EPAC: ALETTA - Post-Tropical

[galaxy401]

Really organizing quickly from the looks of it. I think a major hurricane is looking likely here.

[Kingarabian]

Outflow north of the system remains restricted due to shear, but to the south, a massive feeder band has developed. Maybe RI soon?



Some 2014/2015 vibes with Aletta here.

[Yellow Evan]

EP, 02, 2018060606, , BEST, 0, 141N, 1062W, 35, 1004, TS, 34, NEQ, 90, 90, 0, 0, 1009, 210, 90, 0, 0, E, 0, , 0, 0, ALETTA, M, 0, , 0, 0, 0, 0, genesis-num, 003,

[Yellow Evan]

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

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 35 39 43 48 53 61 68 77 80 77 76 69 59
V (KT) LAND 35 39 43 48 53 61 68 77 80 77 76 69 59
V (KT) LGEM 35 39 43 46 48 51 54 59 62 63 62 58 50
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 8 5 5 5 4 9 7 6 8 11 16 8 10
SHEAR ADJ (KT) 2 0 0 4 2 -6 4 9 4 -2 2 7 8
SHEAR DIR 267 270 266 277 288 302 327 103 148 119 134 159 135
SST (C) 29.6 29.5 29.3 29.2 29.1 28.5 28.1 27.7 27.5 27.1 26.7 26.2 25.6
POT. INT. (KT) 160 158 156 155 154 147 143 139 137 132 128 123 117
200 MB T (C) -52.1 -52.4 -51.9 -51.2 -51.7 -51.8 -51.6 -51.3 -51.5 -50.9 -50.6 -50.0 -49.9
200 MB VXT (C) 0.1 0.1 0.1 0.1 0.3 0.4 0.4 0.5 0.8 0.8 0.8 0.8 1.2
TH_E DEV (C) 8 7 7 7 6 5 5 4 4 3 3 2 2
700-500 MB RH 71 72 72 69 68 69 63 62 62 61 58 61 51
MODEL VTX (KT) 15 18 20 20 22 24 26 30 31 31 35 34 30
850 MB ENV VOR 2 5 6 8 10 30 38 60 81 98 115 121 117
200 MB DIV 116 120 121 121 111 49 56 65 14 41 39 -19 -25
700-850 TADV -6 -5 -5 -5 -4 -2 -10 -5 -2 0 0 0 1
LAND (KM) 557 581 609 631 656 707 784 854 866 835 795 788 829
LAT (DEG N) 14.1 14.2 14.3 14.4 14.5 14.7 14.7 15.0 15.5 16.1 16.7 17.2 17.6
LONG(DEG W) 106.2 106.8 107.3 107.9 108.5 109.5 110.5 111.6 112.6 113.4 113.8 114.5 115.6
STM SPEED (KT) 7 5 5 6 5 5 5 5 5 4 4 5 5
HEAT CONTENT 40 37 32 26 23 22 25 26 16 6 2 1 0

FORECAST TRACK FROM OFCI INITIAL HEADING/SPEED (DEG/KT):295/ 7 CX,CY: -5/ 3
T-12 MAX WIND: 25 PRESSURE OF STEERING LEVEL (MB): 640 (MEAN=550)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 24.6 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 75.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 27.9

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 0. 0. 1. 2. 7. 12. 17. 21. 22. 23. 23. 22.
VERTICAL SHEAR MAG 1. 2. 3. 4. 5. 6. 7. 6. 6. 4. 4. 5.
VERTICAL SHEAR ADJ -0. -0. -0. -1. -0. -0. -1. -1. -0. -0. -0. -0.
VERTICAL SHEAR DIR -1. -2. -3. -4. -7. -8. -7. -7. -6. -6. -6. -6.
PERSISTENCE 2. 3. 4. 5. 5. 4. 4. 3. 2. 2. 1. -0.
200/250 MB TEMP. -0. -0. -1. -1. -2. -3. -3. -3. -3. -4. -4. -3.
THETA_E EXCESS 0. 0. 1. 1. 0. -0. -1. -1. -2. -3. -4. -5.
700-500 MB RH 0. 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1.
MODEL VTX TENDENCY 1. 3. 4. 7. 11. 14. 20. 21. 20. 24. 21. 15.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 0. 0. -0. -0. -1. -1. -2.
200 MB DIVERGENCE 0. 1. 2. 3. 4. 4. 4. 4. 3. 3. 2. 1.
850-700 T ADVEC -0. -0. 0. 0. -0. -0. -1. -1. -1. -1. -1. -1.
ZONAL STORM MOTION -0. -0. -0. -0. -0. -1. -1. -1. -1. -0. -0. -1.
STEERING LEVEL PRES 0. 1. 1. 1. 1. 2. 2. 2. 2. 2. 2. 2.
DAYS FROM CLIM. PEAK -0. -0. -0. -0. 0. -0. -0. -1. -1. -2. -2. -2.
GOES PREDICTORS -0. -0. -0. -1. -1. -1. -1. -0. -0. 0. 0. 0.
OCEAN HEAT CONTENT 0. 0. 1. 1. 1. 1. 1. 1. 0. 0. 0. 0.
----------------------------------------------------------
TOTAL CHANGE 4. 8. 13. 18. 26. 33. 42. 45. 42. 41. 34. 24.

