WPAC: HECTOR - Post-Tropical

[Kingarabian]

18z GFS doesn't look like it will be any better for Hawaii.

Either Hilo or Maui in the crosshairs.

Looks like a big island landfall- further south. That would put a dent in it.

Pretty nasty Big Island hit before high pressure builds back in and saves Maui and Oahu:

[CrazyC83]

If this misses Hawaii well south, there is nothing to recurve it before the dateline either that I can see...

[Kingarabian]

If this misses Hawaii well south, there is nothing to recurve it before the dateline either that I can see...

Looks like once Hector reaches 155W, it has no way to go but west.

[Kingarabian]

They'll probably keep it at 95kts for now and see if the eye can clear out again before upgrading to major.

SATCON is still at 95kts, ADT is holding back the estimates.

CURRENT ESTIMATE
Date (mmddhhmm): 08022200
SATCON: MSLP = 970 hPa MSW = 95 knots
SATCON Member Consensus: 91.0 knots
Pressure -> Wind Using SATCON MSLP: 101 knots
Distance to Outer Closed Isobar Used is 150 nm
Eye Size Correction Used is 7.3 knots Source: MW

Member Estimates

ADT: 975 hPa 82 knots Scene: CDO Date: AUG022200
CIMSS AMSU: 947 hPa 115 knots Bias Corr: 0 (MW) Date: 08021620
ATMS: 966.0 hPa 97.4 knots Date: 08022200
SSMIS: 966.0 hPa 97.4 knots Date: 08022200

[1900hurricane]

If this misses Hawaii well south, there is nothing to recurve it before the dateline either that I can see...

I mentioned this in the WPac thread earlier, but I think it's about a coin flip that Hector manages to cross the International Date Line.

[cycloneye]

SAB at 4.5/5.0.

03/0000 UTC 14.1N 126.3W T4.5/5.0 HECTOR -- East Pacific

[CrazyC83]

It may be going through a lull, perhaps the shear picked up for a moment.

[Yellow Evan]

Good call by SAB to lower to T4.5. This will bomb out to Cat 4 quickly once the shear abates most likely but it'll struggle or possibly weaken before then.

[Kingarabian]

The past 24 hours, GFS guidance has been insisting on this weakening around now. They've over did the weakening, but some weakening wouldn't shock me. Likely inner core fluctuations.

[1900hurricane]

Looks like it could be dealing with some dry air.

[cycloneye]

00z Best Track at 95 kts.

EP, 10, 2018080300, , BEST, 0, 141N, 1263W, 95, 973, HU

[Kingarabian]

COAMPS takes this to Cat.5.

[Twisted-core]

Projected sweii atm 7 metres ...21 feet imperial>..


https://imgur.com/CmZ2emX





wind projection atm.

https://imgur.com/forh7Hp

[Ntxw]

COAMPS takes this to Cat.5.

The best shot at this would be if he took the path well south of Hawaii similar to John.


Definitely some inner structure fluctuations, slight shear, and/or some dry air on the northern side in the short term but will improve later on.

Last full visibles of the day. You can see on the latest frames storm is breathing quite well.

[xtyphooncyclonex]

If it does RI earlier or more rapidly than forecast, 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.

[Kingarabian]

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).

[cycloneye]

Hurricane Hector Discussion Number 10
NWS National Hurricane Center Miami FL EP102018
800 PM PDT Thu Aug 02 2018

Hector's rapid intensification has ended for the moment, with
satellite imagery showing that the eye has become cloud filled
since the last advisory. In addition, recent satellite microwave
data indicate some erosion of the central convection on the north
side of the center, possibly due to shear or a tongue of dry air
working into the cyclone. The initial intensity is held at 95 kt
in best agreement with the most recent CIMSS satellite consensus
intensity estimate, but it is possible that this is a little
generous.

The initial motion is 270/11. A large subtropical ridge to the
north of Hector should steer the cyclone westward for the next
three days or so, and this part of the forecast track is an update
of the previous track. Beyond that time, the large-scale models
forecast a large deep-layer trough to develop over the northeastern
Pacific, causing a weakness in the ridge to the north of Hector, and
leading to the cyclone turning west-northwestward. There is some
spread in the guidance during this time, with the GFS forecasting a
weaker ridge and a more northward track than the ECMWF. Overall,
the guidance envelope has again shifted northward from 72-120 h,
and the new forecast track does likewise in best agreement with the
HCCA corrected consensus and Florida State Superensemble models.

The intensity forecast remains low confidence. While the shear
near Hector should subside during the next 12-24 h, the forecast
track takes the cyclone over slightly cooler sea surface
temperatures during this time. This part of the new intensity
forecast thus calls for little change in strength. From 24-72 h,
the cyclone should move over warmer water in a light shear
environment, which looks favorable for strengthening. However,
there is sharp divergence in the guidance for this part of the
forecast, with the SHIPS and LGEM models forecasting weakening while
the dynamical HWRF, HMON, and COAMPS-TC models forecast
intensification to a major hurricane. The NHC forecast sides with
the dynamical models for this period, and it lies near the upper
edge of the intensity guidance. After 72 h, Hector is expected to
gradually weaken as it moves into a drier air mass.

FORECAST POSITIONS AND MAX WINDS

INIT 03/0300Z 14.1N 126.9W 95 KT 110 MPH
12H 03/1200Z 14.1N 128.6W 95 KT 110 MPH
24H 04/0000Z 14.1N 130.8W 95 KT 110 MPH
36H 04/1200Z 14.0N 132.9W 100 KT 115 MPH
48H 05/0000Z 13.9N 135.1W 105 KT 120 MPH
72H 06/0000Z 14.0N 139.5W 115 KT 130 MPH
96H 07/0000Z 15.0N 144.5W 105 KT 120 MPH
120H 08/0000Z 16.5N 149.5W 95 KT 110 MPH

$$
Forecaster Beven

[xtyphooncyclonex]

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.

[Kingarabian]

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.

I'm sure the steering for Haiyan was different than the current steering over the North and North Western Pacific.

[Kingarabian]

While this is can and probably be subject to change, Hector's forecasted strength by the NHC and most models would mean it to be steered by at least the 300-850mb layer which would look like this:



To get Hector to continue moving west, it needs to drastically weaken before it enters the CPAC and thus be steered by a different layer like the 500-850mb: