2023 Hurricane Season Discussion

[tireman4]

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Tropical Storm Margot Discussion Number 17
NWS National Hurricane Center Miami FL AL142023
Issued by the NWS Weather Prediction Center College Park MD
300 PM GMT Mon Sep 11 2023

Satellite images indicate that Margot is strengthening. A ragged
eye has emerged from the central dense overcast pattern, although
it is open on the east side. Additionally, overnight microwave
data showed the eye pattern on numerous passes, suggesting this is
a real eye feature. With the improvement in the satellite
presentation, the initial wind speed is set to 60 kt, closest to
the D-MINT intensity estimate from UW-CIMSS, but below recent
Dvorak DT estimates of 65 kt.

Margot is moving northward at about 9 kt, and that general motion
should continue for the next few days, with a north-northwest bend
expected by midweek as ridging builds to the east of the storm. A
large mid-latitude ridge is forecast to block Margot's path after
that time, causing the cyclone to basically stall by the weekend.
Guidance is in very good agreement for the first few days, then the
uncertainty grows in unsteady steering currents beneath the ridge,
with aids fanning out in all directions. The new forecast is
similar to the previous one, showing little motion at days 4-5 as a
compromise between the various divergent model solutions.

The storm has a chance to strengthen further over the next couple
of days while it moves over relatively warm waters up to 28 deg C
and in lessening shear. In a few days, an increase in shear and
dry-air entrainment should gradually weaken Margot. This is an
interesting forecast because the dynamical model guidance is well
below the statistical guidance, despite a seemingly conducive
environment for intensification. The new NHC forecast leans
closer to the statistical models, adjusted a bit higher than the
last NHC intensity prediction, similar to the Florida State
Superensemble and NOAA corrected-consensus models.



FORECAST POSITIONS AND MAX WINDS

INIT 11/1500Z 26.1N 40.0W 60 KT 70 MPH
12H 12/0000Z 27.6N 40.0W 65 KT 75 MPH
24H 12/1200Z 29.8N 40.0W 75 KT 85 MPH
36H 13/0000Z 31.9N 40.5W 80 KT 90 MPH
48H 13/1200Z 33.6N 41.4W 80 KT 90 MPH
60H 14/0000Z 34.7N 41.9W 75 KT 85 MPH
72H 14/1200Z 35.8N 41.8W 70 KT 80 MPH
96H 15/1200Z 37.1N 40.9W 65 KT 75 MPH
120H 16/1200Z 37.0N 41.0W 55 KT 65 MPH

$$
Forecaster Blake/Taylor

NNNN

[tireman4]

URNT12 KNHC 111832
VORTEX DATA MESSAGE AL132023
A. 11/18:01:30Z
B. 23.50 deg N 063.93 deg W
C. 700 mb 2662 m
D. 949 mb
E. 175 deg 9 kt
F. OPEN SE
G. CO22-68
H. 87 kt
I. 330 deg 35 nm 17:50:00Z
J. 063 deg 104 kt
K. 329 deg 38 nm 17:49:00Z
L. 81 kt
M. 137 deg 33 nm 18:11:00Z
N. 231 deg 96 kt
O. 136 deg 37 nm 18:12:00Z
P. 8 C / 3052 m
Q. 17 C / 3056 m
R. NA / NA
S. 12345 / 07
T. 0.02 / 2 nm
U. AF309 1713A LEE OB 06
MAX FL WIND 104 KT 329 / 38 NM 17:49:00Z
OUTER EYEWALL CLOSED

[tireman4]

676
WTNT43 KNHC 120851
TCDAT3

Hurricane Lee Discussion Number 28
NWS National Hurricane Center Miami FL AL132023
500 AM AST Tue Sep 12 2023

Lee continues to exhibit a concentric eyewall structure in
conventional satellite imagery. This has been confirmed by the Air
Force Reserve Hurricane Hunters that investigated Lee early this
morning, and they reported the outer eyewall had a large diameter of
80 n mi. The maximum 700-mb flight-level wind measured by the
aircraft was 112 kt in the northeast quadrant, while the SFMR winds
peaked around 90 kt. Although the satellite intensity estimates have
fallen a bit this morning, the reduced flight-level winds support
holding the initial intensity at 100 kt for this advisory. The
minimum pressure of Lee remains 948 mb based on dropsonde data.

Lee is still moving slowly west-northwestward (290/6 kt), with
mid-level ridging established to the north and west of the
hurricane. This steering pattern is expected to change during the
next couple of days as a deep-layer trough moves across the eastern
United States and produces a weakness in this ridge. As a result,
Lee is forecast to turn northward and gradually accelerate during
the middle and latter parts of this week. The track guidance
envelope shows little cross-track spread during the first 3 days of
the forecast period, and this portion of the NHC forecast is fairly
similar to the previous one. While the core of the hurricane is
forecast to pass west of Bermuda, the large wind field of the storm
is likely to bring wind impacts to the island later this week, and
tropical storm watches could be required later today. At days 4-5,
there has been a slight westward shift in the guidance envelope, and
accordingly the NHC track forecast was nudged in that direction
toward the HCCA and TVCA aids.

