霧峰追風者

  四級颶風  
編號：17 E
名稱：Olivia

  基本資料  
擾動編號日期：2018 年 08 月 31 日 02 時
命名日期　　：2018 年 09 月 02 日 19 時
　　　　　　　2018 年 09 月 09 日 11 時 - CPHC接續發報
撤編日期　　：2018 年 09 月 19 日 16 時
登陸地點　　：無

  巔峰時期資料  
近中心最強風速
國家颶風中心(NHC)：115 kts
中太平洋颶風中心(CPHC)：75 kts
海平面最低氣壓：948 百帕

  過去路徑圖  
無

  擾動編號資料  
91E.INVEST.25kts-1009mb-12.4N-105.1W

NHC : 40%

1. Disorganized showers and thunderstorms located several hundred miles
southwest of the southwestern coast of Mexico are associated with an
area of low pressure.  Environmental conditions are expected to be
conducive for gradual development, and a tropical depression is
likely to form this weekend or early next week while the system
moves west-northwestward away from the coast of Mexico.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...high...80 percent.

以上資料來自：NHC、CPHC、颱風論壇整理製作

霧峰追風者

NHC 展望提升至70%。

1. Showers and thunderstorms continue in association with a low
pressure system located several hundred miles south-southwest of
Manzanillo, Mexico.  Gradual development of this system is
anticipated, and a tropical depression is likely to form within the
next couple of days while the system moves generally
west-northwestward, away from the coast of Mexico.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

t02436

升格17E，暫時上望95節。

410
WTPZ42 KNHC 010234
TCDEP2

Tropical Depression Seventeen-E Discussion Number   1
NWS National Hurricane Center Miami FL       EP172018
900 PM MDT Fri Aug 31 2018

Satellite images indicate that the low pressure system located a
little more than 400 miles southwest of Manzanillo, Mexico, has
developed organized deep convection and a well-defined center.
Therefore, the system now qualifies as a tropical depression, the
seventeenth one of the busy 2018 eastern North Pacific hurricane
season.  The center of the system is estimated to be near the
northeastern portion of the deep convection based on recent
microwave data.  The initial intensity is set at 30 kt, in agreement
with a Dvorak classification from TAFB.

The initial motion of the depression is highly uncertain since it
only recently formed, but my best guess is 285/9.  The system is
expected to move a little slower to the west-northwest or northwest
during the next couple of days while it remains to the south of a
weakness in the subtropical ridge.  Beyond that time, the
subtropical ridge is expected to build to the north of the tropical
cyclone, and that should cause it to turn more westward and increase
in forward speed.  The models agree on this overall scenario, but
there is a fair amount of cross-track (north-south) spread.  The NHC
track forecast lies close to the middle of the guidance envelope
near the various consensus models.

The depression is currently experiencing some northeasterly shear,
and that should limit the strengthening process overnight.  However,
the models show the upper-level pattern becoming quite favorable
this weekend.  The expected decrease in shear combined with warm
SSTs and a moist environment should allow the system to steadily
strengthen for most of the forecast period. The NHC intensity
forecast is a little lower than the HCCA model in the short term,
but leans heavily on that guidance from 48 hours and beyond.  It
should also be noted that the GFS, UKMET, and ECMWF models all show
this system deepening significantly during the next several days,
which is a good indication that this cyclone will likely become
another significant hurricane.

FORECAST POSITIONS AND MAX WINDS

INIT  01/0300Z 14.3N 108.4W   30 KT  35 MPH
12H  01/1200Z 15.0N 109.5W   30 KT  35 MPH
24H  02/0000Z 15.6N 110.5W   40 KT  45 MPH
36H  02/1200Z 16.1N 111.5W   45 KT  50 MPH
48H  03/0000Z 16.6N 112.7W   60 KT  70 MPH
72H  04/0000Z 17.0N 115.0W   75 KT  85 MPH
96H  05/0000Z 17.4N 118.3W   85 KT 100 MPH
120H  06/0000Z 18.3N 122.6W   95 KT 110 MPH

$$
Forecaster Cangialosi

t02436

09Z已命名Olivia，巔峰上望85節。

837
WTPZ42 KNHC 020851
TCDEP2

Tropical Storm Olivia Discussion Number   6
NWS National Hurricane Center Miami FL       EP172018
300 AM MDT Sun Sep 02 2018

The tropical cyclone's convection is still not well organized, and
the cloud pattern consists of an irregularly shaped CDO-like
feature with limited banding.  Nonetheless, a couple of
scatterometer overpasses showed that the cyclone had winds to around
40 kt over the southern semicircle of the circulation.  Therefore
the system is being named, and the aforementioned wind speed will be
used for the advisory intensity.  The north-northeasterly shear
that has been affecting the storm is expected to abate somewhat,
which would allow for further strengthening.  The official
intensity forecast is in line with the latest numerical model
consensus, IVCN.  Some of the models show more rapid strengthening
during the next day or two, but this does not seem likely at this
time since the system is still not very well organized and some
shear is expected to continue affecting it.

