NHC Atlantic

Atlantic Tropical Weather Outlook

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 11:39:32 GMT

000
ABNT20 KNHC 061139
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Mon Sep 6 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 Atlantic about 700 miles
east-northeast of the northern Leeward Islands.

Disorganized showers and thunderstorms over the northern portion of
the Yucatan Peninsula and south-central Gulf of Mexico are
associated with a surface trough and an upper-level disturbance.
The system is forecast to move slowly northward or northeastward
over the central and then northeastern Gulf of Mexico, likely
reaching the northern Gulf coast in a few days. Although upper-level
winds are currently unfavorable for development to occur, they are
expected to become marginally conducive for tropical cyclone
formation in a couple of days. The disturbance is then expected to
cross the southeastern United States beginning midweek, and some
development will be possible once it emerges over the Atlantic
waters late this week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Latto

Summary for Hurricane Larry (AT2/AL122021)

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 08:47:26 GMT

...LARGE LARRY STILL A MAJOR HURRICANE... ...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG WESTERN ATLANTIC SHORES LATER THIS WEEK... As of 5:00 AM AST Mon Sep 6 the center of Larry was located near 21.5, -52.4 with movement NW at 12 mph. The minimum central pressure was 956 mb with maximum sustained winds of about 120 mph.

Hurricane Larry Public Advisory Number 23

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 08:47:26 GMT

Issued at 500 AM AST Mon Sep 06 2021 000 WTNT32 KNHC 060847 TCPAT2 BULLETIN Hurricane Larry Advisory Number 23 NWS National Hurricane Center Miami FL AL122021 500 AM AST Mon Sep 06 2021 ...LARGE LARRY STILL A MAJOR HURRICANE... ...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG WESTERN ATLANTIC SHORES LATER THIS WEEK... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...21.5N 52.4W ABOUT 730 MI...1175 KM ENE OF THE NORTHERN LEEWARD ISLANDS ABOUT 1065 MI...1715 KM SE OF BERMUDA MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H PRESENT MOVEMENT...NW OR 305 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...956 MB...28.23 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 21.5 North, longitude 52.4 West. Larry is moving toward the northwest near 12 mph (19 km/h), and this general motion with a slight decrease in forward speed is expected over the next couple of days. A slightly faster northwestward motion is forecast by early Thursday. 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. Some fluctuations in intensity are possible during the next couple of days. Thereafter, some gradual weakening is forecast. Larry is a large hurricane. Hurricane-force winds extend outward up to 70 miles (110 km) from the center, and tropical-storm-force winds extend outward up to 175 miles (280 km). The estimated minimum central pressure is 956 mb (28.23 inches). HAZARDS AFFECTING LAND ---------------------- SURF: Swells generated by Larry are affecting the Lesser Antilles and are expected to spread westward to portions of the Greater Antilles, the Bahamas, and Bermuda today through Tuesday. Significant swells should reach the east coast of the United States and Atlantic Canada by midweek and continue affecting these shores through the end of the week. 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 23

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 08:46:25 GMT

Issued at 0900 UTC MON SEP 06 2021 000 WTNT22 KNHC 060846 TCMAT2 HURRICANE LARRY FORECAST/ADVISORY NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 0900 UTC MON SEP 06 2021 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. HURRICANE CENTER LOCATED NEAR 21.5N 52.4W AT 06/0900Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 305 DEGREES AT 10 KT ESTIMATED MINIMUM CENTRAL PRESSURE 956 MB EYE DIAMETER 55 NM MAX SUSTAINED WINDS 105 KT WITH GUSTS TO 130 KT. 64 KT....... 60NE 50SE 40SW 50NW. 50 KT....... 90NE 80SE 60SW 80NW. 34 KT.......150NE 150SE 100SW 140NW. 12 FT SEAS..300NE 240SE 270SW 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 21.5N 52.4W AT 06/0900Z AT 06/0600Z CENTER WAS LOCATED NEAR 21.3N 52.0W FORECAST VALID 06/1800Z 22.6N 53.6W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 60NE 50SE 40SW 55NW. 50 KT... 90NE 80SE 60SW 80NW. 34 KT...150NE 150SE 100SW 140NW. FORECAST VALID 07/0600Z 23.9N 54.9W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 65NE 55SE 40SW 60NW. 50 KT... 90NE 90SE 70SW 80NW. 34 KT...160NE 150SE 110SW 140NW. FORECAST VALID 07/1800Z 25.3N 56.2W MAX WIND 105 KT...GUSTS 130 KT. 64 KT... 70NE 60SE 40SW 55NW. 50 KT...100NE 90SE 70SW 80NW. 34 KT...160NE 160SE 120SW 140NW. FORECAST VALID 08/0600Z 26.8N 57.5W MAX WIND 100 KT...GUSTS 120 KT. 64 KT... 70NE 60SE 40SW 50NW. 50 KT...100NE 100SE 80SW 90NW. 34 KT...170NE 160SE 120SW 140NW. FORECAST VALID 08/1800Z 28.5N 59.0W MAX WIND 100 KT...GUSTS 120 KT. 50 KT...110NE 100SE 80SW 90NW. 34 KT...170NE 170SE 130SW 140NW. FORECAST VALID 09/0600Z 30.6N 60.6W MAX WIND 95 KT...GUSTS 115 KT. 50 KT...110NE 110SE 80SW 90NW. 34 KT...180NE 180SE 130SW 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 10/0600Z 36.7N 61.0W MAX WIND 90 KT...GUSTS 110 KT. OUTLOOK VALID 11/0600Z 45.5N 52.0W MAX WIND 75 KT...GUSTS 90 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.5N 52.4W NEXT ADVISORY AT 06/1500Z $$ FORECASTER REINHART ]]>

