#24 Postby cycloneye » Thu Sep 14, 2023 8:01 pm
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
Hurricane Margot Discussion Number 21
NWS National Hurricane Center Miami FL AL142023
300 PM GMT Tue Sep 12 2023
After a brief hiatus, Margot has redevloped a fairly clear eye.
Cloud-top temperatures around that eye are cold enough to support
satellite intensity estimates similar to the previous advisory and
the intensity is held at 75 kt. The big change with this advisory is
that ASCAT data valid between 12 and 13 UTC revealed Margot has
grown substantially, with 34 kt and 50 kt winds extending much
farther from the center of the hurricane than previously estimated.
Microwave data also suggest the presence of a double eyewall.
There is high confidence in the track forecast for the next 3 days.
Margot should turn north-northwestward tomorrow while it slows down.
After that, there is considerable uncertainty in the strength of a
ridge that is forecast to build to the north of Margot. The GFS and
ECMWF are on opposite ends of the spectrum, with the GFS showing
Margot moving faster to the north due to a weaker blocking high.
Confidence in the track forecast decreases at day 4 and 5 given the
high spread. The NHC forecast is near the multi-model consensus, but
relatively large changes could be required to later advisories if
one model solution or another becomes more likely.
The aforementioned ASCAT passes also showed that despite the
relatively small eye of Margot, the wind field is fairly spread
out, which may limit the potential for substantial further
intensification. Most of the hurricane models seem to have a good
handle on this, showing Margot more or less maintaining its
intensity for the next several days. Weakening should begin after
3 days as Margot moves over cooler waters, wind shear increases,
and possibly its transition to an extratropical cyclone begins.
FORECAST POSITIONS AND MAX WINDS
INIT 12/1500Z 30.2N 39.4W 75 KT 85 MPH
12H 13/0000Z 31.8N 40.0W 80 KT 90 MPH
24H 13/1200Z 33.3N 41.0W 80 KT 90 MPH
36H 14/0000Z 34.3N 41.6W 75 KT 85 MPH
48H 14/1200Z 35.3N 41.6W 75 KT 85 MPH
60H 15/0000Z 36.3N 41.4W 70 KT 80 MPH
72H 15/1200Z 37.0N 41.5W 70 KT 80 MPH
96H 16/1200Z 38.5N 43.0W 55 KT 65 MPH
120H 17/1200Z 40.5N 43.0W 45 KT 50 MPH
$$
Forecaster D. Zelinsky
Hurricane Margot Discussion Number 22
NWS National Hurricane Center Miami FL AL142023
900 PM GMT Tue Sep 12 2023
As quickly as it re-appeared earlier today, Margot's eye
disappeared again this evening. Consequently, Dvorak-based
intensity estimates have decreased a little, with a blend of Data-T
and Current Intensity values supporting an intensity near 70 kt.
Based on recent AMSR microwave imagery, Margot still has a double
eyewall, and a SAR overpass earlier this morning indicated that the
winds in the outer eyewall were just as high as the inner one.
Margot has continued moving northward today, and should turn
north-northwestward tomorrow. Beyond about 60 h, there is a
significant increase in model forecast spread, and therefore,
forecast uncertainty. The ECMWF and GFS highlight this uncertainty,
showing very different forecasts for a ridge that is supposed to
build to the north of Margot over the next 3 days, which results in
a very different track for the hurricane. However, ensemble
forecasts from those models indicate that their deterministic model
solutions are part of a wide spectrum of possible tracks for Margot.
The ECMWF track ensemble, for instance, has approximately 27 degrees
of latitude spread between members at 120 h. We don't have a clear
reason to favor any one solution at this time, so the NHC forecast
is near the multi-model consensus. It is possible that large track
adjustments will be needed to future NHC forecasts.
For the next few days, Margot's intensity should stay relatively
steady, and this is supported by nearly every normally-reliable
intensity model. Beyond about 72 h, the track of Margot will have an
influence on its intensity, which increases the uncertainty.
