NHC Atlantic

Atlantic Tropical Weather Outlook

nhcwebmaster@noaa.gov (NHC Webmaster) — Wed, 08 Sep 2021 05:07:57 GMT

000
ABNT20 KNHC 080507
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 AM EDT Wed Sep 8 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 several hundred miles
southeast of Bermuda.

Disorganized cloudiness and a few thunderstorms over the central
and eastern Gulf of Mexico are associated with a surface trough
and an upper-level disturbance. The system is expected to move
northeastward over the northeastern Gulf of Mexico later today.
Upper-level winds could become slightly more favorable to support
some tropical or subtropical development as the system nears the
northern Gulf coast tonight or early Thursday. The disturbance is
then expected to cross the southeastern United States, and some
additional development will be possible after it emerges off the
southeastern United States coast late this week. Regardless of
development, areas of heavy rainfall will be possible across
portions of the Florida panhandle and southern Georgia through
Thursday, with localized flooding possible.
* Formation chance through 48 hours...medium...50 percent.
* Formation chance through 5 days...medium...50 percent.

$$
Forecaster Brown

Summary for Hurricane Larry (AT2/AL122021)

nhcwebmaster@noaa.gov (NHC Webmaster) — Wed, 08 Sep 2021 05:47:28 GMT

...LARRY CONTINUES MOVING NORTHWESTWARD OVER THE CENTRAL ATLANTIC... ...DANGEROUS SWELLS TO AFFECT MUCH OF THE WESTERN ATLANTIC BEACHES THIS WEEK... As of 2:00 AM AST Wed Sep 8 the center of Larry was located near 26.2, -57.1 with movement NW at 12 mph. The minimum central pressure was 967 mb with maximum sustained winds of about 115 mph.

Hurricane Larry Public Advisory Number 30A

nhcwebmaster@noaa.gov (NHC Webmaster) — Wed, 08 Sep 2021 05:47:28 GMT

Issued at 200 AM AST Wed Sep 08 2021 000 WTNT32 KNHC 080547 TCPAT2 BULLETIN Hurricane Larry Intermediate Advisory Number 30A NWS National Hurricane Center Miami FL AL122021 200 AM AST Wed Sep 08 2021 ...LARRY CONTINUES MOVING NORTHWESTWARD OVER THE CENTRAL ATLANTIC... ...DANGEROUS SWELLS TO AFFECT MUCH OF THE WESTERN ATLANTIC BEACHES THIS WEEK... SUMMARY OF 200 AM AST...0600 UTC...INFORMATION ---------------------------------------------- LOCATION...26.2N 57.1W ABOUT 625 MI...1010 KM SE OF BERMUDA MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H PRESENT MOVEMENT...NW OR 325 DEGREES AT 12 MPH...19 KM/H MINIMUM CENTRAL PRESSURE...967 MB...28.56 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Watch is in effect for... * Bermuda A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case within the next 36 hours. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 200 AM AST (0600 UTC), the center of the large eye of Hurricane Larry was located near latitude 26.2 North, longitude 57.1 West. Larry is moving toward the northwest near 12 mph (19 km/h), and this general motion is expected to continue through today. A turn toward the north-northwest and north with an increase in forward speed is forecast on Thursday. On the forecast track, the center of Larry should pass east of Bermuda on Thursday. Maximum sustained winds remain near 115 mph (185 km/h) with higher gusts. Larry is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Slow weakening is forecast during the next several days. 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 185 miles (295 km). The estimated minimum central pressure is 967 mb (28.56 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Larry can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT2 and WMO header WTNT42 KNHC. WIND: Tropical storm conditions are possible on Bermuda beginning tonight or early Thursday. SURF: Swells generated by Larry will continue to affect the Leeward Islands, portions of the Greater Antilles, and the Bahamas through midweek, and impact Bermuda through the end of the week. Significant swells from Larry will begin reaching the east coast of the United States and Atlantic Canada today 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 500 AM AST. $$ Forecaster Brown ]]>

