2015 Eastern Pacific Tropical Weather Discussion

[srainhoutx]

Hurricane Blanca now forecast to approach a Category 5 Hurricane on the Saffir-Simpson Scale.

HURRICANE BLANCA DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
1000 AM CDT WED JUN 03 2015

Blanca has rapidly intensified since yesterday and the initial
intensity has been set at 115 kt. This is an increase in
the winds of 60 kt since yesterday at 1200 UTC. The initial
intensity is based on objective and subjective T-numbers which have
reached T6.0 on the Dvorak scale. The hurricane has developed a
distinct pinhole eye in both IR and visible images surrounded by
very deep convection. There is an opportunity for Blanca to
intensify further since the hurricane is located within an ideal
environment of low shear and high ocean heat content as indicated by
statistical-dynamical models. In addition, the Rapid Intensification
Index remains extremely high, and this has been the case during the
past 24 to 36 hours. Beyond 48 hours, the hurricane will encounter
lower SSTs and a gradual weakening should begin.

Blanca is currently trapped within weak steering currents and the
cyclone has barely moved since yesterday and little motion is
anticipated today. During the next 24 hours, the hurricane should
begin a northwestward track with some increase in forward speed as a
high pressure system amplifies over the southwestern Unites States
and Mexico, and a mid-level trough approaches from the northwest.
The NHC forecast is very similar to the previous one and follows
very closely the consensus of the GFS and the ECMWF models.
Since Blanca is a potential threat to Baja California in a few
days, a reconnaissance aircraft will likely investigate the
cyclone on Friday.

Blanca is the earliest second major hurricane to form in the
eastern North Pacific since reliable records began in 1971.


FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 12.4N 104.7W 115 KT 130 MPH
12H 04/0000Z 12.5N 104.7W 125 KT 145 MPH
24H 04/1200Z 13.1N 105.0W 140 KT 160 MPH
36H 05/0000Z 14.2N 105.9W 135 KT 155 MPH
48H 05/1200Z 15.7N 107.1W 130 KT 150 MPH
72H 06/1200Z 18.8N 109.2W 110 KT 125 MPH
96H 07/1200Z 21.5N 110.2W 75 KT 85 MPH
120H 08/1200Z 24.3N 111.2W 45 KT 50 MPH...INLAND

$$
Forecaster Avila

[srainhoutx]

Blanca now expected to reach Category 5 Status during the next 24 to 36 hours.

HURRICANE BLANCA DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
400 PM CDT WED JUN 03 2015

Although the convection is not as strong as earlier today, the eye
is warmer and both objective and subjective T-numbers are
oscillating between 6.0 and 6.5 on the Dvorak scale. On this basis,
the initial intensity is now 120 kt. Blanca has the opportunity to
strengthen further during the next 24 hours as the hurricane moves
within an ideal environment of low shear and high ocean heat
content. The intensity forecast continues to be based primarily on
the SHIPS and LGEM models. The HWRF and GFDL have consistently
under-forecast the intensity of Blanca and in fact, are forecasting
rapid weakening during the next 24 hours. Beyond 48 hours, Blanca
will encounter lower SSTs, and a gradual weakening should begin.

Blanca remains trapped within weak steering currents, and the
cyclone has barely moved today. During the next 24 hours, the
hurricane should begin a northwestward track with some increase in
forward speed as a high pressure system over the southwestern United
States and Mexico amplifies, and a mid-level trough approaches the
coast of California. Based on the latest consensus of the GFS and
the ECMWF models, the NHC forecast has been shifted slightly to the
west from the earlier one. It appears that the high pressure over
Mexico will expand westward more than previously indicated,
which has resulted in the small westward shift of the ECMWF/GFS
model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 03/2100Z 12.3N 104.7W 120 KT 140 MPH
12H 04/0600Z 12.4N 104.8W 125 KT 145 MPH
24H 04/1800Z 13.3N 105.4W 140 KT 160 MPH
36H 05/0600Z 14.5N 106.6W 135 KT 155 MPH
48H 05/1800Z 15.8N 107.8W 125 KT 145 MPH
72H 06/1800Z 19.0N 109.7W 100 KT 115 MPH
96H 07/1800Z 22.0N 110.7W 65 KT 75 MPH
120H 08/1800Z 24.5N 112.0W 40 KT 45 MPH...INLAND

$$
Forecaster Avila

[srainhoutx]

HURRICANE BLANCA DISCUSSION NUMBER 20
NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015
900 AM MDT FRI JUN 05 2015

The intensity of Blanca has been oscillating around 85 and 90 kt
since yesterday. Latest satellite intensity estimates indicate
that there has been no change, and the winds are currently 85 kt.
Deep convection is beginning to increase and is becoming better
organized around the large circulation center. This could be an
indication that some restrengthening is about to begin. The
hurricane has about 24 hours to do so before the SSTs decrease,
which should result in gradual weakening. In fact, Blanca is
forecast to be a tropical storm as it moves near the southern Baja
California peninsula and become a remnant low over the high terrain
of the peninsula. An Air Force Reserve Hurricane Hunter aircraft is
en route to investigate Blanca and will provide more information
regarding the intensity and structure of the cyclone.

