EPAC: ALETTA - Post-Tropical

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Re: EPAC: ALETTA - Tropical Storm

#101 Postby Kingarabian » Thu Jun 07, 2018 2:24 pm

hurricanes1234 wrote:I'd be surprised if it's lower than 70-75 knots right now.


Agree with you, SAB has 4.5 estimate.
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Re: EPAC: ALETTA - Tropical Storm

#102 Postby Kingarabian » Thu Jun 07, 2018 2:59 pm

Shear to the north of the system has subdued noted by the expanding outflow to the N/NE. Good shot at RI in the next 24 hours before conditions become unfavorable again.

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Re: EPAC: ALETTA - Tropical Storm

#103 Postby Yellow Evan » Thu Jun 07, 2018 3:26 pm

Time is running out a little sooner than I thought. Has 24 maybe 30 hours left before SSTs progressively decrease.

* EAST PACIFIC SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* ALETTA EP022018 06/07/18 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 65 67 68 69 73 70 68 60 51 39 30 22 DIS
V (KT) LAND 65 67 68 69 73 70 68 60 51 39 30 22 DIS
V (KT) LGEM 65 68 68 68 67 63 58 52 43 35 28 24 20
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 7 9 6 7 11 12 13 19 11 8 6 11 18
SHEAR ADJ (KT) -2 -1 4 2 -1 0 1 7 11 7 4 0 -2
SHEAR DIR 251 233 222 143 165 169 174 188 218 186 172 159 155
SST (C) 28.3 28.0 27.7 27.5 27.3 27.1 26.7 26.3 25.6 25.0 24.4 24.0 23.9
POT. INT. (KT) 145 142 139 137 135 132 128 124 117 110 104 99 98
200 MB T (C) -51.6 -51.2 -51.8 -51.5 -51.5 -51.6 -51.0 -51.0 -50.8 -50.7 -51.4 -51.3 -51.5
200 MB VXT (C) 0.4 0.6 0.8 0.8 0.7 0.9 0.9 1.1 1.2 1.1 1.0 0.4 0.3
TH_E DEV (C) 5 5 5 5 4 4 3 3 2 2 2 2 2
700-500 MB RH 70 69 65 68 65 66 66 59 54 47 42 36 29
MODEL VTX (KT) 26 27 27 27 30 29 31 29 27 22 19 16 13
850 MB ENV VOR 21 30 35 49 55 60 83 91 105 86 63 53 54
200 MB DIV 45 68 27 87 99 67 45 45 27 -14 21 -2 23
700-850 TADV -3 -4 -8 -4 0 -2 0 0 3 -2 0 0 0
LAND (KM) 683 703 726 757 791 771 732 713 716 752 784 830 886
LAT (DEG N) 15.1 15.3 15.4 15.6 15.7 16.3 16.9 17.5 18.1 18.5 18.8 18.8 18.6
LONG(DEG W) 109.6 110.0 110.4 110.9 111.4 112.3 112.9 113.7 114.6 115.5 116.3 117.1 117.7
STM SPEED (KT) 4 4 5 5 5 4 4 5 5 4 4 3 3
HEAT CONTENT 16 15 16 19 20 11 2 1 0 0 0 0 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):300/ 5 CX,CY: -3/ 3
T-12 MAX WIND: 55 PRESSURE OF STEERING LEVEL (MB): 559 (MEAN=550)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 14.7 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 89.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 10.0

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 1. 1. 2. 2. 2. 0. -2. -4. -6. -8. -9. -11.
VERTICAL SHEAR MAG 0. 0. 1. 1. 1. 1. 0. 0. 1. 2. 2. 1.
VERTICAL SHEAR ADJ 0. -0. -0. -0. -0. -0. -0. -1. -1. -0. -0. -0.
VERTICAL SHEAR DIR -1. -2. -2. -3. -4. -5. -5. -6. -7. -7. -7. -7.
PERSISTENCE 2. 3. 4. 4. 3. 2. 2. 1. 1. 0. -0. -1.
200/250 MB TEMP. -0. -0. -1. -1. -1. -1. -1. -1. -1. -2. -3. -2.
THETA_E EXCESS -0. -0. -0. -1. -1. -2. -3. -5. -6. -7. -9. -10.
700-500 MB RH 0. 0. 0. 0. 0. 0. 0. 0. 0. -0. -1. -2.
MODEL VTX TENDENCY 0. 0. 1. 4. 4. 6. 3. 1. -5. -9. -11. -13.
850 MB ENV VORTICITY 0. -0. -0. -0. -0. -0. -1. -1. -1. -2. -2. -2.
200 MB DIVERGENCE 0. 0. 1. 1. 2. 2. 2. 2. 1. 1. 0. 0.
850-700 T ADVEC -0. -0. 0. 0. -0. -0. -0. -0. -0. 0. 0. 0.
ZONAL STORM MOTION -0. -0. -1. -1. -1. -1. -2. -1. -1. -1. -1. -1.
STEERING LEVEL PRES 0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0. -0.
DAYS FROM CLIM. PEAK -0. -0. -0. -0. 0. -0. -0. -1. -1. -2. -2. -2.
GOES PREDICTORS 0. 0. -0. -0. 0. 1. 1. 1. 2. 2. 2. 2.
OCEAN HEAT CONTENT -0. -0. -0. -0. -0. -1. -1. -1. -1. -1. -0. 0.
----------------------------------------------------------
TOTAL CHANGE 2. 3. 4. 8. 5. 3. -5. -14. -26. -35. -43. -51.

