NHC Atlantic

Atlantic Tropical Weather Outlook

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 05:11:23 GMT

000
ABNT20 KNHC 060511
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 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 800 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 Cangialosi

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 22

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 02:52:52 GMT

Issued at 1100 PM AST Sun Sep 05 2021 000 WTNT42 KNHC 060252 TCDAT2 Hurricane Larry Discussion Number 22 NWS National Hurricane Center Miami FL AL122021 1100 PM AST Sun Sep 05 2021 A series of afternoon and evening passive microwave imagery indicate that Larry has evolved from an earlier stable eyewall structure to one with concentric eyewalls. The most recent microwave pass, a 2201 UTC SSMIS overpass, showed that Larry is likely in the latter stages of this most recent eyewall replacement cycle (ERC), with a new outer eyewall radius of nearly 50 nautical miles. However, geostationary satellite imagery still shows quite a bit of inner eyewall convection and it may take a while longer before this ERC is complete. A recent ASCAT-A pass at 2339 UTC also indicated that Larry's inner-core wind field had expanded further, likely related to this recent ERC. The latest Dvorak intensity estimates from TAFB/SAB remain unchanged from this afternoon, and the initial intensity remains 110 kt this advisory. A NOAA P-3 aircraft will be conducting a research mission into the Larry tomorrow and should provide some helpful in-situ measurements to verify the hurricane's intensity. Larry's motion to the northwest continues to gradually slow down, with the latest estimated motion at 310/10 kt. The forecast track reasoning remains the same. Larry should maintain its northwestward heading for the next 2-3 days as it remains steered around the southern periphery of a mid-level ridge to the hurricane's northeast. After 72 hours, Larry will be reaching the western extent of this ridge while an amplifying mid-latitude trough will be approaching from the northeastern United States. The combination of these features should help Larry recurve, first to the north, and then northeast with accelerating forward motion by the end of the forecast period. The track guidance continues to be in excellent agreement, and very few changes were made to the track forecast this cycle, staying close to the consensus aids HCCA and TVCA. The intensity forecast with Larry is somewhat tricky. Larry's wind field continues to grow, following the multiple ERCs that have occurred over the past few days. At the same time, Larry's forward motion has gradually been slowing down, with the latest estimate down to 10 kts. The combination of Larry's widening wind field with its slower forward motion opens the storm up to possible upwelling of cooler ocean waters near its inner-core. In fact, a drifting buoy that Larry moved over in the past 24 hours showed a significant drop in sea-surface temperatures from 27.5 C to less than 26 C. These in-situ measurements are helpful, because they are lower than the SHIPS-derived sea-surface temperature values and more consistent with the upwelling recently forecast by the HWRF model. Adding to the forecast complexity is the ongoing ERC which could be ending over the next 6-12 hours. The latest NHC intensity forecast is similar to the previous one for the first 24 hours, showing little change in intensity after ERC completion. Thereafter, while dynamical conditions near Larry are expected to become more favorable (lower vertical wind shear), the anticipated upwelling from Larry's large wind field as the storm moves slowly northwestward is forecast to result in gradual decay. The latest NHC intensity forecast is a bit lower than the previous one after 48 hours, following the latest HCCA consensus aid closely. However, Larry's wind field is also forecast to expand over this time period, making the cyclone a prolific swell and surf producer. Key Messages: 1. Large swells generated by Larry are already affecting the Lesser Antilles and will spread to portions of the Greater Antilles, the Bahamas, and Bermuda on Monday and Tuesday. Significant swells should 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 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 06/0300Z 21.0N 51.4W 110 KT 125 MPH 12H 06/1200Z 22.0N 52.6W 110 KT 125 MPH 24H 07/0000Z 23.2N 54.1W 110 KT 125 MPH 36H 07/1200Z 24.6N 55.4W 105 KT 120 MPH 48H 08/0000Z 26.0N 56.7W 100 KT 115 MPH 60H 08/1200Z 27.6N 58.2W 95 KT 110 MPH 72H 09/0000Z 29.4N 59.9W 90 KT 105 MPH 96H 10/0000Z 34.4N 61.6W 85 KT 100 MPH 120H 11/0000Z 42.9N 55.8W 80 KT 90 MPH $$ Forecaster Papin ]]>

Hurricane Larry Wind Speed Probabilities Number 23

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 08:47:15 GMT

Issued at 0900 UTC MON SEP 06 2021 ZCZC MIAPWSAT2 ALL TTAA00 KNHC DDHHMM 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 NNNN ]]>

Hurricane Larry Graphics

nhcwebmaster@noaa.gov (NHC Webmaster) — Mon, 06 Sep 2021 02:54:18 GMT

5-Day Uncertainty Track last updated Mon, 06 Sep 2021 02:54:18 GMT

Wind Speed Probabilities last updated Mon, 06 Sep 2021 03:23:00 GMT