The best estimate of the initial motion is toward the northwest or
320 degrees at 9 kt. The hurricane is moving around the southwestern
periphery of a subtropical ridge over the United States and northern
Mexico. As Blanca gains latitude, it will become steered by the
southerly flow ahead of an approaching mid-latitude trough and
turn more toward the north. The dynamical guidance is now in much
better agreement, bringing the cyclone near or over the southern
Baja California peninsula beyond 48 hours or so. The NHC forecast is
similar to the previous one, and is in the middle of the very tight
guidance envelope.

Moisture associated with Blanca is moving northward and could help
produce heavy rainfall over portions of southwestern Mexico during
the next day or so, especially in areas of mountainous terrain.


FORECAST POSITIONS AND MAX WINDS

INIT 05/1500Z 15.1N 106.9W 85 KT 100 MPH
12H 06/0000Z 16.1N 107.9W 90 KT 105 MPH
24H 06/1200Z 17.6N 109.0W 95 KT 110 MPH
36H 07/0000Z 19.4N 109.8W 75 KT 85 MPH
48H 07/1200Z 21.0N 110.5W 65 KT 75 MPH
72H 08/1200Z 24.5N 111.5W 35 KT 40 MPH...INLAND
96H 09/1200Z 27.0N 112.5W 25 KT 30 MPH...INLAND
120H 10/1200Z 28.0N 113.0W 20 KT 25 MPH...POST-TROP/INLAND

$$
Forecaster Avila

[srainhoutx]

The attachment 06072015 5 AM PDT two_pac_5d0.png is no longer available

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT SUN JUN 7 2015

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Hurricane
Blanca, located a couple of hundred miles south-southwest of Cabo
San Lucas, Mexico.

1. Disorganized showers and thunderstorms several hundred miles south
of the Gulf of Tehuantepec are associated with a trough of low
pressure. Environmental conditions are forecast to become conducive
for some development of this system by midweek while it moves slowly
northwestward or northward.
* Formation chance through 48 hours...low...10 percent
* Formation chance through 5 days...medium...60 percent

Forecaster Blake

[srainhoutx]

INVEST 94E has been designated for the area of disturbed weather S of the Gulf of Tehuantepec.

The attachment 06082015 5 AM PDT two_pac_5d0.png is no longer available

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT MON JUN 8 2015

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical
Storm Blanca, located on the southwestern coast of Baja California
Sur.

1. Shower activity is showing some signs of organization in association
with a broad area of low pressure centered several hundred miles
south of the Gulf of Tehuantepec. Upper-level winds are expected to
be conducive, and a tropical depression is likely to form in a few
days while this system moves slowly northwestward or northward.
* Formation chance through 48 hours...low...30 percent
* Formation chance through 5 days...high...80 percent

Forecaster Blake

[srainhoutx]

94E south of the Gulf of Tehuantepec continues to show signs of developing a low level circulation generally moving slowly to the N or NW toward the Gulf of Tehuantepec.

[srainhoutx]

The National Hurricane Center has increased chances for development of a tropical depression mid week for the area of disturbed weather (INVEST 94E) S of the Gulf of Tehuantepec.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
1100 AM PDT MON JUN 8 2015


For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical
Storm Blanca, located near the southwestern coast of Baja California
Sur.

1. Showers and thunderstorms continue to become better organized in
association with a broad low pressure area centered several hundred
miles south of the Gulf of Tehuantepec. Environmental conditions
appear to be conducive for a tropical depression to form around the
middle of the week while this system moves slowly northwestward or
northward.
* Formation chance through 48 hours...medium...50 percent
* Formation chance through 5 days...high...90 percent

Forecaster Blake

[srainhoutx]

INVEST 94E continues to organize S of the Gulf of Tehuantepec.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT MON JUN 8 2015


For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical
Depression Blanca, located over the southern portion of the Baja
California Peninsula.

1. Showers and thunderstorms are slowly becoming better organized in
association with a broad low pressure area centered several hundred
miles south of the Gulf of Tehuantepec. Environmental conditions
appear to be conducive for a tropical depression to form during
the next two to three days while the this system moves slowly
northwestward or northward.
* Formation chance through 48 hours...medium...60 percent
* Formation chance through 5 days...high...90 percent

Forecaster Beven

[srainhoutx]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT TUE JUN 9 2015

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center has issued the last advisory on
Post-Tropical Cyclone Blanca, located near the central portion of
the Baja California peninsula.

