kt. Given possible minor undersampling and the recent dropping of the hurricane's pressure, the initial advisory intensity is set at 105 kt.

Sam continues to move northwest, or 315/8 kt. The hurricane is expected to continue this northwestward motion around a subtropical ridge over the next few days. By late Thursday or early Friday a turn toward the north is anticipated as Sam rounds the western periphery of the ridge. The cyclone should begin to gradually accelerate during that time in the increasing flow ahead of a mid- to upper-level trough emerging off the U.S. east coast later this week. Model guidance remains in very good agreement on this scenario and the latest NHC forecast track is little changed from the previous one, and lies near tightly clustered consensus track guidance.

The southwesterly winds that brought in some dry air and disrupted Sam's impressive satellite appearance last night appear to have abated. As long as environmental winds surrounding the hurricane remain light, then the dry air surrounding the cyclone should not have as much of an impact on the hurricane's strength over the next few days. Based on the improving inner-core structure appearance of Sam, re-strengthening is forecast over the next 12 h. Thereafter, mainly minor fluctuations in intensity are indicated through 72 h. Beyond that time, increasing vertical wind shear and decreasing sea-surface temperatures should cause Sam to weaken. The latest NHC intensity forecast was nudged slightly upward through 36 h and is on the high end of the guidance. Thereafter, no changes were made, and that portion of the forecast is close to the various multimodel consensus solutions.

Sam's weakening trend ended earlier today, with the intensity likely bottoming out between the issuance of the previous advisory and now. Over the past few hours, microwave data and satellite imagery indicate that the inner core and eyewall of the hurricane are making a comeback. There is now a clear eye in visible imagery, convective cloud tops colder than -65 degrees C wrap completely around the center, and the convective mass is becoming more circular once again. An Air Force Reserve Hurricane Hunter aircraft currently investigating Sam indicates the central pressure has dropped to 957 mb, with peak 700-mb flight-level winds of 106 kt, SFMR values of 100 kt, and dropsonde surface winds of 102 kt. Given possible minor undersampling and the recent dropping of the hurricane's pressure, the initial advisory intensity is set at 105 kt.

Sam continues to move northwest, or 315/8 kt. The hurricane is expected to continue this northwestward motion around a subtropical ridge over the next few days. By late Thursday or early Friday a turn toward the north is anticipated as Sam rounds the western periphery of the ridge. The cyclone should begin to gradually accelerate during that time in the increasing flow ahead of a mid- to upper-level trough emerging off the U.S. east coast later this week. Model guidance remains in very good agreement on this scenario and the latest NHC forecast track is little changed from the previous one, and lies near tightly clustered consensus track guidance.

The southwesterly winds that brought in some dry air and disrupted Sam's impressive satellite appearance last night appear to have abated. As long as environmental winds surrounding the hurricane remain light, then the dry air surrounding the cyclone should not have as much of an impact on the hurricane's strength over the next few days. Based on the improving inner-core structure appearance of Sam, re-strengthening is forecast over the next 12 h. Thereafter, mainly minor fluctuations in intensity are indicated through 72 h. Beyond that time, increasing vertical wind shear and decreasing sea-surface temperatures should cause Sam to weaken. The latest NHC intensity forecast was nudged slightly upward through 36 h and is on the high end of the guidance. Thereafter, no changes were made, and that portion of the forecast is close to the various multimodel consensus solutions.

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