ATL: NADINE - Advisories

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ATL: NADINE - Advisories

#1 Postby cycloneye » Tue Oct 09, 2018 5:07 am

BULLETIN
Tropical Depression Fifteen Special Advisory Number 1
NWS National Hurricane Center Miami FL AL152018
600 AM AST Tue Oct 09 2018

...ANOTHER TROPICAL DEPRESSION FORMS OVER THE EAST ATLANTIC...
...NO THREAT TO LAND...


SUMMARY OF 600 AM AST...1000 UTC...INFORMATION
----------------------------------------------
LOCATION...10.3N 29.7W
ABOUT 475 MI...760 KM SW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 600 AM AST (1000 UTC), the center of Tropical Depression Fifteen
was located near latitude 10.3 North, longitude 29.7 West. The
depression is moving toward the west-northwest near 12 mph (19
km/h). A turn to the northwest is expected tonight and that
general motion should continue on Wednesday and Thursday.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours, and the
system is expected to become a tropical storm by tonight.

The estimated minimum central pressure is 1008 mb (29.77 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Cangialosi


Tropical Depression Fifteen Special Discussion Number 1
NWS National Hurricane Center Miami FL AL152018
600 AM AST Tue Oct 09 2018

Geostationary satellite and recent microwave data indicate that the
low pressure system over the eastern Atlantic Ocean has developed
sufficently organized deep convection and a well-defined center of
circulation to be considered a tropical depression, the fifteenth
one of the 2018 Atlantic hurricane season. The initial intensity is
set at 30 kt, in agreement with Dvorak 2.0/30 kt classifications
from both TAFB and SAB. The depression is expected to strengthen a
little during the next 36 to 48 hours while it remains in favorable
oceanic and atmospheric conditions. Thereafter, a significant
increase in west-southwesterly shear, drier air, and slightly cooler
SSTs should cause weakening. The global models all show the
depression opening up into a trough by day 5, and the official
forecast predicts dissipation accordingly.

The initial motion is uncertain since the system just formed a
well-defined center, but my best guess is 285/10 kt. The
depression is expected to turn northwestward tonight and continue in
that general direction on Wednesday and Thursday as it moves
toward a broad trough over the central Atlantic, the same one that
Leslie is embedded in. After that time, when the system weakens and
becomes shallow, a turn back to the left is forecast. The models
are in fair agreement, and the NHC track forecast lies near the
middle of the guidance envelope.


FORECAST POSITIONS AND MAX WINDS

INIT 09/1000Z 10.3N 29.7W 30 KT 35 MPH
12H 09/1800Z 10.6N 30.8W 30 KT 35 MPH
24H 10/0600Z 11.3N 32.1W 35 KT 40 MPH
36H 10/1800Z 12.4N 33.0W 40 KT 45 MPH
48H 11/0600Z 13.6N 34.0W 40 KT 45 MPH
72H 12/0600Z 16.1N 36.0W 35 KT 40 MPH
96H 13/0600Z 17.5N 39.5W 30 KT 35 MPH
120H 14/0600Z...DISSIPATED

$$
Forecaster Cangialosi
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Re: ATL: NADINE - Advisories

#2 Postby cycloneye » Tue Oct 09, 2018 9:38 am

BULLETIN
Tropical Storm Nadine Advisory Number 2
NWS National Hurricane Center Miami FL AL152018
1100 AM AST Tue Oct 09 2018

...DEPRESSION BECOMES TROPICAL STORM NADINE...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...10.5N 30.0W
ABOUT 480 MI...770 KM SW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES



Tropical Storm Nadine Discussion Number 2
NWS National Hurricane Center Miami FL AL152018
1100 AM AST Tue Oct 09 2018

The cloud pattern of the cyclone features a curved band that wraps
around the eastern and southern parts of the circulation. Dvorak
estimates from TAFB and SAB are both T2.5/35 kt, and that is used
for the initial intensity, making the system a tropical storm. The
environment appears conducive for some additional strengthening
during the next 24 hours or so, with SSTs above 28C and generally
light to moderate westerly shear. After that time, the shear
increases to 25-30 kt and SSTs along the forecast track fall below
27C by 72 hours. These factors should result in weakening, and all
of the global models show the cyclone dissipating in 4 to 5 days.
The NHC forecast follows these trends and is close to the various
consensus aids through the forecast period.

