WPAC: HECTOR - Post-Tropical

[1900hurricane]

Steering will vary with environment. In this case, around tau 72 on the 18Z GFS, a trough will pass well to the north of Hector. However, it could weaken the ridge some and allow the system to slip poleward a little, similar to the Maysak '15 scenario. If the 18Z GFS is taken verbatim, a deeper system will feel the weakness more than a weaker system will. At tau 72, the southern base of the trough is better defined at 500 mb than at 700 mb, and even more defined further south still at 200 mb.







Of course this is taking the GFS verbatim. It is also worth noting that it has often tried to move systems poleward too fast in recent years, particularly with Irma last year. It'll be interesting to see if that bias shows itself here or not.

[1900hurricane]

Just for further visualization (and because I love skew-Ts), here's the area sounding for Hector at tau 72 on the same 18Z GFS run. Note particularly the poleward components in wind vectors between 500-200 mb (deeper steering) vs the more zonal winds below 500 mb (more shallow steering).

[cycloneye]

00z GFS shifts to south of Hilo.

[Kazmit]

Glad to see the GFS sparing Hawaii on this run, similar to the Euro solution. Hopefully it stays this way...

[xtyphooncyclonex]

I do hope this stays away from Hawaii entirely. They've already been through a lot. It would also be interesting to see this actually cross the IDL as a category 4-5. I hope this maintains its intensity without any harm as much as possible. Long-lived fish storms are the best ones to track.

[Alyono]

HURRICANE HECTOR ANALYSED POSITION : 13.8N 126.4W

ATCF IDENTIFIER : EP102018

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 03.08.2018 0 13.8N 126.4W 964 73
1200UTC 03.08.2018 12 13.9N 128.2W 969 68
0000UTC 04.08.2018 24 14.4N 130.3W 971 67
1200UTC 04.08.2018 36 14.5N 132.5W 975 60
0000UTC 05.08.2018 48 14.5N 134.6W 980 57
1200UTC 05.08.2018 60 14.5N 136.6W 981 58
0000UTC 06.08.2018 72 14.7N 138.8W 980 57
1200UTC 06.08.2018 84 15.1N 141.2W 975 64
0000UTC 07.08.2018 96 15.8N 144.1W 969 66
1200UTC 07.08.2018 108 16.1N 147.5W 975 63
0000UTC 08.08.2018 120 16.2N 150.8W 982 58
1200UTC 08.08.2018 132 16.2N 154.2W 987 52
0000UTC 09.08.2018 144 16.3N 157.2W 991 47

[Kingarabian]

00z GFS shifts to south of Hilo.

[img]https://i.imgur.com/I7A9vJg.gif[img]

Yup, good to see. Only problem now is that there's another trough at 165W and that puts Kauai or Oahu at risk of being Iniki'd.

[Kingarabian]

HURRICANE HECTOR ANALYSED POSITION : 13.8N 126.4W

ATCF IDENTIFIER : EP102018

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 03.08.2018 0 13.8N 126.4W 964 73
1200UTC 03.08.2018 12 13.9N 128.2W 969 68
0000UTC 04.08.2018 24 14.4N 130.3W 971 67
1200UTC 04.08.2018 36 14.5N 132.5W 975 60
0000UTC 05.08.2018 48 14.5N 134.6W 980 57
1200UTC 05.08.2018 60 14.5N 136.6W 981 58
0000UTC 06.08.2018 72 14.7N 138.8W 980 57
1200UTC 06.08.2018 84 15.1N 141.2W 975 64
0000UTC 07.08.2018 96 15.8N 144.1W 969 66
1200UTC 07.08.2018 108 16.1N 147.5W 975 63
0000UTC 08.08.2018 120 16.2N 150.8W 982 58
1200UTC 08.08.2018 132 16.2N 154.2W 987 52
0000UTC 09.08.2018 144 16.3N 157.2W 991 47

Both the HWRF and UKMET initialized this at 969, around 4mb stronger. Interesting.

[CrazyC83]

If it does RI, it could take the southern route more certainly. As mentioned several times, a more western component would take place (stronger STR) if the storm is stronger, not weaker.

A deeper and stronger Hector (major hurricane) gets very close to Hawaii because it feels the trough in the north Pacific to the fullest extent. Models and ensembles agree on this scenario.

I believe a cat.2 would get very close to the southern tip of the big island but continues west (what today's 12z Euro showed).

