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Sep
15
2017

Tropical Cyclone Activity Report – Pacific Ocean / Indian Ocean / Arabian Sea

Tropical Cyclone 20W (Talim) is located about 157 NM northwest of Kadena AB, Okinawa, Japan

Tropical Cyclone 15E is located about 1115 miles west-southwest of the southern tip of Baja California

Tropical Cyclone 17E (Norma) is located about 55 miles east-northeast of Socorro Island

PDC Disaster Alert, displaying PDC Active Hazards, Tropical Cyclone segments, positions, wind radii, and the TAOS model for Tropical Cyclone 20W (Talim)

Typhoon 20W (Talim) has weakened into a Tropical Storm in the NW Pacific…moving towards the Japanese Islands

Here’s a satellite image of this system…along with what the computer models are showing

Here’s a looping satellite image of this system

The Joint Typhoon Warning Center reports a large unraveling eye with weakening convection and warming cloud tops.

Upper level analysis shows moderate to favorable wind shear, while poleward outflow remains robust. Due to the nearly stationary motion of TY 20W over the past 24 hours, ocean upwelling has brought cooler waters to the surface…leading to a weakening trend.

TS 20W will continue to track east-northeastward. Sea surface temperatures in the area are expected to improve as the system moves away from the area of upwelling water.

Upper level conditions will remain neutral for the next 36 hours. The intensity is forecast to remain steady around 75 knots, as the system makes landfall  southeast of Sasebo, Japan.

Maximum sustained winds as of the JTWC Warning #30 were 60 knots with gusts of 75 knots

 

PDC Disaster Alert, displaying PDC Active Hazards, Tropical Cyclone segments, positions, wind radii, for retiring TC 16E (Max), Tropical Depression 15, and Tropical Storm Norma

Tropical Depression 15E remains active in the northeast Pacific…moving westward over the open eastern Pacific.

Maximum sustained winds are near 35 mph with higher gusts.

Here’s a satellite image of this system, with the looping version…along with what the computer models are showing

According to the NHC:

For the past several days, convection has developed repeatedly near
the center of the depression, only to dissipate a few hours later.
This trend has continued today, and the depression is currently at a
convective minimum.  The intensity has been held at 30 kt, based on
earlier ASCAT data.  Despite the lack of intensification so far,
most of the guidance continues to show that the depression will
become a tropical storm sometime in the next couple of days.  Only
the LGEM keeps the system weak throughout the forecast, though so
far that has been a good forecast.  For now, my forecast continues
to follow the intensity consensus and shows very gradual weakening
over the next couple of days.  Given the low shear and moderate
SSTs, it would still be a little surprising if the depression never
strengthens.

The depression continues to slow down, and is now drifting westward
at about 2 kt.  Very little change has been made to the track
forecast, and the global models continue to show little motion for
the next day or so while the cyclone remains trapped in weak
steering flow.  After about 24 h, a slow turn toward the north is
expected in response to a mid-level trough located well to the
north.  A turn back toward the west should occur once the
subtropical ridge becomes re-established around day 4.  The NHC
forecast remains near the various consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 16.0N 125.4W   30 KT  35 MPH
 12H  16/1200Z 15.9N 125.7W   30 KT  35 MPH
 24H  17/0000Z 15.9N 126.0W   35 KT  40 MPH
 36H  17/1200Z 16.3N 126.3W   35 KT  40 MPH
 48H  18/0000Z 16.8N 126.3W   40 KT  45 MPH
 72H  19/0000Z 18.0N 126.3W   40 KT  45 MPH
 96H  20/0000Z 18.5N 127.5W   30 KT  35 MPH
120H  21/0000Z 18.0N 130.0W   25 KT  30 MPH...POST-TROP/REMNT LOW


Tropical Storm 17E (Norma)
remains active in the northeast Pacific…moving northwestward over the eastern Pacific.

Maximum sustained winds are near 75 mph with higher gusts.

Here’s a satellite image of this system, with the looping version…along with what the computer models are showing

According to the NHC:

Infrared satellite imagery indicates that banding associated with
Norma has increased during the past few hours.  The convective cloud
tops have cooled and the band surrounding the center has become a
little more solid with the formation of a ragged banding eye. Dvorak
data T-numbers from both TAFB and SAB are 4.0, and with the recent
increase in organization the initial wind speed is increased to 65
kt. Norma becomes the eighth hurricane in the eastern Pacific this
season.

Norma should remain over warm water and within a low shear
environment during the next 24 to 36 h.  These conditions favor
strengthening, but the large size of Norma is likely to keep the
intensification rate in check.  Increasing vertical shear and cooler
waters are expected to impart gradual weakening after 48 hours.  The
latest NHC intensity forecast is similar to the previous advisory
and is close to the SHIPS guidance.

Norma has been moving slowly north-northwestward, with an initial
motion estimate of 335/2 kt.  The hurricane is forecast to move
slowly northward during the next couple of days, while it remains
along the western side of a mid-level ridge.  After that time, the
ECMWF develops a narrow ridge to the north of Norma which causes the
hurricane to turn northwestward.  Meanwhile, the GFS keeps Norma on
a north track over the Baja California peninsula. The trend of the
track guidance has been westward during the past several cycles, so
the NHC forecast lies slightly west of the consensus, and closer to
the ECMWF that has been more consistent over the past few runs.
Given the large spread in the guidance later in the period, the
confidence in the track forecast after 48 hours remains low.

The 48-hour forecast track and wind radii are very close to the
southern tip of the Baja California peninsula.  However, with the
persistent westward shifts in the guidance, a tropical storm watch
does not appear to be needed at this time.  We will assess future
model trends for the possibility of a watch issuance later tonight
or tomorrow.


FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 19.0N 110.2W   65 KT  75 MPH
 12H  16/1200Z 19.3N 110.4W   70 KT  80 MPH
 24H  17/0000Z 20.0N 110.5W   75 KT  85 MPH
 36H  17/1200Z 21.0N 110.9W   75 KT  85 MPH
 48H  18/0000Z 22.0N 111.3W   70 KT  80 MPH
 72H  19/0000Z 23.7N 112.3W   60 KT  70 MPH
 96H  20/0000Z 24.6N 112.6W   45 KT  50 MPH
120H  21/0000Z 25.5N 111.5W   30 KT  35 MPH...INLAND

Eastern North Pacific

Tropical Cyclone 15E

NHC textual forecast advisory
NHC graphical track map
NOAA satellite image

Tropical Cyclone 17E (Norma)

NHC textual forecast advisory
NHC graphical track map
NOAA satellite image

Satellite image of this area

Central North Pacific

There are no current tropical cyclones

Western North Pacific

Tropical cyclone 20W (Tamil) 

JTWC textual forecast warning
JTWC graphical track map
NOAA satellite image

South Pacific

There are no current tropical cyclones

Satellite image of this area

North Indian Ocean

There are no current tropical cyclones

Satellite image of this area

South Indian Ocean

There are no current tropical cyclones

Satellite image of this area

North Arabian Sea

There are no current tropical cyclones

Satellite image of this area

 

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