NHC21Z報判定Elsa已轉溫

637
WTNT45 KNHC 092042
TCDAT5

Post-Tropical Cyclone Elsa Discussion Number  39
NWS National Hurricane Center Miami FL       AL052021
500 PM AST Fri Jul 09 2021

Surface, satellite, and radar data indicate that Elsa's deep
convection remains limited to a shield north of its center and that
a front extends through the center of the cyclone. For those
reasons, Elsa was designated as a post-tropical cyclone at 1800 UTC.
Surface observations of sustained winds a little above 40 kt were
reported across portions of southern Massachusetts and the nearby
waters as Elsa crossed the state, so the intensity estimate remains
45 kt.

Elsa is moving quickly just off the northeast coast of the U.S. with
an initial motion estimate of 040/27 kt. A faster northeastward
motion is expected tonight and on Saturday while the system remains
embedded within a deep mid-latitude trough. Very little change was
made to the NHC track forecast. All available guidance indicates
that Elsa will gradually weaken during the next couple of days. The
GFS, ECMWF, and CMC global models now indicate the cyclone will open
into a trough within the next 48 h or so, and this is reflected in
the NHC forecast.

It is estimated that center of Elsa made landfall along the coast of
Long Island near Southampton around 1430 UTC (10:30 am EDT), and
again near Watch Hill, Rhode Island near 1615 UTC (12:15 pm EDT).
Elsa's classification at the time the center crossed the coast will
be determined in the post-storm analysis. It should also be noted
that the landfall position had little bearing on the location or
timing of the strong winds and heavy rain which were well removed
from the cyclone's center.

Since Elsa is now post-tropical and all coastal tropical storm
warnings have been discontinued, this is the last NHC advisory.  
Additional information on this system can be found in High Seas
Forecasts issued by the National Weather Service, under AWIPS
header NFDHSFAT1, WMO header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php


Key Messages:

1. As Elsa moves off the coast of Maine through this evening, heavy
rainfall could lead to considerable flash and urban flooding.

2. Gusty winds will continue across portions of the southern New
England coast during the next couple of hours. The post-tropical
cyclone is also expected to bring gusty winds to portions of
Atlantic Canada tonight and Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 43.0N  69.5W   45 KT  50 MPH...POST-TROPICAL
12H  10/0600Z 46.2N  64.7W   40 KT  45 MPH...POST-TROP/EXTRATROP
24H  10/1800Z 50.3N  56.1W   40 KT  45 MPH...POST-TROP/EXTRATROP
36H  11/0600Z 54.7N  46.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
48H  11/1800Z...DISSIPATED

$$
Forecaster Zelinsky

NHC預測12H內即將轉化

000
WTNT45 KNHC 091446
TCDAT5

Tropical Storm Elsa Discussion Number  38
NWS National Hurricane Center Miami FL       AL052021
1100 AM EDT Fri Jul 09 2021

The extratropical transition of Elsa is well underway.  A frontal
boundary located over southern New England nearly wraps into the
circulation center, and the primary area of cold cloud tops and
heavy rainfall has now shifted to the northwestern portion of the
cyclone.  Elsa is expected to complete its extratropical transition
this afternoon.  Buoy and surface observations indicate that the
cyclone's intensity has changed little since early this morning.
Based on those data, Elsa's peak winds and minimum pressure
remain 45 kt and 1000 mb for this advisory, respectively.

Elsa continues to move quickly northeastward or 045/27 kt.  The
post-tropical cyclone is forecast to continue accelerating
northeastward over the next day or two as it remains embedded
within deep-layer southwesterly flow.  After 48 hours, the system is
expected to slow before it dissipates over the north Atlantic
around day 3.  The track guidance remains in good agreement, but has
shifted slightly southward after 24 hours and the NHC forecast has
been adjusted accordingly.

Little change in strength is anticipated in the short-term as Elsa
completes its extratropical transition.  After that time, gradual
weakening is anticipated and the wind speed forecast calls for the
system to weaken below gale-force in a couple of days.  The global
models show the post-tropical cyclone dissipating over the north
Atlantic by early next week, and the official forecast follows
suit.

Key Messages:

1. As Elsa moves near southern and coastal New England today, heavy
rainfall could lead to considerable flash and urban flooding.