Based on geostationary imagery and a 0815Z SSMIS pass, the initial
motion estimate is a somewhat uncertain 285/08, with Nadine
currently situated south of a narrow mid-level ridge. The ridge will
weaken as a mid/upper-level trough that Leslie is embedded in digs
southward along 40W longitude. This pattern will cause Nadine to
turn more northwestward by 24 hours. By 96 hours, a weakening Nadine
should bend back to the west as a shallow system. The new NHC track
forecast is a bit to the right of the previous one due to the new
initial position, and lies near HCCA through 48 hours and closer to
the TVCA multi-model consensus after that time.

FORECAST POSITIONS AND MAX WINDS

INIT 09/1500Z 10.5N 30.0W 35 KT 40 MPH
12H 10/0000Z 11.1N 31.0W 40 KT 45 MPH
24H 10/1200Z 11.9N 32.1W 45 KT 50 MPH
36H 11/0000Z 13.0N 33.0W 45 KT 50 MPH
48H 11/1200Z 14.3N 34.1W 40 KT 45 MPH
72H 12/1200Z 16.7N 36.6W 30 KT 35 MPH
96H 13/1200Z 18.0N 40.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 14/1200Z...DISSIPATED

$$
Forecaster Brennan
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Re: ATL: NADINE - Advisories

#3 Postby cycloneye » Tue Oct 09, 2018 3:47 pm

Tropical Storm Nadine Discussion Number 3
NWS National Hurricane Center Miami FL AL152018
500 PM AST Tue Oct 09 2018

Nadine is a sheared tropical cyclone this afternoon with the center
partially exposed on the southwestern side of an increasing area of
convection. Dvorak estimates are unchanged since earlier, so the
initial wind speed remains 35 kt. The shear is forecast to remain
low enough to support strengthening during the next day or so, along
with sufficiently warm waters. However, Nadine should encounter a
large upper trough after that time, which should cause weakening to
begin on Thursday. Later on, cooler SSTs and strong shear are
expected to cause Nadine to degenerate into a trough of low pressure
by the weekend. Model guidance is in fair agreement on this
scenario, and the new NHC prediction is close to the previous one
and the model consensus.

Satellite imagery today shows that Nadine has turned rightward and
is moving 300/7. A northwestward track should begin overnight and
continue for the next few days due to steering from a mid-level
ridge near the Cabo Verde Islands. A westward turn is expected
beyond day 3 as Nadine becomes a shallow system and dissipates. The
track forecast isn't super confident because it is somewhat
dependent on the intensity. For example, a stronger cyclone like the
GFS shows would have the potential to move more toward the north-
northwest as it attempts to remain a vertically coherent system.
Since Nadine isn't expected to get very strong, the official
forecast will stay near or just south of the model consensus, which
results in no significant change to the previous track forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 09/2100Z 10.9N 30.6W 35 KT 40 MPH
12H 10/0600Z 11.6N 31.5W 40 KT 45 MPH
24H 10/1800Z 12.6N 32.5W 45 KT 50 MPH
36H 11/0600Z 13.7N 33.4W 40 KT 45 MPH
48H 11/1800Z 15.0N 34.7W 35 KT 40 MPH
72H 12/1800Z 17.0N 37.5W 25 KT 30 MPH
96H 13/1800Z...DISSIPATED

$$
Forecaster Blake
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Re: ATL: NADINE - Advisories

#4 Postby cycloneye » Tue Oct 09, 2018 9:40 pm

BULLETIN
Tropical Storm Nadine Advisory Number 4
NWS National Hurricane Center Miami FL AL152018
1100 PM AST Tue Oct 09 2018

...NADINE A LITTLE STRONGER...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...11.6N 31.0W
ABOUT 495 MI...800 KM WSW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES


Tropical Storm Nadine Discussion Number 4
NWS National Hurricane Center Miami FL AL152018
1100 PM AST Tue Oct 09 2018

