NHC Atlantic

Atlantic Tropical Weather Outlook

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 11:45:27 GMT

000
ABNT20 KNHC 051145
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sun Sep 5 2021

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Hurricane
Larry, located over the central tropical Atlantic about 900 miles
east of the northern Leeward Islands.

Disorganized showers and thunderstorms over portions of Central
America and the Yucatan Peninsula are associated with a surface
trough and an upper-level disturbance. Locally heavy rains are
likely to continue today over that area. The system is forecast to
move northwestward over the southwestern Gulf of Mexico later today,
then move slowly northward or northeastward over the western or
central Gulf of Mexico. Upper-level winds are only expected to be
marginally conducive for tropical cyclone formation, but some slow
development is possible while the system moves across the Gulf of
Mexico through the middle of the week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Pasch

Summary for Hurricane Larry (AT2/AL122021)

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 08:49:54 GMT

...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG MANY WESTERN ATLANTIC SHORES LATER THIS WEEK DUE TO LARGE SWELLS FROM LARRY... As of 5:00 AM AST Sun Sep 5 the center of Larry was located near 18.8, -49.0 with movement NW at 14 mph. The minimum central pressure was 958 mb with maximum sustained winds of about 120 mph.

Hurricane Larry Public Advisory Number 19

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 08:49:54 GMT

Issued at 500 AM AST Sun Sep 05 2021 000 WTNT32 KNHC 050849 TCPAT2 BULLETIN Hurricane Larry Advisory Number 19 NWS National Hurricane Center Miami FL AL122021 500 AM AST Sun Sep 05 2021 ...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG MANY WESTERN ATLANTIC SHORES LATER THIS WEEK DUE TO LARGE SWELLS FROM LARRY... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...18.8N 49.0W ABOUT 925 MI...1485 KM E OF THE NORTHERN LEEWARD ISLANDS ABOUT 1350 MI...2175 KM SE OF BERMUDA MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H PRESENT MOVEMENT...NW OR 305 DEGREES AT 14 MPH...22 KM/H MINIMUM CENTRAL PRESSURE...958 MB...28.29 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 500 AM AST (0900 UTC), the center of Hurricane Larry was located near latitude 18.8 North, longitude 49.0 West. Larry is moving toward the northwest near 14 mph (22 km/h). A northwestward motion with a slight decrease in forward speed is expected during the next few days. Maximum sustained winds are near 120 mph (195 km/h) with higher gusts. Larry is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Little change in strength is forecast during the next few days, although fluctuations in intensity will be possible. Larry is expected to remain a major hurricane through the middle of this 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). A drifting buoy near the center of Larry recently measured a pressure of 962.9 mb (28.43 inches). HAZARDS AFFECTING LAND ---------------------- SURF: Swells generated by Larry are expected to reach the Lesser Antilles today, and will spread westward to portions of the Greater Antilles, the Bahamas, and Bermuda on Monday and Tuesday. Significant swells will likely reach the east coast of the United States and Atlantic Canada by midweek. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 1100 AM AST. $$ Forecaster Reinhart ]]>

Hurricane Larry Forecast Advisory Number 20

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 14:43:58 GMT

Issued at 1500 UTC SUN SEP 05 2021 ZCZC MIATCMAT2 ALL TTAA00 KNHC DDHHMM HURRICANE LARRY FORECAST/ADVISORY NUMBER 20 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 1500 UTC SUN SEP 05 2021 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. HURRICANE CENTER LOCATED NEAR 19.5N 49.7W AT 05/1500Z POSITION ACCURATE WITHIN 15 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 310 DEGREES AT 11 KT ESTIMATED MINIMUM CENTRAL PRESSURE 955 MB EYE DIAMETER 40 NM MAX SUSTAINED WINDS 110 KT WITH GUSTS TO 135 KT. 64 KT....... 40NE 30SE 25SW 35NW. 50 KT....... 80NE 80SE 40SW 70NW. 34 KT.......140NE 150SE 70SW 130NW. 12 FT SEAS..300NE 240SE 240SW 300NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 19.5N 49.7W AT 05/1500Z AT 05/1200Z CENTER WAS LOCATED NEAR 19.1N 49.3W FORECAST VALID 06/0000Z 20.5N 51.1W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 50NE 40SE 30SW 40NW. 50 KT... 80NE 80SE 50SW 70NW. 34 KT...150NE 150SE 80SW 130NW. FORECAST VALID 06/1200Z 21.9N 52.7W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 50NE 40SE 35SW 50NW. 50 KT... 80NE 80SE 50SW 70NW. 34 KT...150NE 150SE 90SW 130NW. FORECAST VALID 07/0000Z 23.0N 54.0W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 60NE 50SE 40SW 50NW. 50 KT... 90NE 80SE 60SW 80NW. 34 KT...150NE 150SE 100SW 130NW. FORECAST VALID 07/1200Z 24.3N 55.4W MAX WIND 105 KT...GUSTS 130 KT. 64 KT... 60NE 50SE 40SW 50NW. 50 KT... 90NE 90SE 70SW 80NW. 34 KT...160NE 150SE 110SW 130NW. FORECAST VALID 08/0000Z 25.7N 56.7W MAX WIND 105 KT...GUSTS 130 KT. 50 KT... 90NE 90SE 70SW 80NW. 34 KT...160NE 160SE 120SW 130NW. FORECAST VALID 08/1200Z 27.3N 58.1W MAX WIND 105 KT...GUSTS 130 KT. 50 KT...100NE 90SE 70SW 90NW. 34 KT...170NE 160SE 120SW 140NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 09/1200Z 31.1N 61.1W MAX WIND 95 KT...GUSTS 115 KT. OUTLOOK VALID 10/1200Z 37.4N 60.6W MAX WIND 85 KT...GUSTS 105 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 19.5N 49.7W NEXT ADVISORY AT 05/2100Z $$ FORECASTER PASCH NNNN ]]>

