Extratropical Storm Teddy (Hurricane Force)
000
WTNT35 KNHC 230234
TCPAT5
BULLETIN
Post-Tropical Cyclone Teddy Advisory Number 43
NWS National Hurricane Center Miami FL AL202020
1100 PM AST Tue Sep 22 2020
...POST-TROPICAL CYCLONE TEDDY FORECAST TO PRODUCE DESTRUCTIVE
WAVES, HEAVY RAIN AND STRONG WINDS FOR PORTIONS OF NOVA SCOTIA
TONIGHT THROUGH WEDNESDAY...
SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...42.8N 63.9W
ABOUT 125 MI...200 KM S OF HALIFAX NOVA SCOTIA
ABOUT 590 MI...950 KM WSW OF CAPE RACE NEWFOUNDLAND
ABOUT 465 MI...745 KM SSW OF PORT AUX BASQUES NEWFOUNDLAND
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...957 MB...28.26 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
None.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for...
* South coast of Nova Scotia from Digby to Meat Cove
* Port aux Basques to Francois Newfoundland
A Tropical Storm Watch is in effect for...
* Meat Cove to Tidnish Nova Scotia
* North of Digby to Fort Lawrence Nova Scotia
* Magdalen Islands Quebec
* Prince Edward Island
A Tropical Storm Warning means that tropical storm conditions are
expected within the warning area.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area.
Interests elsewhere in Atlantic Canada should closely monitor the
progress of Teddy.
For storm information specific to your area, please monitor
products issued by your national meteorological service.
DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Post-Tropical Cyclone Teddy
was located near latitude 42.8 North, longitude 63.9 West. The
post-tropical cyclone is moving toward the north near 18 mph (30
km/h), and a turn toward the north-northeast is expected by early
Wednesday. On the forecast track, the center will move over
eastern Nova Scotia on Wednesday, and then near or over
Newfoundland by Wednesday night, and be east of Labrador on
Thursday.
Maximum sustained winds have decreased to near 80 mph (130 km/h)
with higher gusts. Although weakening is likely tonight and
Wednesday, Teddy should be a strong post-tropical cyclone when it
moves near and over Nova Scotia.
Hurricane-force winds extend outward up to 125 miles (205 km) from
the center and tropical-storm-force winds extend outward up to 540
miles (870 km).
The estimated minimum central pressure is 957 mb (28.26 inches).
HAZARDS AFFECTING LAND
----------------------
Key messages for Teddy can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT5 and WMO header WTNT45 KNHC
and on the web at www.hurricanes.gov/text/MIATCDAT5.shtml.
STORM SURGE: A dangerous storm surge is expected to produce
significant coastal flooding near and to the east of where the
center makes landfall in Nova Scotia. Near the coast, the surge
will be accompanied by very large and destructive waves.
SURF: Large swells generated by Teddy are affecting Bermuda, the
Lesser Antilles, the Greater Antilles, the Bahamas, the east coast
of the United States, and Atlantic Canada. These swells are likely
to cause life-threatening surf and rip current conditions. Please
consult products from your local weather office.
WIND: Tropical storm conditions are occurring in the Nova Scotia
warning area. Tropical storm conditions could begin in the
watch areas by early Wednesday. Tropical storm conditions
are expected to begin in the Newfoundland warning area on Wednesday
afternoon.
RAINFALL: Through Thursday, Teddy is expected to produce rainfall
accumulations of 2 to 4 inches (50 to 100 mm) with isolated totals
of 6 inches (150 mm) across sections of Atlantic Canada.
NEXT ADVISORY
-------------
Next intermediate advisory at 200 AM AST.
Next complete advisory at 500 AM AST.
$$
Forecaster Roberts
000
WTNT45 KNHC 230236
TCDAT5
Post-Tropical Cyclone Teddy Discussion Number 43
NWS National Hurricane Center Miami FL AL202020
1100 PM AST Tue Sep 22 2020
Extratropical transition has been ongoing since last night, with
the cyclone's associated rain shield expanding over a great
distance in the northern semicircle. In addition, multiple
dropsonde observations from the Air Force Reserve hurricane hunters
and buoy data show a sharp temperature gradient of nearly 20
degrees F from northwest quadrant to the southeast, indicative of
the cyclone's involvement with the strong baroclinic frontal zone.
Accordingly, Teddy has become a strong post-tropical extratropical
cyclone. Highest flight-level winds recorded this evening were 83
kt about 85 miles northeast of the center and the highest SFMR
surface winds were 63 kt. A recent METOP-C scatterometer pass
showed sustained winds no higher than 59 kt in the east quadrant.
A blend of these data yields an initial intensity of 70 kt for this
advisory. Further gradual weakening is forecast through the period
as a result of the rapidly decreasing sea surface temperatures
(less than 20C) north of the North Wall of the gulf stream. The
NHC forecast indicates Teddy approaching the coast of Nova Scotia
below hurricane strength, but still as a strong post-tropical
extratropical low. Teddy should continue to gradually spin down as
the cyclone moves north-northeastward toward Newfoundland.
The initial motion is estimated to be northward, or 010/16 kt.
A north-northeastward turn is forecast later tonight or early
Wednesday in response to an approaching mid-latitude shortwave
trough moving out of the northeast U.S. Teddy should move over
Nova Scotia tomorrow and near the island of Newfoundland, and the
adjacent waters of the Gulf of St. Lawrence Wednesday night.
Afterward, the post-tropical cyclone will likely be absorbed by an
even larger high latitude extratropical cyclone near Greenland.
There has been no significant changes made to the NHC forecast
track this evening, and it's in best agreement with the HFIP
Corrected Consensus Approach model.
Key Messages:
1. Teddy is expected to transition to a powerful post-tropical
cyclone as it moves near or over portions of Atlantic Canada
late today through Thursday. The most significant hazard expected
from Teddy is large destructive waves forecast along the southern
coast of Nova Scotia through Wednesday.
2. Very large swells produced by Teddy are expected to affect
portions of Bermuda, the Leeward Islands, the Greater Antilles, the
Bahamas, the east coast of the United States, and Atlantic Canada
during the next few days. These swells are expected to cause
life-threatening surf and rip current conditions.
3. Tropical Storm Watches and Warnings are in effect for portions
of Nova Scotia, Newfoundland, Prince Edward Island and the Magdalen
Islands, and heavy rainfall across Atlantic Canada is expected
through Thursday.
FORECAST POSITIONS AND MAX WINDS
INIT 23/0300Z 42.8N 63.9W 70 KT 80 MPH...POST-TROPICAL
12H 23/1200Z 45.3N 62.3W 60 KT 70 MPH...INLAND
24H 24/0000Z 49.8N 58.7W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 24/1200Z 54.7N 54.9W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 25/0000Z...ABSORBED BY A LARGER LOW
$$
Forecaster Roberts
posted by Advackia at 8:41 PM
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