EPAC: LESTER - Post-Tropical

[Kingarabian]

Dr. Jeff Master's take on the track Lester may take:

Figure 6. The Fujiwhara effect causes two tropical cyclones near each other to rotate around a common midpoint. This motion is on top of the preexisting movement of each cyclone. Image credit: Hong Kong Observatory.


Ironically, the coexistence of Madeline and Lester may help keep either one from a direct landfall on Hawaii, thanks to the Fujiwhara effect, which was discovered nearly a century ago by Japanese researcher Sakuhei Fujiwhara. When two tropical cyclones get within about 800 miles of each other, the interaction tends to make the pair rotate around a common point in between, with the effect superimposed on the storm’s preexisting motions. In a case like this, the easterm storm (Lester) would angle northward and the western storm (Madeline) would angle southward. Both effects would tend to angle Madeline and Lester away from Hawaii.

https://www.wunderground.com/blog/JeffM ... rynum=3406

[Yellow Evan]

Code: Select all

EP, 13, 2016083000,   , BEST,   0, 181N, 1312W, 120,  947, HU,  34, NEQ,  120,  100,   80,  100, 1011,  200,  15,   0,   0,   E,   0,    ,   0,   0,     LESTER, D,
EP, 13, 2016083000,   , BEST,   0, 181N, 1312W, 120,  947, HU,  50, NEQ,   60,   50,   40,   50, 1011,  200,  15,   0,   0,   E,   0,    ,   0,   0,     LESTER, D,
EP, 13, 2016083000,   , BEST,   0, 181N, 1312W, 120,  947, HU,  64, NEQ,   30,   25,   20,   25, 1011,  200,  15,   0,   0,   E,   0,    ,   0,   0,     LESTER, D,


[Yellow Evan]

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* LESTER EP132016 08/30/16 00 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 120 117 113 106 102 93 86 78 71 65 58 55 52
V (KT) LAND 120 117 113 106 102 93 86 78 71 65 58 55 52
V (KT) LGEM 120 117 112 107 102 94 86 78 71 65 60 56 54
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 14 13 10 8 8 8 8 2 3 0 2 4 6
SHEAR ADJ (KT) -7 -8 -7 -4 -3 -2 -2 1 1 4 1 -1 -4
SHEAR DIR 83 100 96 92 106 120 122 222 236 186 153 218 296
SST (C) 26.8 26.8 27.1 27.2 27.1 26.7 26.6 26.8 26.8 26.5 26.5 26.6 26.8
POT. INT. (KT) 133 133 135 136 135 131 130 132 132 129 130 131 133
200 MB T (C) -52.2 -52.6 -52.7 -52.6 -52.0 -52.2 -52.1 -52.3 -52.1 -52.3 -52.3 -52.5 -52.2
200 MB VXT (C) 0.7 0.9 1.0 0.9 0.8 0.7 0.6 0.5 0.5 0.6 0.6 0.5 0.4
TH_E DEV (C) 6 5 5 5 6 6 6 6 6 6 6 5 5
700-500 MB RH 42 41 39 42 43 43 42 38 38 40 43 43 45
MODEL VTX (KT) 24 23 23 22 24 25 25 24 24 23 21 20 18
850 MB ENV VOR 46 57 52 66 66 57 47 46 41 40 50 55 51
200 MB DIV 4 0 -2 -6 5 24 17 23 24 9 7 7 13
700-850 TADV 0 -1 -1 -2 -2 -3 0 5 3 5 5 2 2
LAND (KM) 1977 2079 2184 2102 1982 1741 1497 1253 1009 754 507 292 145
LAT (DEG N) 18.1 18.2 18.3 18.3 18.2 18.2 18.4 18.6 18.9 19.4 20.2 21.0 21.8
LONG(DEG W) 131.2 132.5 133.7 134.9 136.0 138.3 140.6 142.9 145.2 147.6 150.0 152.5 155.1
STM SPEED (KT) 13 12 11 11 11 11 11 11 12 12 12 12 13
HEAT CONTENT 4 5 9 9 15 14 3 8 6 2 4 8 4