Hurricane Larry Forecast Advisory Number 31

nhcwebmaster@noaa.gov (NHC Webmaster) — Wed, 08 Sep 2021 08:47:52 GMT

Issued at 0900 UTC WED SEP 08 2021 ZCZC MIATCMAT2 ALL TTAA00 KNHC DDHHMM HURRICANE LARRY FORECAST/ADVISORY NUMBER 31 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 0900 UTC WED SEP 08 2021 CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY... NONE. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WATCH IS IN EFFECT FOR... * BERMUDA A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE WITHIN THE NEXT 36 HOURS. INTERESTS IN SOUTHEASTERN NEWFOUNDLAND SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. HURRICANE CENTER LOCATED NEAR 26.5N 57.3W AT 08/0900Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 325 DEGREES AT 9 KT ESTIMATED MINIMUM CENTRAL PRESSURE 967 MB MAX SUSTAINED WINDS 100 KT WITH GUSTS TO 120 KT. 64 KT....... 60NE 50SE 40SW 50NW. 50 KT.......100NE 90SE 70SW 90NW. 34 KT.......160NE 160SE 120SW 150NW. 12 FT SEAS..360NE 300SE 330SW 330NW. 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 26.5N 57.3W AT 08/0900Z AT 08/0600Z CENTER WAS LOCATED NEAR 26.2N 57.1W FORECAST VALID 08/1800Z 28.0N 58.7W MAX WIND 95 KT...GUSTS 115 KT. 64 KT... 60NE 50SE 40SW 50NW. 50 KT...100NE 90SE 70SW 90NW. 34 KT...160NE 160SE 120SW 150NW. FORECAST VALID 09/0600Z 30.1N 60.6W MAX WIND 95 KT...GUSTS 115 KT. 64 KT... 70NE 60SE 40SW 50NW. 50 KT...100NE 100SE 70SW 90NW. 34 KT...170NE 170SE 120SW 140NW. FORECAST VALID 09/1800Z 32.9N 61.9W MAX WIND 90 KT...GUSTS 110 KT. 64 KT... 70NE 60SE 40SW 50NW. 50 KT...110NE 100SE 80SW 90NW. 34 KT...180NE 170SE 120SW 140NW. FORECAST VALID 10/0600Z 36.7N 61.6W MAX WIND 85 KT...GUSTS 105 KT. 64 KT... 60NE 50SE 40SW 50NW. 50 KT...110NE 100SE 80SW 90NW. 34 KT...180NE 180SE 140SW 140NW. FORECAST VALID 10/1800Z 41.7N 58.3W MAX WIND 80 KT...GUSTS 100 KT. 50 KT...110NE 110SE 80SW 80NW. 34 KT...200NE 200SE 160SW 130NW. FORECAST VALID 11/0600Z 47.3N 52.4W MAX WIND 75 KT...GUSTS 90 KT. 50 KT...110NE 110SE 80SW 60NW. 34 KT...200NE 200SE 190SW 120NW. 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 12/0600Z 58.8N 40.0W...POST-TROP/EXTRATROP MAX WIND 60 KT...GUSTS 75 KT. OUTLOOK VALID 13/0600Z 65.0N 33.0W...POST-TROP/EXTRATROP MAX WIND 45 KT...GUSTS 55 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 26.5N 57.3W INTERMEDIATE PUBLIC ADVISORY...WTNT32 KNHC/MIATCPAT2...AT 08/1200Z NEXT ADVISORY AT 08/1500Z $$ FORECASTER BROWN NNNN ]]>

Hurricane Larry Forecast Discussion Number 30

nhcwebmaster@noaa.gov (NHC Webmaster) — Wed, 08 Sep 2021 02:43:23 GMT

Issued at 1100 PM AST Tue Sep 07 2021 000 WTNT42 KNHC 080243 TCDAT2 Hurricane Larry Discussion Number 30 NWS National Hurricane Center Miami FL AL122021 1100 PM AST Tue Sep 07 2021 Larry's eye has become a little better defined since the previous advisory, and the eyewall convective cloud tops have cooled, with a nearly solid ring of -65C to -70C now surrounding the eye. Data from an Air Force Reserve Hurricane Hunter aircraft indicate that the central pressure has risen slightly to 966-968 mb and that peak 700-mb flight-level winds measured were 106 kt in the northeast quadrant. These data would suggest that the intensity has decreased a little to 95-96 kt. However, the peak flight-level wind of 106 kt was measured in the wake of a strong eyewall convective burst, suggesting that stronger winds could have been present in that convection. Also, if the surrounding eyewall convective ring closes off during the nocturnal convective maximum period in another six hours, then Dvorak intensity estimates would increase from the current T5.0/90 kt to T5.5/102 kt. Thus, Larry's intensity has been maintained at 100 kt for this advisory in order to avoid possible intensity vacillations. The initial motion estimate is 325/10 kt, based on reconnaissance aircraft fixes over the past 12 hours. There remains no significant change to the track forecast or reasoning over the past 48 hours. The latest NHC model guidance remains in strong agreement on Larry continuing to move northwestward and then northward around the western periphery of a deep-layer subtropical ridge during the next 48 hours or so. After passing east of Bermuda by early day 3, the hurricane is forecast to accelerate northeastward and move into the mid-latitude westerlies ahead of a large, eastward-moving trough that is currently approaching the northeastern United States and Atlantic Canada. By day 5, Larry is expected to move across the far north Atlantic. The new NHC track forecast is similar to the previous advisory track, and lies along the eastern edge of the tightly packed simple- and corrected-consensus track models. Larry's upper-level outflow pattern remains impressive, and has even expanded and accelerated on the east side owing to a southward-digging upper-level trough, which has enhanced the outflow in that part of the hurricane. The vertical wind shear affecting Larry is expected to remain low for the next 24 hours or so while the hurricane passes over even warmer sea-surface temperatures (SST) approaching 29.7 deg C, even though the oceanic heat content will be decreasing. However, entrainment of dry mid-level air along with eye fluctuations are expected to offset the warmer SSTs. Thus, a slow but steady decrease in intensity through 48-60 hours is expected. Late in the forecast period, colder waters and increasing southwesterly vertical wind shear exceeding 30 kt should induce a faster rate of weakening. By 96-120 hours, the global models also indicate Larry will be merging with a frontal zone. Therefore, the new intensity forecast continues to show extratropical transition during that time period. The official intensity forecast is similar to the previous advisory, and closely follows the simple- and corrected-consensus intensity models IVCN and NOAA-HCCA. Key Messages: 1. Large swells generated by Larry will continue to affect the Lesser Antilles, portions of the Greater Antilles, and the Bahamas through midweek. 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. The center of Larry is forecast to pass east of Bermuda on Thursday, but given Larry's large size, tropical storm conditions are possible there Thursday, along with a risk of heavy rainfall and coastal flooding. A Tropical Storm Watch is in effect for Bermuda and interests there should closely monitor the latest forecast updates. 3. Larry is forecast to move near or over portions of southeastern Newfoundland late Friday and Friday night as it transitions to a hurricane-force post-tropical cyclone. There is a risk of impacts from high winds, rainfall, and storm surge in portions of Newfoundland, and interests there should monitor the progress of Larry and updates to the forecast. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 25.8N 56.8W 100 KT 115 MPH 12H 08/1200Z 27.2N 58.0W 95 KT 110 MPH 24H 09/0000Z 29.2N 59.6W 95 KT 110 MPH 36H 09/1200Z 31.5N 61.3W 90 KT 105 MPH 48H 10/0000Z 34.6N 61.8W 90 KT 105 MPH 60H 10/1200Z 39.1N 60.1W 85 KT 100 MPH 72H 11/0000Z 44.5N 55.7W 80 KT 90 MPH 96H 12/0000Z 56.2N 43.6W 65 KT 75 MPH...POST-TROP/EXTRATROP 120H 13/0000Z 62.8N 33.6W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ Forecaster Stewart ]]>

Hurricane Larry Wind Speed Probabilities Number 30

nhcwebmaster@noaa.gov (NHC Webmaster) — Wed, 08 Sep 2021 02:42:52 GMT

Issued at 0300 UTC WED SEP 08 2021 000 FONT12 KNHC 080242 PWSAT2 HURRICANE LARRY WIND SPEED PROBABILITIES NUMBER 30 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122021 0300 UTC WED SEP 08 2021 AT 0300Z THE CENTER OF HURRICANE LARRY WAS LOCATED NEAR LATITUDE 25.8 NORTH...LONGITUDE 56.8 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 100 KTS...115 MPH...185 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 WED 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 WED 12Z WED 00Z THU 12Z THU 00Z FRI 00Z SAT 00Z SUN PERIODS TO TO TO TO TO TO TO 12Z WED 00Z THU 12Z THU 00Z FRI 00Z SAT 00Z SUN 00Z MON FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT HIBERNIA OILFD 34 X X( X) X( X) X( X) 4( 4) 42(46) X(46) HIBERNIA OILFD 50 X X( X) X( X) X( X) X( X) 13(13) X(13) HIBERNIA OILFD 64 X X( X) X( X) X( X) X( X) 4( 4) X( 4) CAPE RACE NFLD 34 X X( X) X( X) X( X) 35(35) 44(79) X(79) CAPE RACE NFLD 50 X X( X) X( X) X( X) 10(10) 37(47) X(47) CAPE RACE NFLD 64 X X( X) X( X) X( X) 3( 3) 17(20) X(20) ILE ST PIERRE 34 X X( X) X( X) X( X) 33(33) 19(52) X(52) ILE ST PIERRE 50 X X( X) X( X) X( X) 10(10) 14(24) X(24) ILE ST PIERRE 64 X X( X) X( X) X( X) 3( 3) 7(10) X(10) BURGEO NFLD 34 X X( X) X( X) X( X) 15(15) 11(26) X(26) BURGEO NFLD 50 X X( X) X( X) X( X) 2( 2) 4( 6) X( 6) BURGEO NFLD 64 X X( X) X( X) X( X) X( X) 2( 2) X( 2) PTX BASQUES 34 X X( X) X( X) X( X) 8( 8) 5(13) X(13) EDDY POINT NS 34 X X( X) X( X) X( X) 4( 4) X( 4) X( 4) SYDNEY NS 34 X X( X) X( X) X( X) 12(12) 2(14) X(14) SABLE ISLAND 34 X X( X) X( X) X( X) 33(33) 1(34) X(34) SABLE ISLAND 50 X X( X) X( X) X( X) 11(11) X(11) X(11) SABLE ISLAND 64 X X( X) X( X) X( X) 3( 3) 1( 4) X( 4) HALIFAX NS 34 X X( X) X( X) X( X) 4( 4) X( 4) X( 4) BERMUDA 34 X 1( 1) 18(19) 10(29) 1(30) X(30) X(30) BERMUDA 50 X X( X) 2( 2) 1( 3) X( 3) X( 3) X( 3) $$ FORECASTER STEWART ]]>

Hurricane Larry Graphics

nhcwebmaster@noaa.gov (NHC Webmaster) — Wed, 08 Sep 2021 05:47:33 GMT

5-Day Uncertainty Track last updated Wed, 08 Sep 2021 05:47:33 GMT

Wind Speed Probabilities last updated Wed, 08 Sep 2021 03:23:01 GMT