WPAC: HECTOR - Post-Tropical

[Kingarabian]

Pretty close call here on the Euro with a major hurricane recurving a couple of hundred miles off of the Big Island of Hawaii. Thankfully it's a long way out.

[Yellow Evan]

12z ECMWF has this rounding a ridge with a sharp turn near 148W OTS.

[Yellow Evan]

:uarrow: No reason not to go to TS status with SAB at T2.5.

I know right? The NHC almost always waits for 2.5 classification before an upgrade to TS. This has maintained deep convection and curved bands for quite sometime meaning this has been a TD IMO and with a T2.5 from SAB it's ready to be named.

Last night this wasn't ready but this has likely been a TD since 12z.

[Yellow Evan]

* EAST PACIFIC 2018 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* INVEST EP932018 07/31/18 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 30 33 37 41 44 51 57 64 68 71 71 67 61
V (KT) LAND 30 33 37 41 44 51 57 64 68 71 71 67 61
V (KT) LGEM 30 32 35 37 40 45 49 53 57 61 62 60 55
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 6 8 7 8 11 12 12 5 10 7 12 19 24
SHEAR ADJ (KT) 1 0 0 1 2 0 -3 -3 -3 0 0 1 2
SHEAR DIR 55 63 62 58 49 52 51 27 359 328 304 288 285
SST (C) 28.2 28.1 28.2 28.2 28.0 27.8 27.1 27.1 26.9 27.5 27.8 27.7 27.2
POT. INT. (KT) 147 146 147 147 145 142 135 135 134 140 143 142 136
200 MB T (C) -53.9 -53.6 -53.7 -54.0 -54.0 -54.0 -54.1 -53.8 -54.1 -54.0 -53.9 -53.8 -54.1
200 MB VXT (C) 0.0 -0.1 0.0 0.0 0.0 0.0 0.0 0.0 -0.2 -0.2 -0.3 -0.3 -0.3
TH_E DEV (C) 7 7 6 6 6 6 5 5 5 6 5 6 7
700-500 MB RH 65 66 67 66 64 62 57 56 57 58 58 56 51
MODEL VTX (KT) 6 7 7 7 8 8 9 10 10 12 12 12 12
850 MB ENV VOR -22 -25 -25 -25 -15 -4 3 21 14 30 34 42 35
200 MB DIV 4 2 17 42 46 56 63 64 33 27 -35 -20 -17
700-850 TADV -5 -4 -4 -4 -3 0 -1 0 -6 -7 -6 -8 -6
LAND (KM) 1324 1356 1398 1457 1522 1647 1761 1937 2135 2338 2340 2119 1912
LAT (DEG N) 12.5 xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x
LONG(DEG W) 116.1 xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 11 11 11 11 11 10 10 11 12 11 12 12 11
HEAT CONTENT 13 12 12 12 11 14 26 28 9 9 9 9 8

FORECAST TRACK FROM OFPI INITIAL HEADING/SPEED (DEG/KT):290/ 10 CX,CY: -8/ 3
T-12 MAX WIND: 25 PRESSURE OF STEERING LEVEL (MB): 596 (MEAN=584)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 15.7 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 71.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 5.6

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. 0. -1. -1. -2. -3.
SST POTENTIAL 0. 0. 0. 1. 5. 10. 15. 21. 24. 27. 28. 28.
VERTICAL SHEAR MAG 1. 2. 3. 3. 4. 4. 5. 4. 4. 3. 2. 1.
VERTICAL SHEAR ADJ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
VERTICAL SHEAR DIR 1. 2. 3. 4. 6. 9. 11. 11. 10. 8. 5. 3.
PERSISTENCE 1. 2. 2. 2. 2. 1. 1. 1. 1. 1. 1. 1.
200/250 MB TEMP. 0. 0. 0. 0. -1. -2. -3. -4. -4. -4. -4. -3.
THETA_E EXCESS 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1.
700-500 MB RH 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
MODEL VTX TENDENCY 0. 1. 1. 1. 2. 3. 4. 5. 7. 8. 8. 7.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1.
200 MB DIVERGENCE 0. 0. -1. -1. 0. 0. 0. 0. 0. 0. -1. -2.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. -1. -1. -1.
ZONAL STORM MOTION 0. 0. 0. 0. 1. 1. 1. 1. 0. 0. 0. 0.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
GOES PREDICTORS 1. 1. 1. 2. 1. 0. 0. -1. -1. -1. -2. -2.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
RI POTENTIAL 0. 0. 0. 0. 0. 0. -1. 0. 0. 0. 1. 1.
----------------------------------------------------------
TOTAL CHANGE 3. 7. 11. 14. 21. 27. 34. 38. 41. 41. 37. 31.