Depending on the exact evolution and path of Margot, it could hold
its intensity for a bit longer, or quickly begin a transition to a
remnant low. The NHC forecast is in the middle of these solutions,
showing steady weakening, but the uncertainty in the intensity
forecast is also unusually high.
FORECAST POSITIONS AND MAX WINDS
INIT 12/2100Z 31.7N 39.6W 70 KT 80 MPH
12H 13/0600Z 33.2N 40.2W 75 KT 85 MPH
24H 13/1800Z 34.4N 41.0W 70 KT 80 MPH
36H 14/0600Z 35.4N 41.2W 70 KT 80 MPH
48H 14/1800Z 36.4N 40.7W 70 KT 80 MPH
60H 15/0600Z 37.1N 40.6W 70 KT 80 MPH
72H 15/1800Z 37.5N 41.0W 65 KT 75 MPH
96H 16/1800Z 38.1N 42.5W 50 KT 60 MPH
120H 17/1800Z 40.0N 43.0W 45 KT 50 MPH
$$
Forecaster D. Zelinsky
NNNN
Hurricane Margot Discussion Number 23
NWS National Hurricane Center Miami FL AL142023
300 AM GMT Wed Sep 13 2023
Margot's satellite appearance has improved since the previous
advisory. Infrared imagery indicates deep convection wraps
around the center, with cold cloud tops. Infrared and proxy-vis
satellite depict that an eye may also be trying to reappear. A
recent scatterometer pass shows that the system continues to have a
very large wind field. Subjective Dvorak estimates for this cycle
were T4.0/T4.5 from TAFB and SAB, respectively. Using a blend of
these estimates and the improved satellite appearance, the initial
intensity for this advisory is raised to 75 kt.
Margot has started to move north-northwestward, and should continue
this motion with a slightly slower forward speed on Wednesday. In
about 2 to 3 days, there continues to be significant divergence in
the guidance envelope, and therefore there is higher than normal
forecast uncertainty. A ridge is forecast to build north of Margot
over the next couple of days. The GFS and ECMWF have two very
different solutions with how Margot interacts with this ridge, and
are on opposite sides of the guidance suite. The current NHC
forecast has not been adjusted much from the previous one, which
remains near the multi-model consensus aids, as there is no reason
to favor either global model solution at this time. It is possible
that larger track adjustments will be needed to future NHC
forecasts.
Margot's intensity should stay relatively steady, with slight
fluctuations, up or down, during the next several days. The
intensity guidance is in fairly good agreement in the short-term.
However, in about 2 to 3 days, similar to the track forecast there
is uncertainty in the intensity forecast as they are dependent on
one another. The NHC intensity forecast is similar to the previous
one, and lies near the multi-model consensus showing steady
weakening towards the end of the forecast period.
FORECAST POSITIONS AND MAX WINDS
INIT 13/0300Z 32.7N 39.7W 75 KT 85 MPH
12H 13/1200Z 34.0N 40.4W 75 KT 85 MPH
24H 14/0000Z 35.1N 40.8W 70 KT 80 MPH
36H 14/1200Z 36.1N 40.6W 70 KT 80 MPH
48H 15/0000Z 36.9N 40.2W 70 KT 80 MPH
60H 15/1200Z 37.3N 40.2W 65 KT 75 MPH
72H 16/0000Z 37.5N 40.6W 60 KT 70 MPH
96H 17/0000Z 38.4N 42.4W 50 KT 60 MPH
120H 18/0000Z 40.6N 42.0W 45 KT 50 MPH
$$
Forecaster Kelly
Hurricane Margot Discussion Number 24
NWS National Hurricane Center Miami FL AL142023
900 AM GMT Wed Sep 13 2023
The eye of Margot has been obscured by clouds to varying degrees
overnight, but has begun to warm in the latest infrared satellite
images this morning. Recent AMSR2 microwave images reveal the
hurricane has a compact inner core, with a concentric outer ring of
convection that is broken to the northwest. Earlier scatterometer
data indicated a secondary wind maximum exists within this outer
band. The vortex is slightly tilted with height, as the mid-level
89-GHz eye lies to the southwest of the 37-GHz center. The
intensity for this advisory remains 75 kt based on consensus T4.5
Dvorak classifications from TAFB and SAB.