CURRENT MAX WIND (KT): 35. LAT, LON: 14.1 106.2

** 2017 E.PACIFIC RI INDEX EP022018 ALETTA 06/06/18 06 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 5.0
POT = MPI-VMAX (KT) : 121.4 40.5 to 149.3 0.74 4.8
850-200 MB SHEAR (KT) : 5.5 18.9 to 1.4 0.76 6.7
HEAT CONTENT (KJ/cm2) : 31.6 0.0 to 106.7 0.30 2.1
MAXIMUM WIND (kt) : 35.0 22.5 to 132.0 0.36 2.3
D200 (10**7s-1) : 117.8 -33.0 to 156.2 0.80 4.7
STD DEV OF IR BR TEMP : 24.6 37.8 to 2.1 0.37 2.3
% AREA WITH TPW <45 mm: 0.0 62.3 to 0.0 1.00 -1.8
2nd PC OF IR BR TEMP : -0.2 2.2 to -1.9 0.57 0.4
BL DRY-AIR FLUX (w/m2): 111.2 735.9 to -82.5 0.76 0.0

SHIPS Prob RI for 20kt/ 12hr RI threshold= 18% is 2.4 times sample mean ( 7.7%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 34% is 2.2 times sample mean (15.3%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 27% is 2.6 times sample mean (10.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 22% is 3.0 times sample mean ( 7.5%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 0% is 0.0 times sample mean ( 5.2%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 27% is 3.3 times sample mean ( 8.1%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 29% is 3.9 times sample mean ( 7.4%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 18% is 3.2 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: 18.1% 33.7% 26.6% 22.2% 0.0% 27.1% 29.0% 17.7%
Logistic: 10.1% 29.4% 27.2% 25.7% 15.1% 21.0% 20.1% 6.4%
Bayesian: 9.0% 17.8% 5.6% 1.4% 0.2% 3.8% 2.4% 2.5%
Consensus: 12.4% 26.9% 19.8% 16.4% 5.1% 17.3% 17.2% 8.9%

## ANNULAR HURRICANE INDEX (AHI) EP022018 ALETTA 06/06/18 06 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) ##

[Ntxw]

[Yellow Evan]

ASCAT ahead of Dvorak here

06/0545 UTC 13.7N 106.0W T2.0/2.0 02E -- East Pacific

[Ntxw]

BULLETIN
Tropical Storm Aletta Advisory Number 2
NWS National Hurricane Center Miami FL EP022018
300 AM MDT Wed Jun 06 2018

...TROPICAL STORM ALETTA FORMS WELL SOUTH OF MEXICO AND IS NOT A
THREAT TO LAND...


SUMMARY OF 300 AM MDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...14.1N 106.5W
ABOUT 370 MI...595 KM SSW OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
The first tropical storm of the 2018 eastern North Pacific season
has formed. At 300 AM MDT (0900 UTC), the center of Tropical Storm
Aletta was located near latitude 14.1 North, longitude 106.5 West.
Aletta is moving toward the west near 7 mph (11 km/h), but a gradual
turn to the west-northwest with no significant change in forward
speed is expected during the next 2 to 3 days.

Maximum sustained winds have increased to near 45 mph (75 km/h)
with higher gusts. Aletta is expected to become a hurricane by
early Thursday.

Tropical-storm-force winds extend outward up to 105 miles (165 km)
to the east of the center.

