CPAC: LANE - Post-Tropical

[ncapps]

When will the NOAA G-IV data be ingested into models for operational output? 0Z?

[Kingarabian]

When will the NOAA G-IV data be ingested into models for operational output? 0Z?

00z most likely. But it'll likely take more than one mission before the models reach a consensus.

[Yellow Evan]

Through hour 132. Veering west.

[Yellow Evan]

UKMET further north.

612

WTNT80 EGRR 191603



MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC



AND ATLANTIC



GLOBAL MODEL DATA TIME 12UTC 19.08.2018



HURRICANE LANE ANALYSED POSITION : 12.5N 143.1W



ATCF IDENTIFIER : EP142018



VERIFYING TIME POSITION STRENGTH TENDENCY

-------------- -------- -------- --------

12UTC 19.08.2018 12.5N 143.1W MODERATE

00UTC 20.08.2018 12.8N 145.4W MODERATE LITTLE CHANGE

12UTC 20.08.2018 12.8N 147.5W MODERATE LITTLE CHANGE

00UTC 21.08.2018 12.8N 149.5W MODERATE LITTLE CHANGE

12UTC 21.08.2018 13.1N 151.2W MODERATE WEAKENING SLIGHTLY

00UTC 22.08.2018 13.5N 153.2W MODERATE LITTLE CHANGE

12UTC 22.08.2018 13.8N 155.2W MODERATE LITTLE CHANGE

00UTC 23.08.2018 14.2N 157.1W MODERATE LITTLE CHANGE

12UTC 23.08.2018 15.1N 158.7W STRONG INTENSIFYING SLIGHTLY

00UTC 24.08.2018 16.4N 160.4W STRONG INTENSIFYING SLIGHTLY

12UTC 24.08.2018 18.0N 161.3W STRONG LITTLE CHANGE

00UTC 25.08.2018 19.6N 162.1W STRONG WEAKENING SLIGHTLY

12UTC 25.08.2018 20.9N 162.5W STRONG LITTLE CHANGE





THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE

RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS

AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.



BULLETINS ARE NOW AVAILABLE WHICH PROVIDE EXPLICIT GUIDANCE

ON CENTRAL PRESSURE AND MAXIMUM WIND SPEED.

FOR FURTHER INFORMATION CONTACT TROPICAL_CYCLONES@METOFFICE.GOV.UK



MET OFFICE, EXETER, UK



TOO 191603

[ncapps]

UKMET further north.

Nothing close to the GFS though.

[Alyono]

Ec still says no chance

[ncapps]

Don't trust the 12z GFS run bringing #Lane into Hawaii. Feedback vorticity in the Maui Channel (being amplified because of Lane's approach) is causing Lane's vort center to merge w/ falsely generated vort, resulting in an abrupt N turn into the Big Island w/o proper steering.

Found this analysis interesting on what the GFS is doing with its turn.

[Kingarabian]

Don't trust the 12z GFS run bringing #Lane into Hawaii. Feedback vorticity in the Maui Channel (being amplified because of Lane's approach) is causing Lane's vort center to merge w/ falsely generated vort, resulting in an abrupt N turn into the Big Island w/o proper steering.

Found this analysis interesting on what the GFS is doing with its turn.

No offense to them but that's not a good reason in to not believing the GFS. Maybe when Lane gets close to the Big Island then sure their reasoning could make sense, as models have a hard time resolving the Big Island's volcanoes.

The real difference here is around the 48 hours mark. Euro, with what looks to have is a weaker Lane initially, recurves the system gradually -- probably due to the trough being delayed or the system not strong enough initially to feel it sooner:


GFS with a stronger Lane initially, prior to the 48 hour mark is already stair stepping the system WNW:

[Kingarabian]

I think the CPHC will start to factor in the GFS soon:

 https://twitter.com/firebomb56/status/1031270190741303296




If they don't warn about a recurve towards Hawaii scenario, It could be a repeat of 1992 Iniki:

The Central Pacific Hurricane Center (CPHC) failed to issue tropical cyclone warnings and watches for the hurricane well in advance. For several days prior to the disaster, the CPHC and the news media forecast Iniki to remain well south of the island chain, with the only effect being some high surf conditions.

