FLORIDA
STORMS
Hurricane Larry
LOCATED
970 MI E OF THE LEEWARD ISLANDS
WINDS
125 MPH
PRESSURE
958 MB
MOVING
WNW AT 14 MPH
From the National Hurricane Center at 500 PM AST Sat Sep 04 2021
Larry is a large and powerful hurricane.
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DISCUSSION

1. Large swells generated by Larry are expected to first reach the Lesser Antilles on Sunday and will spread to portions of the Greater Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant swells will likely reach the east coast of the United States and Atlantic Canada around midweek. 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 week.

2. Larry is forecast to approach Bermuda during the next several days, possibly as a major hurricane, bringing a risk of strong winds, heavy rainfall, and coastal flooding to the island by the middle of next week. While it is too soon to determine the magnitude of these hazards and potential impacts on Bermuda, interests there should monitor changes to the forecast during the next several days.

1. Large swells generated by Larry are expected to first reach the Lesser Antilles on Sunday and will spread to portions of the Greater Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant swells will likely reach the east coast of the United States and Atlantic Canada around midweek. 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 week.

2. Larry is forecast to approach Bermuda during the next several days, possibly as a major hurricane, bringing a risk of strong winds, heavy rainfall, and coastal flooding to the island by the middle of next week. While it is too soon to determine the magnitude of these hazards and potential impacts on Bermuda, interests there should monitor changes to the forecast during the next several days.

1. Large swells generated by Larry are expected to first reach the Lesser Antilles on Sunday and will spread to portions of the Greater Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant swells will likely reach the east coast of the United States and Atlantic Canada around midweek. 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 week.

2. Larry is forecast to approach Bermuda during the next several days, possibly as a major hurricane, bringing a risk of strong winds, heavy rainfall, and coastal flooding to the island by the middle of next week. While it is too soon to determine the magnitude of these hazards and potential impacts on Bermuda, interests there should monitor changes to the forecast during the next several days.

1. Large swells generated by Larry are expected to first reach the Lesser Antilles on Sunday and will spread to portions of the Greater Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant swells will likely reach the east coast of the United States and Atlantic Canada around midweek. 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 week.

2. Larry is forecast to approach Bermuda during the next several days, possibly as a major hurricane, bringing a risk of strong winds, heavy rainfall, and coastal flooding to the island by the middle of next week. While it is too soon to determine the magnitude of these hazards and potential impacts on Bermuda, interests there should monitor changes to the forecast during the next several days.

There are no coastal watches or warnings in effect.

There are no coastal watches or warnings in effect.

SURF: Swells generated by Larry are expected to reach the Lesser Antilles on Sunday, and will continue to spread westward to portions of the Greater Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant swells will likely reach the eastern United States coastline after Labor Day. These swells are likely to cause life threatening surf and rip current conditions. Please consult products from your local weather office.

SURF: Swells generated by Larry are expected to reach the Lesser Antilles on Sunday, and will continue to spread westward to portions of the Greater Antilles, the Bahamas, and Bermuda Monday and Tuesday. Significant swells will likely reach the eastern United States coastline after Labor Day. These swells are likely to 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 Larry was located near latitude 17.4 North, longitude 47.1 West. Larry is moving toward the west northwest near 14 mph (22 km/h). A somewhat slower west northwest to northwest motion is expected during the next few days. Maximum sustained winds are near 125 mph (205 km/h) with higher gusts. Larry is a category 3 hurricane on the Saffir Simpson Hurricane Wind Scale. Some additional strengthening is forecast over the next day or so, followed by some intensity fluctuations. However, Larry is expected to remain at major hurricane strength through the early part of next week. Hurricane force winds extend outward up to 45 miles (75 km) from the center and tropical storm force winds extend outward up to 160 miles (260 km). The estimated minimum central pressure is 958 mb (28.29 inches).