The estimated minimum central pressure is 1000 mb (29.53 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 900 AM MDT.

$$
Forecaster Avila

[Twisted-core]

locked n loaded.

https://imgur.com/Zk5aniP
EC




https://imgur.com/y26Bz3w
GFS likes two csnes on the run

[cycloneye]

Tropical Storm Aletta Discussion Number 2
NWS National Hurricane Center Miami FL EP022018
300 AM MDT Wed Jun 06 2018

Deep convection has increased significantly during the past 12
hours, and the cloud pattern is better organized with the formation
of a few cyclonically curved bands. The outflow is fair in all
quadrants. An ASCAT pass a few hours ago, indicate that the winds
are between 35 to 40 kt, but these winds are confined to a band to
the east of the center. On this basis, the depression has been
upgraded to Tropical Storm Aletta, the first named system of the
2018 eastern North Pacific season.

An prevailing environment of low shear favors intensification, and
although the Rapid Intensification Indices are not as high as
earlier, they are still on the high side. The NHC forecast calls for
Aletta to become a hurricane in 36 hours as indicated in the
previous forecast. After 3 days, when the cyclone reaches cooler
water and higher shear, a gradual weakening is anticipated.

It appears that Aletta is moving toward the west at about 6 kt
around the periphery of a subtropical ridge centered over
northwestern Mexico. However, a weakness in the ridge should cause
the cyclone to gradually gain some latitude during the next few days
with no significant change in forward speed. The NHC forecast
follows the model consensus, and it is basically centered in the
middle of the guidance envelope bounded by the GFS to the north
and the ECMWF to the south.


FORECAST POSITIONS AND MAX WINDS

INIT 06/0900Z 14.1N 106.5W 40 KT 45 MPH
12H 06/1800Z 14.2N 107.4W 45 KT 50 MPH
24H 07/0600Z 14.4N 108.5W 55 KT 65 MPH
36H 07/1800Z 14.6N 109.3W 65 KT 75 MPH
48H 08/0600Z 15.0N 110.5W 75 KT 85 MPH
72H 09/0600Z 15.5N 112.5W 80 KT 90 MPH
96H 10/0600Z 16.5N 114.5W 70 KT 80 MPH
120H 11/0600Z 17.0N 116.0W 50 KT 60 MPH

$$
Forecaster Avila

[tolakram]

COD Floater: http://weather.cod.edu/satrad/exper/?pa ... rbars=data

[cycloneye]

Code: Select all

   * EAST PACIFIC SHIPS INTENSITY FORECAST          *
                    * IR SAT DATA AVAILABLE,       OHC AVAILABLE     *
                    *  ALETTA      EP022018  06/06/18  12 UTC        *

TIME (HR)          0     6    12    18    24    36    48    60    72    84    96   108   120
V (KT) NO LAND    40    44    47    50    54    59    66    71    72    72    64    55    43
V (KT) LAND       40    44    47    50    54    59    66    71    72    72    64    55    43
V (KT) LGEM       40    44    47    49    50    50    49    50    49    49    45    39    32
Storm Type      TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP  TROP

SHEAR (KT)        11     8     6     5     4     7     3    10     7    12    17    13    13
SHEAR ADJ (KT)    -2     0     6     5     3     4    15     6     3     4     7    11     2
SHEAR DIR        250   257   264   271   273   253    92   107   151   146   176   163   156
SST (C)         29.3  29.0  28.9  28.8  28.6  27.9  27.4  27.2  27.1  26.7  25.9  25.5  25.4
POT. INT. (KT)   157   153   152   150   148   141   136   133   133   129   120   115   113
200 MB T (C)   -52.4 -51.9 -51.3 -51.8 -52.1 -51.0 -51.6 -51.2 -51.6 -50.8 -50.6 -50.0 -50.9
200 MB VXT (C)   0.2   0.2   0.2   0.3   0.3   0.3   0.5   0.5   0.5   0.6   0.8   0.8   0.9
TH_E DEV (C)       8     7     6     6     5     5     5     4     3     3     2     2     2
700-500 MB RH     71    71    68    68    71    66    65    65    64    60    58    55    51
MODEL VTX (KT)    19    21    21    22    23    26    28    30    31    34    33    31    25
850 MB ENV VOR     6    10     5     8    15    24    43    63    91   103   122   119    97
200 MB DIV       110   119   120    94    48    47    17    42    16    62    -5    -4   -38
700-850 TADV      -4    -5    -5   -10    -6    -5    -8    -1     0     0     0     3     1
LAND (KM)        549   576   601   622   646   693   774   811   808   805   817   851   897
LAT (DEG N)     14.6  14.8  14.9  15.0  15.0  15.4  15.7  15.9  16.2  16.7  17.4  17.6  17.5
LONG(DEG W)    106.8 107.5 108.2 108.6 109.0 110.0 111.2 112.2 113.0 114.0 115.2 115.9 116.4
STM SPEED (KT)     7     7     5     4     4     6     5     5     5     6     5     3     2
HEAT CONTENT      29    24    19    17    17    16    23    18     7     3     0     0     0