Margot has begun to slow down while moving northward (350/10 kt)
within the flow between a deep-layer ridge over the eastern Atlantic
and a narrow upper trough to its west. A general northward motion
should continue over the next day or so before the track forecast
becomes very challenging. Margot is forecast to become caught in
weak steering currents, with the global models showing a blocking
ridge developing to the north of the cyclone by late week into the
weekend. There are significant differences between the GFS and ECMWF
with regards to the strength and position of this ridge, which has
large implications in the longer-range track of Margot. Based on the
overall shift in the guidance suite this cycle, the latest NHC
forecast shows little net motion between 36-72 h as Margot meanders
over the central Atlantic. This is a fairly large departure from the
previous advisory, but better represents the latest consensus track
solutions. At days 4-5, most models (except for the ECMWF) show the
ridge sliding eastward, but overall track forecast confidence is
very low and larger future adjustments could be necessary.
It is possible that Margot is at or near its peak intensity. The
deep-layer shear is forecast to increase during the next 24 h, and
thereafter the coupled atmosphere-ocean models indicate the slow
motion of the storm is likely to result in upwelling of cooler
waters. In addition, the surrounding environment is expected to
become drier and more subsident by this weekend. The NHC intensity
forecast has been lowered from the previous one and shows steady
weakening beyond 36 h, in good agreement with the latest HCCA and
IVCN aids. Although this forecast keeps Margot a tropical cyclone
through day 5, simulated satellite imagery from the global models
suggests these environmental factors could cause the system to lose
organized convection and become post-tropical early next week.
FORECAST POSITIONS AND MAX WINDS
INIT 13/0900Z 33.6N 40.0W 75 KT 85 MPH
12H 13/1800Z 34.5N 40.5W 75 KT 85 MPH
24H 14/0600Z 35.6N 40.5W 70 KT 80 MPH
36H 14/1800Z 36.5N 39.9W 70 KT 80 MPH
48H 15/0600Z 36.9N 39.5W 65 KT 75 MPH
60H 15/1800Z 36.7N 39.4W 60 KT 70 MPH
72H 16/0600Z 36.5N 39.7W 55 KT 65 MPH
96H 17/0600Z 36.5N 42.5W 45 KT 50 MPH
120H 18/0600Z 38.0N 43.0W 40 KT 45 MPH
$$
Forecaster Reinhart
Hurricane Margot Discussion Number 25
NWS National Hurricane Center Miami FL AL142023
Issued by the NWS Weather Prediction Center College Park MD
300 PM GMT Wed Sep 13 2023
Margot continues to exhibit a double eyewall structure based on
a recent SAR pass over the storm, with a well-defined inner core.
GOES-16 IR data shows the inner-eye feature occasionally obscured by
clouds, but overall the organization of Margot has changed little
over the last several hours. The latest microwave data in
conjunction with the SAR pass suggests the initial intensity may be
just a tad stronger compared to continuity, and so it will be set at
80 kt for this advisory.
Margot is slowing down as it moves within the flow between a
deep-layer ridge over the eastern Atlantic and a narrow upper trough
to its west. A general north to north-northwest motion should
continue over the next day or so before the track forecast becomes
very challenging. Margot is expected to become caught in weak
steering currents, with the global models showing a blocking ridge
developing to the north of the cyclone by late week into the
weekend. There are significant differences between the GFS and ECMWF
with regards to the strength and position of this ridge, which has
large implications in the longer-range track of Margot. The overall
consensus of the guidance suggests that Margot could make a
clockwise loop as the ridge builds, and the latest NHC forecast
shows little net motion between 36-72 hrs as the cyclone meanders
over the central Atlantic. At days 4-5, most models (except for the
ECMWF) show the ridge sliding eastward, allowing for Margot to
gain latitude, and the overall track forecast confidence remains
low.