1. Although the associated shower activity has recently decreased,
satellite data indicate that the area of low pressure several
hundred miles south of Gulf Tehuantepec has become better defined
since yesterday. Environmental conditions remain conducive for a
tropical depression to form during the next couple of days while
this system moves slowly northwestward or northward.
* Formation chance through 48 hours...medium...60 percent
* Formation chance through 5 days...high...90 percent

Forecaster Blake

[srainhoutx]

The 12Z Track and Intensity guidance for 94E.

[srainhoutx]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
1100 AM PDT TUE JUN 9 2015

For the eastern North Pacific...east of 140 degrees west longitude:

1. Showers and thunderstorms continue to show signs of organization in
association with an area of low pressure located several hundred
miles south of the Gulf of Tehuantepec. Environmental conditions
appear to be conducive for a tropical depression to form during the
next couple of days while this system moves slowly northwestward or
northward.
* Formation chance through 48 hours...medium...60 percent
* Formation chance through 5 days...high...90 percent

Forecaster Blake

[srainhoutx]

The National Hurricane Center has increased chances that 94E will develop into a tropical depression to 80% within the next 48 hours.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT WED JUN 10 2015

For the eastern North Pacific...east of 140 degrees west longitude:

1. Showers and thunderstorms associated with a low pressure area a
few hundred miles southwest of the Gulf of Tehuantepec have become
better organized since yesterday. Environmental conditions are
conducive for development, and a tropical depression is likely to
form later today or on Thursday while this system moves slowly
northwestward or northward.
* Formation chance through 48 hours...high...80 percent
* Formation chance through 5 days...high...90 percent

Forecaster Landsea

[srainhoutx]

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
0935 AM EDT WED 10 JUNE 2015
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 11/1100Z TO 12/1100Z JUNE 2015
TCPOD NUMBER.....15-016

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK: FIX A DEVELOPING SYSTEM AT
12/1730Z NEAR 15.0N 97.5W

[srainhoutx]

Sure looks like a tropical cyclone has developed this afternoon SE of Acapulco.

[srainhoutx]

TROPICAL DEPRESSION THREE-E DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL EP032015
400 PM CDT WED JUN 10 2015

Satellite imagery indicates that the deep convection associated
with the low pressure system located southwest of the Gulf of
Tehuantepec has become sufficiently well organized to designate the
formation of a tropical depression. Therefore, advisories are
being initiated at this time. The cyclone should remain in an
environment of low vertical shear and over warm waters for the next
several days, so steady strengthening seems to be a good bet. The
official wind speed forecast is generally above the intensity model
consensus. There is significant uncertainty in the longer range
intensity forecast, depending on how much the system interacts with
land.

Center fixes have had a fair amount of scatter, and my best
estimate of the initial motion is 315/8 kt. During the next 72
hours, the cyclone is likely to respond to a mid-level weakness over
the Gulf of Mexico by turning northward and north-northeastward.
Later in the forecast period, a mid-level ridge to the northwest is
expected to cause the system to turn toward the west-northwest and
move parallel the coast. The GFS model takes the system close to
the coast in 72 hours, but the ECMWF and GFDL model tracks keep the
cyclone offshore and are much farther to the west than the GFS
solution. As a compromise, the official track forecast is close
to the model consensus TVCN albeit not as far west as TVCN by 120
hours. Given the large divergence of the model tracks, this is a
low confidence forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 10/2100Z 12.4N 98.7W 30 KT 35 MPH
12H 11/0600Z 13.0N 99.4W 35 KT 40 MPH
24H 11/1800Z 13.4N 99.9W 45 KT 50 MPH
36H 12/0600Z 14.0N 99.6W 55 KT 65 MPH
48H 12/1800Z 14.5N 99.2W 65 KT 75 MPH
72H 13/1800Z 15.5N 99.0W 70 KT 80 MPH
96H 14/1800Z 16.5N 100.5W 75 KT 85 MPH
120H 15/1800Z 17.5N 103.5W 75 KT 85 MPH

$$
Forecaster Pasch

[ticka1]

I don't see this crossing into the GOM instead it looks like it hugs the coastline in the Pacific. I know we will still get the moisture flow which is why our rain chances are increased for the weekend.

[Paul Robison]

I don't see this crossing into the GOM instead it looks like it hugs the coastline in the Pacific. I know we will still get the moisture flow which is why our rain chances are increased for the weekend.

But perhaps not as much moisture for heavy rain as we would if it did actually cross into the Bay of Campeche/Gulf of Mexico.