At 500 PM AST (2100 UTC), the center of Hurricane Larry was located near latitude 17.4 North, longitude 47.1 West. Larry is moving toward the west northwest near 14 mph (22 km/h). A somewhat slower west northwest to northwest motion is expected during the next few days. Maximum sustained winds are near 125 mph (205 km/h) with higher gusts. Larry is a category 3 hurricane on the Saffir Simpson Hurricane Wind Scale. Some additional strengthening is forecast over the next day or so, followed by some intensity fluctuations. However, Larry is expected to remain at major hurricane strength through the early part of next week. Hurricane force winds extend outward up to 45 miles (75 km) from the center and tropical storm force winds extend outward up to 160 miles (260 km). The estimated minimum central pressure is 958 mb (28.29 inches).

Larry remains a formidable hurricane this afternoon. Both visible and infrared satellite bands show the hurricane has a well-defined and warm eye (greater than 10 C) surrounded by a cold ring of eyewall convection (-60 to -70 C). An AMSR2 microwave pass received at 1630 UTC showed the well-defined eye of Larry, though the 89 GHz channel hinted that the eyewall was weaker on its eastern side. Taking a look at the high-density atmospheric motion vectors (AMVs), available thanks to a GOES-16 1-minute updating domain over Larry, there is some restriction of Larry's outflow to the southwest. Flight-level wind data from the NASA-DC8 aircraft conducting a research mission around Larry also showed some light southwesterly flow between 10-20 kt just a few degrees to the south and west of the storm center. These data suggest that the upper-level wind environment is not as pristine as earlier suggested by SHIPS guidance, with the southwesterly flow likely restricting Larry's outflow in that quadrant. The SAB/TAFB subjective Dvorak intensity estimates are unchanged from this morning, and the latest UW-CIMSS ADT and SATCON estimates have also plateaued in the 105-110 kt range. Therefore, Larry was maintained as a 110 kt hurricane this advisory.

Larry remains on a west-northwest track this afternoon, but a bit slower at 300/12 kt. There has been little change to the track philosophy over the next several days, as the guidance is in good agreement that Larry will maintain a continued west-northwest heading while gradually slowing down as it rounds the southern periphery of a large mid-level ridge. However, there has been a notable eastward shift in the track guidance in the short-term. The latest ECMWF run, which had previously been on the southwest side of the track guidance envelope, is now very similar or even a tad east of the latest GFS run. This shift has also resulted in an eastward adjustment in the consensus aids this afternoon. The latest NHC track forecast was adjusted a bit to the right early on, but not as far right as the HCCA and TVCA aids. After 72 hours, the track guidance actually converges very close to the previous track forecast, and few changes were needed after this time period. Based on this forecast, Larry will continue moving across the central Atlantic in the coming days, and be approaching Bermuda from the southeast in the day 4 to 5 forecast period.

The existence of some light upper-level southwesterly flow ahead of Larry today was bit of a surprise, since the SHIPS guidance from the last few days suggested the shear-vector would be out of the east and weak. Indeed, the latest ECMWF-SHIPS guidance now shows moderate southwesterly vertical wind shear beginning earlier, and peaking between 20-25 knots in 36 to 48 hours. While the GFS-SHIPS shear remains much lower, given what I'm seeing from the latest upper-level flow in front of Larry, the ECMWF seems closer to correct. For this reason, the latest NHC intensity guidance now shows a bit of weakening after 24 hours, when the shear magnitude is expected to peak as the hurricane interacts with a large tropical upper-tropospheric trough (TUTT) located to its northwest. However, Larry has a large and vertically-deep circulation, and ultimately it will win the battle against the more vertically shallow TUTT, which is forecast to cut off and move away from the hurricane's expansive upper-level outflow. By 60 hours, this change in the synoptic pattern should once again reduce the vertical wind shear over Larry, and it will have a chance to achieve a secondary peak between the 60-84 hour time-frame. However, eyewall replacement cycles could also occur at any time over the next 2-5 days, providing additional intensity fluctuations that make this a challenging intensity forecast. The latest NHC intensity forecast is lower than the previous one, but still remains higher than the latest HCCA consensus aid. Regardless of the details, Larry is expected to remain a large major hurricane over the next 3-4 days.