Deep convection has been increasing in the eastern semicircle of
Nadine, with the center close to the western edge of large
convective band. Overall, the satellite presentation has improved
in the past several hours, although the outflow is limited west of
the center. While subjective estimates are unchanged from the last
advisory, microwave-based estimates suggest Nadine is somewhat
stronger, so the initial wind speed is set to 40 kt. Light or
moderate shear is anticipated during the next day or so, along
with sufficiently warm waters, which should promote strengthening.
However, Nadine should encounter a large upper trough after that
time, which will likely cause weakening to begin on Thursday. Later
on, cooler SSTs and strong shear are expected to cause Nadine to
degenerate into a trough of low pressure by the weekend. The most
significant change is that the model guidance is notably higher
than the last cycle, with a few models even making Nadine a
hurricane eventually. That seems unlikely given the strength of
the forecast shear, but the forecast is nudged higher than the
previous one and the model consensus.

Nadine continues to turn rightward and is now moving northwestward
at about 7 kt. This general course is forecast for the next couple
of days due to steering from a mid-level ridge near the Cabo Verde
Islands. After that time, a west-northwestward or westward turn is
expected as Nadine becomes a shallow system and dissipates. The
model spread is still fairly wide, with the stronger guidance
generally on the eastern side of the model envelope, and the weaker
guidance on the western side. There is definitely a slight trend
to the northeast with the latest model guidance, and since we are
expecting a stronger system, the official forecast is adjusted in
that direction, but not nearly as far to the right as most of the
GFS-based guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 10/0300Z 11.6N 31.0W 40 KT 45 MPH
12H 10/1200Z 12.3N 31.7W 45 KT 50 MPH
24H 11/0000Z 13.4N 32.7W 50 KT 60 MPH
36H 11/1200Z 14.8N 33.7W 45 KT 50 MPH
48H 12/0000Z 16.0N 35.0W 35 KT 40 MPH
72H 13/0000Z 17.5N 38.0W 25 KT 30 MPH
96H 14/0000Z...DISSIPATED

$$
Forecaster Blake
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Re: ATL: NADINE - Advisories

#5 Postby cycloneye » Wed Oct 10, 2018 4:59 am

Tropical Storm Nadine Discussion Number 5
NWS National Hurricane Center Miami FL AL152018
500 AM AST Wed Oct 10 2018

Nadine continues to gradually strengthen. Microwave images indicate
that the storm is beginning to develop an inner core with a
concentrated area of deep convection noted in infrared satellite
imagery. The initial intensity is raised to 45 kt, in agreement
with 3.0/45 kt Dvorak classifications from TAFB and SAB. Nadine has
about another day to strengthen while it remains in favorable
atmospheric conditions of low wind shear and high moisture, and over
warm waters. The NHC intensity forecast follows the HCCA and IVCN
guidance and brings Nadine to 55 kt during that time period.
Thereafter, the global models all show a sharp increase in
southwesterly shear and that should end the opportunity for
strengthening and cause weakening. The combination of strong shear,
drier air, and slightly cooler SSTs should cause the cyclone to open
into a trough in 3 to 4 days, or perhaps even sooner.

The compact storm is moving north-northwestward at 6 kt, and the
center is a little to the right of the previous forecast track. A
continued northwest to north-northwest motion is expected during the
next couple of days while Nadine moves toward a trough over the
east-central Atlantic, the same trough that Leslie is embedded in.
After that time, the weak and shallow system should turn to the left
until dissipation. The NHC track forecast has been adjusted a
little to the right of the previous one due to the more northward
initial motion and position.

FORECAST POSITIONS AND MAX WINDS

INIT 10/0900Z 12.1N 31.1W 45 KT 50 MPH
12H 10/1800Z 12.8N 31.7W 50 KT 60 MPH
24H 11/0600Z 13.9N 32.5W 55 KT 65 MPH
36H 11/1800Z 15.1N 33.4W 45 KT 50 MPH
48H 12/0600Z 16.0N 34.7W 35 KT 40 MPH
72H 13/0600Z 17.3N 38.3W 25 KT 30 MPH
96H 14/0600Z...DISSIPATED

$$
Forecaster Cangialosi
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Re: ATL: NADINE - Advisories