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):270/ 13 CX,CY: -12/ 0
T-12 MAX WIND: 110 PRESSURE OF STEERING LEVEL (MB): 462 (MEAN=586)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 8.9 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 96.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 30 KT IN 24 HR): 0.0

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
----------------------------------------------------------
SAMPLE MEAN CHANGE 0. 0. 1. 1. 1. 1. 1. 1. 0. -1. -1. -2.
SST POTENTIAL -3. -6. -10. -14. -24. -34. -43. -50. -55. -59. -61. -61.
VERTICAL SHEAR MAG -2. -4. -5. -5. -3. -1. 3. 7. 9. 11. 11. 9.
VERTICAL SHEAR ADJ 1. 1. 2. 2. 3. 3. 2. 2. 1. 1. 1. 1.
VERTICAL SHEAR DIR 0. 0. 0. 0. 0. 0. 0. -1. -2. -2. -2. -2.
PERSISTENCE 3. 4. 3. 3. 1. -1. -2. -2. -2. -2. -2. -2.
200/250 MB TEMP. 0. 0. 0. -1. -1. 0. 0. 1. 1. 0. 0. 0.
THETA_E EXCESS 0. 0. 0. 0. -1. -1. -1. -1. -1. -1. -2. -2.
700-500 MB RH 0. -1. -1. -1. -2. -3. -4. -5. -5. -6. -6. -7.
MODEL VTX TENDENCY 0. 0. -1. 0. 1. 2. 1. 0. -1. -3. -4. -6.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1.
200 MB DIVERGENCE 0. -1. -1. -2. -2. -3. -3. -3. -3. -3. -2. -2.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1.
ZONAL STORM MOTION 0. 1. 1. 1. 2. 3. 3. 2. 2. 1. 1. 1.
STEERING LEVEL PRES 0. 0. -1. -1. -1. -1. -1. -2. -2. -2. -2. -3.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. 1. 2. 2. 3. 3.
GOES PREDICTORS 0. 0. 0. -1. 0. 1. 2. 2. 3. 4. 4. 4.
OCEAN HEAT CONTENT 0. 0. 0. -1. -1. -1. -1. -1. 0. 0. 0. 0.
----------------------------------------------------------
TOTAL CHANGE -3. -7. -14. -18. -27. -34. -42. -49. -55. -62. -65. -68.

CURRENT MAX WIND (KT): 120. LAT, LON: 18.1 131.2

** 2015 E. Pacific RI INDEX EP132016 LESTER 08/30/16 00 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MOREMAXIMUM WIND INCREASE IN NEXT 24-h)

Predictor Value RI Predictor Range Scaled Value(0-1) % Contribution
12 HR PERSISTENCE (KT): 10.0 -22.0 to 38.5 0.53 999.0
POT = MPI-VMAX (KT) : 14.5 40.3 to 144.5 0.00 0.0
HEAT CONTENT (KJ/cm2) : 8.4 0.0 to 75.9 0.11 999.0
STD DEV OF IR BR TEMP : 8.9 38.9 to 2.1 0.82 999.0
850-200 MB SHEAR (KT) : 10.5 18.9 to 1.4 0.48 999.0
MAXIMUM WIND (kt) : 120.0 22.5 to 132.0 0.16 999.0
D200 (10**7s-1) : 0.2 -11.0 to 135.3 0.08 999.0
BL DRY-AIR FLUX (w/m2): 1023.8 638.0 to -68.2 0.00 0.0
2nd PC OF IR BR TEMP : 0.4 2.1 to -1.7 0.44 999.0
% AREA WITH TPW <45 mm: 33.5 81.4 to 0.0 0.59 999.0