The deep-layer shear is forecast to increase during the next 24 to
36 hrs, and this coupled with a likelihood of the upwelling of
cooler waters should result in a weakening trend. Drier air
surrounding the storm will also be a factor in causing a weakening
cyclone going into the weekend. The NHC intensity forecast is close
to the previous forecast and shows gradual decrease in strength
through 72 hrs, and in good agreement with the consensus of the
intensity aids. Although this forecast keeps Margot a tropical
cyclone through day 5, simulated satellite imagery from the global
models suggests these environmental factors could cause the system
to lose organized convection and become post-tropical early next
week as the storm lingers west of the Azores.
FORECAST POSITIONS AND MAX WINDS
INIT 13/1500Z 34.1N 40.4W 80 KT 90 MPH
12H 14/0000Z 35.0N 40.7W 75 KT 85 MPH
24H 14/1200Z 36.0N 40.2W 75 KT 85 MPH
36H 15/0000Z 36.8N 39.5W 70 KT 80 MPH
48H 15/1200Z 36.9N 39.4W 65 KT 75 MPH
60H 16/0000Z 36.5N 39.4W 60 KT 70 MPH
72H 16/1200Z 36.3N 40.2W 50 KT 60 MPH
96H 17/1200Z 36.0N 42.5W 45 KT 50 MPH
120H 18/1200Z 38.0N 42.5W 45 KT 50 MPH
$$
Forecaster Orrison/Blake
Hurricane Margot Discussion Number 26
NWS National Hurricane Center Miami FL AL142023
Issued by the NWS Weather Prediction Center College Park MD
900 PM GMT Wed Sep 13 2023
Very little change is noted with Margot's convective structure
since the last advisory. The cyclone continues to exhibit a double
eyewall structure based on a 1527Z AMSR-2 pass, and Margot's eye
still occasionally appears in conventional GOES-16 IR and VIS
imagery. Given the lack of change with the hurricane's internal
structure and appearance, the intensity will be maintained at 80 kt
for this advisory. The motion has bent just slightly to the right
since this morning and is now moving due north at 6 kt.
Margot continues to gradually slow down as it moves within the flow
between a deep-layer ridge over the eastern Atlantic and a narrow
upper trough to its west. A general northward motion should continue
over the next day or so before the track forecast becomes very
challenging. Margot will then become caught in weak steering
currents, with the global models showing a blocking ridge developing
to the north of the cyclone by late week into the weekend. There
remain notable differences between the GFS and ECMWF with regards to
the strength and position of this ridge, which has large
implications in the longer-range track of Margot, but there has been
some tightening of the model consensus since this morning. This
supports the storm making a gradual clockwise loop between 36-72 hrs
as the ridge initially builds north of the cyclone and then slides
off to the east. By 120 hrs, the storm will likely begin
accelerating off to the northeast as it gets picked up by the
westerlies, but the overall track forecast confidence remains low
given the model spread late in the forecast period.
Increasing deep-layer shear during the next 24 to 36 hrs,
entrainment of drier air, and a likelihood of Margot upwelling
cooler waters should result in a steady weakening of the cyclone
going through the end of the week and into the weekend. The NHC
intensity forecast is close to the previous one and shows a gradual
decrease in strength through 72 hrs, in good agreement with the
consensus of the intensity aids. Although this forecast keeps Margot
a tropical cyclone through day 5, simulated satellite imagery from
the global models suggests these increasingly hostile environmental
factors could cause the system to lose organized convection and
become post-tropical by early next week as the storm lingers west
of the Azores.