[srainhoutx]

TROPICAL DEPRESSION THREE-E DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP032015
400 AM CDT THU JUN 11 2015


The depression does not appear to be strengthening yet. The
cyclone has a broad circulation with some evidence of multiple
centers. A pair of ASCAT passes at 0330 and 0415 UTC showed
maximum winds in the 25-30 kt range. Given that the convective
pattern has not changed much since the time of the ASCAT data, the
initial wind speed is kept at 30 kt. This intensity estimate is a
little lower than the Dvorak classifications from TAFB, SAB, and
UW-CIMSS ADT which are all T2.5/35 kt.

The initial motion estimate is an uncertain 305/7. The system is
expected to slow down and turn northward later today or tonight
when a mid- to upper-level trough over the Gulf of Mexico cuts off
and drifts westward. The low aloft is expected to weaken this
weekend, which should allow ridging to become better established to
the north of the tropical cyclone. This pattern change should
cause the system to turn west-northwestward and increase in
forward speed in a few days. Although a fair amount of spread still
exists in the model solutions, they have come into better agreement
compared to previous cycles. In fact, most of the guidance has
shifted south and west away from the coast of southern Mexico, and
the official track forecast follows that trend.

The depression is expected to remain over warm water and in a moist
airmass for the next several days. These conditions support
steady intensification. A slightly inhibiting factor is vertical
wind shear, which is forecast by the SHIPS model to be around 15
kt for the next few days. The official intensity forecast is just
an update of the previous one and shows gradual intensification
through the period. This forecast lies at the high end of the
guidance, in best agreement with the SHIPS model. It should be
noted that the future intensity of the system is dependent on how
much it interacts with land, so if the system gets closer to the
coast than predicted, the longer range part of the forecast could be
too high.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0900Z 13.1N 100.2W 30 KT 35 MPH
12H 11/1800Z 13.5N 100.5W 40 KT 45 MPH
24H 12/0600Z 14.1N 100.6W 45 KT 50 MPH
36H 12/1800Z 14.4N 100.5W 55 KT 65 MPH
48H 13/0600Z 14.7N 100.4W 65 KT 75 MPH
72H 14/0600Z 15.5N 100.9W 70 KT 80 MPH
96H 15/0600Z 16.5N 103.4W 75 KT 85 MPH
120H 16/0600Z 17.5N 105.5W 80 KT 90 MPH

$$
Forecaster Cangialosi

[srainhoutx]

Tropical Storm Carlos has formed in the Eastern Pacific S of Acapulco. The official Advisory should be out with the 10 AM CDT Advisory Package.

[srainhoutx]

Tropical Storm Carlos forms 230 miles S of Acapulco.

TROPICAL STORM CARLOS DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP032015
1000 AM CDT THU JUN 11 2015

The organization of the tropical cyclone has gradually increased,
with a curved band of deep convection wrapping more than half way
around the system's center. The intensity is analyzed to be 35 kt
based upon a blend of TAFB, SAB, and ADT Dvorak estimates with
consideration that the pattern recognition methods were apparently
a bit biased high in comparison with the ASCAT scatterometer
winds overnight. Thus the system is upgraded to Carlos, the third
tropical storm of the season in the Eastern North Pacific.

Even though the cyclone is over very warm waters, Carlos is likely
to continue to intensify at a moderate pace due to about 15 kt of
northeasterly vertical shear expected during the next two to three
days. At the longer forecast times, the shear may decrease as
Carlos approaches the axis of the upper-tropospheric ridge.
However, a dry and more stable environment at that time may preclude
substantial intensification. Given that Carlos' track now is
projected to remain away from the Mexican coast for at least
the short-term, it is less likely that land influences will affect
the system. The official intensity forecast is based upon a blend
of the LGEM and SHIPS statistical-dynamical models and is slightly
lower than that from the previous advisory.

Carlos is moving toward the northwest at about 5 kt. Shortly, a
developing trough over the Gulf of Mexico will cause the steering
pattern to weaken and Carlos should meander northward for the
next couple of days. In three to four days, a deep-layered ridge
will become re-established north of Carlos and help propel it
northwest or west-northwestward at a slow forward speed,
paralleling the southwestern Mexican coast. The official track
prediction is based upon the TVCN multi-model track consensus and
is just slightly southwest of that from the previous advisory.

FORECAST POSITIONS AND MAX WINDS

INIT 11/1500Z 13.6N 100.4W 35 KT 40 MPH
12H 12/0000Z 14.0N 100.7W 45 KT 50 MPH
24H 12/1200Z 14.2N 100.8W 50 KT 60 MPH
36H 13/0000Z 14.4N 100.7W 60 KT 70 MPH
48H 13/1200Z 14.7N 100.7W 65 KT 75 MPH
72H 14/1200Z 15.6N 101.7W 70 KT 80 MPH
96H 15/1200Z 16.8N 104.1W 70 KT 80 MPH
120H 16/1200Z 17.7N 106.4W 75 KT 85 MPH

$$
Forecaster Landsea