2020 tropical storm / hurricane thread

[HereOnThePrimalEdge]

The GFS (NOAA) forecast shows the storm tracking north between BI and Maui. The ECMWF (European) model shows it headed straight towards Puna.

I just checked the latest update for ECMWF, and it’s track has moved north since this morning.  It shows the eye missing Big Island entirely, and grazing Kaupo on the south coast of Maui.  All islands are still within the cone.  

I’ve been following ECMWF for a few years now since a Punaweb member referred to it as the gold standard.  I believe it was Chunkster?  I’ve found it has a good track record.  

https://www.wunderground.com/wundermap?lat=19.7&lon=-155.1&wxstn=0&satellite=1&hur=1
On right side of page scroll down, click Model Data.

[terracore]

How do you make the toggle "stick" ? The path doesn't change for me if I select ECMWF or GFS. When I use Windy it shows much different paths.

The cyclocane spag models do show most of the models pointing towards Maui.

[HereOnThePrimalEdge]

How do you make the toggle "stick" ? The path doesn't change for me if I select ECMWF or GFS.

Model Data loads ECMWF by default.  I’ve never been able to get it to switch over to GFS.
Does Windy show the projected hurricane path?

[ChunksterK]

" . . . referred to it as the gold standard. I believe it was Chunkster?"

Yes, that was me. One of today's official bulletins actually said that the forecasters had moved the expected track away from the average of the models "in deference to the ECMWF." Hurricane expert Dr. Jeff Masters has also spoken highly of it in his published remarks.

However promising for Puna the current forecast is, I don't take any chances with these things. We have bought gas for the generator and took down four wobbly ohia trees near the house and power lines today. (BTW, got a great chainsaw at Ace in Keaau for $239 that our friend who works at Home Depot says is better than what they have for the price.) I have the plywood sheets ready for the picture windows, but I'm holding off on screwing them on. The Frau has laid in a good supply of food and she will fill our emergency water containers tomorrow. Speaking of Frau Chunkster, things stay pretty much tied down all the time with her on the premises, so there isn't much of that to do. I really hope it's all for nothing, though. We don't need that kind of excitement.

[Punaperson]

As someone who has really poor internet connectivity, and cell phone reception only at the top of my driveway, I want to thank all of you who post information on this thread. It is very helpful to have the information in words for someone who has problems downloading any type of video/satellite imagery. It is very much appreciated.

[terracore]

Still one to keep an eye on, but the latest forecast shows it going either north of us, or well north of us:

000
WTPA42 PHFO 241438
TCDCP2

Hurricane Douglas Discussion Number 17
NWS Central Pacific Hurricane Center Honolulu HI EP082020
500 AM HST Fri Jul 24 2020

Douglas remains a powerful hurricane early this morning, although
the satellite presentation has degraded quite a bit since last
evening, with eye of the tropical cyclone now nearly completely
cloud filled. The latest current intensity estimates from the
satellite agencies came in with 5.5 (102 knots) from PHFO and SAB,
5.0 (90 knots) from JTWC, while ADT came in at 5.9 (112 knots).
Taking a blend of the estimates above and accounting for recent
satellite trends, the intensity with this advisory will be lowered
to 105 knots. Douglas continues to move rapidly to the
west-northwest, with an initial motion set at 295/16 knots.

Hurricane Douglas recently moved over slightly cooler sea surface
temperatures (SSTs) of around 78F, and this seems to have been
enough to lead to the weakening seen in satellite imagery. Despite
relatively low vertical wind shear values forecast to affect the
tropical cyclone during the next couple days, SSTs will remain
unfavorable for intensification. The official intensity forecast
calls for steady weakening during the next couple days as Douglas
nears Hawaii, with the cyclone expected to be a 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.
Depending on the amount of interaction with the high terrain of the
Big Island and Maui, the tropical cyclone could weaken faster than
indicated in the official forecast, which 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 Sunday through Monday, before exiting to the west
of the state. The official forecast continues to hug the southern
end of the guidance envelope out of respect for the ECMWF, but if
model trends continue, this track may need to be adjusted further
northward in future advisory packages.

Based on the latest intensity and track forecasts, Hurricane or
Tropical Storm watches will likely be required for portions of the
eastern end of the state (Big Island and the Maui County Islands)
later today.