#6 Postby cycloneye » Wed Oct 10, 2018 9:52 am

Tropical Storm Nadine Discussion Number 6
NWS National Hurricane Center Miami FL AL152018
1100 AM AST Wed Oct 10 2018

Several microwave overpasses after 0600 UTC indicated that Nadine
very quickly developed a well-defined mid-level eye overnight.
This signature is typically associated with strengthening tropical
cyclones. Although more recent visible imagery indicates that strong
shear has since caused the cyclone to become tilted with height, a
pair of ASCAT passes around 1200 UTC indicated maximum winds of
45-50 kt. Given the small size of the tropical storm, the ASCAT
likely under-sampled the true maximum, so the initial intensity has
been raised to 55 kt. Due to limitations in our ability to observe
the intensity of small tropical storms far from land, it should be
noted that this estimate is fairly uncertain.

Since the tropical storm appears to have become more tilted since
last night, further strengthening is not likely. Shear analysis
from UW-CIMSS shows that Nadine is moving into a region of 20-30 kt
of westerly shear, and SHIPS diagnostics indicate that the shear
could increase to near 40 kt in another couple of days. All of the
intensity guidance indicates that Nadine will weaken quickly by
tomorrow, and it could become a depression by 72 h. Dissipation
will likely follow shortly after, as shown by nearly all of the
global and regional models.

The aforementioned ASCAT passes were very helpful in locating the
center of Nadine at 1200 UTC, and the tropical storm is moving
northwestward, or 325/6 kt. A northwestward to north-northwestward
motion at a similar forward speed is anticipated for the next day or
two. By Friday, a turn toward the west will likely begin as the
low-level circulation of Nadine becomes separated from its
convection and turns westward in the low-level easterlies. Nadine
is essentially on the track of the previous NHC forecast, and no
significant changes to the track forecast were required.


FORECAST POSITIONS AND MAX WINDS

INIT 10/1500Z 12.6N 31.6W 55 KT 65 MPH
12H 11/0000Z 13.5N 32.1W 55 KT 65 MPH
24H 11/1200Z 14.6N 32.9W 50 KT 60 MPH
36H 12/0000Z 15.7N 33.9W 45 KT 50 MPH
48H 12/1200Z 16.5N 35.2W 35 KT 40 MPH
72H 13/1200Z 17.5N 39.1W 30 KT 35 MPH
96H 14/1200Z...DISSIPATED

$$
Forecaster Zelinsky
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Re: ATL: NADINE - Advisories

#7 Postby cycloneye » Wed Oct 10, 2018 3:48 pm

Tropical Storm Nadine Discussion Number 7
NWS National Hurricane Center Miami FL AL152018
500 PM AST Wed Oct 10 2018

The exposed low-level center of Nadine is now peeking out from
beneath its upper cloud canopy. The initial intensity has been held
at 55 kt out of respect for earlier ASCAT data, but it is possible
that some weakening has occurred since this morning. Strong westerly
wind shear will likely prevent Nadine from becoming any better
organized going forward, so the official intensity forecast now
calls for steady weakening for the next 2 days. All of the dynamical
models indicate that Nadine will degenerate into a trough of low
pressure within the next 72 h, and the NHC forecast now shows
dissipation occuring by that point.

Nadine is moving steadily northwestward with an initial motion of
315/7 kt. As long as Nadine remains a tropical cyclone, it should
stay on a similar heading, and the models are in generally good
agreement on its track. The NHC track forecast has been adjusted a
little to the southwest, and is generally close to the TVCX and HCCA
consensus aids at all times. From 48 h onward, the cyclone or its
remnant trough will likely be entirely separated from its convection
and turn westward in low-level easterly flow.