CURRENT MAX WIND (KT): 30. LAT, LON: 12.5 116.1

** 2018 E. Pacific RI INDEX EP932018 INVEST 07/31/18 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
POT = MPI-VMAX (KT) : 118.2 40.5 to 149.3 0.71 5.9
12 HR PERSISTENCE (KT) : 5.0 -22.0 to 44.0 0.41 4.0
850-200 MB SHEAR (KT) : 8.1 19.6 to 1.4 0.63 5.0
HEAT CONTENT (KJ/CM2) : 12.0 1.8 to 106.7 0.10 0.6
D200 (10**7s-1) : 22.2 -33.0 to 156.2 0.29 2.0
STD DEV OF IR BR TEMP : 15.7 37.8 to 2.1 0.62 3.5
MAXIMUM WIND (KT) : 30.0 22.5 to 132.0 0.22 1.2
BL DRY-AIR FLUX (W/M2) : 122.6 721.6 to -82.5 0.74 -3.6
%area of TPW <45 mm upshear : 0.0 62.3 to 0.0 1.00 0.6
2nd PC OF IR BR TEMP : -0.9 2.2 to -1.9 0.76 0.6

SHIPS Prob RI for 20kt/ 12hr RI threshold= 10% is 1.7 times climatological mean ( 6.1%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 21% is 1.7 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 20% is 2.4 times climatological mean ( 8.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 14% is 2.3 times climatological mean ( 6.0%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 9% is 2.2 times climatological mean ( 4.0%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 16% is 2.5 times climatological mean ( 6.5%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 19% is 3.1 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 11% is 2.3 times climatological mean ( 4.8%)

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: 10.3% 21.1% 19.9% 13.6% 8.8% 16.5% 18.5% 11.3%
Logistic: 10.7% 32.8% 17.1% 10.0% 2.9% 9.3% 5.1% 7.8%
Bayesian: 0.2% 5.8% 0.4% 0.1% 0.1% 0.8% 1.1% 0.0%
Consensus: 7.1% 19.9% 12.5% 7.9% 3.9% 8.9% 8.3% 6.4%
DTOPS: 0.0% 9.0% 6.0% 3.0% 0.0% 2.0% 5.0% 12.0%

## ANNULAR HURRICANE INDEX (AHI) EP932018 INVEST 07/31/18 18 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

CONTRIBUTIONS TO ANNULAR INDEX

[Kazmit]

Hopefully the Euro will shift the recurve further east, or go back to taking it below the islands like the GFS. I'll be in Hawaii next week, and this is making me nervous.

[Kingarabian]

Anti-cyclone has been building over the system. Note the improving shear conditions west of 130W:

[Yellow Evan]

Mid-level shear also improving.

[cycloneye]

A couple of days ago this was almost dead so who thought then this system would be a relativly good ACE producer but it looks it will gain a good deal.

[Yellow Evan]

The biggest caveats to the system will be:
1.Abrupt increased in mid-level shear (not uncommon for systems that track this far west) but due to its small size, it's more vulnerable to such increases
2.Dry air that could disrupt the inner core for a few hours (background state isn't the most favorable so this might be more susceptible than normal)

This will run into a wall of shear in about 5 days if CMISS maps hold and this is reflected by the SHIPS output. My guess is this becomes at least a hurricane but there's more uncertainty than normal.