Hurricane Larry Forecast Discussion Number 19

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 08:55:28 GMT

Issued at 500 AM AST Sun Sep 05 2021 000 WTNT42 KNHC 050855 TCDAT2 Hurricane Larry Discussion Number 19 NWS National Hurricane Center Miami FL AL122021 500 AM AST Sun Sep 05 2021 Larry remains a powerful hurricane this morning. The system has a warm, well-defined eye with a large diameter of around 40 n mi. Larry's central dense overcast has become more symmetric overnight, although the upper-level outflow is still somewhat restricted on the southwestern side of the hurricane. This is likely an indication of some vertical wind shear impinging on the cyclone. However, recent AMSR2 microwave data indicate that the vortex is still well-aligned vertically, with a pronounced eyewall that slopes outward with height. The initial intensity is held at 105 kt for this advisory based on consensus T5.5/102 kt Dvorak classifications from TAFB and SAB, and a recent UW-CIMSS ADT estimate of 105 kt. The initial motion of Larry is northwestward, or 305/12 kt. Larry is expected to continue moving northwestward for the next several days around the southwestern periphery of a mid-level ridge over the central Atlantic. By Thursday, the cyclone is forecast to accelerate northward ahead of a deep-layer trough that will move off the east coast of the United States later this week. The latest track guidance is very tightly clustered, and the official NHC forecast is similar to the previous one and lies near the multi-model consensus aids. Confidence remains high in Larry's track forecast given the excellent model agreement. The hurricane is still expected to make its closest approach to Bermuda at days 4 and 5, but it remains too early to pinpoint how close it will come to the island. Even if the center passes east of Bermuda as forecast, it could still be large enough to produce some impacts on the island. Over the next few days, some fluctuations in Larry's intensity are possible. The oceanic heat content along the forecast track is certainly sufficient for some intensification. However, vertical wind shear associated with an upper-level trough/low to the west of Larry may inhibit strengthening at times during the next couple of days, especially if the stronger shear values in the ECMWF-based SHIPS guidance are realized. Given Larry's large eye size, it does not appear as if the cyclone is poised to significantly intensify. The official NHC intensity forecast shows slight strengthening in the near-term, but then levels off the intensity through 48 h. The NHC forecast keeps Larry at major hurricane intensity through day 4, as the environment appears favorable enough between 48-96 h for Larry to maintain its organization, even as the cyclone gains latitude. Overall, this forecast lies on the high end of the intensity guidance, above the HFIP corrected consensus approach (HCCA) and the other multi-model consensus aids. Key Messages: 1. Large swells generated by Larry are expected to reach the Lesser Antilles today and will spread to portions of the Greater Antilles, the Bahamas, and Bermuda on Monday and Tuesday. Significant swells will likely reach the east coast of the United States and Atlantic Canada by 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 this 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 this week. While it is too soon to determine the magnitude of these hazards and potential impacts on Bermuda, interests there should closely monitor the latest forecast updates during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 18.8N 49.0W 105 KT 120 MPH 12H 05/1800Z 19.9N 50.4W 110 KT 125 MPH 24H 06/0600Z 21.2N 52.1W 110 KT 125 MPH 36H 06/1800Z 22.4N 53.6W 110 KT 125 MPH 48H 07/0600Z 23.6N 55.0W 110 KT 125 MPH 60H 07/1800Z 25.0N 56.4W 105 KT 120 MPH 72H 08/0600Z 26.5N 57.8W 105 KT 120 MPH 96H 09/0600Z 30.4N 60.8W 100 KT 115 MPH 120H 10/0600Z 36.5N 61.0W 90 KT 105 MPH $$ Forecaster Reinhart ]]>

Hurricane Larry Wind Speed Probabilities Number 19

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 08:49:54 GMT

Issued at 0900 UTC SUN SEP 05 2021 000 FONT12 KNHC 050849 PWSAT2 HURRICANE LARRY WIND SPEED PROBABILITIES NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 0900 UTC SUN SEP 05 2021 AT 0900Z THE CENTER OF HURRICANE LARRY WAS LOCATED NEAR LATITUDE 18.8 NORTH...LONGITUDE 49.0 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 105 KTS...120 MPH...195 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z SUN AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 06Z SUN 18Z SUN 06Z MON 18Z MON 06Z TUE 06Z WED 06Z THU PERIODS TO TO TO TO TO TO TO 18Z SUN 06Z MON 18Z MON 06Z TUE 06Z WED 06Z THU 06Z FRI FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT SABLE ISLAND 34 X X( X) X( X) X( X) X( X) X( X) 5( 5) BERMUDA 34 X X( X) X( X) X( X) X( X) 17(17) 17(34) BERMUDA 50 X X( X) X( X) X( X) X( X) 4( 4) 9(13) BERMUDA 64 X X( X) X( X) X( X) X( X) 2( 2) 4( 6) $$ FORECASTER REINHART ]]>

Hurricane Larry Graphics

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 08:57:24 GMT

5-Day Uncertainty Track last updated Sun, 05 Sep 2021 08:57:24 GMT

Wind Speed Probabilities last updated Sun, 05 Sep 2021 09:23:00 GMT