The center was somewhat elongated in the scatterometer data, but
appeared to be located a little north of the previous working best
track.  The initial motion is a rather uncertain 300/8 kt.  A weak
mid-level ridge to the north of Olivia should lead to a slow
west-northwestward to northwestward motion over the next day or two.
Thereafter, a strengthening ridge is likely to cause a turn toward
the west with some increase in forward speed.  Late in the forecast
period, the dynamical model consensus indicates a turn back to the
west-northwest.  The official track forecast is a little north of
the previous one, mainly due to the recent re-positioning of the
center.

FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 16.0N 112.2W   40 KT  45 MPH
12H  02/1800Z 16.6N 112.7W   45 KT  50 MPH
24H  03/0600Z 17.2N 113.6W   50 KT  60 MPH
36H  03/1800Z 17.5N 114.8W   60 KT  70 MPH
48H  04/0600Z 17.6N 116.6W   70 KT  80 MPH
72H  05/0600Z 17.7N 120.2W   85 KT 100 MPH
96H  06/0600Z 19.0N 124.5W   85 KT 100 MPH
120H  07/0600Z 20.5N 130.0W   75 KT  85 MPH

$$
Forecaster Pasch

t02436

底層圍好了，已經評價90節，NHC保守上望100節。

233
WTPZ42 KNHC 041440
TCDEP2

Hurricane Olivia Discussion Number  15
NWS National Hurricane Center Miami FL       EP172018
800 AM PDT Tue Sep 04 2018

Olivia has become better organized since the last advisory, with
conventional satellite imagery indicating the formation of a 25 n
mi wide eye and a surrounding cold ring of cloud tops in the
eyewall.  Satellite intensity estimates from TAFB and SAB have
increased to 90 kt, and that will be the initial intensity for this
advisory.  This burst of rapid intensification has occurred even
though the analyzed easterly shear in the SHIPS model and analyses
from CIMSS is in the 15-20 kt range.

How much additional intensification will occur is uncertain.  The
intensity guidance suggests that continued shear and decreasing sea
surface temperatures along the forecast track will allow only about
12 h of additional strengthening, and most of the guidance forecasts
only modest strengthening during this time.  However, it is unlikely
that the current rapid intensification will stop that quickly.
Based on this, the new intensity forecast calls for a peak intensity
of 100 kt in 12 h at the upper edge of the intensity guidance, and
it is possible Olivia could get stronger.  After 24 h, the cooler
sea surface temperatures and entrainment of dry air should cause a
gradual weakening even though the shear is forecast to decrease.

The initial motion remains 275/10.  As noted previously, a
building subtropical ridge over the eastern Pacific is forecast
to induce a westward and west-northwestward motion with increasing
forward speed during the next several days.  The model guidance
supports this scenario with a tight clustering, and the new NHC
track forecast is again an update of the previous forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 17.0N 118.2W   90 KT 105 MPH
12H  05/0000Z 17.2N 119.9W  100 KT 115 MPH
24H  05/1200Z 17.4N 122.1W  100 KT 115 MPH
36H  06/0000Z 18.0N 124.5W   95 KT 110 MPH
48H  06/1200Z 18.8N 127.2W   85 KT 100 MPH
72H  07/1200Z 20.5N 133.0W   75 KT  85 MPH
96H  08/1200Z 22.0N 138.5W   60 KT  70 MPH
120H  09/1200Z 23.0N 143.5W   50 KT  60 MPH

$$
Forecaster Beven

t02436

03Z評價110節達到巔峰，09Z已經減弱為100節。

ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM

Hurricane Olivia Discussion Number  17
NWS National Hurricane Center Miami FL       EP172018
800 PM PDT Tue Sep 04 2018

Olivia is displaying a well-defined eye this evening embedded within
a circular central dense overcast.  The rapid intensification seems
to have leveled off, since Dvorak estimates have increased only
slightly, but still support a higher wind speed of 110 kt.

Moderate easterly shear, gradually decreasing sea surface
temperatures, and dry air aloft along the forecast track of Olivia
will likely cause the hurricane to slowly weaken by late Wednesday.
The new intensity forecast is slightly higher than the last one,
near or a bit above the model consensus.  The forecast is on the
higher side of the guidance because I don't feel particularly
confident about this weakening, given the poor performance of the
guidance for this hurricane so far.

Olivia is moving a little south of due west, 265/10.  A
building subtropical ridge over the eastern Pacific is forecast
to cause the hurricane to move westward and west-northwestward
with increasing forward speed during the next several days.
Near the end of the forecast, model guidance is showing a stronger
ridge, and a westward turn is possible.  The guidance envelope has
shifted southward on this cycle, and the official NHC prediction is
adjusted in that direction.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0300Z 16.7N 120.1W  110 KT 125 MPH
12H  05/1200Z 16.9N 121.7W  110 KT 125 MPH
24H  06/0000Z 17.5N 124.2W  105 KT 120 MPH
36H  06/1200Z 18.2N 126.8W  100 KT 115 MPH
48H  07/0000Z 19.1N 129.7W   90 KT 105 MPH
72H  08/0000Z 20.9N 135.2W   75 KT  85 MPH
96H  09/0000Z 22.0N 140.5W   65 KT  75 MPH
120H  10/0000Z 22.5N 145.5W   60 KT  70 MPH

$$
Forecaster Blake

NNNN

霧峰追風者

風眼清空，NHC 強度升四級颶風。

345
WTPZ42 KNHC 070232
TCDEP2

Hurricane Olivia Discussion Number  26
NWS National Hurricane Center Miami FL       EP172018
800 PM PDT Thu Sep 06 2018