SHIPS Prob RI for 20kt/ 12hr RI threshold= 0% is 0.0 times sample mean ( 6.3%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 0% is 0.0 times sample mean (12.9%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 0% is 0.0 times sample mean ( 8.6%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 0% is 0.0 times sample mean ( 5.8%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 0% is 0.0 times sample mean ( 4.1%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 0% is 0.0 times sample mean ( 7.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 0% is 0.0 times sample mean ( 5.9%)

Matrix of RI probabilities
---------------------------------------------------------------------
RI (kt / h) | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48
---------------------------------------------------------------------
SHIPS-RII: 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Logistic: 1.7% 0.1% 0.3% 0.1% 0.1% 0.0% 0.0%
Bayesian: 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%
Consensus: 0.6% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0%

## ANNULAR HURRICANE INDEX (AHI) EP132016 LESTER 08/30/16 00 UTC ##
## PASSED SCREENING STEP, MIGHT BE ANNULAR, CALCULATE AHI FROM DISCRIMINANT ANALYSIS ##
## AHI=100 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

[Ntxw]

Finally 120kts.

[Kingarabian]

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* LESTER EP132016 08/30/16 00 UTC *

If those values stand, Lester could very well remain a major hurricane till its closest approach to the islands...

[Yellow Evan]

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* LESTER EP132016 08/30/16 00 UTC *

If those values stand, Lester could very well remain a major hurricane till its closest approach to the islands...

Doubtful, since the storm will be moving over Madeline's cold wake in about 3 days.

[Yellow Evan]

18z GFS. My suspicious is that the global models are overdoing this interaction like they tend to do.

[Kingarabian]

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* LESTER EP132016 08/30/16 00 UTC *

If those values stand, Lester could very well remain a major hurricane till its closest approach to the islands...

Doubtful, since the storm will be moving over Madeline's cold wake in about 3 days.

I hope so. But it wont be for long, maybe 24 hours max. And if Lester maintains its annular characteristics, then the cooler SST's won't do much.

[cycloneye]

HURRICANE LESTER DISCUSSION NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016
800 PM PDT MON AUG 29 2016

Lester is a powerful category 4 hurricane. The eye of the
hurricane, which is now about 20 n mi wide, has expanded and cleared
out during the last several hours. Visible satellite images also
indicate that mesovorticies exist within the eye. The convective
pattern has been very symmetric, and the hurricane continues to have
an annular appearance in satellite images. The latest Dvorak
classifications from TAFB and SAB were 6.5/127 kt and 5.5/102 kt,
respectively. Based on these estimates and automated Dvorak values
from CIMSS at the University of Wisconsin, the initial wind speed
is raised a little to 120 kt. Lester is estimated to have
strengthened at an impressive rate of 45 kt during the past 24
hours.

The major hurricane is likely near its peak intensity, but
fluctuations in strength are possible in the short term. Beyond
that time, marginally warm sea surface temperatures and a stable air
mass suggest that Lester will likely weaken gradually during the
next several days. The NHC intensity forecast is similar to the
previous one and is fairly close to the intensity model consensus.

Lester continues to move due westward about 12 kt on the south
side of a strong mid-level high pressure system. A continued
westward track at about the same forward speed is predicted during
the next few days while the system remains to the south of the
ridge. After that time, a slight turn toward the west-northwest is
likely due to some interaction with another tropical cyclone,
Madeline, to its west-southwest. The models remain tightly
clustered, and the NHC official track forecast lies near the middle
of the guidance envelope. This forecast takes Lester close to the
Hawaiian Islands in about 5 days.

FORECAST POSITIONS AND MAX WINDS

INIT 30/0300Z 18.1N 131.8W 120 KT 140 MPH
12H 30/1200Z 18.2N 133.7W 115 KT 130 MPH
24H 31/0000Z 18.2N 136.0W 105 KT 120 MPH
36H 31/1200Z 18.3N 138.3W 95 KT 110 MPH
48H 01/0000Z 18.3N 140.5W 90 KT 105 MPH
72H 02/0000Z 19.0N 145.0W 85 KT 100 MPH
96H 03/0000Z 20.3N 149.9W 80 KT 90 MPH
120H 04/0000Z 22.0N 154.8W 70 KT 80 MPH

$$
Forecaster Cangialosi

[Yellow Evan]

Cloud tops seem to be warming and the eye is cooling for some reason.