Larry has developed a large eye this evening that is 40-45 n mi in diameter, and the surrounding cloud tops have warmed somewhat. There have been no microwave passes over the hurricane for quite some time to assess its structure, but conventional satellite images suggest that Larry has taken on some annular characteristics (and the objective screening algorithm tagged it as marginally annular). Dvorak CI numbers and objective estimates are all between 100-102 kt, so Larry's initial intensity is lowered slightly to 105 kt.

Larry's motion remains west-northwestward (300 degrees) at 12 kt. The hurricane is expected to turn northwestward tonight or early Sunday around the southwestern periphery of a mid-level high centered over the central Atlantic, and then maintain that heading with some decrease in forward speed through day 4. By day 5, Larry should turn northward and accelerate between the high and an approaching deep-layer trough over the eastern United States. The updated NHC track forecast is largely unchanged from the previous advisory and is of high confidence since there is lower-than-normal spread among the track models. Larry is forecast to make its closest approach to Bermuda in 4 to 5 days while it recurves around the ridge, but despite the high-confidence forecast, there is still uncertainty on how close that approach will be since several GEFS and ECMWF ensemble members bring Larry's center very close to or over the island. Even with a track east of the island, Larry will be large enough to possibly cause some impacts on Bermuda.

Water vapor imagery shows some restriction to the outflow in the southwestern quadrant, which could be indicative of some shear. There continues to be some discrepancy among the models on how much shear the hurricane will contend with as it approaches a mid-/upper-level trough located north of the Leeward Islands. The GFS keeps the shear over Larry fairly low since it's farther from the trough, while the ECMWF increases the shear to moderate or strong levels during the next 48 hours. If Larry reaches the area of stronger shear, its intensity would obviously be adversely affected. In terms of structure, significant re-intensification is now less likely since Larry has such a large eye and an expanding wind field. On the positive side, the hurricane will be moving over gradually warmer waters for the next 3 days or so. Given these conflicting factors, the updated NHC intensity forecast allows for some slight restrengthening in the short term but then keeps Larry's intensity steady for the next 3 days. Many of the intensity models are even lower than what's shown in this forecast, so additional adjustments may be required in future advisories.

Larry remains a formidable hurricane this afternoon. Both visible and infrared satellite bands show the hurricane has a well-defined and warm eye (greater than 10 C) surrounded by a cold ring of eyewall convection (-60 to -70 C). An AMSR2 microwave pass received at 1630 UTC showed the well-defined eye of Larry, though the 89 GHz channel hinted that the eyewall was weaker on its eastern side. Taking a look at the high-density atmospheric motion vectors (AMVs), available thanks to a GOES-16 1-minute updating domain over Larry, there is some restriction of Larry's outflow to the southwest. Flight-level wind data from the NASA-DC8 aircraft conducting a research mission around Larry also showed some light southwesterly flow between 10-20 kt just a few degrees to the south and west of the storm center. These data suggest that the upper-level wind environment is not as pristine as earlier suggested by SHIPS guidance, with the southwesterly flow likely restricting Larry's outflow in that quadrant. The SAB/TAFB subjective Dvorak intensity estimates are unchanged from this morning, and the latest UW-CIMSS ADT and SATCON estimates have also plateaued in the 105-110 kt range. Therefore, Larry was maintained as a 110 kt hurricane this advisory.

Larry remains on a west-northwest track this afternoon, but a bit slower at 300/12 kt. There has been little change to the track philosophy over the next several days, as the guidance is in good agreement that Larry will maintain a continued west-northwest heading while gradually slowing down as it rounds the southern periphery of a large mid-level ridge. However, there has been a notable eastward shift in the track guidance in the short-term. The latest ECMWF run, which had previously been on the southwest side of the track guidance envelope, is now very similar or even a tad east of the latest GFS run. This shift has also resulted in an eastward adjustment in the consensus aids this afternoon. The latest NHC track forecast was adjusted a bit to the right early on, but not as far right as the HCCA and TVCA aids. After 72 hours, the track guidance actually converges very close to the previous track forecast, and few changes were needed after this time period. Based on this forecast, Larry will continue moving across the central Atlantic in the coming days, and be approaching Bermuda from the southeast in the day 4 to 5 forecast period.