  FORECAST TRACK FROM OFCI      INITIAL HEADING/SPEED (DEG/KT):285/  7      CX,CY:  -6/  2
  T-12 MAX WIND:  30            PRESSURE OF STEERING LEVEL (MB):  646  (MEAN=550)
  GOES IR BRIGHTNESS TEMP. STD DEV.  50-200 KM RAD:  21.8 (MEAN=14.5)
  % GOES IR PIXELS WITH T < -20 C    50-200 KM RAD:  80.0 (MEAN=65.0)
  PRELIM RI PROB (DV .GE. 55 KT IN 48 HR):           17.8

                        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          0.   1.   2.   3.   7.  11.  14.  16.  17.  18.  17.  16.
  VERTICAL SHEAR MAG     0.   1.   2.   3.   5.   6.   6.   6.   5.   4.   3.   3.
  VERTICAL SHEAR ADJ     0.  -0.  -1.  -1.  -1.  -2.  -2.  -1.  -1.  -0.  -0.  -1.
  VERTICAL SHEAR DIR    -1.  -2.  -3.  -5.  -8.  -9.  -8.  -8.  -8.  -8.  -8.  -8.
  PERSISTENCE            2.   3.   4.   5.   4.   4.   3.   2.   2.   1.   0.  -0.
  200/250 MB TEMP.      -0.  -0.  -1.  -1.  -2.  -2.  -2.  -2.  -3.  -3.  -3.  -3.
  THETA_E EXCESS         0.   0.   0.   0.  -0.  -1.  -1.  -2.  -3.  -5.  -6.  -8.
  700-500 MB RH          0.   0.   0.   0.   0.   0.   1.   1.   1.   1.   1.   1.
  MODEL VTX TENDENCY     1.   1.   3.   5.   9.  13.  16.  17.  19.  17.  14.   7.
  850 MB ENV VORTICITY   0.   0.   0.   0.   0.   0.   0.  -0.  -1.  -1.  -1.  -2.
  200 MB DIVERGENCE      0.   1.   2.   3.   3.   2.   2.   2.   2.   1.   1.   0.
  850-700 T ADVEC       -0.  -0.   0.   0.  -0.  -0.  -1.  -1.  -1.  -1.  -1.  -1.
  ZONAL STORM MOTION    -0.  -0.  -0.  -0.  -0.  -0.  -0.  -0.  -0.  -0.  -0.  -0.
  STEERING LEVEL PRES    0.   1.   1.   1.   2.   2.   2.   2.   2.   2.   2.   2.
  DAYS FROM CLIM. PEAK  -0.  -0.  -0.  -0.   0.  -0.  -0.  -1.  -1.  -2.  -2.  -2.
  GOES PREDICTORS        0.  -0.  -0.  -0.  -0.  -0.   0.   0.   0.   1.   1.   1.
  OCEAN HEAT CONTENT     0.   0.   0.   0.   0.   0.   0.   0.  -0.  -0.  -0.   0.
                        ----------------------------------------------------------
  TOTAL CHANGE           4.   7.  10.  14.  19.  26.  31.  32.  32.  24.  15.   3.

                CURRENT MAX WIND (KT):   40. LAT, LON:   14.6   106.8

      ** 2017 E.PACIFIC RI INDEX EP022018 ALETTA     06/06/18  12 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)   :   111.9      40.5  to  149.3       0.66           3.9
 850-200 MB SHEAR (KT) :     6.9      18.9  to    1.4       0.69           5.6
 HEAT CONTENT (KJ/cm2) :    21.2       0.0  to  106.7       0.20           1.3
 MAXIMUM WIND (kt)     :    40.0      22.5  to  132.0       0.50           3.0
 D200 (10**7s-1)       :    98.2     -33.0  to  156.2       0.69           3.8
 STD DEV OF IR BR TEMP :    21.8      37.8  to    2.1       0.45           2.6
 % AREA WITH TPW <45 mm:     0.0      62.3  to    0.0       1.00          -1.6
 2nd PC OF IR BR TEMP  :    -0.4       2.2  to   -1.9       0.65           0.4
 BL DRY-AIR FLUX (w/m2):   124.0     735.9  to  -82.5       0.75           0.0
 
