EPAC: IGNACIO - Post-Tropical

[Yellow Evan]

Needs to close off an eye, but it has time. Not as large as previous pass either IIRC.

[Kingarabian]

Needs to close off an eye, but it has time. Not as large as previous pass either IIRC.

00z GFS has a Julio 2014.

[Yellow Evan]

Needs to close off an eye, but it has time. Not as large as previous pass either IIRC.

00z GFS has a Julio 2014.

Pretty much. Despite a strong ridge.

[Kingarabian]

[Kingarabian]

00z Euro continues to be south of Hawaii. Maybe it'll shift back north @ 12z.

Also, HWRF slightly more NE.

[Kingarabian]

TAFB:

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EP, 12, 201508270600,  10, DVTS,         CI,  , 1240N, 13800W,      , 2,  77, 2,     ,  ,     ,    ,     ,     ,     ,     ,     ,  ,  ,  ,  ,  ,    ,    , E,   SAB,  AS,   IM, 3, 4545 /////,      ,   , GOES15, LLCC, T, DT=5.0 BO EMB  MET=4.5 PT=4.0 FTBO MET
EP, 12, 201508270600,  10, DVTS,         CI,  , 1190N, 13800W,      , 3,  90, 2,  970, 2, DVRK,    ,     ,     ,     ,     ,     ,  ,  ,  ,  ,  ,    ,    , E,  TAFB,  MF,    I, 5, 5050 /////,      ,   , GOES15,  CSC, T,

SAB:

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  27/0600 UTC   12.4N    138.0W       T4.5/4.5         IGNACIO -- East Pacific 

[cycloneye]

HURRICANE IGNACIO DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122015
200 AM PDT THU AUG 27 2015

Very cold cloud tops persist near the center of Ignacio, although
the overall cloud pattern is not very symmetric and no eye is
present in conventional satellite data. However, microwave images
show an eye beneath the cirrus clouds, but not well established
in the low-level channel. Current intensity estimates range from 75
to 90 kt, and since the cloud pattern isn't particularly well
organized, I've elected to go on the low end of the estimates with
75 kt as the initial intensity.

The initial motion estimate remains 290/11. A west-northwestward
motion is expected to continue throughout the forecast period due to
a strong subtropical ridge to the north of Ignacio producing a deep
layer of east-southeasterly steering flow. Models are continuing
to struggle with the strength of the ridge in the long range
period, with a variety of solutions from the normally reliable
global models. Since the track consensus is virtually unchanged,
the NHC forecast will stay very close to the previous one and wait
for a stronger signal before making any significant modifications.

Further strengthening seems likely with Ignacio over the next couple
of days with light-to-moderate easterly shear, warm water and a
moist atmosphere. By days 3 and 5, thermodynamic and oceanic
conditions are expected to become less favorable, with an increase
in southwesterly shear, and gradual weakening is expected to occur
during that time. The official intensity forecast is similar to the
previous advisory, and is close to the consensus model IVCN.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 12.6N 138.5W 75 KT 85 MPH
12H 27/1800Z 13.2N 139.9W 85 KT 100 MPH
24H 28/0600Z 14.2N 141.9W 95 KT 110 MPH
36H 28/1800Z 15.1N 143.7W 100 KT 115 MPH
48H 29/0600Z 15.9N 145.2W 100 KT 115 MPH
72H 30/0600Z 17.2N 147.9W 95 KT 110 MPH
96H 31/0600Z 18.5N 150.5W 85 KT 100 MPH
120H 01/0600Z 20.0N 153.5W 75 KT 85 MPH

$$
Forecaster Blake

[Kingarabian]

06Z shifts a bit more west closer to Hawaii:

[Kingarabian]

00z Euro ensembles:

[Kingarabian]

06z HWRF shifts back to WSW:



Ignacio increasing its banding:

[Extratropical94]

Latest BT:
EP, 12, 2015082712, , BEST, 0, 126N, 1390W, 80, 982, HU

[Yellow Evan]