Olivia's satellite presentation is an outstanding example of an
annular hurricane with the shape of a truck tire.  In fact, the
Annular Hurricane Index on the SHIPS model output is 100. The
hurricane has a distinct clear eye surrounded by a ring of very deep
convection. The Dvorak numbers, both objective and subjective, are
T6.0, and on this basis, the winds are increased to 115 kt in this
advisory. The current annular pattern indicates that hurricane
should weaken more slowly that indicated by guidance in the short
term. Nevertheless, since the ocean is a little bit cooler along the
forecast track, very gradual weakening is forecast through the next
5 days. The confidence in the intensity forecast is not very high.

On the contrary, the confidence in the track forecast is high.
Olivia is fully embedded within the easterly flow south of a
subtropical high, and the hurricane is moving toward the
west-northwest or 290 degrees at 12 kt. The subtropical high will
persist, and most likely expand farther westward, and this flow
pattern will force Olivia to move on the general westward track or
even south of due west by the end of the forecast period. Guidance
for the next 5 days is in extremely good agreement, and the NHC
forecast in on top of the skinny guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT  07/0300Z 19.1N 129.7W  115 KT 130 MPH
12H  07/1200Z 19.7N 131.6W  115 KT 130 MPH
24H  08/0000Z 20.5N 134.2W  100 KT 115 MPH
36H  08/1200Z 21.2N 136.8W   90 KT 105 MPH
48H  09/0000Z 21.5N 139.5W   85 KT 100 MPH
72H  10/0000Z 21.8N 144.5W   75 KT  85 MPH
96H  11/0000Z 22.0N 148.5W   70 KT  80 MPH
120H  12/0000Z 21.5N 152.5W   65 KT  75 MPH

$$
Forecaster Avila

t02436

即將在明天進入中太，五天後以TS強度正面影響夏威夷。

224
WTPZ42 KNHC 080256
TCDEP2

Hurricane Olivia Discussion Number  30
NWS National Hurricane Center Miami FL       EP172018
800 PM PDT Fri Sep 07 2018

The cloud pattern of Olivia has continued to degrade this evening
with warming of the inner core, and a decreasing eye temperature. A
compromise of the Dvorak satellite intensity estimates, and an
earlier SATCON analysis, support decreasing the initial wind speed
to 85 kt.  Olivia still has an annular appearance with the cloud
pattern consisting of an inner core with little to no outer bands.

Continued slow weakening is forecast during the next 3 days as
Olivia moves over marginal sea surface temperatures of about 25C and
into an increasingly drier, more stable thermodynamic environment.
Afterward, Olivia will move back over slightly warmer waters and
remain in a low shear environment, so little change in strength is
expected through day 3. Through the remaining portion of the
forecast, southwesterly vertical wind shear of 15-20 kt should
induce more significant weakening.

Olivia's motion is estimated to be west-northwestward, or 290/13 kt,
and is being steered by a strong deep-layer subtropical ridge that
extends from Mexico and the southwestern U.S. westward into the
central Pacific.  The cyclone is forecast to move west-northwestward
for 72 hours or so before turning to the west, or even
west-southwest, as the aforementioned ridge builds to the north. The
official forecast has been adjusted south of the previous forecast
beyond day 3 to conform more with the NOAA-HCCA and TVCN consensus
models.  On the forecast track, Olivia is expected to cross into the
central Pacific basin by late Saturday and approach the Hawaiian
Islands in 4 to 5 days.

KEY MESSAGES

1. Olivia is forecast to approach the main Hawaiian Islands from
the east early next week, but it is too soon to determine the exact
location and magnitude of any impacts.  Interests in Hawaii should
monitor the progress of Olivia this weekend and use this time to
enact your hurricane action plan.

2.  Do not focus on the exact track or intensity forecast, or any
specific landfall location, as errors can be large at extended time
ranges. Tropical storm or hurricane conditions could be felt
anywhere in the islands as significant impacts could extend well
away from the center.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 20.9N 135.2W   85 KT 100 MPH
12H  08/1200Z 21.3N 137.3W   80 KT  90 MPH
24H  09/0000Z 21.6N 140.0W   75 KT  85 MPH
36H  09/1200Z 21.8N 142.6W   70 KT  80 MPH
48H  10/0000Z 21.8N 145.0W   65 KT  75 MPH
72H  11/0000Z 21.7N 149.0W   65 KT  75 MPH
96H  12/0000Z 20.9N 152.8W   55 KT  65 MPH
120H  13/0000Z 19.5N 157.3W   45 KT  50 MPH

$$
Forecaster Roberts/Birchard