FORECAST POSITIONS AND MAX WINDS
INIT 13/2100Z 34.7N 40.6W 80 KT 90 MPH
12H 14/0600Z 35.5N 40.6W 75 KT 85 MPH
24H 14/1800Z 36.4N 40.0W 70 KT 80 MPH
36H 15/0600Z 36.7N 39.5W 65 KT 75 MPH
48H 15/1800Z 36.5N 39.4W 65 KT 75 MPH
60H 16/0600Z 36.0N 39.9W 60 KT 70 MPH
72H 16/1800Z 35.6N 41.0W 50 KT 60 MPH
96H 17/1800Z 36.5N 43.0W 45 KT 50 MPH
120H 18/1800Z 39.5N 41.5W 45 KT 50 MPH
$$
Forecaster Orrison/Blake
NNNN
Hurricane Margot Discussion Number 27
NWS National Hurricane Center Miami FL AL142023
300 AM GMT Thu Sep 14 2023
Margot's satellite depiction has become more ragged during the last
few hours. An earlier microwave pass showed that the center was
partially opened on the northern and western sides of the system.
Dry air is beginning to wrap into the center of the system, which
has caused some of the banding features to become broken. The center
has been cloud filled since the previous advisory, with overall
warming cloud tops. Satellite Dvorak current intensity estimates
were both 4.5 from TAFB and SAB. Given these estimates and the
degraded satellite depiction, the initial intensity for this
advisory is lowered to 75 kt.
Margot continues to gradually slow down as it moves within the flow
between a deep-layer ridge over the eastern Atlantic and an upper
trough to its west. A general northward motion should continue over
the next day or so. The steering pattern becomes fairly weak with a
blocking ridge to the north of the system, causing Margot to meander
over the north Atlantic and make a gradual clockwise loop over the
next 2 to 3 days. There are still some large differences in the
guidance envelope in the long term, but slightly better agreement
than 24 h ago. By the end of the period, the storm will likely
begin accelerating off to the east-northeast as it gets picked up by
the westerlies, but the overall track forecast confidence remains
low given the model spread.
Margot's convective structure has degraded this evening. The system
is entering a less favorable environment, with dry air entrainment
beginning to erode some of the structure. Deep-layer shear is also
forecast to increase, and upwelling of cooler waters due to the lack
of forward motion should result in weakening of the system through
the weekend. The NHC intensity forecast is similar to the previous
advisory and lies near the corrected consensus aids, the HCCA and
IVCN. Although the forecast keeps Margot a tropical cyclone through
day 5, simulated satellite imagery from the global models suggests
these increasingly hostile environmental factors could cause the
system to lose organized convection and become post-tropical sooner.
FORECAST POSITIONS AND MAX WINDS
INIT 14/0300Z 35.2N 40.5W 75 KT 85 MPH
12H 14/1200Z 35.9N 40.2W 70 KT 80 MPH
24H 15/0000Z 36.4N 39.6W 65 KT 75 MPH
36H 15/1200Z 36.4N 39.3W 60 KT 70 MPH
48H 16/0000Z 36.1N 39.6W 55 KT 65 MPH
60H 16/1200Z 35.6N 40.5W 50 KT 60 MPH
72H 17/0000Z 35.5N 41.7W 45 KT 50 MPH
96H 18/0000Z 37.2N 43.2W 45 KT 50 MPH
120H 19/0000Z 40.4N 40.2W 45 KT 50 MPH
$$
Forecaster Kelly
Hurricane Margot Discussion Number 28
NWS National Hurricane Center Miami FL AL142023
900 AM GMT Thu Sep 14 2023
The satellite structure of Margot has continued to deteriorate. The
low-level center has been partially exposed in GOES-16 proxy-visible
satellite images, and recent AMSR2 microwave data show the inner
core convection has eroded. These changes appear to be the result of
some southwesterly shear over the system and dry air intrusions into
the circulation. Presently, deep convection is limited to a couple
of curved bands that wrap around the northern portion of the system.