Hurricane Larry Forecast Discussion Number 23

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 08:52:55 GMT

Issued at 500 AM AST Mon Sep 06 2021 000 WTNT42 KNHC 060852 TCDAT2 Hurricane Larry Discussion Number 23 NWS National Hurricane Center Miami FL AL122021 500 AM AST Mon Sep 06 2021 Recent microwave data indicate that Larry has likely completed an eyewall replacement cycle (ERC). The 0530 UTC AMSR2 imagery reveals that the hurricane now has a large, single eyewall structure with an eye diameter greater than 50 n mi, in contrast with the concentric eyewall structure noted yesterday. Larry's large eye appears somewhat ragged in conventional satellite imagery, as some convective debris clouds associated with the old eyewall continue to erode. Earlier scatterometer data confirmed that the 50- and 64-kt wind radii of Larry have broadened, likely as a result of the ERC. Based on a blend of the 102-kt Dvorak estimates from TAFB and SAB and a 107-kt ADT current intensity estimate, the initial intensity is set at 105 kt for this advisory. NOAA aircraft is scheduled to conduct a research mission into Larry later today, which should provide more information about Larry's structure and intensity. Larry is moving northwestward, or 305/10 kt. The track forecast for Larry remains of high confidence. The hurricane is expected to continue moving northwestward through midweek along the western periphery of a mid-level subtropical ridge over the central Atlantic. On Thursday, Larry is forecast to turn northward within the flow of an upper-level trough that is expected to move off the coast of the northeastern United States. By Friday, Larry should accelerate northeastward and recurve into the mid-latitudes, passing near or offshore Atlantic Canada. The latest track guidance is tightly clustered once again. Thus, the official NHC track forecast is virtually unchanged from the previous one and remains near the consensus aids HCCA and TVCA. Larry is forecast to pass east of Bermuda and make its closest approach to the island on Thursday. Given Larry's large size, some impacts could be felt even if the center remains well east of the island as forecast. The intensity forecast remains more complex. Now that the ERC is likely completed, some strengthening cannot be ruled out in the near-term if the large, consolidated eyewall is able to contract. However, the SHIPS guidance suggests some weak to moderate westerly shear is still present, and Larry's broad wind field could result in some upwelling of cooler waters that may inhibit intensification. Ultimately, these mixed signals suggest that some intensity fluctuations could occur over the next 24-36 h, and so the NHC intensity forecast shows little net change during this time. Thereafter, only gradual weakening is shown as the large hurricane will remain in a reasonably favorable environment of weak to moderate shear and warm SSTs through the 72-96 h period. By day 5, the cyclone will likely be in the process of extratropical transition, still as a powerful cyclone. Overall, the NHC intensity forecast lies on the higher end of the guidance, between the stronger statistical-dynamical models DSHP/LGEM and the weaker multi-model consensus aids IVCN/HCCA. Key Messages: 1. Large swells generated by Larry are affecting the Lesser Antilles and will spread to portions of the Greater Antilles, the Bahamas, and Bermuda today through Tuesday. Significant swells should reach the east coast of the United States and Atlantic Canada by midweek and continue affecting these shores through the end of the week. 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 guidance of lifeguards and local officials this week. 2. Larry is forecast to approach Bermuda during the next few days as a large and powerful 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 06/0900Z 21.5N 52.4W 105 KT 120 MPH 12H 06/1800Z 22.6N 53.6W 110 KT 125 MPH 24H 07/0600Z 23.9N 54.9W 110 KT 125 MPH 36H 07/1800Z 25.3N 56.2W 105 KT 120 MPH 48H 08/0600Z 26.8N 57.5W 100 KT 115 MPH 60H 08/1800Z 28.5N 59.0W 100 KT 115 MPH 72H 09/0600Z 30.6N 60.6W 95 KT 110 MPH 96H 10/0600Z 36.7N 61.0W 90 KT 105 MPH 120H 11/0600Z 45.5N 52.0W 75 KT 85 MPH $$ Forecaster Reinhart ]]>

