EPAC: DOUGLAS - Remnants

[Kingarabian]

Kingarabian stay safe there.

Thank you, you too! The Atlantic is beasting right now.

Yes and one may be a big problem for me next week.

Thoughts and prayers to you guys. Be proactive! I prepped for this storm Monday and Tuesday fortunately.

[Flyinman]

Well, I can say I never thought I would post in this part of the Forum.

However, I’m currently on the South Shore of Kauai and following diligently. I appreciate all of your information and assuming I am able, I will give reports.

[Kingarabian]

Well, I can say I never thought I would post in this part of the Forum.

However, I’m currently on the South Shore of Kauai and following diligently. I appreciate all of your information and assuming I am able, I will give reports.

Welcome!

[Chris90]

2-3 hours ago I was guesstimating 105kts/963mb. I think it might still be close there. Maybe recon will find something like 100kts/966mb now.

[Kingarabian]

Looks like TS force winds extend more than the CPHCs estimate.

[CrazyC83]

So far, Recon supports at least 95 kt. They may leave it at 100 kt until the whole thing is sampled.

[Kingarabian]

So far, Recon supports at least 95 kt. They may leave it at 100 kt until the whole thing is sampled.

Since the storm is moving west I'm assuming the strongest winds would be in the NE quad right?

[CrazyC83]

So far, Recon supports at least 95 kt. They may leave it at 100 kt until the whole thing is sampled.

Since the storm is moving west I'm assuming the strongest winds would be in the NE quad right?

NW quad is the right-front quadrant in a storm moving west.

[Mauistorms]

So far, Recon supports at least 95 kt. They may leave it at 100 kt until the whole thing is sampled.

Since the storm is moving west I'm assuming the strongest winds would be in the NE quad right?

If its moving due west I thought the strongest would be the north west quad..but i'm very new at this.

[Kingarabian]

So far, Recon supports at least 95 kt. They may leave it at 100 kt until the whole thing is sampled.

Since the storm is moving west I'm assuming the strongest winds would be in the NE quad right?

NW quad is the right-front quadrant in a storm moving west.

Okay thanks makes sense.

[Kingarabian]

Surprised winds are that high with this presentation.


Clearly feeling the effects of cooler waters. Models do attempt to restrengthen it as it nears Hawaii but shear is also expected to pick up.

[TheStormExpert]

Surprised winds are that high with this presentation.
https://i.imgur.com/woTrV7B.png

Clearly feeling the effects of cooler waters. Models do attempt to restrengthen it as it nears Hawaii but shear is also expected to pick up.

Yeah I doubt Douglas is still a major. Likely only a Cat.1 or low-end Cat.2 looking at that presentation.

[Chris90]

I think 100kts is generous, the highest gust an eyewall dropsonde measured on the way down was 105kts. I think 85-90kts is more reasonable. It's degrading decently quick right now.

Any kind of maintenance near this strength though is trouble. I'd like to see some continued degradation of the structure and convection, Hawaii doesn't need anything like this. I think chances for a hurricane strike are decreasing though as long as Douglas continues with his weakening.

[Astromanía]

Waters are hot just around Hawaii tho, I don't know how much shear will be there when Douglas reach the islands, but it's the only thing it can save us for a potential hurricane landfall

[NXStumpy_Robothing]

SFMR readings and other recon reading still support an intensity of 90-95kt with a minimum central pressure of around 972-975mb. The degradation of its appearance on satellite imagery is due to two things - the EWRC that recon says is occurring, and the coldest SSTs it's having to traverse through between now and Hawaii.

Unfortunately, a weaker system now enhances the possibility of a direct impact on Hawaii later, as a stronger system now would be able to push further north and clear the Hawaiian islands. Let's hope that shear rips this thing apart before it reaches the Big Island.

[Bocadude85]

Waters are hot just around Hawaii tho, I don't know how much shear will be there when Douglas reach the islands, but it's the only thing it can save us for a potential hurricane landfall

Things are looking slightly better tonight for us in the islands, seems Douglas may pass just to our north. Of course we will still get some bad weather but we may avoid the worst of the winds.

[Kingarabian]

SFMR readings and other recon reading still support an intensity of 90-95kt with a minimum central pressure of around 972-975mb. The degradation of its appearance on satellite imagery is due to two things - the EWRC that recon says is occurring, and the coldest SSTs it's having to traverse through between now and Hawaii.

Unfortunately, a weaker system now enhances the possibility of a direct impact on Hawaii later, as a stronger system now would be able to push further north and clear the Hawaiian islands. Let's hope that shear rips this thing apart before it reaches the Big Island.

I agree. It makes sense why there's so much discrepancy.

GFS/HWRF/HMON - The models that keep this a deep vortex are the ones that have Douglas climb and clear the islands completely.
UKMET/Euro - The models with a moderate system don't lift it north as aggressively and eventually hit Oahu and Kauai.
CMC/ICON/GEFS/EPS/GEPS -The models and ensembles keep it a weak tropical storm and crash it into the Big Island or Maui.