2. Tropical storm conditions are expected to continue in portions
of the warning area in Long Island and southern New England
through this afternoon. Gusty winds are expected over portions of
Atlantic Canada tonight and Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT  09/1500Z 41.0N  72.1W   45 KT  50 MPH
12H  10/0000Z 44.0N  67.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
24H  10/1200Z 48.4N  60.3W   40 KT  45 MPH...POST-TROP/EXTRATROP
36H  11/0000Z 52.2N  51.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
48H  11/1200Z 56.5N  41.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
60H  12/0000Z 60.0N  32.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
72H  12/1200Z...DISSIPATED

$$
Forecaster Brown

正沿美國東岸北上,將逐漸轉化為溫帶氣旋

000
WTNT45 KNHC 082056
TCDAT5

Tropical Storm Elsa Discussion Number  35
NWS National Hurricane Center Miami FL       AL052021
500 PM EDT Thu Jul 08 2021

A NOAA NOS observing site at Wrightsville Beach, North Carolina,
recently reported a sustained wind of 41 kt, so Elsa's maximum winds
are now estimated to be 45 kt.  A number of other observing sites in
the vicinity have also reported sustained tropical-storm-force
winds.  Elsa's slight strengthening may be the result of baroclinic
forcing associated with an approaching short-wave trough. The
system's cloud tops have warmed somewhat during the day, but it is
still producing some very heavy rains.

Elsa's low-level center is a bit elongated from southwest to
northeast, but surface synoptic data indicate that it has moved into
northern North Carolina.  The storm continues to gradually
accelerate toward the northeast, and the initial motion estimate is
040/18 kt.  A faster northeastward motion is expected over the next
1-2 days as the cyclone moves along with the mid-latitude
southwesterly flow ahead of a broad mid-tropospheric trough over the
eastern United States and Canada.  Elsa should move near or
over southeastern New England and Atlantic Canada within the next
24-48 hours.  The official track forecast remains close to the
previous one and similar to the multi-model consensus, TVCA.

The global models suggest that not much additional strengthening is
likely.  Simulated satellite imagery from these models show an
extratropical appearance in 24-36 hours so the official forecast
shows an extratropical transition by late Friday.  This is also
supported by cyclone phase analyses of the model fields from
Florida State University.


Key Messages:

1.As Elsa moves from North Carolina to Virginia today and this
evening, heavy rainfall may result in limited flash and urban
flooding. Heavy rainfall from the Mid-Atlantic into New England
through Friday could lead to considerable flash and urban flooding.

2. Tropical storm conditions should continue along portions of the
North Carolina coast this afternoon and spread over the
mid-Atlantic coast later today or tonight.  Tropical storm
conditions are expected in portions of the southern New England
states and New York by Friday.  Gusty winds are expected over
portions of Atlantic Canada Friday night and Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT  08/2100Z 36.3N  78.3W   45 KT  50 MPH...INLAND
12H  09/0600Z 38.7N  75.1W   45 KT  50 MPH...INLAND
24H  09/1800Z 42.5N  70.0W   45 KT  50 MPH...OVER WATER
36H  10/0600Z 47.0N  63.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
48H  10/1800Z 51.5N  54.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
60H  11/0600Z 56.0N  45.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
72H  11/1800Z...DISSIPATED

$$
Forecaster Pasch

於17Z前後已登錄佛州

TXNT28 KNES 071742
TCSNTL

A.  05L (ELSA)

B.  07/1730Z

C.  30.3N

D.  83.5W

E.  THREE/GOES-E

F.  OVERLAND

G.  IR/EIR/VIS

H.  REMARKS...THE SYSTEM'S LLCC HAS NOW PROGRESSED OVERLAND. THIS WILL
BE THE FINAL BULLETIN UNLESS THE SYSTEM REEMERGES BACK OVER THE WATER
AS A TROPICAL SYSTEM IN SATELLITE IMAGERY.

I.  ADDL POSITIONS

    NIL


...SAMBUCCI

000
WTNT35 KNHC 071753
TCPAT5

BULLETIN
Tropical Storm Elsa Intermediate Advisory Number 30A
NWS National Hurricane Center Miami FL       AL052021
200 PM EDT Wed Jul 07 2021

...ELSA INLAND AND WEAKENING OVER NORTHERN FLORIDA...


