CPAC: ISELLE - Post-Tropical

[Yellow Evan]

[Alyono]

I do see some light shear to the west of this. So it shouldn't remain an annular cat 4 monster until it goes through Hawaii

The bad news is, the EC shows this as a hurricane at landfall on the Big Island and brings near hurricane winds (about 60 kts) into Maui

that is, with an initialization around a minimal hurricane

[hurricanes1234]

Very impressive!!!! A Category 4? Oh my gosh! And look at the perfect ring of convection around the eye now!!!

[wxman57]

There are no records of a hurricane ever striking Hawaii from the E to ESE. Iniki (1992) and Dot (1959) struck from the S and SSE. I doubt that either Iselle or Julio will survive to strike the Hawaiian islands as a hurricane. Maybe a 40-45 kt TS and rapidly weakening at landfall.

[Yellow Evan]

I do see some light shear to the west of this. So it shouldn't remain an annular cat 4 monster until it goes through Hawaii

The bad news is, the EC shows this as a hurricane at landfall on the Big Island and brings near hurricane winds (about 60 kts) into Maui

that is, with an initialization around a minimal hurricane

According to the SHIPS. the "great Hawaiian shear" will kick in a little under four days.

[Yellow Evan]

GFS on board with a weak TS near landfall.



HWRF has it hitting as a minimal hurricane.



Ditto with the GFDL.

[euro6208]

Nice category 4 hurricane...I can't see this making landfall as a hurricane though, dry air or shear will likely play a major role in this storm's life...

[Yellow Evan]

There are no records of a hurricane ever striking Hawaii from the E to ESE. Iniki (1992) and Dot (1959) struck from the S and SSE. I doubt that either Iselle or Julio will survive to strike the Hawaiian islands as a hurricane. Maybe a 40-45 kt TS and rapidly weakening at landfall.

Iwa also struck the islands (in that hurricane-force winds occurred over the islands) w/o making landfall though that came from the SW.

Hiki 50 came from the E to pass through the islands as a high end TS.

[euro6208]

As for ALL wpac,cpac,and cpac storms, it's kinda sad that a system in the atlantic gets more attention...even though weaker. I guess maybe it's the location of a storm since many here are based in the U.S but still only 15 pages vs over 60 for bertha? literally no mention of this in any news outlet but bertha is mentioned...

Where are these people coming from when the ATL is active with a storm but disappear when the ATL is dead?

[Yellow Evan]

As for ALL wpac,cpac,and cpac storms, it's kinda sad that a system in the atlantic gets more attention...even though weaker. I guess maybe it's the location of a storm since many here are based in the U.S but still only 15 pages vs over 60 for bertha? literally no mention of this in any news outlet but bertha is mentioned...

Where are these people coming from when the ATL is active with a storm but disappear when the ATL is dead?

Agreed, given that this is a US threat and a Cay 4, but EPAC has gotten much more attention the past few years, and especially this year.

[Yellow Evan]

Please god no

[euro6208]

As for ALL wpac,cpac,and cpac storms, it's kinda sad that a system in the atlantic gets more attention...even though weaker. I guess maybe it's the location of a storm since many here are based in the U.S but still only 15 pages vs over 60 for bertha? literally no mention of this in any news outlet but bertha is mentioned...

Where are these people coming from when the ATL is active with a storm but disappear when the ATL is dead?

Agreed, given that this is a US threat and a Cay 4, but EPAC has gotten much more attention the past few years, and especially this year.

The EPAC has Hawaii and and WPAC has Guam, U.S state and territory...interesting that low interest...

[euro6208]

[Macrocane]

Beautiful hurricane, almost perfect annular.

[CrazyC83]

Any chance this could reach or approach Cat 5 intensity?

[Yellow Evan]

Any chance this could reach or approach Cat 5 intensity?

It's crossed my mind, but I highly doubt it.

[galaxy401]

HURRICANE ISELLE DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092014
800 AM PDT MON AUG 04 2014

Iselle continues to intensify and has reached category 4 strength.
Convective cloud tops as cold as -75C surround the eye, which has
grown to a diameter of 25-30 n mi. Dvorak estimates were a
consensus T6.0/115 kt from TAFB and SAB at 1200 UTC, and the
objective UW-CIMSS ADT has crept up to T6.3/122 kt since that time.
Based on these estimates, the initial intensity is raised to 120
kt. Vertical shear is expected to remain light for the next 24 hours
or so while Iselle moves over gradually cooler SSTs. Since Iselle
has some characteristics of an annular hurricane, it is likely to
change little in intensity during the next day or so, and even when
it begins to weaken, the trend should be gradual. On day 3, Iselle
will be moving over the coldest water (between 25 and 26C) along
its forecast track, and vertical shear is expected to increase to
about 15-20 kt. Both factors should induce quicker weakening at
that time. The NHC intensity forecast remains above all of the
typically used intensity models during the first 24 hours, is very
close to the consensus on days 2-3, and then more closely follows
the decay shown by the LGEM model toward the latter part of the
forecast period.

Iselle's initial motion is 275/9 kt. A mid- to upper-level
shortwave trough is swinging by to the north of the hurricane and
eroding the subtropical ridge, which should cause Iselle to slow
down a bit during the next 24 hours. After that time, a mid-level
high is forecast to develop and strengthen between Hawaii and
California, forcing Iselle to turn west-northwestward and accelerate
as it approaches and moves near the Hawaiian Islands. The track
guidance has been stable and tightly clustered for a few cycles now,
and no significant changes were required to the NHC track forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 04/1500Z 16.2N 136.5W 120 KT 140 MPH
12H 05/0000Z 16.2N 137.7W 115 KT 135 MPH
24H 05/1200Z 16.3N 139.2W 110 KT 125 MPH
36H 06/0000Z 16.8N 141.4W 95 KT 110 MPH
48H 06/1200Z 17.4N 144.2W 80 KT 90 MPH
72H 07/1200Z 19.0N 150.5W 60 KT 70 MPH...EAST OF HAWAII
96H 08/1200Z 21.0N 157.0W 50 KT 60 MPH...NEAR HAWAII
120H 09/1200Z 22.5N 162.0W 45 KT 50 MPH...WEST OF HAWAII

$$
Forecaster Berg

[CrazyC83]

I'd say the later stage intensities are especially uncertain. Mixed signals for sure.

[Yellow Evan]

Iselle is truly mindblowing. Hopefully it weakens by the time it reaches Hawaii.

[Kingarabian]

As I suspected, category 4. Can't under estimate that shear though.