The objective and subjective satellite intensity estimates have
markedly decreased, and the initial intensity is lowered to 65 kt,
in best agreement with recent UW-CIMSS SATCON and TAFB Dvorak
current intensity estimates. However, this could be generous given
the rapidly degrading satellite presentation.
Margot continues to slow down this morning, and it appears the
center has recently turned north-northeastward (015/5 kt). The
cyclone is likely to stall and meander over the next couple of days
in response to a building ridge to its north and west. In general,
the track models agree that Margot will make a gradual clockwise
loop while it pivots around the ridge that is forecast to slowly
slide eastward over the weekend. However, there is still large
spread in the various model solutions while the steering currents
remain weak. The updated NHC forecast tries to reflect the latest
trends of the multi-model consensus aids and shows little movement
between 12-60 h. By early next week, the ridge should become
re-positioned to the east of Margot, allowing the system to turn
northward and become caught up in the mid-latitude westerlies.
In addition to the ongoing shear, several factors suggest Margot is
likely to continue weakening during the next several days. The
cyclone is over marginal SSTs, and the coupled atmosphere-ocean
models indicate the slow-moving storm is likely to upwell even
cooler waters while it meanders over the central Atlantic. Also,
more bouts of dry air entrainment within a drier and more subsident
environment will make it difficult for Margot to sustain convection
near its center, as suggested by the GFS and ECMWF simulated
satellite imagery. The NHC forecast shows continued weakening
through early next week with Margot becoming extratropical in 120 h
while accelerating into the mid-latitudes. Although not explicitly
forecast, it is noted that the hostile conditions could render
Margot devoid of deep convection even sooner.
FORECAST POSITIONS AND MAX WINDS
INIT 14/0900Z 35.9N 40.3W 65 KT 75 MPH
12H 14/1800Z 36.4N 39.8W 60 KT 70 MPH
24H 15/0600Z 36.6N 39.2W 55 KT 65 MPH
36H 15/1800Z 36.4N 39.0W 55 KT 65 MPH
48H 16/0600Z 35.9N 39.5W 50 KT 60 MPH
60H 16/1800Z 35.4N 40.6W 50 KT 60 MPH
72H 17/0600Z 35.2N 42.0W 45 KT 50 MPH
96H 18/0600Z 37.5N 43.3W 45 KT 50 MPH
120H 19/0600Z 40.5N 39.0W 40 KT 45 MPH...POST-TROP/EXTRATROP
$$
Forecaster Reinhart
Hurricane Margot Discussion Number 29
NWS National Hurricane Center Miami FL AL142023
Issued by the NWS Weather Prediction Center College Park MD
300 PM GMT Thu Sep 14 2023
The double-eyewall structure of Margot has changed this morning,
with the inner-eye almost completely dissipated, and the outer
eyewall has taken over as the dominant feature. This is confirmed
by scatterometer data from ASCAT-B and a SAR pass around 9 UTC. The
initial wind speed is set to 70 kt, a compromise between higher SAR
estimates and Dvorak values closer to 65 kt. Note that the
hurricane- and storm-force wind radii have been changed/expanded
significantly due to the SAR/scatterometer data.
Margot has turned further to the right, or 030/5. A blocking ridge
over the north-central Atlantic should force Margot to slow down
and execute a clockwise loop during the next few days. After the
ridge shifts eastward, the hurricane could gain some latitude and
begin to move more to the northeast at the end of the forecast
period. Model guidance is coming into better agreement on this
solution, although there is considerable spread at long range with
the GFS faster and more to the northeast than the ECMWF-based
guidance. The new NHC forecast is shifted southward in the near
term with the GFS coming more into line with the other guidance,
and ends up in almost the same spot as the last forecast by day 5.