CURRENT MAX WIND (KT): 65. LAT, LON: 15.1 109.6

** 2017 E.PACIFIC RI INDEX EP022018 ALETTA 06/07/18 18 UTC **
(SHIPS-RII PREDICTOR TABLE for 30 KT OR MORE MAXIMUM 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 44.0 0.48 4.6
POT = MPI-VMAX (KT) : 74.4 40.5 to 149.3 0.31 1.8
850-200 MB SHEAR (KT) : 7.9 18.9 to 1.4 0.63 5.1
HEAT CONTENT (KJ/cm2) : 17.2 0.0 to 106.7 0.16 1.0
MAXIMUM WIND (kt) : 65.0 22.5 to 132.0 0.90 5.4
D200 (10**7s-1) : 65.2 -33.0 to 156.2 0.52 2.8
STD DEV OF IR BR TEMP : 14.7 37.8 to 2.1 0.65 3.8
% AREA WITH TPW <45 mm: 0.0 62.3 to 0.0 1.00 -1.6
2nd PC OF IR BR TEMP : -0.7 2.2 to -1.9 0.70 0.5
BL DRY-AIR FLUX (w/m2): 249.8 735.9 to -82.5 0.59 0.0

SHIPS Prob RI for 20kt/ 12hr RI threshold= 23% is 3.0 times sample mean ( 7.7%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 29% is 1.9 times sample mean (15.3%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 23% is 2.2 times sample mean (10.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 20% is 2.7 times sample mean ( 7.5%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 18% is 3.4 times sample mean ( 5.2%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 21% is 2.6 times sample mean ( 8.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 14% is 1.9 times sample mean ( 7.4%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 0% is 0.0 times sample mean ( 5.5%)

Matrix of RI probabilities
------------------------------------------------------------------------------
RI (kt / h) | 20/12 | 25/24 | 30/24 | 35/24 | 40/24 | 45/36 | 55/48 |65/72
------------------------------------------------------------------------------
SHIPS-RII: 22.9% 28.7% 23.4% 20.3% 17.9% 20.8% 14.1% 0.0%
Logistic: 7.3% 6.3% 3.8% 2.4% 0.9% 1.6% 0.2% 0.0%
Bayesian: 2.4% 9.5% 2.5% 1.0% 0.2% 0.2% 0.0% 0.0%
Consensus: 10.9% 14.9% 9.9% 7.9% 6.3% 7.6% 4.8% 0.0%

## ANNULAR HURRICANE INDEX (AHI) EP022018 ALETTA 06/07/18 18 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=3 NFAIL=4 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##
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Re: EPAC: ALETTA - Tropical Storm

#104 Postby Kingarabian » Thu Jun 07, 2018 3:33 pm

:uarrow: As long as shear remains low, 26C is ample enough to maintain strength if not intensify. So I would say it actually has about 48 hours left of ideal conditions. If shear remains around 10-12kts, It can maintain hurricane strength for another 84 hours. Only issue is dry air and how much gets entrained in the system.
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Re: EPAC: ALETTA - Hurricane

#105 Postby cycloneye » Thu Jun 07, 2018 3:36 pm

Hurricane Aletta Discussion Number 8
NWS National Hurricane Center Miami FL EP022018
300 PM MDT Thu Jun 07 2018

An eye has become apparent in visible geostationary satellite
imagery, although the central deep convection is not very symmetric
on enhanced infrared imagery. Based on a blend of objective and
subjective Dvorak T-numbers, the current intensity is estimated to
be 65 kt, which makes Aletta the first eastern North Pacific
hurricane of 2018. Since the system should continue to traverse a
warm ocean and experience weak vertical shear for the next day or
two, additional strengthening is forecast. By Saturday some
increase in shear is likely, which should cause weakening to
commence. The official intensity forecast is at the high end of
the numerical guidance.

Aletta has been moving somewhat north of the previous track
projections, and the initial motion is about 300/5 kt. The main
factors controlling the steering of the hurricane are a mid-level
ridge to the northeast and a weakness in the ridge to the northwest
of Aletta, as well as the future intensity of the cyclone. There is
significantly more spread in the track guidance model than is usual
for an east Pacific tropical cyclone. The GFS and HWRF, which
depict a stronger system, have the northernmost tracks. The ECMWF,
which does not show that strong of a cyclone in its forecast,
predicts the southernmost track. The official forecast lies between
these options and is close to the corrected consensus guidance.
This is somewhat north of the previous NHC track.