[hurricanes1234]

Cloud tops seem to be warming and the eye is cooling for some reason.

Yes. I noticed that too. I think it may have peaked this time but who knows, I've been so wrong about this hurricane ever since it weakened the first time.

[1900hurricane]

I've been noticing it too. The degradation of convection almost looks like eyewall replacement to me, although I've seen nothing to think one is occurring otherwise. Maybe a little dry air ingestion perhaps?

On a somewhat related note, I hate how all the microwave passes come at one and then there's nothing for well over six hours this year. It's driving me insane!

[wxmann_91]

It looks like Lester's been hit with a bit of easterly shear... the CDO is a little more asymmetric now, coinciding with the warming of cloud tops and cooling of the eye.

[cycloneye]

HURRICANE LESTER DISCUSSION NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016
200 AM PDT TUE AUG 30 2016

Lester has begun to weaken. The areal extent of deep convection
within the hurricane's central dense overcast (CDO) has decreased
substantially, and the CDO has lost much of its axisymmetry since
late yesterday. In addition, the eye has warmed and become a little
less defined. The recent weakening could be associated with an
increase in easterly shear over the cyclone as analyzed by UW-CIMSS
and SHIPS model output. Dvorak T-numbers have responded by suddenly
decreasing. A blend of the latest TAFB Final T- and CI-numbers,
including the UW-CIMSS ADT values, is used to lower the initial
intensity estimate to 110 kt.

The initial motion estimate is 275/12. A strong mid-level ridge
over the east-central subtropical Pacific should continue to steer
Lester just north of due west for the next couple of days. A
probable binary interaction with Madeline should cause Lester's
heading to turn west-northwestward as the hurricane approaches the
Hawaiian Islands in 3-5 days. The NHC track forecast is barely
adjusted relative to the previous one, and is closest to a blend of
the GFS and ECMWF solutions.

The intensity forecast is, again, quite challenging. The delicate
balance of environmental factors leading to Lester's annular
structure yesterday may have been disrupted by the recent uptick in
easterly shear. With the shear forecast to diminish over the next
day or so while the cyclone continues to move over nearly constant
SSTs, Lester could regain its annular characteristics. This would
allow Lester to sustain a higher intensity during the next 2-3 days
than what the intensity guidance indicates. After that time, the
ECMWF shows a less conducive environment than the GFS, which could
result in a more decided weakening. Given the greater than normal
uncertainty, the NHC forecast stays close to the multi-model
consensus throughout the period.

Lester's wind radii have been adjusted based on a partial ASCAT
overpass.

FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 18.2N 133.2W 110 KT 125 MPH
12H 30/1800Z 18.3N 135.1W 100 KT 115 MPH
24H 31/0600Z 18.4N 137.5W 90 KT 105 MPH
36H 31/1800Z 18.4N 139.7W 90 KT 105 MPH
48H 01/0600Z 18.5N 141.9W 85 KT 100 MPH
72H 02/0600Z 19.3N 146.4W 80 KT 90 MPH
96H 03/0600Z 20.8N 151.2W 70 KT 80 MPH
120H 04/0600Z 22.7N 156.4W 60 KT 70 MPH

$$
Forecaster Kimberlain

[cycloneye]

HURRICANE LESTER DISCUSSION NUMBER 24
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016
800 AM PDT TUE AUG 30 2016

Lester continues to slowly weaken. The eye of the hurricane has
become less defined in satellite images and although convection
remains quite deep, it is more asymmetric than it was overnight.
Recent microwave data also reveal that the eyewall has eroded some
on the north side. A blend of the latest TAFB and SAB Final T- and
CI-numbers, including the UW-CIMSS ADT values, is used to lower the
initial intensity to 105 kt. Sea surface temperatures ahead of
Lester only lower slightly along the expected track and the wind
shear is expected to be generally light. The SHIPS model does
show the environmental moisture decreasing near Lester during the
next several days. These conditions should cause a gradual
weakening of Lester, and the NHC intensity forecast follows the
trend of the previous one and stays near the intensity model
consensus.