FORECAST POSITIONS AND MAX WINDS

INIT 10/2100Z 13.1N 32.2W 55 KT 65 MPH
12H 11/0600Z 13.8N 32.9W 50 KT 60 MPH
24H 11/1800Z 14.8N 34.0W 45 KT 50 MPH
36H 12/0600Z 15.7N 35.1W 40 KT 45 MPH
48H 12/1800Z 16.2N 36.8W 35 KT 40 MPH
72H 13/1800Z...DISSIPATED

$$
Forecaster Zelinsky
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Re: ATL: NADINE - Advisories

#8 Postby cycloneye » Wed Oct 10, 2018 9:52 pm

Tropical Storm Nadine Discussion Number 8
NWS National Hurricane Center Miami FL AL152018
1100 PM AST Wed Oct 10 2018

Another burst of deep convection has formed near the center of
Nadine, which is typical in sheared tropical cyclones. A recent
ASCAT pass indicated several believable 50-55 kt winds, so the
initial intensity is held at 55 kt for this advisory. The shear is
only forecast to increase over the next couple of days, which
should lead to weakening, especially by Friday. All of the dynamical
models indicate that Nadine will degenerate into a trough of low
pressure over the weekend, and no significant changes were made to
the previous forecast.

Nadine continues to move northwestward due to a ridge near the Cabo
Verde Islands. This general course is forecast for the next day or
so until Nadine become a more shallow system, which should cause
the cyclone to turn toward the west-northwest. The previous
interpolated forecast came in basically on top of the new consensus
and corrected-consensus guidance, so the new track forecast is very
close to the previous NHC prediction.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0300Z 13.6N 32.7W 55 KT 65 MPH
12H 11/1200Z 14.3N 33.4W 50 KT 60 MPH
24H 12/0000Z 15.3N 34.5W 40 KT 45 MPH
36H 12/1200Z 16.0N 36.0W 35 KT 40 MPH
48H 13/0000Z 16.5N 37.5W 30 KT 35 MPH
72H 14/0000Z...DISSIPATED

$$
Forecaster Blake
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Re: ATL: NADINE - Advisories

#9 Postby cycloneye » Thu Oct 11, 2018 4:59 am

Tropical Storm Nadine Discussion Number 9
NWS National Hurricane Center Miami FL AL152018
500 AM AST Thu Oct 11 2018

Nadine is a sheared tropical storm with the low-level center located
near the western edge of the main area of deep convection. An ASCAT
pass from several hours ago showed maximum winds in the 50-55 kt
range, and since the satellite appearance has not changed much, the
initial intensity is held at 55 kt. This value is near the high end
of the satellite-based intensity estimates. The environment near
Nadine is expected to become even more hostile during the next
couple of days due to the combined effects of strong west-
southwesterly shear and drier air. Therefore, steady weakening is
forecast, and dissipation is expected to occur in 2 to 3 days when
the shear is forecast to be in excess of 30 kt. The models are in
good agreement, and little change was made to the previous NHC
intensity forecast.

The storm is moving northwestward at 7 kt. The track forecast
reasoning is unchanged from previous advisories. Nadine is expected
to continue moving northwestward for about another day while the
tropical storm remains relatively deep, or vertically coherent.
After that time, the weakening and increasingly shallow cyclone is
forecast to turn to the left in the low-level flow, and that motion
should continue until the system dissipates. The NHC track forecast
lies near the middle of the guidance envelope, and it is not too
different than the previous one.

FORECAST POSITIONS AND MAX WINDS

INIT 11/0900Z 14.1N 33.3W 55 KT 65 MPH
12H 11/1800Z 14.9N 34.1W 45 KT 50 MPH
24H 12/0600Z 15.7N 35.4W 40 KT 45 MPH
36H 12/1800Z 16.3N 37.0W 35 KT 40 MPH
48H 13/0600Z 16.7N 39.0W 30 KT 35 MPH
72H 14/0600Z...DISSIPATED

$$
Forecaster Cangialosi
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Re: ATL: NADINE - Advisories

#10 Postby cycloneye » Thu Oct 11, 2018 10:53 am

Tropical Storm Nadine Discussion Number 10
NWS National Hurricane Center Miami FL AL152018
1100 AM AST Thu Oct 11 2018

Nadine is strongly sheared and the low-level center of the
tropical storm is now completely exposed, nearly 50 n mi to the
southwest of the nearest deep convection. Satellite intensity
estimates have decreased since last night, so the intensity has
been lowered to 50 kt. This value is still on the high side of the
available intensity estimates, but Nadine's intensity has generally
been near the top of the intensity estimates for the past few days.