FORECAST POSITIONS AND MAX WINDS

INIT 07/2100Z 15.3N 110.0W 65 KT 75 MPH
12H 08/0600Z 15.6N 110.5W 75 KT 85 MPH
24H 08/1800Z 16.1N 111.5W 80 KT 90 MPH
36H 09/0600Z 16.5N 112.3W 80 KT 90 MPH
48H 09/1800Z 17.1N 113.0W 75 KT 85 MPH
72H 10/1800Z 18.7N 114.6W 60 KT 70 MPH
96H 11/1800Z 19.3N 116.7W 45 KT 50 MPH
120H 12/1800Z 19.5N 118.5W 30 KT 35 MPH

$$
Forecaster Pasch
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Re: EPAC: ALETTA - Tropical Storm

#106 Postby storminabox » Thu Jun 07, 2018 5:48 pm

Kingarabian wrote:Shear to the north of the system has subdued noted by the expanding outflow to the N/NE. Good shot at RI in the next 24 hours before conditions become unfavorable again.

Image


Yeah Aletta looks like it is finally getting its act together now. This system may get a good deal stronger than what a lot of the models are showing.
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Re: EPAC: ALETTA - Hurricane

#107 Postby Yellow Evan » Thu Jun 07, 2018 5:56 pm

Image

Dry air ls lurking but it's made tremendous progress today. I still have reservations about a major but it's at least making a run at it. Comparing its appearance today to yesterday's is like night and day.
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Re: EPAC: ALETTA - Hurricane

#108 Postby Yellow Evan » Thu Jun 07, 2018 5:57 pm

----- Current Analysis -----
Date : 07 JUN 2018 Time : 220000 UTC
Lat : 15:20:54 N Lon : 110:05:24 W


CI# /Pressure/ Vmax
4.4 / 980.3mb/ 74.6kt


Final T# Adj T# Raw T#
4.4 4.4 3.7

Center Temp : -66.4C Cloud Region Temp : -65.3C

Scene Type : UNIFORM CDO CLOUD REGION w/ MW EYE

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : EAST PACIFIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : MW ON
Weakening Flag : OFF
Rapid Dissipation Flag : OFF
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Re: EPAC: ALETTA - Hurricane

#109 Postby NDG » Thu Jun 07, 2018 6:30 pm

What a difference 24 hrs make.
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Re: EPAC: ALETTA - Hurricane

#110 Postby Kingarabian » Thu Jun 07, 2018 6:31 pm

Maybe CMG when the eye clear outs again?

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Re: EPAC: ALETTA - Hurricane

#111 Postby Kingarabian » Thu Jun 07, 2018 6:34 pm

Latest SSMIS pass missed the center. Should have a couple more on the way soon.
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Re: EPAC: ALETTA - Hurricane

#112 Postby Sciencerocks » Thu Jun 07, 2018 6:45 pm

If that eye starts to clear this thing could easily jump up 20-25 knots over night.
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Re: EPAC: ALETTA - Hurricane

#113 Postby Yellow Evan » Thu Jun 07, 2018 6:46 pm

Image

T5.0 this frame. At least for now, this is bombing out.
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Re: EPAC: ALETTA - Hurricane

#114 Postby Kingarabian » Thu Jun 07, 2018 6:48 pm

Yellow Evan wrote:[img]https://i.imgur.com/Kstox2m.gif[img]

T5.0 this frame. At least for now, this is bombing out.


SAB will put out its estimate soon.
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Re: EPAC: ALETTA - Hurricane

#115 Postby Kingarabian » Thu Jun 07, 2018 6:55 pm

Compared to the AMSR2 pass taken @ 2030Z, this SSMIS pass shows that Aletta has constricted its eyewall quite a bit. Lot's of evidence that RI is going on and this thing is on its way to Cat.3 within the next 6 hours.

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Re: EPAC: ALETTA - Hurricane

#116 Postby Yellow Evan » Thu Jun 07, 2018 7:03 pm

Kingarabian wrote:
Yellow Evan wrote:[img]https://i.imgur.com/Kstox2m.gif[img]

T5.0 this frame. At least for now, this is bombing out.


SAB will put out its estimate soon.


Pretty sure SAB and TAFB estimate the next frame.
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Re: EPAC: ALETTA - Hurricane

#117 Postby Ntxw » Thu Jun 07, 2018 7:19 pm

Making a quick run at a major

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Re: EPAC: ALETTA - Hurricane

#118 Postby Kingarabian » Thu Jun 07, 2018 7:42 pm

Yellow Evan wrote:
Kingarabian wrote:
Yellow Evan wrote:[img]https://i.imgur.com/Kstox2m.gif[img]

T5.0 this frame. At least for now, this is bombing out.


SAB will put out its estimate soon.


Pretty sure SAB and TAFB estimate the next frame.


SAB backed up yoir estimate, came in with 5.0 as well.
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Re: EPAC: ALETTA - Hurricane

#119 Postby Twisted-core » Thu Jun 07, 2018 7:51 pm

Image
This system looks in a intense ri phase, with a more than reasonable chance @ reaching
cat4 intensity @ peak.
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Re: EPAC: ALETTA - Hurricane

#120 Postby cycloneye » Thu Jun 07, 2018 7:52 pm

Cat 2:

EP, 02, 2018060800, , BEST, 0, 155N, 1101W, 85, 973, HU
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