Based on Lee's current satellite structure, as well as its slow
forward motion and large wind field, little near-term strengthening
is expected. Going forward, the large hurricane appears likely to
begin upwelling cooler waters along its path, and in a few days it
will encounter the cool wake left behind by recent western Atlantic
hurricanes. Thus, gradual weakening is forecast through midweek.
Later, the aforementioned trough is expected to produce stronger
deep-layer shear over Lee, and the hurricane is forecast to move
over significantly cooler waters as it passes north of the Gulf
Stream. As a result, more significant weakening is shown at days
4-5, along with completion of its extratropical transition. Despite
the weakening that is forecast, keep in mind that the expanding wind
field of Lee will produce impacts well away from the storm center.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. There is an increasing risk of strong winds, rainfall, and high
surf impacts to Bermuda later this week, and tropical storm watches
could be required for the island later today.

3. It remains too soon to know what level of additional impacts Lee
might have along the Northeastern U.S. coast and Atlantic Canada
late this week and this weekend. However, since wind and rainfall
hazards will extend well away from the center as Lee grows in size,
users should continue to monitor updates to Lee's forecast during
the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 24.0N 65.4W 100 KT 115 MPH
12H 12/1800Z 24.4N 66.2W 100 KT 115 MPH
24H 13/0600Z 25.3N 67.0W 100 KT 115 MPH
36H 13/1800Z 26.6N 67.5W 95 KT 110 MPH
48H 14/0600Z 28.3N 67.9W 90 KT 105 MPH
60H 14/1800Z 30.4N 68.0W 85 KT 100 MPH
72H 15/0600Z 32.9N 67.6W 80 KT 90 MPH
96H 16/0600Z 39.0N 66.7W 70 KT 80 MPH
120H 17/0600Z 44.5N 66.0W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

[tireman4]

000
WTNT44 KNHC 120847
TCDAT4

Hurricane Margot Discussion Number 20
NWS National Hurricane Center Miami FL AL142023
900 AM GMT Tue Sep 12 2023

Margot's eye became obscured in infrared satellite imagery a couple
of hours ago, but the hurricane still has a well-defined Central
Dense Overcast surrounded by convective banding features. A dry
slot has become entrained into the eastern part of the circulation,
between the CDO and the outermost banding. Based on consensus
Dvorak estimates of T4.5 from TAFB and SAB, the initial intensity
is raised to 75 kt.

Margot is moving northward (360/11 kt) along the western periphery
of a mid-level ridge emanating out of western Africa, and this
steering mechanism should keep the hurricane on a general
northward or north-northwestward trajectory for the next few
days. A blocking ridge is forecast to form in 2-3 days over the
north Atlantic, which is likely to cause Margot to slow down during
the middle to latter part of the forecast period. However, the
ridge may be relatively progressive, and by day 5 many of the track
models show the storm picking up some speed again once the ridge
gets out of the way. The most notable change in the NHC track
forecast is that it's faster than the previous prediction on days 4
and 5 to better align with the latest guidance.

The hurricane is currently within a strongly diffluent environment
to the east of an upper-level trough, but the environment is
forecast to evolve to an anticyclone aloft and low shear within the
next 12 hours. Continued strengthening is therefore likely, but
any intensification trend could be halted soon after 24 hours when
the hurricane slows down and potentially upwells cooler waters.
The NHC intensity forecast is above the intensity consensus during
the first day or two and is closest to the statistical-dynamical
guidance. Weakening is likely to occur after 48 hours due to
cooler waters and an increase in deep-layer shear.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 29.3N 39.5W 75 KT 85 MPH
12H 12/1800Z 30.9N 39.9W 80 KT 90 MPH
24H 13/0600Z 32.7N 40.8W 85 KT 100 MPH
36H 13/1800Z 34.0N 41.7W 85 KT 100 MPH
48H 14/0600Z 35.0N 42.1W 85 KT 100 MPH
60H 14/1800Z 36.0N 41.9W 80 KT 90 MPH
72H 15/0600Z 36.9N 41.6W 75 KT 85 MPH
96H 16/0600Z 38.2N 42.6W 60 KT 70 MPH
120H 17/0600Z 40.4N 43.4W 50 KT 60 MPH

$$
Forecaster Berg

[snowman65]

Enough about Lee.. non-factor.

[tireman4]

Enough about Lee.. non-factor.

Well, with all due respect, this 2023 Hurricane Discussion. Lee and Margot are hurricanes ( or tropical systems). Second, there are people on this forum that have loved ones in the area that Lee might come close to. Third, I appreciate your input, but this is an information board and information is being posted. If you have issues or concerns, please contact me by DM. !!!!!!!

[Stratton20]

snowman65 may be a non factor to you, not to some folks thougb it isnt

[tireman4]

From Mr. 57..