The EPS weaken it to a TS then restrengthen it on approach. It all comes down to what Douglas wants to and is able to do. Current trends say that Douglas will be a shell of himself upon approach and that Hawaiian shear waiting for him is nasty.

[Kingarabian]

Very close to clearing Hawaii now. But If I was in Maui I would watch this very closely... Good calls by the CPHC to issue a TS Warning for both Maui and the Big Island.



This CPHC forecast is heavily reliant on Douglas being a hurricane in the next 24 hours with most ensemble members do not show. But the CPHC did very well with Hurricane Lane's track.

[Bocadude85]

Perhaps the best bet is a 40-50kts landfall on Maui or Oahu? A compromise between the stronger operational globals and the ensembles.

[Kingarabian]

Hurricane Douglas Discussion Number 20
NWS Central Pacific Hurricane Center Honolulu HI EP082020
1100 PM HST Fri Jul 24 2020

Douglas remains a powerful hurricane this evening as confirmed by
the U.S. Air Force 53rd Weather Reconnaissance Squadron. The
Hurricane Hunters found maximum flight level winds of 108 knots (97
knots with appropriate wind reduction factor to the surface from
the 700 mb flight level) and SFMR winds of 93 knots. Based on
these data and recent trends showing a degraded satellite
presentation, the initial intensity for this advisory will be
lowered to 95 knots. Douglas continues to move rapidly to the west-
northwest, with an initial motion set at 295/16 knots.

Despite relatively low vertical wind shear values forecast to
affect the tropical cyclone during the next day or so, SSTs will
remain below 26C. As a result, the official intensity forecast
calls for slow but steady weakening during the next couple days as
Douglas nears Hawaii, with the cyclone expected to be a minimal
category 1 hurricane or strong tropical storm approaching the
eastern end of the state late Saturday night or Sunday. Continued
weakening is then forecast as Douglas tracks westward over or near
the other main Hawaiian islands and west of the state early next
week. The official intensity forecast has changed very
little from the previous advisory, and generally follows a blend of
the corrected consensus and statistical model guidance.

Douglas is forecast to move rapidly off to the west-northwest
during the next couple days toward a weakness in the sub-tropical
ridge north of the Hawaiian islands. The subtropical ridge is
forecast to strengthen north of the state over the weekend, and
this should steer the tropical cyclone westward over or very near
the Hawaiian Islands late Saturday night through Sunday
night, before exiting to the west of the state early next week. The
official track forecast is virtually identical to the
previous advisory, and continues to hug the southern end of the
guidance envelope. This track is roughly in between the corrected
consensus guidance HCCA and the ECMWF and GFS ensemble mean tracks.

Based on the latest intensity and track forecast, Tropical Storm
Warnings have been issued for Hawaii County and Maui County. A
Hurricane Watch remains in effect for Hawaii County, Maui County and
Oahu. A Hurricane or Tropical Storm Warning may be required for Oahu
on Saturday. A Hurricane or Tropical Storm Watch may be required
for Kauai County on Saturday.

Key Messages

1. Douglas continues to approach the main Hawaiian Islands,
potentially passing dangerously close to, or over, the islands
Saturday night through Sunday night. The close passage of Douglas
brings a triple threat of hazards, including but not limited to
damaging winds, flooding rainfall, and dangerously high surf,
especially along east facing shores.

2. It is vital that you do not focus on the exact forecast track or
intensity of Douglas, and remain prepared for changes to the
forecast. Due to Douglas' angle of approach to the islands, any
small changes in the track could lead to significant differences in
where the worst weather occurs. Even if the center remains
offshore, severe impacts could still be realized over the islands,
as they extend well away from the center.

3. Terrain effects can cause strong localized acceleration of
the wind through gaps and where winds blow downslope. These
acceleration areas will shift with time as Douglas passes near the
islands. Winds will also be stronger at the upper floors of
high rise buildings.


FORECAST POSITIONS AND MAX WINDS

INIT 25/0900Z 18.5N 146.7W 95 KT 110 MPH
12H 25/1800Z 19.3N 149.0W 85 KT 100 MPH
24H 26/0600Z 20.3N 151.9W 75 KT 85 MPH
36H 26/1800Z 21.1N 154.8W 70 KT 80 MPH
48H 27/0600Z 21.8N 157.7W 65 KT 75 MPH
60H 27/1800Z 22.4N 160.8W 60 KT 70 MPH
72H 28/0600Z 22.9N 164.1W 55 KT 65 MPH
96H 29/0600Z 24.0N 171.0W 45 KT 50 MPH
120H 30/0600Z 25.0N 177.5W 35 KT 40 MPH

$$
Forecaster Jelsema