EPAC: IVETTE - Post-Tropical

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cycloneye
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Re: EPAC: IVETTE - Tropical Storm

#61 Postby cycloneye » Sun Aug 07, 2016 6:41 am

TROPICAL STORM IVETTE DISCUSSION NUMBER 19
NWS NATIONAL HURRICANE CENTER MIAMI FL EP102016
200 AM PDT SUN AUG 07 2016

Convection has redeveloped on the northern side of Ivette, although
the center remains partially exposed. An ASCAT-A pass at 6Z
revealed maximum winds of 35-40 kt, and since thunderstorm activity
has increased markedly since that time, the initial wind speed is
kept at 40 kt. Ivette is forecast to gradually spin down over the
next few days due to cooling waters, strong shear and entrainment of
dry air aloft. A strong surface high over the central Pacific
should cause an enhanced gradient on the northern side of Ivette,
similar to Howard's synoptic situation last week. Thus, Ivette will
probably have an extended weakening phase, and the official forecast
reflects this situation, ending up a little higher than the previous
advisory at day 2 and 3. The global models continue to show the
system opening up into a trough by day 4.

The storm remains on track and is moving 290/10 kt. Ivette should
gradually turn westward and west-southwestward over the next few
days as it becomes a shallow remnant low. No significant changes
were made to the previous forecast, and the new NHC track
prediction continues to be positioned only a small distance south
of the model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 07/0900Z 16.9N 137.3W 40 KT 45 MPH
12H 07/1800Z 17.4N 138.6W 35 KT 40 MPH
24H 08/0600Z 18.0N 140.3W 30 KT 35 MPH
36H 08/1800Z 18.4N 141.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 09/0600Z 18.4N 143.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 10/0600Z 17.5N 148.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 11/0600Z...DISSIPATED

$$
Forecaster Blake
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Re: EPAC: IVETTE - Tropical Storm

#62 Postby cycloneye » Sun Aug 07, 2016 9:42 am

TROPICAL STORM IVETTE DISCUSSION NUMBER 20
NWS NATIONAL HURRICANE CENTER MIAMI FL EP102016
800 AM PDT SUN AUG 07 2016

Ivette generated a new burst of deep convection around the time of
the last advisory, and that burst has been persisting. However,
satellite data show that the center remains partially exposed to
the southwest of this cloud mass due to strong southwesterly
vertical wind shear. An overnight ASCAT pass showed at least 35-kt
winds, and the initial intensity estimate is held at 40 kt since the
cloud pattern is as organized or perhaps slightly better than 6
hours ago.

The future for Ivette looks bleak. The cyclone is forecast to
encounter even stronger southwesterly shear in the next few days,
along with increasingly drier air and marginal sea surface
temperatures. These factors suggest that Ivette's time as a
tropical cyclone would likely come to a close sooner rather than
later, and the official forecast calls for remnant low status in 36
hours in agreement with the global models. The new intensity
forecast is identical to the previous one and is in agreement with
the bulk of the intensity guidance, with dissipation shown in 2
days.

Ivette has been maintaining a west-northwestward motion of 290/10.
This general motion should continue today as the cyclone is steered
by the flow on the south side of a subtropical ridge. A westward
and west-southwestward change in the cyclone's heading is likely
once Ivette becomes a shallower cyclone in about 24 hours. The new
forecast track is hardly changed from the previous one, and is near
the multi-model conensus.

FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 17.2N 138.4W 40 KT 45 MPH
12H 08/0000Z 17.7N 139.6W 35 KT 40 MPH
24H 08/1200Z 18.3N 141.3W 30 KT 35 MPH
36H 09/0000Z 18.5N 143.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 09/1200Z 18.3N 145.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 10/1200Z...POST-TROP/REMNT LOW

$$
Forecaster Kimberlain
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Re: EPAC: IVETTE - Tropical Storm

#63 Postby cycloneye » Sun Aug 07, 2016 3:35 pm

TROPICAL STORM IVETTE DISCUSSION NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL EP102016
200 PM PDT SUN AUG 07 2016

The burst of deep convection from earlier has begun to diminish,
leaving Ivette's low-level center exposed. A Dvorak satellite
classification of T2.5 is used to lower the initial intensity
estimate to 35 kt on this advisory. Ivette is living on borrowed
time, according to the global models. Although another diurnal
burst of convection is possible again tonight, even greater
southwesterly shear, combined with an increasingly drier and
more stable air, should soon contribute to Ivette's demise. The
official NHC forecast shows the cyclone slowly weakening during the
next day or so and becoming a remnant low in 36 hours. Dissipation
is forecast in about 2 days.

