EPAC: LESTER - Post-Tropical

[Kingarabian]

GFS and the Euro show this mainlining longitude. But the storm seems to be moving more W than previously thought. So they may be underestimating the ridge.

[Kingarabian]

Looks like it's about to RI?

[Kingarabian]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 27 AUG 2016 Time : 050000 UTC
Lat : 17:56:26 N Lon : 116:45:21 W


CI# /Pressure/ Vmax
4.4 / 982.0mb/ 74.6kt


Final T# Adj T# Raw T#
4.4 4.4 5.6

Assuming all agencies will go 4.5-5.0.

[cycloneye]

HURRICANE LESTER DISCUSSION NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016
200 AM PDT SAT AUG 27 2016

Satellite imagery shows that Lester is continuing to intensify, with
an eye gradually becoming better defined inside a central dense
overcast. Various subjective and objective satellite intensity
estimates are near 75 kt, and that value is the initial intensity
for this advisory. The hurricane has good cirrus outflow in the
northwestern semicircle.

The initial motion is now 280/9. Lester is south of a strong
deep-layer subtropical ridge, and the dynamical models forecast
this feature to build westward to the north of the hurricane through
the forecast period. The forecast guidance remains tightly
clustered around an almost due west motion with an increase in
forward speed during the next several days. The new forecast track
is an update of the previous track and lies near the center of the
guidance envelope.

Lester is expected to remain in a low-shear environment during the
forecast period, so the main external factors controlling the
intensity will be sea surface temperatures and possible dry air
entrainment. During the first 48 hours or so, the hurricane will be
over generally warm water. Based on current trends, this part of
the intensity forecast has been raised significantly from the
previous advisory and calls for a peak intensity of 95 kt. After
48 hours, a combination of slightly cooler water and dry air
entrainment should cause a gradual weakening. Overall, the new
intensity forecast lies near the upper edge of the guidance.

FORECAST POSITIONS AND MAX WINDS

INIT 27/0900Z 17.9N 117.4W 75 KT 85 MPH
12H 27/1800Z 18.0N 118.8W 85 KT 100 MPH
24H 28/0600Z 18.1N 121.0W 90 KT 105 MPH
36H 28/1800Z 18.2N 123.5W 95 KT 110 MPH
48H 29/0600Z 18.4N 126.3W 95 KT 110 MPH
72H 30/0600Z 18.5N 132.0W 90 KT 105 MPH
96H 31/0600Z 18.5N 137.5W 85 KT 100 MPH
120H 01/0600Z 18.0N 142.5W 80 KT 90 MPH

$$
Forecaster Beven

[Kingarabian]

No doubt, a major hurricane.

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 27 AUG 2016 Time : 100000 UTC
Lat : 17:45:21 N Lon : 117:30:20 W


CI# /Pressure/ Vmax
5.3 / 965.1mb/ 97.2kt


Final T# Adj T# Raw T#
5.3 5.5 5.5

Estimated radius of max. wind based on IR : 24 km

Center Temp : +9.4C Cloud Region Temp : -56.3C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

[Kingarabian]

[Ntxw]

Eye is a little ragged but I agree, this is looks like a major. 4th of the season if it is and if it can hold on to the colder cloud tops a little longer.

[cycloneye]

TTAA00 KNHC DDHHMM

HURRICANE LESTER DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016
800 AM PDT SAT AUG 27 2016

Lester has been slowly strengthening. Since the last advisory, the
eye has cleared out, warmed and become better defined. The cyclone
has also been maintaining a compact and fairly symmetric central
dense overcast but with no prominent banding features. Satellite
classifications are T4.5/77 kt and T5.0/90 kt from TAFB and SAB,
respectively. A blend of these is used to raise the initial
intensity estimate to 80 kt.

Lester's heading has become more westerly during the past several
hours, and the initial motion estimate is 275/08. A strong
subtropical ridge should hold sway to the north of Lester for at
leastthe next 3 days, keeping the cyclone on a nearly due-west
course. The track guidance is tightly clustered during this time,
resulting in a high confidence forecast. After 72 hours, the model
spread increases, with the GFS-based solutions on the northern
side of the guidance envelope and the ECMWF to the south. The
differences between the models are related to their handling of a
mid-latitude trough approaching the California coast, which could
weaken the ridge to the north of Lester. The ECMWF maintains a
stronger ridge and thus depicts a more westerly track, while the
GFS-based guidance shows Lester gaining more latitude as a result of
a weaker ridge. The new NHC track foreast is adjusted slightly
north of the previous one from 72-120 hours and is close to a
consensus of these models.

Global models forecast a nearly uniform easterly flow at all levels
over Lester throughout the forecast period, implying a low-shear
environment for the foreseeable future. Sea surface temperatures
should gradually decrease along Lester's track but be warm enough to
support additional intensification, except perhaps when it
encounters a pocket of somewhat cooler waters between 130W and 140W
in 2 to 4 days. The main issue governing Lester's intensity is
likely to be the dryness of the air surrounding it, with both the
GFS and ECMWF models indicating unusually dry air affecting the
cyclone during the period. The NHC intensity forecast calls for
only modest intensification the next day or two, during a time when
environmental conditions appear most optimal. After that time, the
extremely dry conditions and more marginal SSTs suggest that a slow
weakening would be the best forecast. The new intensity forecast is
lower than the previous one throughout the period. The NHC forecast
is above the multi-model consensus in the short term and generally
near it after 72 hours.