[NDG]

Hank Dolce
@tropicstopics
Don't trust the 12z GFS run bringing #Lane into Hawaii. Feedback vorticity in the Maui Channel (being amplified because of Lane's approach) is causing Lane's vort center to merge w/ falsely generated vort, resulting in an abrupt N turn into the Big Island w/o proper steering.

 https://twitter.com/tropicstopics/status/1031256082771894272

[cycloneye]

Hurricane Lane Discussion Number 20
NWS Central Pacific Hurricane Center Honolulu HI EP142018
1100 AM HST Sun Aug 19 2018

After lacking a distinct eye through the night, Lane regained this
feature near sunrise. However, after a few hours the eye began to
cloud over once again. Nevertheless, this system remains
well-organized this morning, with a concentric convective ring and
good outflow to the north through northeast. Outflow elsewhere is a
bit restricted, a result of the 17 kt of vertical shear noted by
UW-CIMSS. The latest subjective Dvorak intensity estimates range
from 6.5/127 kt (PHFO), to 5.0/90 kt (SAB). PTWC estimated 6.0/115
kt, while ADT from UW-CIMSS was 109 kt. This is quite a wide range,
possibly the result of the overnight loss and sudden reappearance of
a distinct eye right around analysis time. Initial intensity is set
at 110 kt for this advisory, representing a slight adjustment upward
using a blend of estimates.

Initial motion is 280/12 kt as Lane continues tracking just a shade
north of due west along the southern flank of a large subtropical
ridge. A frontal boundary far northwest of the main Hawaiian Islands
is forecast to move southeast as it weakens, eroding the western
portion of the ridge from day 3 and beyond. The spread in track
guidance continues to be rather wide beyond 48 hours as each model
handles this ridge erosion differently. However, consensus guidance
continues to be most helpful. The forecast track was nudged
slightly northward through 36 hours, due to initial motion, but
remains quite close to the previous track from 48 through 96 hours,
following TVCX consensus. Forecast points from 120 hours and beyond
lie between CMCI and ECMWF solutions. GFS remains near the right
edge of the guidance envelope, affecting all associated ensembles.
A NOAA G-IV aircraft plans to do a synoptic sampling in the
environment around the Hawaiian Islands and Lane later today. The
valuable data collected during this mission will be available to
better initialize the forecast models.

The intensity forecast follows the logic of the previous one, only
with a slightly higher initial intensity. Lane will remain over
27-28 degree C waters through the forecast period, with 10 to 20 kt
of vertical shear through most of its track, at least according to
the ECMWF-derived SHIPS run. Gradual weakening is forecast through
the forecast period, closely following FSSE and SHIPS. The
weakening curve lies just above IVCN consensus. Note that the latest
CIRA analysis of Ocean Heat Content shows a local maximum along the
track starting around day 3. If this verifies, Lane may remain
stronger than anticipated beyond day 3.

Lane is forecast to pass south of the main Hawaiian Islands
Wednesday and Thursday, potentially causing local impacts as it
tracks west-northwestward. Interests in these islands should watch
the progress of Lane closely, since long-range track and intensity
forecast errors can be large.


FORECAST POSITIONS AND MAX WINDS

INIT 19/2100Z 13.5N 144.6W 110 KT 125 MPH
12H 20/0600Z 13.8N 146.3W 105 KT 120 MPH
24H 20/1800Z 14.1N 148.4W 105 KT 120 MPH
36H 21/0600Z 14.3N 150.2W 100 KT 115 MPH
48H 21/1800Z 14.6N 152.0W 95 KT 110 MPH
72H 22/1800Z 15.2N 155.3W 85 KT 100 MPH
96H 23/1800Z 16.5N 158.4W 75 KT 85 MPH
120H 24/1800Z 18.2N 161.4W 70 KT 80 MPH

$$
Forecaster Powell

[Kingarabian]

Hank Dolce
@tropicstopics
Don't trust the 12z GFS run bringing #Lane into Hawaii. Feedback vorticity in the Maui Channel (being amplified because of Lane's approach) is causing Lane's vort center to merge w/ falsely generated vort, resulting in an abrupt N turn into the Big Island w/o proper steering.

[tweet]https://twitter.com/tropicstopics/status/1031256082771894272[tweet]

Ah I see what he means now. Regardless of hurricane season or not, that vorticity between the Big island and Maui has been there on the GFS ever since these high-res maps came out on Weatherbell a few years ago.

[Kingarabian]

18z GFS through 24 hours:

[Kingarabian]

GFS trend through 30 hours:

[Alyono]

may be seeing a slight but temporary increase in shear that has caused this to degrade a bit recently. Still, we should see some intensification into Tuesday

[AJC3]

may be seeing a slight but temporary increase in shear that has caused this to degrade a bit recently. Still, we should see some intensification into Tuesday

Looks like that shear may have punched some dry air into Lane's circulation. It spat out a pretty large arcus cloud not too long ago.

[Kingarabian]

Here's the difference between the Euro and the GFS:

[Kingarabian]

18z GFS hours 24-72:

[Yellow Evan]

Further north so far. Through 78 hours.

[Yellow Evan]

Again into the Big Island.