Key Messages:

1. Douglas is expected to move near or over portions of the main
Hawaiian Islands Sunday through Monday, and there is an increasing
chance that strong winds, dangerous surf, and heavy rainfall could
affect portions of the state beginning late Saturday night or
Sunday. Interests on the Hawaiian Islands should continue to monitor
the progress of Douglas and the official forecasts as they evolve
during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 24/1500Z 16.4N 141.9W 105 KT 120 MPH
12H 25/0000Z 17.4N 144.3W 95 KT 110 MPH
24H 25/1200Z 18.6N 147.5W 85 KT 100 MPH
36H 26/0000Z 19.6N 150.4W 75 KT 85 MPH
48H 26/1200Z 20.5N 153.4W 70 KT 80 MPH
60H 27/0000Z 21.1N 156.1W 65 KT 75 MPH
72H 27/1200Z 21.7N 158.8W 55 KT 65 MPH
96H 28/1200Z 22.5N 165.0W 50 KT 60 MPH
120H 29/1200Z 23.5N 171.5W 45 KT 50 MPH

$$
Forecaster Jelsema

[HereOnThePrimalEdge]

Thanks for the update terracore.
The projected path for Douglas now takes it slightly north of Maui, off the coast from Haiku, Paia, etc.
But definitely keep an eye on it.  Even it the storm passes that far north of Puna, high wind and heavy rain could affect us due to its size.  Here’s a satellite photo of the islands with Douglas closing in from the east.  On its current track Puna is within the outer bands, and we are still in the cone:

Hurricane Douglas Photo

[terracore]

000
WTPA22 PHFO 242038
TCMCP2

HURRICANE DOUGLAS FORECAST/ADVISORY NUMBER 18
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP082020
2100 UTC FRI JUL 24 2020

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

A HURRICANE WATCH HAS BEEN ISSUED FOR THE BIG ISLAND OF HAWAII AND
FOR MAUI COUNTY...INCLUDING MAUI...LANAI...MOLOKAI AND KAHOOLAWE.

SUMMARY OF WATCHES AND WARNING IN EFFECT...

A HURRICANE WATCH IS IN EFFECT FOR...
* BIG ISLAND OF HAWAII
* MAUI COUNTY...INCLUDING MAUI...LANAI...MOLOKAI AND KAHOOLAWE

A HURRICANE WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE
WITHIN THE WATCH AREA...IN THIS CASE WITHIN 36 TO 48 HOURS.

INTERESTS ELSEWHERE IN THE HAWAIIAN ISLANDS SHOULD MONITOR
THE PROGRESS OF THIS SYSTEM.

HURRICANE CENTER LOCATED NEAR 17.0N 143.5W AT 24/2100Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 16 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 967 MB
EYE DIAMETER 15 NM
MAX SUSTAINED WINDS 100 KT WITH GUSTS TO 120 KT.
64 KT....... 20NE 20SE 10SW 20NW.
50 KT....... 60NE 50SE 30SW 60NW.
34 KT.......100NE 80SE 50SW 100NW.
12 FT SEAS..270NE 180SE 180SW 240NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 17.0N 143.5W AT 24/2100Z
AT 24/1800Z CENTER WAS LOCATED NEAR 16.7N 142.7W

FORECAST VALID 25/0600Z 17.9N 145.9W
MAX WIND 90 KT...GUSTS 110 KT.
64 KT... 20NE 20SE 10SW 20NW.
50 KT... 60NE 50SE 30SW 60NW.
34 KT...100NE 80SE 50SW 100NW.

FORECAST VALID 25/1800Z 19.1N 149.0W
MAX WIND 80 KT...GUSTS 100 KT.
64 KT... 20NE 20SE 10SW 20NW.
50 KT... 60NE 50SE 30SW 60NW.
34 KT...120NE 90SE 50SW 120NW.

FORECAST VALID 26/0600Z 20.0N 151.9W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 10NE 10SE 0SW 10NW.
50 KT... 50NE 40SE 30SW 50NW.
34 KT...110NE 80SE 70SW 110NW.

FORECAST VALID 26/1800Z 20.8N 154.7W
MAX WIND 65 KT...GUSTS 80 KT.
64 KT... 10NE 0SE 0SW 10NW.
50 KT... 50NE 40SE 20SW 50NW.
34 KT...110NE 80SE 50SW 110NW.

FORECAST VALID 27/0600Z 21.3N 157.5W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 40NE 30SE 10SW 40NW.
34 KT...100NE 70SE 50SW 100NW.

FORECAST VALID 27/1800Z 21.8N 160.4W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 10SE 0SW 30NW.
34 KT... 90NE 60SE 40SW 90NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 28/1800Z 23.0N 166.7W
MAX WIND 50 KT...GUSTS 60 KT.

OUTLOOK VALID 29/1800Z 24.2N 172.8W
MAX WIND 45 KT...GUSTS 55 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 17.0N 143.5W

INTERMEDIATE PUBLIC ADVISORY...WTNT32 PHFO/HFOTCPCP2...AT 25/0000Z

NEXT ADVISORY AT 25/0300Z

$$
FORECASTER BIRCHARD

---

670
WTPA42 PHFO 242057
TCDCP2

Hurricane Douglas Discussion Number 18
NWS Central Pacific Hurricane Center Honolulu HI EP082020
1100 AM HST Fri Jul 24 2020

After a period of rapid intensification yesterday, Douglas'
satellite appearance has degraded somewhat over the past 12 hours
or so. However, a fairly large but ragged and cloud-filled eye is
still noted in conventional satellite images. Subjective Dvorak
current intensity estimates were 5.5/105 kt from SAB and HFO, 5.1/93
kt from ADT, while SATCON estimated was near 100 kt. A blend of
these led to an initial intensity estimate of 100 kt for this
advisory.

The initial motion for this advisory is a steady 295/16 kt, as
Douglas continues to be steered by a robust mid-level ridge
centered to the northeast. As Douglas draws closer to the main
Hawaiian Islands, it will be reaching the western periphery of the
ridge, and model guidance indicates that this will allow the cyclone
to gain some latitude over the next 2 days, with some reduction in
forward speed. Thereafter, the mid-level ridge is forecast to
subtly build to the north of Douglas, potentially inducing a turn
toward the west, with some increase in forward speed. The updated
track forecast is nearly identical to the previous, lies along the
southern side of the guidance, and is very close to ECMWF guidance
that has been performing well thus far with Douglas. On the
forecast track, Douglas will move dangerously close to the Hawaiian
Islands. A Hurricane Watch has been issued for Maui County and
the Big Island, and may need to be expanded to additional areas
later today or tonight.

The intensity forecast continues to anticipate a slow but steady
weakening of the cyclone as it traverses cooler waters, and later
encounters increased vertical wind shear as waters warm somewhat
near the Hawaiian Islands. Little overall change to the ongoing
forecast was made, and the updated forecast closely follows the
GFS- and ECMWF-based SHIPS guidance, and is close to the intensity
consensus IVCN.

Key Messages

1. Douglas will continue to quickly approach the main Hawaiian
Islands, passing dangerously close to, or over, the islands on
Sunday. Dangerous, life-threatening surf will arrive ahead of the
hurricane on Saturday. Heavy rain and increasing winds are possible
on the Big Island starting Saturday night, and could quickly spread
up the chain Sunday.

2. It is important not to focus on the exact forecast track. Due
to Douglas' angle of approach to Hawaii, any small changes in the
track could lead to significant differences in where the worst
weather will occur.

3. Wind gusts near mountains and higher terrain can be
significantly enhanced as they blow downslope.


FORECAST POSITIONS AND MAX WINDS

INIT 24/2100Z 17.0N 143.5W 100 KT 115 MPH
12H 25/0600Z 17.9N 145.9W 90 KT 105 MPH
24H 25/1800Z 19.1N 149.0W 80 KT 90 MPH
36H 26/0600Z 20.0N 151.9W 70 KT 80 MPH
48H 26/1800Z 20.8N 154.7W 65 KT 75 MPH
60H 27/0600Z 21.3N 157.5W 60 KT 70 MPH
72H 27/1800Z 21.8N 160.4W 55 KT 65 MPH
96H 28/1800Z 23.0N 166.7W 50 KT 60 MPH
120H 29/1800Z 24.2N 172.8W 45 KT 50 MPH

$$
Forecaster Birchard

[1@3_aBc]

Not sure if it's just personal anticipation, but today feels like a storm is closing in.
It is due tomorrow night, probably expected.
I still think of it as being 2 days away.

About to leave to drop off garbage and pickup water and extra,
just charged up all batteries for tools in case of needing to make repairs during the storm, or an extended  power loss.
And, just found our Sun Shower bag. It kept us in showers for a week after Iselle.

[alaskyn66]

Looking kinda hurricaney..
https://rammb-slider.cira.colostate.edu/?sat=goes-17&z=2&im=12&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=full_disk&p%5B0%5D=geocolor&x=7224&y=6816