Steady weakening is still anticipated because the shear is forecast
by all models to increase further during the next day or two. By
72 h, if not sooner, all of the dynamical models forecast that
Nadine will have lost its deep convection and degenerated into a
trough of low pressure. No significant changes were made to the NHC
intensity forecast.

Nadine is still moving northwestward at 7 kt. Since Nadine's
surface circulation has become completely exposed and the vortex is
likely becoming very shallow, a quicker turn toward the
west-northwest and west is now shown in the official track forecast.
The track forecast has therefore been adjusted toward the southwest
at most forecast times, but is still close to HCCA and TVCN through
the short forecast period.

FORECAST POSITIONS AND MAX WINDS

INIT 11/1500Z 14.1N 34.0W 50 KT 60 MPH
12H 12/0000Z 14.8N 34.9W 40 KT 45 MPH
24H 12/1200Z 15.5N 36.3W 35 KT 40 MPH
36H 13/0000Z 15.9N 38.0W 35 KT 40 MPH
48H 13/1200Z 16.2N 40.2W 30 KT 35 MPH
72H 14/1200Z...DISSIPATED

$$
Forecaster Zelinsky
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Re: ATL: NADINE - Advisories

#11 Postby cycloneye » Thu Oct 11, 2018 3:39 pm

Tropical Storm Nadine Discussion Number 11
NWS National Hurricane Center Miami FL AL152018
500 PM AST Thu Oct 11 2018

Nadine continues to be strongly sheared. A brief burst of deep
convection occurred near the center of the cyclone a few hours ago,
but the center has since become exposed once again. The initial
intensity has been decreased to 45 kt based primary on the latest
TAFB and SAB Dvorak fixes. Additional weakening is likely over the
next day or so while Nadine remains strongly sheared. The regional
and global models now show Nadine degenerating into a trough of low
pressure within 48 h, and this is reflected in the new NHC forecast.

The tropical storm is moving west-northwestward with an initial
speed of 7 kt. The models are in good agreement that Nadine will
continue on a similar heading and speed for the next 24 h or so,
before turning toward the west as it weakens. The NHC forecast has
been nudged to the southwest at most forecast points, and is
generally near the HFIP Corrected Consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 11/2100Z 14.5N 34.9W 45 KT 50 MPH
12H 12/0600Z 14.9N 36.0W 40 KT 45 MPH
24H 12/1800Z 15.5N 37.7W 35 KT 40 MPH
36H 13/0600Z 15.7N 40.0W 30 KT 35 MPH
48H 13/1800Z...DISSIPATED

$$
Forecaster Zelinsky
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Re: ATL: NADINE - Advisories

#12 Postby cycloneye » Thu Oct 11, 2018 10:06 pm

Tropical Storm Nadine Discussion Number 12
NWS National Hurricane Center Miami FL AL152018
1100 PM AST Thu Oct 11 2018

Although Nadine remains under the influence of strong southwesterly
shear, a new burst of convection went up a few hours ago and covered
the low-level center again. The initial intensity remains 45 kt
based on consensus T3.0 Dvorak estimates from TAFB and SAB. Even
stronger shear is expected to cause Nadine to weaken during the
next day or two, and the global models all agree that the system
will open up into a trough by 48 hours. The updated NHC forecast
is unchanged from the previous one.

Nadine is moving west-northwestward, or 295/8 kt. A low-level
ridge is forecast to steer the cyclone west-northwestward and then
westward at an increasing speed until it dissipates by 48 hours.
The new track guidance has bended slightly southwestward on this
cycle, and the updated NHC track forecast has been shifted in that
direction toward the multi-model consensus aids and HCCA guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0300Z 14.9N 35.5W 45 KT 50 MPH
12H 12/1200Z 15.2N 36.6W 40 KT 45 MPH
24H 13/0000Z 15.6N 38.7W 35 KT 40 MPH
36H 13/1200Z 15.8N 41.5W 30 KT 35 MPH
48H 14/0000Z...DISSIPATED

$$
Forecaster Berg
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Re: ATL: NADINE - Advisories

#13 Postby cycloneye » Fri Oct 12, 2018 4:52 am

Tropical Storm Nadine Discussion Number 13
NWS National Hurricane Center Miami FL AL152018
500 AM AST Fri Oct 12 2018

A 0353 UTC AMSR-2 microwave overpass and GOES-16 shortwave infrared
imagery show that the 30-40 kt of west-southwesterly shear, depicted
in the UW-CIMSS shear analysis, is partially exposing, or
decoupling, Nadine's surface circulation from the convective mass.
The cloud pattern, however, hasn't changed during the past 6 hours
and in fact, the cloud top temperatures in the curved band over the
north semicircle have decreased somewhat. TAFB and SAB satellite
intensity estimates remained unchanged, and the initial intensity is
held at 45 kt.

