NHC Atlantic

Atlantic Tropical Weather Outlook

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 05:08:17 GMT

000
ABNT20 KNHC 050508
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 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 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 Cangialosi

Summary for Hurricane Larry (AT2/AL122021)

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 02:33:19 GMT

...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG MANY WESTERN ATLANTIC SHORES NEXT WEEK DUE TO LARRY'S LARGE SWELLS... As of 11:00 PM AST Sat Sep 4 the center of Larry was located near 18.0, -48.0 with movement WNW at 14 mph. The minimum central pressure was 958 mb with maximum sustained winds of about 120 mph.

Hurricane Larry Public Advisory Number 18

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 02:33:19 GMT

Issued at 1100 PM AST Sat Sep 04 2021 000 WTNT32 KNHC 050233 TCPAT2 BULLETIN Hurricane Larry Advisory Number 18 NWS National Hurricane Center Miami FL AL122021 1100 PM AST Sat Sep 04 2021 ...DANGEROUS SURF AND RIP CURRENTS EXPECTED ALONG MANY WESTERN ATLANTIC SHORES NEXT WEEK DUE TO LARRY'S LARGE SWELLS... SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...18.0N 48.0W ABOUT 910 MI...1465 KM E OF THE LEEWARD ISLANDS ABOUT 1440 MI...2315 KM SE OF BERMUDA MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H PRESENT MOVEMENT...WNW OR 300 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 1100 PM AST (0300 UTC), the large eye of Hurricane Larry was located near latitude 18.0 North, longitude 48.0 West. Larry is moving toward the west-northwest near 14 mph (22 km/h). A turn toward the northwest is expected overnight, with Larry maintaining that heading at gradually slower speeds through Tuesday. 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 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). HAZARDS AFFECTING LAND ---------------------- SURF: Swells generated by Larry are expected to reach the Lesser Antilles on Sunday, and will spread westward 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 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 500 AM AST. $$ Forecaster Berg ]]>

Hurricane Larry Forecast Advisory Number 18

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 02:32:48 GMT

Issued at 0300 UTC SUN SEP 05 2021 000 WTNT22 KNHC 050232 TCMAT2 HURRICANE LARRY FORECAST/ADVISORY NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 0300 UTC SUN SEP 05 2021 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. HURRICANE CENTER LOCATED NEAR 18.0N 48.0W AT 05/0300Z POSITION ACCURATE WITHIN 15 NM PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 12 KT ESTIMATED MINIMUM CENTRAL PRESSURE 958 MB EYE DIAMETER 40 NM MAX SUSTAINED WINDS 105 KT WITH GUSTS TO 130 KT. 64 KT....... 40NE 30SE 25SW 35NW. 50 KT....... 80NE 70SE 30SW 70NW. 34 KT.......140NE 130SE 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 18.0N 48.0W AT 05/0300Z AT 05/0000Z CENTER WAS LOCATED NEAR 17.7N 47.5W FORECAST VALID 05/1200Z 19.1N 49.5W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 50NE 40SE 30SW 40NW. 50 KT... 80NE 70SE 40SW 70NW. 34 KT...140NE 140SE 80SW 130NW. FORECAST VALID 06/0000Z 20.5N 51.3W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 50NE 40SE 40SW 50NW. 50 KT... 80NE 70SE 50SW 70NW. 34 KT...140NE 140SE 90SW 130NW. FORECAST VALID 06/1200Z 21.7N 53.0W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 60NE 50SE 40SW 50NW. 50 KT... 80NE 80SE 60SW 70NW. 34 KT...150NE 140SE 100SW 130NW. FORECAST VALID 07/0000Z 23.0N 54.5W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 60NE 50SE 40SW 50NW. 50 KT... 90NE 90SE 70SW 80NW. 34 KT...160NE 150SE 110SW 130NW. FORECAST VALID 07/1200Z 24.2N 56.0W MAX WIND 110 KT...GUSTS 135 KT. 50 KT... 90NE 90SE 70SW 80NW. 34 KT...170NE 160SE 110SW 130NW. FORECAST VALID 08/0000Z 25.8N 57.5W MAX WIND 105 KT...GUSTS 130 KT. 50 KT...100NE 90SE 70SW 80NW. 34 KT...170NE 170SE 120SW 130NW. 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 09/0000Z 29.4N 60.5W MAX WIND 100 KT...GUSTS 120 KT. OUTLOOK VALID 10/0000Z 35.1N 61.4W MAX WIND 90 KT...GUSTS 110 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 18.0N 48.0W NEXT ADVISORY AT 05/0900Z $$ FORECASTER BERG ]]>

Hurricane Larry Forecast Discussion Number 18

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 02:34:50 GMT

Issued at 1100 PM AST Sat Sep 04 2021 000 WTNT42 KNHC 050234 TCDAT2 Hurricane Larry Discussion Number 18 NWS National Hurricane Center Miami FL AL122021 1100 PM AST Sat Sep 04 2021 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. Key Messages: 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. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 18.0N 48.0W 105 KT 120 MPH 12H 05/1200Z 19.1N 49.5W 110 KT 125 MPH 24H 06/0000Z 20.5N 51.3W 110 KT 125 MPH 36H 06/1200Z 21.7N 53.0W 110 KT 125 MPH 48H 07/0000Z 23.0N 54.5W 110 KT 125 MPH 60H 07/1200Z 24.2N 56.0W 110 KT 125 MPH 72H 08/0000Z 25.8N 57.5W 105 KT 120 MPH 96H 09/0000Z 29.4N 60.5W 100 KT 115 MPH 120H 10/0000Z 35.1N 61.4W 90 KT 105 MPH $$ Forecaster Berg ]]>

Hurricane Larry Wind Speed Probabilities Number 18

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 02:34:19 GMT

Issued at 0300 UTC SUN SEP 05 2021 000 FONT12 KNHC 050234 PWSAT2 HURRICANE LARRY WIND SPEED PROBABILITIES NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 0300 UTC SUN SEP 05 2021 AT 0300Z THE CENTER OF HURRICANE LARRY WAS LOCATED NEAR LATITUDE 18.0 NORTH...LONGITUDE 48.0 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 00Z 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 00Z SUN 12Z SUN 00Z MON 12Z MON 00Z TUE 00Z WED 00Z THU PERIODS TO TO TO TO TO TO TO 12Z SUN 00Z MON 12Z MON 00Z TUE 00Z WED 00Z THU 00Z FRI FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT BERMUDA 34 X X( X) X( X) X( X) X( X) 11(11) 22(33) BERMUDA 50 X X( X) X( X) X( X) X( X) 3( 3) 9(12) BERMUDA 64 X X( X) X( X) X( X) X( X) 1( 1) 6( 7) $$ FORECASTER BERG ]]>

Hurricane Larry Graphics

nhcwebmaster@noaa.gov (NHC Webmaster) — Sun, 05 Sep 2021 02:36:14 GMT

5-Day Uncertainty Track last updated Sun, 05 Sep 2021 02:36:14 GMT

Wind Speed Probabilities last updated Sun, 05 Sep 2021 03:22:49 GMT