[Yellow Evan]

* EAST PACIFIC 2018 SHIPS INTENSITY FORECAST *
* IR SAT DATA AVAILABLE, OHC AVAILABLE *
* INVEST EP932018 07/31/18 18 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 30 33 37 41 44 51 57 64 68 71 71 67 61
V (KT) LAND 30 33 37 41 44 51 57 64 68 71 71 67 61
V (KT) LGEM 30 32 35 37 40 45 49 53 57 61 62 60 55
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 6 8 7 8 11 12 12 5 10 7 12 19 24
SHEAR ADJ (KT) 1 0 0 1 2 0 -3 -3 -3 0 0 1 2
SHEAR DIR 55 63 62 58 49 52 51 27 359 328 304 288 285
SST (C) 28.2 28.1 28.2 28.2 28.0 27.8 27.1 27.1 26.9 27.5 27.8 27.7 27.2
POT. INT. (KT) 147 146 147 147 145 142 135 135 134 140 143 142 136
200 MB T (C) -53.9 -53.6 -53.7 -54.0 -54.0 -54.0 -54.1 -53.8 -54.1 -54.0 -53.9 -53.8 -54.1
200 MB VXT (C) 0.0 -0.1 0.0 0.0 0.0 0.0 0.0 0.0 -0.2 -0.2 -0.3 -0.3 -0.3
TH_E DEV (C) 7 7 6 6 6 6 5 5 5 6 5 6 7
700-500 MB RH 65 66 67 66 64 62 57 56 57 58 58 56 51
MODEL VTX (KT) 6 7 7 7 8 8 9 10 10 12 12 12 12
850 MB ENV VOR -22 -25 -25 -25 -15 -4 3 21 14 30 34 42 35
200 MB DIV 4 2 17 42 46 56 63 64 33 27 -35 -20 -17
700-850 TADV -5 -4 -4 -4 -3 0 -1 0 -6 -7 -6 -8 -6
LAND (KM) 1324 1356 1398 1457 1522 1647 1761 1937 2135 2338 2340 2119 1912
LAT (DEG N) 12.5 xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x xx.x
LONG(DEG W) 116.1 xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x xxx.x
STM SPEED (KT) 11 11 11 11 11 10 10 11 12 11 12 12 11
HEAT CONTENT 13 12 12 12 11 14 26 28 9 9 9 9 8

FORECAST TRACK FROM OFPI INITIAL HEADING/SPEED (DEG/KT):290/ 10 CX,CY: -8/ 3
T-12 MAX WIND: 25 PRESSURE OF STEERING LEVEL (MB): 596 (MEAN=584)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 15.7 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 71.0 (MEAN=65.0)
PRELIM RI PROB (DV .GE. 55 KT IN 48 HR): 5.6

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. 0. -1. -1. -2. -3.
SST POTENTIAL 0. 0. 0. 1. 5. 10. 15. 21. 24. 27. 28. 28.
VERTICAL SHEAR MAG 1. 2. 3. 3. 4. 4. 5. 4. 4. 3. 2. 1.
VERTICAL SHEAR ADJ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
VERTICAL SHEAR DIR 1. 2. 3. 4. 6. 9. 11. 11. 10. 8. 5. 3.
PERSISTENCE 1. 2. 2. 2. 2. 1. 1. 1. 1. 1. 1. 1.
200/250 MB TEMP. 0. 0. 0. 0. -1. -2. -3. -4. -4. -4. -4. -3.
THETA_E EXCESS 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1.
700-500 MB RH 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
MODEL VTX TENDENCY 0. 1. 1. 1. 2. 3. 4. 5. 7. 8. 8. 7.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 1. 1. 1. 1. 1. 1. 1.
200 MB DIVERGENCE 0. 0. -1. -1. 0. 0. 0. 0. 0. 0. -1. -2.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. -1. -1. -1.
ZONAL STORM MOTION 0. 0. 0. 0. 1. 1. 1. 1. 0. 0. 0. 0.
STEERING LEVEL PRES 0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
GOES PREDICTORS 1. 1. 1. 2. 1. 0. 0. -1. -1. -1. -2. -2.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
RI POTENTIAL 0. 0. 0. 0. 0. 0. -1. 0. 0. 0. 1. 1.
----------------------------------------------------------
TOTAL CHANGE 3. 7. 11. 14. 21. 27. 34. 38. 41. 41. 37. 31.