The hurricane should gradually weaken as the large system slows
down and upwells cooler water, along with Margot crossing over its
own path. Additionally, there is plenty of mid-level dry air in
the surrounding environment that could be mixed in the core
eventually. The updated forecast is adjusted higher initially
because of the current intensity, but is blended back with the
previous forecast and consensus aids at longer term. Margot could
become a post-tropical cyclone without deep convection early next
week, but it really depends on how it handles the more hostile
conditions. Given how resilient this season's tropical cyclones
have been, it could be optimistic that Margot is post-tropical on
day 5.
FORECAST POSITIONS AND MAX WINDS
INIT 14/1500Z 36.5N 39.8W 70 KT 80 MPH
12H 15/0000Z 36.8N 39.3W 65 KT 75 MPH
24H 15/1200Z 36.7N 38.9W 65 KT 75 MPH
36H 16/0000Z 36.2N 38.8W 60 KT 70 MPH
48H 16/1200Z 35.5N 39.5W 55 KT 65 MPH
60H 17/0000Z 35.0N 41.0W 50 KT 60 MPH
72H 17/1200Z 35.1N 42.3W 45 KT 50 MPH
96H 18/1200Z 37.5N 43.3W 45 KT 50 MPH
120H 19/1200Z 40.0N 39.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
$$
Forecaster Fracasso/Blake
Hurricane Margot Discussion Number 30
NWS National Hurricane Center Miami FL AL142023
Issued by the NWS Weather Prediction Center College Park MD
900 PM GMT Thu Sep 14 2023
An inner eyewall redeveloped today, with the outer eyewall
persisting. Outflow is well-established to Margot's north and
northeast, near the base of a shortwave trough in the northeast
Atlantic. Vertical wind shear over the hurricane appears modest and
not enough to cause additional weakening. The initial wind speed
remains set to 70 kt, a compromise between the earlier higher SAR
estimates and Dvorak values closer to 65 kt, as Margot does not
appear to have degraded today.
Margot has turned further to the right, or 050/4. A blocking ridge
over the north-central Atlantic should force Margot to slow down and
execute a clockwise loop during the next few days. After the ridge
shifts eastward, the hurricane should gain some latitude and begin
to move more to the northeast at the end of the forecast period.
Model guidance is in good agreement on this general idea, although
there is considerable spread at long range with the GFS faster and
more to the northeast than the ECMWF-based guidance. The new
forecast remains close to continuity, near or just behind the model
consensus.
The hurricane should gradually weaken as the large system slows down
and upwells cooler water, along with it crossing over its own cold
wake. Simulated satellite imagery indicates that over the weekend,
Margot could be struggling to maintain convection near its center.
There is plenty of mid-level dry air in the surrounding environment,
as it navigates around the center of a warm-core high, which could
be mixed in the core. Margot could become a post-tropical cyclone
without deep convection early next week, but that really depends on
how it handles the more hostile conditions and if it can regain
convection as it tries to escape into the westerlies. Given how
resilient this season's tropical cyclones have been, it could be
optimistic that Margot is post-tropical on day 5.
FORECAST POSITIONS AND MAX WINDS
INIT 14/2100Z 36.9N 39.3W 70 KT 80 MPH
12H 15/0600Z 36.9N 38.9W 65 KT 75 MPH
24H 15/1800Z 36.4N 38.8W 65 KT 75 MPH
36H 16/0600Z 35.8N 39.2W 60 KT 70 MPH
48H 16/1800Z 35.4N 40.4W 50 KT 60 MPH
60H 17/0600Z 35.4N 41.8W 45 KT 50 MPH
72H 17/1800Z 35.7N 43.3W 45 KT 50 MPH
96H 18/1800Z 38.6N 42.6W 50 KT 60 MPH
120H 19/1800Z 40.2N 37.9W 45 KT 50 MPH...POST-TROP/EXTRATROP
$$
Forecaster Roth/Blake
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