 SHIPS Prob RI for 20kt/ 12hr RI threshold=  18% is   2.3 times sample mean ( 7.7%)
 SHIPS Prob RI for 25kt/ 24hr RI threshold=  30% is   1.9 times sample mean (15.3%)
 SHIPS Prob RI for 30kt/ 24hr RI threshold=  24% is   2.3 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=  17% is   3.3 times sample mean ( 5.2%)
 SHIPS Prob RI for 45kt/ 36hr RI threshold=  25% is   3.1 times sample mean ( 8.1%)
 SHIPS Prob RI for 55kt/ 48hr RI threshold=  21% is   2.9 times sample mean ( 7.4%)
 SHIPS Prob RI for 65kt/ 72hr RI threshold=  12% is   2.1 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:    17.6%   29.8%   23.5%   20.4%   17.0%   24.8%   21.4%   11.6%
    Logistic:     5.7%   15.1%   12.3%   10.7%    4.9%    7.3%    7.8%    1.5%
    Bayesian:     8.4%    4.3%    0.2%    0.0%    0.0%    0.1%    1.2%    0.2%
   Consensus:    10.6%   16.4%   12.0%   10.4%    7.3%   10.7%   10.1%    4.4%

   ##         ANNULAR HURRICANE INDEX (AHI) EP022018 ALETTA     06/06/18  12 UTC         ##
   ## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=2 NFAIL=5                          ##
   ## AHI=  0   (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR

[cycloneye]

Tropical Storm Aletta Discussion Number 3
NWS National Hurricane Center Miami FL EP022018
900 AM MDT Wed Jun 06 2018

The cloud pattern of the storm is gradually becoming better
organized, but most of the deep convection is confined to the
eastern and southern portions of the circulation. Cirrus cloud
motions suggest that the upper-level outflow is slightly restricted
over the northwest quadrant, but vertical shear is not very strong
over the system. Dvorak intensity estimates from both TAFB and SAB
are unchanged from the previous synoptic time so the current
intensity is held at 40 kt for this advisory. Since Aletta should
remain over warm waters with modest shear over the next several
days, strengthening is likely. The model guidance is not very
bullish on intensification, however. Given the apparently
favorable environment, the official forecast is at the high end of
the guidance.

Based on a recent GMI microwave image, the center is repositioned a
little to the north of the previous track. This gives an
estimated initial motion of 280/6 kt. A mid-level ridge extending
from Mexico into the eastern Pacific should induce a westward or
slightly north of west motion over the next several days. The
latest GFS and its ensemble mean are on the northern side of the
track guidance envelope and the ECMWF forecast is near the southern
side. The official forecast essentially splits the difference and
lies quite close to the dynamical model consensus, and is not much
different from the previous NHC track.

FORECAST POSITIONS AND MAX WINDS

INIT 06/1500Z 14.7N 107.1W 40 KT 45 MPH
12H 07/0000Z 14.8N 108.0W 50 KT 60 MPH
24H 07/1200Z 15.0N 109.2W 55 KT 65 MPH
36H 08/0000Z 15.2N 110.4W 65 KT 75 MPH
48H 08/1200Z 15.4N 111.4W 75 KT 85 MPH
72H 09/1200Z 16.0N 113.3W 80 KT 90 MPH
96H 10/1200Z 17.0N 115.0W 60 KT 70 MPH
120H 11/1200Z 18.0N 117.0W 40 KT 45 MPH

$$
Forecaster Pasch

[Kingarabian]

Interesting look on satellite today. It looks tilted with LLC remaining west of the MLC, likely due to the effects of shear. Still plenty of strong convection that would support RI as soon as conditions allow it.

[cycloneye]

Popping out.

[Kingarabian]

ADT up to 3.5, SAB at 2.5.

Trying to pull the LLC back in under the convection:

[Yellow Evan]

I'm gonna be honest. I think Storm2k is hyping Aletta a bit to much. Wind shear is low and waters are warm but typical for this time of year, dry air is causing problems, and ASCAT suggest the center isn't well defined, although it's an improvement from yesterday. This likely becomes a hurricane but this is going to have to consolidate a bit for serious intensification. There's like 60 hours left, but if this isn't a hurricane by tomorrow night, forget a major hurricane.