CURRENT MAX WIND (KT): 30. LAT, LON: 12.5 116.1

** 2018 E. Pacific RI INDEX EP932018 INVEST 07/31/18 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
POT = MPI-VMAX (KT) : 118.2 40.5 to 149.3 0.71 5.9
12 HR PERSISTENCE (KT) : 5.0 -22.0 to 44.0 0.41 4.0
850-200 MB SHEAR (KT) : 8.1 19.6 to 1.4 0.63 5.0
HEAT CONTENT (KJ/CM2) : 12.0 1.8 to 106.7 0.10 0.6
D200 (10**7s-1) : 22.2 -33.0 to 156.2 0.29 2.0
STD DEV OF IR BR TEMP : 15.7 37.8 to 2.1 0.62 3.5
MAXIMUM WIND (KT) : 30.0 22.5 to 132.0 0.22 1.2
BL DRY-AIR FLUX (W/M2) : 122.6 721.6 to -82.5 0.74 -3.6
%area of TPW <45 mm upshear : 0.0 62.3 to 0.0 1.00 0.6
2nd PC OF IR BR TEMP : -0.9 2.2 to -1.9 0.76 0.6

SHIPS Prob RI for 20kt/ 12hr RI threshold= 10% is 1.7 times climatological mean ( 6.1%)
SHIPS Prob RI for 25kt/ 24hr RI threshold= 21% is 1.7 times climatological mean (12.5%)
SHIPS Prob RI for 30kt/ 24hr RI threshold= 20% is 2.4 times climatological mean ( 8.4%)
SHIPS Prob RI for 35kt/ 24hr RI threshold= 14% is 2.3 times climatological mean ( 6.0%)
SHIPS Prob RI for 40kt/ 24hr RI threshold= 9% is 2.2 times climatological mean ( 4.0%)
SHIPS Prob RI for 45kt/ 36hr RI threshold= 16% is 2.5 times climatological mean ( 6.5%)
SHIPS Prob RI for 55kt/ 48hr RI threshold= 19% is 3.1 times climatological mean ( 5.9%)
SHIPS Prob RI for 65kt/ 72hr RI threshold= 11% is 2.3 times climatological mean ( 4.8%)

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: 10.3% 21.1% 19.9% 13.6% 8.8% 16.5% 18.5% 11.3%
Logistic: 10.7% 32.8% 17.1% 10.0% 2.9% 9.3% 5.1% 7.8%
Bayesian: 0.2% 5.8% 0.4% 0.1% 0.1% 0.8% 1.1% 0.0%
Consensus: 7.1% 19.9% 12.5% 7.9% 3.9% 8.9% 8.3% 6.4%
DTOPS: 0.0% 9.0% 6.0% 3.0% 0.0% 2.0% 5.0% 12.0%

## ANNULAR HURRICANE INDEX (AHI) EP932018 INVEST 07/31/18 18 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=4 NFAIL=3 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

CONTRIBUTIONS TO ANNULAR INDEX

[Kingarabian]

Hopefully the Euro will shift the recurve further east, or go back to taking it below the islands like the GFS. I'll be in Hawaii next week, and this is making me nervous.

Even though climo now supports a Hawaii threat, fortunately it'll be tough. Comes down to strength and location of the system, TUTT location, then steering -- the latter two factors being the toughest.

[Yellow Evan]

Hopefully the Euro will shift the recurve further east, or go back to taking it below the islands like the GFS. I'll be in Hawaii next week, and this is making me nervous.

Even though climo now supports a Hawaii threat, fortunately it'll be tough. Comes down to strength and location of the system, TUTT location, then steering -- the latter two factors being the toughest.

Historical model biases would favor the recurve shifting west not east. I'm inclined to think the biggest hindrance is be the Great Hawaiian Shear but it's hard to say how much of an impact that would have this far out.