The Decay SHIPS statistical intensity model indicates that the shear
will persist and increase a little more which should cause Nadine to
spin down and dissipate in 48 hours, or possibly sooner. The
large-scale models all show the cyclone opening up into a trough of
low pressure and ultimately dissipating over the deep tropical
central Atlantic at that time. The official forecast follows suit
and is an update of the previous advisory.

The initial motion is estimated to be west-northwestward, or 295/7
kt. A low to mid-level ridge anchored between Nadine to the south
and Hurricane Leslie to the north, should steer the cyclone
west-northwestward and then westward at an accelerated pace until
dissipation. The NHC forecast has again been adjusted a little
south and toward both the NOAA-HCCA and TVCN consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 15.2N 35.5W 45 KT 50 MPH
12H 12/1800Z 15.4N 37.2W 40 KT 45 MPH
24H 13/0600Z 15.6N 39.7W 30 KT 35 MPH
36H 13/1800Z 15.8N 42.7W 30 KT 35 MPH
48H 14/0600Z...DISSIPATED

$$
Forecaster Roberts
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Re: ATL: NADINE - Advisories

#14 Postby cycloneye » Fri Oct 12, 2018 3:35 pm

Tropical Storm Nadine Discussion Number 15
NWS National Hurricane Center Miami FL AL152018
500 PM AST Fri Oct 12 2018

The center of Nadine is now completely exposed to the west of a
waning area of deep convection due to 35-40 kt of southwesterly
shear. Based on a blend of the latest Dvorak CI and Final-T numbers
from TAFB and SAB, the initial intensity has been reduced to 35 kt.
This could be a little generous, but hopefully ASCAT will sample
the system later this evening to provide a better idea of how much
the winds have weakened. The NHC intensity forecast has been lowered
from the previous one, and now shows Nadine becoming a depression by
12 hours and a remnant low by 24 hours, but both could happen
sooner.

The now shallow cyclone has turned west-northwestward, with an
initial motion estimate of 285/13. Nadine and its remnants should
move quickly westward in the low-level trade wind flow until
dissipation. The new NHC track is close to the middle of the
guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 12/2100Z 16.4N 37.7W 35 KT 40 MPH
12H 13/0600Z 16.5N 39.7W 30 KT 35 MPH
24H 13/1800Z 16.7N 42.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 14/0600Z...DISSIPATED

$$
Forecaster Brennan
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Re: ATL: NADINE - Advisories

#15 Postby cycloneye » Fri Oct 12, 2018 9:34 pm

Remnants Of Nadine Discussion Number 16
NWS National Hurricane Center Miami FL AL152018
1100 PM AST Fri Oct 12 2018

ASCAT data indicate that Nadine no longer has a closed circulation
nor a well-defined center. This is also confirmed by low cloud
motions from GOES-16. Thus Nadine has degenerated into an open
wave, and this is the last advisory on this system. The initial wind
speed is reduced to 30 kt to match the value from the scatterometer.
Strong shear should cause the remnants to slowly weaken as the
system moves quickly westward beneath the Atlantic subtropical
ridge.

Future information on the remnants of Nadine can be found in High
Seas Forecasts issued by the National Weather Service, under AWIPS
header NFDHSFAT1, WMO header FZNT01 KWBC, and available on the Web
at https://ocean.weather.gov/shtml/NFDHSFAT1.shtml.


FORECAST POSITIONS AND MAX WINDS

INIT 13/0300Z 16.0N 39.5W 30 KT 35 MPH...REMNANTS OF NADINE
12H 13/1200Z...DISSIPATED

$$
Forecaster Blake
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