Ivette continues on a west-northwestward track or 290/09. This
general motion is forecast to continue for another 12 hours or so.
However, a westward and then west-southwestward change in the
cyclone's heading is likely after that time when Ivette becomes a
shallower cyclone. The new NHC forecast track is about the same as
the previous one and is very near the multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 17.3N 139.0W 35 KT 40 MPH
12H 08/0600Z 17.9N 140.2W 35 KT 40 MPH
24H 08/1800Z 18.4N 141.7W 30 KT 35 MPH
36H 09/0600Z 18.3N 143.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 09/1800Z 18.1N 145.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 10/1800Z...DISSIPATED

$$
Forecaster Kimberlain
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Re: EPAC: IVETTE - Tropical Storm

#64 Postby Kingarabian » Sun Aug 07, 2016 3:45 pm

That trough parked over Hawaii continues to save the day.
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Re: EPAC: IVETTE - Tropical Depression

#65 Postby hurricanes1234 » Sun Aug 07, 2016 10:42 pm

Down to a depression. Next advisory to be issued by CPHC.

000
WTPZ45 KNHC 080247
TCDEP5

TROPICAL DEPRESSION IVETTE DISCUSSION NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL EP102016
800 PM PDT SUN AUG 07 2016

The deep convection that was near the center of Ivette earlier in
the day has been sheared away, with the closest area of
thunderstorms about 80 n mi northeast of the center. This is
the result of 20-25 kt of southwesterly shear. A pair of ASCAT
passes from several hours ago showed maximum winds near 35 kt in
the northern portion of the circulation. Assuming some spin down
since that time, the initial intensity is lowered to 30 kt, making
Ivette a tropical depression. This intensity estimate is also in
agreement with the Dvorak classifications from TAFB and SAB.
Although some deep convection could return near the center,
continued strong southwesterly shear and dry air should limit the
organization of this activity and cause weakening. Ivette is
expected to degenerate to a remnant low on Monday, and dissipate to
the east of the Hawaiian Islands in 2 to 3 days.

The shallow cyclone has turned westward in the low-level flow. A
general westward motion at about 10 kt is expected until the
cyclone dissipates. The NHC official track forecast lies on the
southern edge of the guidance, and is adjusted to the south of the
previous prediction.

The next advisory on Ivette will be issued by the Central Pacific
Hurricane Center in Honolulu, Hawaii.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0300Z 17.2N 139.8W 30 KT 35 MPH
12H 08/1200Z 17.6N 141.0W 30 KT 35 MPH
24H 09/0000Z 17.8N 142.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 09/1200Z 17.7N 144.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 10/0000Z 17.4N 147.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 11/0000Z...DISSIPATED

$$
Forecaster Cangialosi
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Re: EPAC: IVETTE - Tropical Storm

#66 Postby cycloneye » Mon Aug 08, 2016 5:04 am

TROPICAL DEPRESSION IVETTE DISCUSSION NUMBER 23
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102016
1100 PM HST SUN AUG 07 2016

Tropical Depression Ivette remains poorly organized as it enters
the Central Pacific, with all the deep convection displaced
well to the north of the exposed low-level circulation center
(LLCC). Dvorak current intensity estimates from SAB and PHFO both
show 2.0/30 kt, and the latest UW-CIMSS ADT estimate is 1.8/28 kt.
A recent 08/0645Z ASCAT pass sampled the western portion of the
system, showing some 30 kt wind barbs to the northwest of the
LLCC. As a result, the initial intensity for this advisory will be
maintained at 30 kt. The initial motion based on a combination of
visible and infrared satellite loops over the past 6 to 12 hours has
been set at 270/08 kt.

Ivette is becoming an increasingly shallow system due to persistent
southwesterly vertical wind shear of 20-30 kt, as diagnosed by
SHIPS and the UW-CIMSS shear product. As a result, the depression is
expected to largely be driven by the low-level trade wind flow as it
tracks off to the west or west-southwest during the next couple of
days. The CPHC official track forecast lies on the southern edge of
the guidance, and has been adjusted to the south of the previous
forecast.

The system is forecast to move over sea surface temperatures near
27C during the next couple of days, while continuing to experience
very unfavorable southwesterly wind shear. While intermittent deep
convection may continue to flare up well to the north or northeast
of the LLCC, it seems unlikely that Ivette will be able to maintain
sufficient convective organization to be classified as a tropical
cyclone for much longer. Therefore, Ivette is forecast to become a
remnant low in 24 hours, with dissipation expected well to the east
of the Hawaiian Islands in 2 to 3 days.