[Kingarabian]

[CyclonicFury]

Should be enough to initiate advisories on TS Hector at 21z.

[Yellow Evan]

Yeah this is obviously Hector. I could be talked into going as high as 40 knots.

[cycloneye]

Tropical Depression Ten-E Discussion Number 1
NWS National Hurricane Center Miami FL EP102018
200 PM PDT Tue Jul 31 2018

The broad low pressure system and area of disturbed weather that the
NHC has been tracking for the past several days has finally become
well-defined enough and has acquired sufficient organized deep
convection near the center to be classified as a tropical
depression. The low-level center is estimated to be just inside the
southeastern edge of the figure-6 cloud mass based on conventional
and microwave satellite fix data. The initial intensity estimate of
30 kt is based on Dvorak satellite classifications of T2.0/30 kt
from TAFB and T2.5/35 kt from SAB, along with uncontaminated 30-kt
winds in a 1634 UTC Scatsat-1 scatterometer pass.

The initial motion estimate is west-northwestward or 290/11 kt. A
deep-layer ridge to the north of the depression should keep the
tropical cyclone moving toward the west-northwest for the next 48
hours or so, followed by a turn toward the west thereafter due to
the ridge building slightly southward on days 3-5. The NHC track
forecast closely follows a blend of the consensus models TVCN and
HCCA since this is the first forecast on this system.

Although the comma-shaped cloud pattern is suggestive of a slightly
stronger system, microwave imagery and the Scatsat-1 pass indicate
that the circulation envelope is elongated northeast-to-southwest,
and that westerly winds likely only extend about 30 n mi to the
south of the center. Due to the cyclone's irregular shape, the peak
winds are being held lower than the Dvorak T2.5 data-T numbers.
Visible satellite imagery shows the tops of shallow convection in
the eastern semicircle blowing off toward the west, which is
indicative of modest mid-level shear undercutting the favorable
high-level cirrus outflow layer. This mid-level flow is also likely
producing some intrusions of dry air, a negative condition that
should act to inhibit inner-core convective development in the short
term. These aforementioned unfavorable environmental conditions, in
conjunction with the irregular shape of the cyclone's circulation,
should result in only slow strengthening for the next 48 hours or
so, despite the very favorable deep-layer, low vertical wind shear
environment. In the 48-72 h period, both the GFS and ECMWF models
are forecasting the shear to increase to near 15 kt, which should
act to maintain only slow development. By days 4 and 5, the shear is
forecast to abate, and the cyclone is forecast to become a hurricane
by 120 hours. The intensity forecast follows the trend of the HCCA
and IVCN intensity consensus models, but is slightly higher due to
the HMON model showing immediate weakening, which is pulling down
the consensus intensity forecasts.

FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 12.7N 116.7W 30 KT 35 MPH
12H 01/0600Z 13.1N 118.4W 35 KT 40 MPH
24H 01/1800Z 13.6N 120.3W 40 KT 45 MPH
36H 02/0600Z 13.8N 122.4W 45 KT 50 MPH
48H 02/1800Z 14.0N 124.6W 50 KT 60 MPH
72H 03/1800Z 13.8N 128.7W 55 KT 65 MPH
96H 04/1800Z 13.7N 132.6W 60 KT 70 MPH
120H 05/1800Z 13.6N 136.7W 65 KT 75 MPH

$$
Forecaster Stewart

[Kingarabian]

Hopefully the Euro will shift the recurve further east, or go back to taking it below the islands like the GFS. I'll be in Hawaii next week, and this is making me nervous.

Even though climo now supports a Hawaii threat, fortunately it'll be tough. Comes down to strength and location of the system, TUTT location, then steering -- the latter two factors being the toughest.

Historical model biases would favor the recurve shifting west not east. I'm inclined to think the biggest hindrance is be the Great Hawaiian Shear but it's hard to say how much of an impact that would have this far out.

Yeah Hurricanes Kilo and Ana were good example for this, where models kept shifting the recurves west.

