CPAC: ISELLE - Post-Tropical

[Alyono]

if the shear gets very low, this could become annular, which may allow it to better handle the cooler SSTs.

We cannot rule out a full hurricane in Hawaii. GFDL and HWRF both have this as a hurricane approaching Hawaii

[Yellow Evan]

Hmmm I wonder how hard this will hit Oahu.

Too early too tell for sure, but I think it is more likely to hit the Big Island than Oahu.

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[Yellow Evan]

if the shear gets very low, this could become annular, which may allow it to better handle the cooler SSTs.

I was thinking that myself. According to the SHIPS, shear is suppose to get low. This is starting to remind me of Flossie 07.

[Yellow Evan]

We cannot rule out a full hurricane in Hawaii. GFDL and HWRF both have this as a hurricane approaching Hawaii

Here is the HWRF, which brings it and 97E close as borderline hurricane.



Giving the strong ridge, troughing over Gulf of Alaska, this does not favor Hawaii landfalls, troughing near the dateline does.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[somethingfunny]

The GFS and CMC still bring this right into Hawaii as a strong system (not as strong as they depict "Julio" will be, but still stronger than anything Hawaii has seen in a couple of decades). The ECM was a holdout, sending a much weaker low, likely a remnant, to the south of Hawaii. It's trended closer on the 12z run.

Iselle approaching, August 7th (12z Euro)


A glancing blow from a rapidly weakening system, August 8th. (12z Euro)

[Alyono]

the EC is weak on that run because it takes Iselle directly across the 13,000 foot mountains of the Big Island

[Yellow Evan]

the EC is weak on that run because it takes Iselle directly across the 13,000 foot mountains of the Big Island

That tears up systems easily and sometimes causes them to make a wobble S (in Flossie 07's case) or N (in Flossie 13's case).


The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Yellow Evan]

So close to a major.

EP, 09, 2014080300, , BEST, 0, 151N, 1306W, 95, 968, HU, 64, NEQ, 20, 15, 10, 20, 1009, 200, 15, 0, 0, E, 0, , 0, 0, ISELLE, D,

[supercane4867]

Eye became less defined a bit due to blow up of convection

[Yellow Evan]

If the eye becomes more defined, I think we could have a major at 03z.

[CrazyC83]

TXPZ24 KNES 030020
TCSENP

A. 09E (ISELLE)

B. 03/0000Z

C. 15.1N

D. 130.6W

E. ONE/GOES-W

F. T5.0/5.0/D1.0/24HRS

G. IR/EIR/VIS

H. REMARKS...DT OF 5.0 IS BASED ON MG EYE SURROUNDED BY B EMBEDDED IN
LG. NO EYE ADJUSTMENT. MET IS 5.5 AND PT IS 5.0. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...RAMIREZ
`

[CrazyC83]

Based on all that data, I would go with 95 kt for the intensity. Some 5.5s and 6.0s but not terribly convincing. I'd need to see a super-high ADT to go up to a major at 8 pm.

[Yellow Evan]

Based on all that data, I would go with 95 kt for the intensity. Some 5.5s and 6.0s but not terribly convincing. I'd need to see a super-high ADT to go up to a major at 8 pm.

The ATCF agrees with you.

[Yellow Evan]

bye bye eye

[Alyono]

with the eye less defined, I'd leave the winds at 85 kts

[bahamaswx]

Beautiful storm.

[Yellow Evan]

with the eye less defined, I'd leave the winds at 85 kts

Ignoring TAFB, the data does not support that. I think they'll go with 90 or 95 knts.

[Alyono]

The Dvoraks were made with a visible eye. Make them now, and you wont be getting 5.0 or 5.5

[Yellow Evan]

The Dvoraks were made with a visible eye. Make them now, and you wont be getting 5.0 or 5.5

Dennis 99 in the ATL was still a borderline Cat 2 w/o any visible eye IIRC.

Ditto with Celia 10.

AFAIK there is still an eye on microwave.

[cycloneye]

HURRICANE ISELLE DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP092014
800 PM PDT SAT AUG 02 2014

Iselle is still strengthening. The central dense overcast has
become more symmetric since the last advisory, with cloud top
temperatures cooling slightly. The eye was also becoming better
defined but has recently become obscured by overshooting convective
tops. Satellite intensity estimates from TAFB and SAB at 0000 UTC
were T5.0/90 kt and UW-CIMSS ADT values are at 5.4/99 kt. These
data support increasing the initial intensity estimate to 95 kt.

The initial motion estimate is just north of due west or 275/09. A
subtropical ridge north of Iselle should allow the current motion to
persist in the short term. However, a mid-latitude trough digging
roughly along 130W should temporarily weaken the ridge during the
next day or two, causing the forward speed of Iselle to nominally
decrease. When the subtropical ridge rebuilds over the central
Pacific after day 3, Iselle should move on a westward and then
west-northwestward heading a faster forward speed. The track
guidance is in relatively good agreement throughout the forecast
period, and the forecast track is adjusted only slightly to the
south in the direction of the multi-model consensus TVCE.

It is difficult to see Iselle strengthening much further. Although
northeasterly shear over the cyclone is forecast to decrease during
the next couple of days, the thermodynamic contribution from the
environment should gradually become less favorable. This would
suggest that some additional intensification is possible in the very
short term, followed by slow weakening after 24 hours. The one
caveat would be that with little shear and marginally favorable
thermodynamic conditions Iselle could evolve into an annular
hurricane and maintain a somewhat higher intensity during the next
few days. By days 4 and 5, even less favorable thermodynamic
factors and an uptick in south-southwesterly shear should result in
quicker weakening as Iselle approaches the Hawaiian Islands. The
intensity forecast is somewhat higher than the previous one in the
short term and represents a blend of the multi-model consensus and
FSU Superensemble output.


FORECAST POSITIONS AND MAX WINDS

INIT 03/0300Z 15.2N 131.0W 95 KT 110 MPH
12H 03/1200Z 15.4N 132.6W 100 KT 115 MPH
24H 04/0000Z 15.6N 134.6W 95 KT 110 MPH
36H 04/1200Z 15.7N 136.4W 90 KT 105 MPH
48H 05/0000Z 15.8N 137.9W 85 KT 100 MPH
72H 06/0000Z 15.9N 141.2W 75 KT 85 MPH
96H 07/0000Z 16.6N 146.2W 60 KT 70 MPH
120H 08/0000Z 17.8N 152.4W 45 KT 50 MPH

$$
Forecaster Kimberlain