FORECAST POSITIONS AND MAX WINDS

INIT 27/1500Z 18.0N 118.4W 80 KT 90 MPH
12H 28/0000Z 18.0N 119.9W 85 KT 100 MPH
24H 28/1200Z 18.1N 122.4W 90 KT 105 MPH
36H 29/0000Z 18.2N 125.1W 90 KT 105 MPH
48H 29/1200Z 18.4N 128.0W 85 KT 100 MPH
72H 30/1200Z 18.6N 133.7W 80 KT 90 MPH
96H 31/1200Z 18.6N 138.7W 75 KT 85 MPH
120H 01/1200Z 18.7N 143.5W 70 KT 80 MPH

$$
Forecaster Kimberlain

[Ntxw]

[hurricanes1234]

Wow

CI# /Pressure/ Vmax
5.4 / 962.2mb/ 99.6kt

[Ntxw]

This is a formidable cane. Worthy of 100kts IMO

[cycloneye]

HURRICANE LESTER DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016
200 PM PDT SAT AUG 27 2016

Lester's cloud pattern has increased some in organization during
the last several hours. The cyclone's small central dense
overcast has become more symmetric, with a well-defined 20 n mi
wide eye evident in visible satellite imagery. A broken band is
also wrapping around the southeastern semicircle of the Lester's
circulation. Dvorak T-numbers are a consensus T5.0 from both
satellite agencies. Based on these data, the initial intensity
estimate is increased to 90 kt.

Lester has been moving a little faster, and the initial motion
estimate is 270/11. A strong subtropical ridge to the north of
Lester should steer the cyclone on a nearly due-west course for at
least the next few days. After about 72 hours, there are
differences in the strength of the subtropical ridge north of
Lester, which are somewhat dependent on the progression of a
mid-latitude trough through the eastern Pacific. There also exists
some potential for binary interaction with Madeline late in the
forecast period, which could impart a more poleward motion to
Lester. The GFS-based guidance continues to lie on the northern side
of the guidance envelope, while the latest ECMWF solution remains on
the southern edge. The new track forecast is nearly identical to the
previous one through 48 hours but has been shifted northward in the
direction of a consensus of the ECMWF, HWRF, GFS, and UKMET models
after that time.

A nearly uniform easterly flow over Lester throughout the
troposphere is forecast for several days, resulting in a low-shear
environment. SSTs should be warm enough next day or so for
some intensification, but the environment around Lester will be
drying. In about 36 to 48 hours, the hurricane should begin to
traverse a region of lower SSTs between 130W and 140W. This will
occur at a time when global models forecast the near-storm
environment to become extremely dry. Slow weakening should commence
around this time and throughout the remainder of the forecast
period. This scenario is in line with the guidance, and the new
intensity forecast is in best agreement with the multi-model
consensus and LGEM.


FORECAST POSITIONS AND MAX WINDS

INIT 27/2100Z 17.9N 119.6W 90 KT 105 MPH
12H 28/0600Z 18.0N 121.3W 95 KT 110 MPH
24H 28/1800Z 18.2N 123.9W 95 KT 110 MPH
36H 29/0600Z 18.3N 126.8W 90 KT 105 MPH
48H 29/1800Z 18.5N 129.6W 85 KT 100 MPH
72H 30/1800Z 18.8N 135.0W 80 KT 90 MPH
96H 31/1800Z 18.9N 139.8W 75 KT 85 MPH
120H 01/1800Z 19.5N 144.6W 70 KT 80 MPH

$$
Forecaster Kimberlain

NNNN

[Yellow Evan]

Why isn't the NHC factoring in ADT?

----- Current Analysis -----
Date : 27 AUG 2016 Time : 193000 UTC
Lat : 17:50:49 N Lon : 119:21:30 W


CI# /Pressure/ Vmax
5.4 / 963.2mb/ 99.6kt


Final T# Adj T# Raw T#
5.3 5.4 5.4

Estimated radius of max. wind based on IR : 22 km

Center Temp : +13.1C Cloud Region Temp : -56.6C

Scene Type : EYE

[Kingarabian]

Why isn't the NHC factoring in ADT?

No idea. IMO,I think factoring ADT defers from system to system. If they believe Dvorak estimates may be over doing it they'll do their best to go with the most conservative fix. If the system looks really healthy and firing very deep convection, they'll go with the higher fix.

[Kingarabian]

But Lester continues to look better and better.

[Ntxw]

This is a major in my mind. It continues to look better and better agreed. Don't agree with the conservative forecast.

[Kingarabian]

This is a major in my mind. It continues to look better and better agreed. Don't agree with the conservative forecast.

Just need SAB or TAFB to join the ADT and they'll upgrade.

[Kazmit]

Lester's looking fantastic, reminds me of Blas.

[CrazyC83]

I'd go with 100 kt looking at that image.

[hurricanes1234]

No need to worry.

Personally I think we'll be seeing a Category 3 by tonight if these trends continue, then a slow weakening trend after.

Reminds me a little of Darby 2016 and Daniel 2012.