[Yellow Evan]

Even though climo now supports a Hawaii threat, fortunately it'll be tough. Comes down to strength and location of the system, TUTT location, then steering -- the latter two factors being the toughest.

Historical model biases would favor the recurve shifting west not east. I'm inclined to think the biggest hindrance is be the Great Hawaiian Shear but it's hard to say how much of an impact that would have this far out.

Yeah Hurricanes Kilo and Ana were good example for this, where models kept shifting the recurves west.

It's the same overall setup, with the global models underdoing ridge in the case of a westward tracking system that causes many ATL storms that are initially modeled OTS to become dangerous US threats and why re-curves are often delayed west in the WPAC.

[storminabox]

Tropical Depression Ten-E Discussion Number 1
NWS National Hurricane Center Miami FL EP102018
200 PM PDT Tue Jul 31 2018

The broad low pressure system and area of disturbed weather that the
NHC has been tracking for the past several days has finally become
well-defined enough and has acquired sufficient organized deep
convection near the center to be classified as a tropical
depression. The low-level center is estimated to be just inside the
southeastern edge of the figure-6 cloud mass based on conventional
and microwave satellite fix data. The initial intensity estimate of
30 kt is based on Dvorak satellite classifications of T2.0/30 kt
from TAFB and T2.5/35 kt from SAB, along with uncontaminated 30-kt
winds in a 1634 UTC Scatsat-1 scatterometer pass.

The initial motion estimate is west-northwestward or 290/11 kt. A
deep-layer ridge to the north of the depression should keep the
tropical cyclone moving toward the west-northwest for the next 48
hours or so, followed by a turn toward the west thereafter due to
the ridge building slightly southward on days 3-5. The NHC track
forecast closely follows a blend of the consensus models TVCN and
HCCA since this is the first forecast on this system.

Although the comma-shaped cloud pattern is suggestive of a slightly
stronger system, microwave imagery and the Scatsat-1 pass indicate
that the circulation envelope is elongated northeast-to-southwest,
and that westerly winds likely only extend about 30 n mi to the
south of the center. Due to the cyclone's irregular shape, the peak
winds are being held lower than the Dvorak T2.5 data-T numbers.
Visible satellite imagery shows the tops of shallow convection in
the eastern semicircle blowing off toward the west, which is
indicative of modest mid-level shear undercutting the favorable
high-level cirrus outflow layer. This mid-level flow is also likely
producing some intrusions of dry air, a negative condition that
should act to inhibit inner-core convective development in the short
term. These aforementioned unfavorable environmental conditions, in
conjunction with the irregular shape of the cyclone's circulation,
should result in only slow strengthening for the next 48 hours or
so, despite the very favorable deep-layer, low vertical wind shear
environment. In the 48-72 h period, both the GFS and ECMWF models
are forecasting the shear to increase to near 15 kt, which should
act to maintain only slow development. By days 4 and 5, the shear is
forecast to abate, and the cyclone is forecast to become a hurricane
by 120 hours. The intensity forecast follows the trend of the HCCA
and IVCN intensity consensus models, but is slightly higher due to
the HMON model showing immediate weakening, which is pulling down
the consensus intensity forecasts.

FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 12.7N 116.7W 30 KT 35 MPH
12H 01/0600Z 13.1N 118.4W 35 KT 40 MPH
24H 01/1800Z 13.6N 120.3W 40 KT 45 MPH
36H 02/0600Z 13.8N 122.4W 45 KT 50 MPH
48H 02/1800Z 14.0N 124.6W 50 KT 60 MPH
72H 03/1800Z 13.8N 128.7W 55 KT 65 MPH
96H 04/1800Z 13.7N 132.6W 60 KT 70 MPH
120H 05/1800Z 13.6N 136.7W 65 KT 75 MPH

$$
Forecaster Stewart

I’m surprised they didn’t upgrade it to a TS.

[Kingarabian]

200mb wind setup on the 12z Euro is potentially dangerous for Hawaii, especially if it's underdoing the high pressure and Ten-E gets further west. Has the TUTT well north of the islands.