HAFS A & B are trending farther east, taking Lee into New Brunswick at a faster pace. Let's see if the EC speeds it up at 12Z and catches the trof. It'll be transitioning to ET by the time it passes east of Cape Cod Saturday morning. Larger wind field, no core of intense winds. Big issue for southern New England will be the 30-40 mph wind. Trees have leaves on them this time or year, unlike when nor'easters produce this kind of wind. Also, the ground is saturated from recent rains, making trees more apt to fall.

P.S.
Yes, EC has a faster movement and takes the center inland into New Brunswick. However, by then, there won't be anything near the center to make landfall.

[DoctorMu]

Enough about Lee.. non-factor.

Well, with all due respect, this 2023 Hurricane Discussion. Lee and Margot are hurricanes ( or tropical systems). Second, there are people on this forum that have loved ones in the area that Lee might come close to. Third, I appreciate your input, but this is an information board and information is being posted. If you have issues or concerns, please contact me by DM. !!!!!!!

Large windfield (500 miles) by the time Lee reaches east of Cape Cod.

[tireman4]

000
WTNT43 KNHC 130853
TCDAT3

Hurricane Lee Discussion Number 32
NWS National Hurricane Center Miami FL AL132023
500 AM AST Wed Sep 13 2023

Lee's structure is very gradually declining in organization. The
hurricane has a ragged but somewhat elliptical 25-30 n mi wide eye,
but deep convection has become eroded a bit within the western
semicircle, possibly due to some moderate westerly shear. In
addition, a 0607 UTC AMSR-2 microwave pass showed that the eyewall
was open on the southwest side at that time. Subjective and
objective satellite estimates range from 90-105 kt, so Lee's
initial intensity remains 100 kt for now.

The hurricane is very slowly making its turn around a west-central
Atlantic mid-level high, with its motion now northwestward at
325/5 kt. The track guidance is tightly clustered during the next
2 days or so, showing Lee turning and accelerating toward the
north-northwest and north between the high and a shortwave trough
swinging across the Great Lakes region. Lee's core is forecast to
pass west of Bermuda in 36-48 hours, but tropical storm conditions
are likely to begin there late tonight or early Thursday due to the
hurricane's large wind field. On days 3 and 4, Lee is expected to
maintain a general northward track offshore the northeastern U.S.
However, the global models are suggesting that the hurricane
will interact with a remnant mid-level trough over the mid-Atlantic
states, causing Lee to possibly bend just west of due north while
it moves across the Gulf of Maine. Under the assumption that the
global models will have a better handle on this mid-latitude
pattern as compared to the regional hurricane models, the NHC track
forecast is close to a consensus of the GFS and ECMWF models (GFEX)
on days 3, 4, and 5, and therefore ends up being a bit west and
then north of the previous prediction on those days.

A number of factors--including Lee's broad structure, increasing
shear, and potential upwelling of cooler waters--are likely to lead
to a very gradual decrease in the hurricane's maximum winds during
the next 3 days or so. In addition, Lee is likely to begin
extratropical transition in 2-3 days, with that process expected to
be complete just before the cyclone's center reaches the coast of
Maine, New Brunswick, or Nova Scotia in about 4 days. That said,
Lee's expected post-tropical transition will not diminish potential
wind, rain, and coastal flooding impacts in New England and Atlantic
Canada due to the system's broad wind field.

It should again be noted that the 34- and 50-kt wind speed
probabilities beyond 36 hours in the text and graphical products are
likely underestimating the risk of those winds occurring. This is
because the forecast wind field of Lee is considerably larger than
average compared to the wind field used to derive the wind speed
probability product.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. Tropical storm conditions, heavy rainfall, and high surf are
expected to impact Bermuda beginning late tonight or early Thursday,
and a Tropical Storm Warning is in effect for the island.

3. There is an increasing risk of wind, coastal flooding, and rain
impacts from Lee in portions of New England and Atlantic Canada
beginning on Friday and continuing through the weekend. Watches may
be required for portions of these areas later today or tonight.
Due to Lee's large size, hazards will extend well away from the
center, and there will be little to no significance on exactly where
the center reaches the coast.


FORECAST POSITIONS AND MAX WINDS

INIT 13/0900Z 25.7N 67.1W 100 KT 115 MPH
12H 13/1800Z 26.6N 67.6W 95 KT 110 MPH
24H 14/0600Z 28.4N 68.1W 90 KT 105 MPH
36H 14/1800Z 30.5N 68.3W 85 KT 100 MPH
48H 15/0600Z 33.0N 68.0W 80 KT 90 MPH
60H 15/1800Z 36.1N 67.4W 75 KT 85 MPH
72H 16/0600Z 39.6N 67.3W 70 KT 80 MPH
96H 17/0600Z 45.2N 67.3W 50 KT 60 MPH...POST-TROP/INLAND
120H 18/0600Z 51.0N 61.4W 35 KT 40 MPH...POST-TROP/INLAND

$$
Forecaster Berg