A cat.1 moves safely west south of Hawaii (what yesterdays OP Euro run showed, and what today's EPS runs showed).

Nope, it is the opposite.

It was mentioned during Haiyan, one of the strongest storms in history. It continued moving west, even further than initially anticipated, because it unexpectedly strengthened higher---- to 170 knots.

There were pro mets who've cited this.

Same thing happened in 2015 with Joaquin. The unexpected rapid intensification to cat 4 is what trapped it in the Bahamas and then pushed it out; the lower level flow turned it northwest into the Mid-Atlantic.

[Alyono]

ICON shifted north into downtown Hilo

[Kingarabian]

ICON shifted north into downtown Hilo

GFS's scenario has been a double edged sword so far. Trough before 145W could threaten Hilo or Maui, while a trough near 165W could threaten Kauai or Oahu.

[CrazyC83]

ICON shifted north into downtown Hilo

GFS's scenario has been a double edged sword so far. Trough before 145W could threaten Hilo or Maui, while a trough near 165W could threaten Kauai or Oahu.

The 165 trough is a scarier scenario, since not just more people in the path but also it would be far less likely to weaken if it curls around the Big Island and the recurves. The SST's are higher southwest of the islands than east, and there is typically less shear.

[cycloneye]

06z Best Track remains at 95 kts.

EP, 10, 2018080306, , BEST, 0, 140N, 1273W, 95, 975, HU

[Kingarabian]

00z Euro slower:

[cycloneye]

Updated 06z Best Track down to 90 kts.

EP, 10, 2018080306, , BEST, 0, 140N, 1273W, 90, 975, HU

[Kingarabian]

Eye possibly clearing out again:

[cycloneye]

Hurricane Hector Discussion Number 11
NWS National Hurricane Center Miami FL EP102018
200 AM PDT Fri Aug 03 2018

Although Hector appeared to be disrupted by moderate northeasterly
shear earlier this evening, its satellite presentation is generally
back on the upswing. A WindSat pass around 0213 UTC revealed that
the tiny mid-level eye of the hurricane was still intact, and this
feature has at times been apparent once again in longwave and
shortwave IR imagery. The initial intensity has been set at 90 kt
based on the Dvorak CI numbers from TAFB and SAB.

Even though the shear no longer appears to be a significant
inhibiting factor, marginal sea surface temperatures and mid-level
humidity could still be limiting factors for the intensity of
Hector. All of the intensity guidance indicates that little change
in intensity will occur over the next 24-36 hours, so only gradual
strengthening is forecast. By days 2 and 3, the hurricane will be
moving over warmer waters once again, so some additional
strengthening seems likely at that time. This scenario is supported
by the dynamical intensity models, all of which depict Hector as a
strong major hurricane. The statistical guidance notably shows
gradual weakening during this period, so confidence in this part of
the forecast is low. By 96 h, Hector is expected to move over
cooler SSTs and into a drier environment, so steady weakening is
forecast. The new NHC intensity forecast is similar to the previous
advisory and still favors the dynamical model solutions.

The initial motion is now 270/10 kt. No significant changes have
been made to the track forecast. Hector is expected to be steered
westward by a large subtropical ridge for the next few days. A turn
toward the west-northwest is anticipated early next week as a large
deep-layer trough over the northern Pacific weakens the ridge. There
is still a large amount of spread in the global models regarding the
forward speed of Hector as it begins to turn west-northwestward.
Despite the large spread, the consensus has not changed much, so the
new NHC track forecast lies practically on top of the previous
forecast, and remains close to the consensus aids HCCA and FSSE.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0900Z 14.0N 127.8W 90 KT 105 MPH
12H 03/1800Z 14.0N 129.4W 90 KT 105 MPH
24H 04/0600Z 14.0N 131.6W 95 KT 110 MPH
36H 04/1800Z 14.0N 133.7W 100 KT 115 MPH
48H 05/0600Z 13.9N 135.8W 105 KT 120 MPH
72H 06/0600Z 14.5N 140.1W 110 KT 125 MPH
96H 07/0600Z 15.5N 145.5W 100 KT 115 MPH
120H 08/0600Z 16.5N 150.5W 90 KT 105 MPH

$$
Forecaster Zelinsky

[cycloneye]

06z GFS has crossover to WPAC

[euro6208]

Whereas EURO doesn't...

[xtyphooncyclonex]

Made this... lol