FORECAST POSITIONS AND MAX WINDS

INIT 08/0900Z 17.1N 140.6W 30 KT 35 MPH
12H 08/1800Z 17.1N 141.9W 30 KT 35 MPH
24H 09/0600Z 17.0N 143.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 09/1800Z 16.7N 145.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 10/0600Z 16.0N 148.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 11/0600Z...DISSIPATED

$$
Forecaster Jelsema/Jacobson
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Re: EPAC: IVETTE - Tropical Depression

#67 Postby hurricanes1234 » Mon Aug 08, 2016 12:21 pm

Ivette is still around? :lol: :lol:

WTPA44 PHFO 081434
TCDCP4

TROPICAL DEPRESSION IVETTE DISCUSSION NUMBER 24
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102016
500 AM HST MON AUG 08 2016

Southwesterly vertical wind shear is taking its toll on Ivette, as
the low-level circulation center (LLCC) of the depression has now
been devoid of deep convection for over 12 hours. The latest fixes
from the satellite agencies indicate that the system has weakened,
with PHFO coming in with a Dvorak current intensity estimate of
1.5/25 kt, while SAB/JTWC now indicate that the system is too weak
to classify. Meanwhile, UW-CIMSS ADT shows a current intensity of
1.8/28 kt. Based on the 08/0645Z ASCAT pass showing a small area
of 30 kt wind barbs as it sampled the western semicircle of the
system, the intensity will be conservatively held at 30 kt for this
advisory. The initial motion has been set at 265/07 kt based on
satellite agency fixes and infrared satellite animations during the
past 6 to 12 hours.

Ivette will remain in a very hostile environment during the next
couple of days, with the current southwesterly wind shear of 20-30
kt forecast to continue. As a result, the shallow system is expected
to largely be driven by the low-level trade wind flow as it tracks
off to the west-southwest through dissipation. The CPHC official
track forecast remains on the southern edge of the guidance, and has
been adjusted slightly to the south of the previous forecast.

The system is forecast to move over sea surface temperatures near
27C during the next couple of days, but the hostile vertical wind
shear is expected to win the battle with organized deep convection
unlikely to redevelop near the LLCC. As a result, Ivette will likely
become a remnant low later today, with dissipation expected by 48
hours.


FORECAST POSITIONS AND MAX WINDS

INIT 08/1500Z 17.0N 141.1W 30 KT 35 MPH
12H 09/0000Z 16.9N 142.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 09/1200Z 16.6N 144.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 10/0000Z 16.0N 146.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 10/1200Z...DISSIPATED

$$
Forecaster Jelsema/Jacobson
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Re: EPAC: IVETTE - Post-Tropical

#68 Postby cycloneye » Mon Aug 08, 2016 7:13 pm

POST-TROPICAL CYCLONE IVETTE DISCUSSION NUMBER 25
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102016
1100 AM HST MON AUG 08 2016

Organized deep convection over the center of Ivette has been absent
for a sufficient amount of time for the system to be deemed a post-
tropical remnant low, with a well-developed low cloud swirl marking
the remains. With the lack of convection, subjective Dvorak
intensity estimates indicate that the system is too weak to
classify. The initial intensity for this advisory has been reduced
to 25 kt, based on some weakening since an overnight ASCAT pass that
indicated 30 kt. Persistent southwesterly shear of 25-30 kt will
preclude redevelopment as any thunderstorms that may develop will be
quickly sheared northeastward.

The initial motion for this advisory is 270/07 kt, with Ivette being
carried toward the west in the low-level trade wind flow provided by
a surface high far to the north. Ivette is forecast to move toward
the west-southwest as it becomes increasingly weak over the next day
or so, with an increase in forward speed. The updated track forecast
lies close to the previous, and very close to a tightly clustered
guidance suite. Unlike other remnant lows that have been able to
persist for several days while traversing the central Pacific this
season, global models and SHIPS guidance indicate that post-tropical
Ivette will dissipate within 48 hours, and the official forecast
continues to do so.

This is the last advisory issued by the Central Pacific Hurricane
Center on this system. Further information on the remnant low can be
found in High Seas Forecasts issued by the National Weather Service
in Honolulu, under AWIPS header HFOHSFNP, WMO header FZPN40 PHFO,
and on the web at http://www.prh.noaa.gov/hnl/pages/HSFNP.php.


FORECAST POSITIONS AND MAX WINDS

INIT 08/2100Z 17.1N 141.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
12H 09/0600Z 17.1N 143.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 09/1800Z 16.9N 145.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 10/0600Z 16.2N 147.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 10/1800Z...DISSIPATED

$$

Forecaster Birchard
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