[Kingarabian]

I'm gonna be honest. I think Storm2k is hyping Aletta a bit to much. Wind shear is low and waters are warm but typical for this time of year, dry air is causing problems, and ASCAT suggest the center isn't well defined, although it's an improvement from yesterday. This likely becomes a hurricane but this is going to have to consolidate a bit for serious intensification. There's like 60 hours left, but if this isn't a hurricane by tomorrow night, forget a major hurricane.

I understand last year was a dull in regards to EPAC activity, but let's not forget how potent this basin can be and how storms are generally under-forecast-ed and exceed expectations.

[cycloneye]

Tropical Storm Aletta Discussion Number 4
NWS National Hurricane Center Miami FL EP022018
300 PM MDT Wed Jun 06 2018

Aletta's cloud pattern has not become noticeably better organized
during the day, and the banding features are not very well
defined in enhanced infrared imagery. There is a dry intrusion
over the northwest quadrant of the circulation with some
restriction of the upper-level outflow over that quadrant as well.
Dvorak classifications from both TAFB and SAB give a current
intensity of 35 kt but a recent scatterometer pass indicated that
the maximum winds are close to 40 kt, and that value will be used
for the advisory intensity. Although the storm has not
strengthened since early this morning, it is anticipated that the
cyclone will be moving through fairly low vertical shear and over
SSTs of 28 or 29 deg C during the next few days. This favorable
environment should cause intensification. The official forecast,
which is close to the simple or corrected model consensus guidance,
continues to call for Aletta to become a hurricane by late Thursday
or early Friday.

High temporal and spatial resolution GOES-16 imagery suggested
multiple low-level swirls near the estimated center position.
Based on geostationary and microwave imagery along with the
scatterometer data, the initial motion continues to be slowly
westward or 270/7 kt. The flow on the south side of a mid-level
ridge extending from Mexico into the eastern North Pacific should
continue to steer Aletta westward to west-northwestward over the
next few days. In 3-4 days, most of the track guidance shows the
cyclone bending a little more to the right in response to a
weakness in the ridge. As was the case in the previous cycle, the
GFS shows the northernmost track and the ECMWF the southernmost.
The official forecast lies between these extremes and is close to
the model consensus. This is a tad slower than the previous NHC
forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 06/2100Z 14.2N 107.9W 40 KT 45 MPH
12H 07/0600Z 14.4N 109.0W 50 KT 60 MPH
24H 07/1800Z 14.5N 110.0W 55 KT 65 MPH
36H 08/0600Z 14.7N 111.0W 65 KT 75 MPH
48H 08/1800Z 15.0N 112.0W 70 KT 80 MPH
72H 09/1800Z 16.0N 113.6W 80 KT 90 MPH
96H 10/1800Z 17.3N 115.6W 70 KT 80 MPH
120H 11/1800Z 18.0N 117.0W 45 KT 50 MPH

$$
Forecaster Pasch

[gatorcane]

I'm gonna be honest. I think Storm2k is hyping Aletta a bit to much. Wind shear is low and waters are warm but typical for this time of year, dry air is causing problems, and ASCAT suggest the center isn't well defined, although it's an improvement from yesterday. This likely becomes a hurricane but this is going to have to consolidate a bit for serious intensification. There's like 60 hours left, but if this isn't a hurricane by tomorrow night, forget a major hurricane.

I understand last year was a dull in regards to EPAC activity, but let's not forget how potent this basin can be and how storms are generally under-forecast-ed and exceed expectations.

Yes the EPAC is a beast of a basin. I recall last year the models were overly optimistic on some majors that didn't end up coming to fruition but I can see some storms exceeding some expectations this year in the EPAC particularly as we head into July.

As for Aletta, WV loop out of the EPAC shows quite a bit of dry air to contend with:

http://rammb.cira.colostate.edu/ramsdis ... display=24

[cycloneye]

@pppapin
Zoomed in #GOES16 view of #TC #Aletta in the #EPAC reveals a vortex that has multiple mesovorticies rotating around the mean center, displaced west of the convection. Combo of dry air flanking west side & broad structure argues against substantial intensification in short term.

 https://twitter.com/pppapin/status/1004471310246768640