The major hurricane remains on a due westward course at 12 kt. A
strong mid-level ridge over the east-central subtropical Pacific
should continue to steer Lester westward for the next couple of
days. After that time, a slight turn to the west-northwest is
predicted, due to possible binary interaction with Madeline, when
Lester approaches the Hawaiian Islands in 3-5 days. The NHC track
forecast is very similar to the previous one, and lies close to the
various consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT 30/1500Z 18.1N 134.4W 105 KT 120 MPH
12H 31/0000Z 18.1N 136.1W 95 KT 110 MPH
24H 31/1200Z 18.1N 138.3W 90 KT 105 MPH
36H 01/0000Z 18.2N 140.6W 85 KT 100 MPH
48H 01/1200Z 18.5N 142.8W 80 KT 90 MPH
72H 02/1200Z 19.8N 147.2W 75 KT 85 MPH
96H 03/1200Z 21.4N 152.4W 65 KT 75 MPH
120H 04/1200Z 23.4N 157.6W 60 KT 70 MPH

$$
Forecaster Cangialosi

[hurricanes1234]

Perhaps one last attempt to restrengthen unexpectedly?

[Yellow Evan]

Perhaps one last attempt to restrengthen unexpectedly?

Honestly this has plenty of time, and will likely fluctuate a lot in intensity over the next 48 to 72 hours

[Ntxw]

He's looking better than earlier this morning with much deeper convection.

[cycloneye]

HURRICANE LESTER DISCUSSION NUMBER 25
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132016
200 PM PDT TUE AUG 30 2016

The weakening trend of Lester appears to have stopped for the time
being. Satellite images show a well-defined 15 n mi diameter eye
surrounded by a solid ring of deep convection. The Dvorak
classifications from TAFB and SAB were both 5.5/102 kt and automated
values from CIMSS at the University of Wisconsin are 5.9/112 kt.
Based on these data, the initial wind speed is held at 105 kt for
this advisory. The environment ahead of Lester is not hostile, but
slightly lower sea-surface temperatures and drier air along its
track should cause the hurricane to gradually weaken through the
forecast period. The NHC intensity forecast follows the trend of the
previous one and stays near the intensity model consensus.

The major hurricane is now moving a little south of due west at
12 kt. A strong mid-level ridge over the east-central subtropical
Pacific should continue to steer Lester westward for the next couple
of days. After that time, a slight turn to the west-northwest is
predicted, due to possible binary interaction with Madeline, when
Lester moves near or just north of the Hawaiian Islands in 3-5
days. The NHC track forecast is a little to the south of the
previous one and lies near the middle of the guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 30/2100Z 17.8N 135.6W 105 KT 120 MPH
12H 31/0600Z 17.8N 137.2W 100 KT 115 MPH
24H 31/1800Z 17.9N 139.4W 95 KT 110 MPH
36H 01/0600Z 18.1N 141.5W 85 KT 100 MPH
48H 01/1800Z 18.5N 143.8W 80 KT 90 MPH
72H 02/1800Z 19.9N 148.4W 75 KT 85 MPH
96H 03/1800Z 21.5N 153.4W 65 KT 75 MPH
120H 04/1800Z 23.3N 158.3W 60 KT 70 MPH

$$
Forecaster Cangialosi

[hurricanes1234]

Numbers going up again. If this trend maintains itself, IMO we could see another attempt at reintensification.

CI# /Pressure/ Vmax
6.2 / 946.3mb/119.8kt


Final T# Adj T# Raw T#
6.2 6.1 6.1