Hurricane Larry Wind Speed Probabilities Number 23

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 08:47:59 GMT

Issued at 0900 UTC MON SEP 06 2021 324 FONT12 KNHC 060847 PWSAT2 HURRICANE LARRY WIND SPEED PROBABILITIES NUMBER 23 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 0900 UTC MON SEP 06 2021 AT 0900Z THE CENTER OF HURRICANE LARRY WAS LOCATED NEAR LATITUDE 21.5 NORTH...LONGITUDE 52.4 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 MON 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 MON 18Z MON 06Z TUE 18Z TUE 06Z WED 06Z THU 06Z FRI PERIODS TO TO TO TO TO TO TO 18Z MON 06Z TUE 18Z TUE 06Z WED 06Z THU 06Z FRI 06Z SAT FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT HIBERNIA OILFD 34 X X( X) X( X) X( X) X( X) X( X) 29(29) HIBERNIA OILFD 50 X X( X) X( X) X( X) X( X) X( X) 9( 9) HIBERNIA OILFD 64 X X( X) X( X) X( X) X( X) X( X) 4( 4) CAPE RACE NFLD 34 X X( X) X( X) X( X) X( X) X( X) 40(40) CAPE RACE NFLD 50 X X( X) X( X) X( X) X( X) X( X) 18(18) CAPE RACE NFLD 64 X X( X) X( X) X( X) X( X) X( X) 8( 8) ILE ST PIERRE 34 X X( X) X( X) X( X) X( X) X( X) 23(23) ILE ST PIERRE 50 X X( X) X( X) X( X) X( X) X( X) 9( 9) ILE ST PIERRE 64 X X( X) X( X) X( X) X( X) X( X) 3( 3) BURGEO NFLD 34 X X( X) X( X) X( X) X( X) X( X) 13(13) BURGEO NFLD 50 X X( X) X( X) X( X) X( X) X( X) 3( 3) BURGEO NFLD 64 X X( X) X( X) X( X) X( X) X( X) 1( 1) PTX BASQUES 34 X X( X) X( X) X( X) X( X) X( X) 8( 8) EDDY POINT NS 34 X X( X) X( X) X( X) X( X) X( X) 4( 4) SYDNEY NS 34 X X( X) X( X) X( X) X( X) X( X) 10(10) SYDNEY NS 50 X X( X) X( X) X( X) X( X) X( X) 3( 3) SYDNEY NS 64 X X( X) X( X) X( X) X( X) X( X) 1( 1) SABLE ISLAND 34 X X( X) X( X) X( X) X( X) 2( 2) 19(21) SABLE ISLAND 50 X X( X) X( X) X( X) X( X) X( X) 8( 8) SABLE ISLAND 64 X X( X) X( X) X( X) X( X) X( X) 3( 3) HALIFAX NS 34 X X( X) X( X) X( X) X( X) 1( 1) 3( 4) BERMUDA 34 X X( X) X( X) X( X) 13(13) 28(41) 1(42) BERMUDA 50 X X( X) X( X) X( X) 2( 2) 14(16) X(16) BERMUDA 64 X X( X) X( X) X( X) 1( 1) 7( 8) X( 8) $$ FORECASTER REINHART ]]>

Hurricane Larry Graphics

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 08:54:42 GMT

5-Day Uncertainty Track last updated Mon, 06 Sep 2021 08:54:42 GMT

Wind Speed Probabilities last updated Mon, 06 Sep 2021 09:22:55 GMT