27/1200 UTC 12.7N 139.1W T4.5/4.5 IGNACIO -- East Pacific

[Yellow Evan]

----- Current Analysis -----
Date : 27 AUG 2015 Time : 123000 UTC
Lat : 12:24:25 N Lon : 139:20:13 W


CI# /Pressure/ Vmax
4.6 / 978.1mb/ 79.6kt


Final T# Adj T# Raw T#
4.6 4.6 4.6

Center Temp : -75.1C Cloud Region Temp : -77.6C

[galaxy401]

HURRICANE IGNACIO DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122015
800 AM PDT THU AUG 27 2015

Ignacio continues to produce cloud tops colder than -80C near the
center. A recent GPM over pass showed a 20-25 n mi wide eye
forming under the overcast. However, the eye is ragged, and the
deep convection in the eyewall is mainly southwest of the center.
Satellite intensity estimates from TAFB and SAB are 90 kt and 77 kt,
and the CIMSS Advanced Dvorak Technique is estimating 80 kt. Based
on these data, the initial intensity is increased to 80 kt.

The initial motion is now 285/11. There is little change in the
forecast philosophy since the previous advisory, with the
subtropical ridge north of Ignacio expected to steer the cyclone
generally west-northwestward through the forecast period with a
gradual decrease in forward speed. Some spread in the track
guidance develops by day 5, as the ECMWF turns a weaker Ignacio
westward while the GFS turns a stronger Ignacio northwestward.
Despite this, the consensus models and the center of the guidance
envelope are near the previous forecast, and the new forecast is a
slightly faster update of the previous forecast.

Ignacio should remain over warm sea surface temperatures and in an
environment of light vertical wind shear for at least the next two
days, which should allow continued strengthening to a major
hurricane. After that time, the cyclone should encounter increasing
westerly shear and move over slightly cooler water, which should
start a gradual weakening. The new intensity forecast follows this
scenario and is basically unchanged since the previous advisory.
One note of uncertainty in the intensity forecast is that the GFS
shear at day 5, which is used in the SHIPS and LGEM models, looks
weaker than that forecast by the ECMWF and UKMET models. Should the
latter models verify, Ignacio could weaken faster than currently
forecast.

Ignacio is expected to move into the Central Pacific basin at about
1800Z. Therefore, this is the last advisory on this system by the
National Hurricane Center. Subsequent advisories will be issued by
the Central Pacific Hurricane Center in Honolulu, Hawaii.


FORECAST POSITIONS AND MAX WINDS

INIT 27/1500Z 12.9N 139.5W 80 KT 90 MPH
12H 28/0000Z 13.6N 141.1W 90 KT 105 MPH
24H 28/1200Z 14.5N 143.1W 95 KT 110 MPH
36H 29/0000Z 15.4N 144.8W 100 KT 115 MPH
48H 29/1200Z 16.1N 146.1W 100 KT 115 MPH
72H 30/1200Z 17.5N 149.0W 95 KT 110 MPH
96H 31/1200Z 19.0N 151.5W 85 KT 100 MPH
120H 01/1200Z 20.5N 154.0W 75 KT 85 MPH

$$
Forecaster Beven

[Kingarabian]

Going annular? Lost its banding features quite fast.

[Alyono]

looks like a CCC pattern. May be the end of intensification for a bit

[Yellow Evan]

Maybe, also appears to be some mid-level shear.

[Alyono]

Maybe, also appears to be some mid-level shear.

yep, the microwave pass indicates the center is well east of 140W. Not much deep convection either. Maybe NHC will have another advisory to issue on this one

[Yellow Evan]

Maybe, also appears to be some mid-level shear.

yep, the microwave pass indicates the center is well east of 140W. Not much deep convection either. Maybe NHC will have another advisory to issue on this one

Shear seems to be coming from the SE. But any relaxation of the shear could give the eye a chance to clear.

[Kingarabian]

Euro shifts N of Hawaii.