The existence of some light upper-level southwesterly flow ahead of Larry today was bit of a surprise, since the SHIPS guidance from the last few days suggested the shear-vector would be out of the east and weak. Indeed, the latest ECMWF-SHIPS guidance now shows moderate southwesterly vertical wind shear beginning earlier, and peaking between 20-25 knots in 36 to 48 hours. While the GFS-SHIPS shear remains much lower, given what I'm seeing from the latest upper-level flow in front of Larry, the ECMWF seems closer to correct. For this reason, the latest NHC intensity guidance now shows a bit of weakening after 24 hours, when the shear magnitude is expected to peak as the hurricane interacts with a large tropical upper-tropospheric trough (TUTT) located to its northwest. However, Larry has a large and vertically-deep circulation, and ultimately it will win the battle against the more vertically shallow TUTT, which is forecast to cut off and move away from the hurricane's expansive upper-level outflow. By 60 hours, this change in the synoptic pattern should once again reduce the vertical wind shear over Larry, and it will have a chance to achieve a secondary peak between the 60-84 hour time-frame. However, eyewall replacement cycles could also occur at any time over the next 2-5 days, providing additional intensity fluctuations that make this a challenging intensity forecast. The latest NHC intensity forecast is lower than the previous one, but still remains higher than the latest HCCA consensus aid. Regardless of the details, Larry is expected to remain a large major hurricane over the next 3-4 days.

Larry has developed a large eye this evening that is 40-45 n mi in diameter, and the surrounding cloud tops have warmed somewhat. There have been no microwave passes over the hurricane for quite some time to assess its structure, but conventional satellite images suggest that Larry has taken on some annular characteristics (and the objective screening algorithm tagged it as marginally annular). Dvorak CI numbers and objective estimates are all between 100-102 kt, so Larry's initial intensity is lowered slightly to 105 kt.

Larry's motion remains west-northwestward (300 degrees) at 12 kt. The hurricane is expected to turn northwestward tonight or early Sunday around the southwestern periphery of a mid-level high centered over the central Atlantic, and then maintain that heading with some decrease in forward speed through day 4. By day 5, Larry should turn northward and accelerate between the high and an approaching deep-layer trough over the eastern United States. The updated NHC track forecast is largely unchanged from the previous advisory and is of high confidence since there is lower-than-normal spread among the track models. Larry is forecast to make its closest approach to Bermuda in 4 to 5 days while it recurves around the ridge, but despite the high-confidence forecast, there is still uncertainty on how close that approach will be since several GEFS and ECMWF ensemble members bring Larry's center very close to or over the island. Even with a track east of the island, Larry will be large enough to possibly cause some impacts on Bermuda.

Water vapor imagery shows some restriction to the outflow in the southwestern quadrant, which could be indicative of some shear. There continues to be some discrepancy among the models on how much shear the hurricane will contend with as it approaches a mid-/upper-level trough located north of the Leeward Islands. The GFS keeps the shear over Larry fairly low since it's farther from the trough, while the ECMWF increases the shear to moderate or strong levels during the next 48 hours. If Larry reaches the area of stronger shear, its intensity would obviously be adversely affected. In terms of structure, significant re-intensification is now less likely since Larry has such a large eye and an expanding wind field. On the positive side, the hurricane will be moving over gradually warmer waters for the next 3 days or so. Given these conflicting factors, the updated NHC intensity forecast allows for some slight restrengthening in the short term but then keeps Larry's intensity steady for the next 3 days. Many of the intensity models are even lower than what's shown in this forecast, so additional adjustments may be required in future advisories.

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