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...30.3N 83.5W
ABOUT 105 MI...170 KM W OF JACKSONVILLE FLORIDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

All warnings have been discontinued south of the Suwannee River,
Florida.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* West coast of Florida from the Suwannee River to the Aucilla River

A Tropical Storm Warning is in effect for...
* West coast of Florida from the Suwannee River to the Ochlockonee
River
* Mouth of St. Marys River, Georgia to Little River Inlet, South
Carolina

A Tropical Storm Watch is in effect for...
* North of Little River Inlet, South Carolina to Sandy Hook, New
Jersey
* Pamlico and Albemarle Sounds
* Chesapeake Bay south of North Beach and the tidal Potomac south
of Cobb Island
* Delaware Bay south of Slaughter Beach

A Storm Surge Warning means there is a danger of life-threatening
inundation, from rising water moving inland from the coastline,
in the indicated locations. For a depiction of areas at risk,
please see the National Weather Service Storm Surge Watch/Warning
Graphic, available at hurricanes.gov.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area.

Interests in southeastern New England and the Canadian Maritimes
should monitor the progress of Elsa.

For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.


DISCUSSION AND OUTLOOK
----------------------
At 200 PM EDT (1800 UTC), the center of Tropical Storm Elsa was
located near latitude 30.3 North, longitude 83.5 West.  Elsa is
moving toward the north near 14 mph (22 km/h).  A turn toward
the north-northeast is expected this evening, followed by a faster
northeastward motion by late Thursday.  On the forecast track, Elsa
will move over Georgia tonight, over South Carolina early on
Thursday, over North Carolina later on Thursday, and move near or
over the mid-Atlantic coast on Friday.

Maximum sustained winds have decreased to near 50 mph (85 km/h)
with higher gusts.  Continued weakening is expected through
tomorrow as Elsa moves over land.

Tropical-storm-force winds extend outward up to 70 miles (110 km)
from the center.

The estimated minimum central pressure is 1002 mb (29.59 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Elsa can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT5, WMO header WTNT45 KNHC and
on the web at
www.hurricanes.gov/graphics_at5.shtml?key_messages.

WIND: Tropical storm conditions will continue along the Gulf coast
of Florida in the warning area today.  Tropical storm conditions are
expected in the Tropical Storm Warning area along the Georgia coast
by late today or tonight and along the South Carolina coast tonight
and early Thursday.  Tropical storm conditions are possible in the
watch area in the mid-Atlantic and northeastern states by Thursday
night and Friday.

STORM SURGE: The combination of a storm surge and the tide will
cause normally dry areas near the coast to be flooded by rising
waters moving inland from the shoreline.  The water could reach the
following heights above ground somewhere in the indicated areas if
the peak surge occurs at the time of high tide...

Suwannee River to Aucilla River...2 to 4 ft
Middle of Longboat Key, FL to Suwannee River including Tampa Bay...1
to 3 ft
Aucilla River to Ochlockonee River...1 to 3 ft
Mouth of St. Marys River to South Santee River...1 to 2 ft

Surge-related flooding depends on the relative timing of the surge
and the tidal cycle, and can vary greatly over short distances.  For
information specific to your area, please see products issued by
your local National Weather Service forecast office.

RAINFALL: Elsa is expected to produce the following rainfall amounts
and impacts the rest of this week:

Across western and northern portions of the Florida Peninsula...3
to 6 inches with localized maximum storm totals up to 9 inches
today, which may result in considerable flash and urban flooding,
along with minor to isolated moderate river flooding.

Across portions of southeast Georgia and the Lowcountry of South
Carolina, 2 to 4 inches with isolated maximum totals up to 6 inches
will be possible, which may result in considerable flash and urban
flooding.

Across eastern North Carolina into southeastern Virginia...1 to 3
inches with isolated totals up to 5 inches tonight through Thursday
night, which could lead to isolated flash and urban flooding.

Across the Northeast and New England, 1 to 3 inches with isolated
totals up to 5 inches Thursday into Friday will be possible. This
could lead to isolated flash and urban flooding.

TORNADOES: A few tornadoes are possible today and tonight across
northern Florida and southeastern Georgia into eastern South
Carolina.  The tornado threat should shift to the eastern Carolinas
and far southeast Virginia on Thursday.

SURF: Swells will continue to affect portions of the west coast of
Florida through today.  These swells are likely to cause
life-threatening surf and rip current conditions.  Please consult
products from your local weather office for more details.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM EDT.

$$
Forecaster Pasch/Papin/Brown