EPAC: DOUGLAS - Remnants

[Kingarabian]

Why is ADT being so bad today.

[Kingarabian]

ADT should be thrown out if it does not adjust correctly in the next 2 hours.

Eyewall is currently pretty strong, strong enough to be reflected on the pretty low resolution ATMS:

[Kingarabian]

 https://twitter.com/wxmann/status/1286049219393064960

[aspen]

Convection is on the shallow side, but overall Douglas still looks great. I think this is around 90-100 kt right now. Diurnal max is coming in a few hours and could help the system strengthen some more.

[Highteeld]

Probably near 100 knots now. Eye is ragged, but symmetrizing

[NXStumpy_Robothing]

100kt is probably a smidge generous for Douglas. Based upon current appearance and duration of the pulsing hot towers (and the warming of the cloud tops around the center), I'd argue that this system is currently somewhere between 85 and 95kt.

Keep in mind, the official intensity (issued 3 hours ago) keeps it at 70kt, and the NHC is one of the most reliable weather agencies (if not the most reliable agency) for tropical cyclones. We shouldn't be too trigger-happy regarding intensities at the current time.

[Kingarabian]

:uarrow: 100kt is probably a smidge generous for Douglas. Based upon current appearance and duration of the pulsing hot towers (and the warming of the cloud tops around the center), I'd argue that this system is currently somewhere between 85 and 95kt.

Keep in mind, the official intensity (issued 3 hours ago) keeps it at 70kt, and the NHC is one of the most reliable weather agencies (if not the most reliable agency) for tropical cyclones. We shouldn't be too trigger-happy regarding intensities at the current time.

I love and respect the NHC. And I don't disagree that they will go on the low end side, considering their last advisory. However to me, this is clearly a 100kt major hurricane. A strong eyewall is present on MW imagery.

[Astromanía]

https://i.imgur.com/yXqi4mQ.png

Hurricane Douglas Discussion Number 10
NWS National Hurricane Center Miami FL EP082020
1100 AM HST Wed Jul 22 2020

Douglas's structure has continued to improve, with a more
well-defined eye becoming apparent in visible and microwave
satellite images. Subjective Dvorak intensity estimates from TAFB
and SAB range from T4.0/65 kt and T5.0/90 kt, while the latest
UW-CIMSS ADT is 4.0. Douglas's initial intensity is therefore
raised to 70 kt as a blend of the satellite estimates.

The hurricane has begun to gain some latitude, and the initial
motion is just north of due west, or 275/14 kt. The track forecast
reasoning has not changed since earlier this morning, with a
persistent mid-tropospheric ridge to Douglas's north expected to be
the main driving force for the entire 5-day forecast period.
Douglas is forecast to turn west-northwestward by this evening, and
then maintain that heading with some increase in forward speed
through day 4 as it approaches the Hawaiian Islands. A bend back
to the west is then expected at the end of the forecast period.
The new NHC track forecast lies right along the forecast path from
the previous advisory through 60 hours, although it has been
shifted slightly north on days 3-5 based on an overall shift of the
guidance envelope at those times. Confidence in the track forecast
at this stage is rather high.

Intensity-wise, low shear and sea surface temperature of 28-29C
favor continued strengthening, potentially at a rapid rate for the
next 24 hours. SHIPS, HCCA, and the Florida State Superensemble
all bring the intensity near or at major hurricane strength in
24-36 hours, which qualifies as rapid intensification. The NHC
intensity forecast is in line with these models and lies near the
upper bound of the guidance envelope given the favorable
conditions. Some weakening is expected to begin by 48 hours due to
cooler waters, but since vertical shear is not expected to increase
until around day 4, the weakening rate is likely to be gradual.
This forecast increases the chance that Douglas could maintain
hurricane intensity as it approaches the Hawaiian Islands, and all
interests on the islands should monitor the forecasts as they
evolve over the next few days.

Key Messages:

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

FORECAST POSITIONS AND MAX WINDS

INIT 22/2100Z 12.1N 130.9W 70 KT 80 MPH
12H 23/0600Z 12.7N 132.9W 85 KT 100 MPH
24H 23/1800Z 13.8N 135.8W 100 KT 115 MPH
36H 24/0600Z 15.1N 138.9W 100 KT 115 MPH
48H 24/1800Z 16.4N 141.9W 90 KT 105 MPH
60H 25/0600Z 17.6N 145.0W 80 KT 90 MPH
72H 25/1800Z 18.7N 148.0W 75 KT 85 MPH
96H 26/1800Z 20.0N 154.0W 65 KT 75 MPH...NEAR HAWAII
120H 27/1800Z 21.0N 160.0W 55 KT 65 MPH...NEAR HAWAII

$$
Forecaster Berg

The issue here compared to Julio 2014/Ignacio 2015/Lester 2016 is that the models and their ensembles show the ridge filling back in.

This doesn't look good Kingarabian, has ever been a forecast cone including every island before?

[Kingarabian]

See how the shear is being pushed back. Similar situation with Lane 2018.

[Kingarabian]

https://i.imgur.com/yXqi4mQ.png

Hurricane Douglas Discussion Number 10
NWS National Hurricane Center Miami FL EP082020
1100 AM HST Wed Jul 22 2020

Douglas's structure has continued to improve, with a more
well-defined eye becoming apparent in visible and microwave
satellite images. Subjective Dvorak intensity estimates from TAFB
and SAB range from T4.0/65 kt and T5.0/90 kt, while the latest
UW-CIMSS ADT is 4.0. Douglas's initial intensity is therefore
raised to 70 kt as a blend of the satellite estimates.

The hurricane has begun to gain some latitude, and the initial
motion is just north of due west, or 275/14 kt. The track forecast
reasoning has not changed since earlier this morning, with a
persistent mid-tropospheric ridge to Douglas's north expected to be
the main driving force for the entire 5-day forecast period.
Douglas is forecast to turn west-northwestward by this evening, and
then maintain that heading with some increase in forward speed
through day 4 as it approaches the Hawaiian Islands. A bend back
to the west is then expected at the end of the forecast period.
The new NHC track forecast lies right along the forecast path from
the previous advisory through 60 hours, although it has been
shifted slightly north on days 3-5 based on an overall shift of the
guidance envelope at those times. Confidence in the track forecast
at this stage is rather high.

Intensity-wise, low shear and sea surface temperature of 28-29C
favor continued strengthening, potentially at a rapid rate for the
next 24 hours. SHIPS, HCCA, and the Florida State Superensemble
all bring the intensity near or at major hurricane strength in
24-36 hours, which qualifies as rapid intensification. The NHC
intensity forecast is in line with these models and lies near the
upper bound of the guidance envelope given the favorable
conditions. Some weakening is expected to begin by 48 hours due to
cooler waters, but since vertical shear is not expected to increase
until around day 4, the weakening rate is likely to be gradual.
This forecast increases the chance that Douglas could maintain
hurricane intensity as it approaches the Hawaiian Islands, and all
interests on the islands should monitor the forecasts as they
evolve over the next few days.

Key Messages:

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

FORECAST POSITIONS AND MAX WINDS

INIT 22/2100Z 12.1N 130.9W 70 KT 80 MPH
12H 23/0600Z 12.7N 132.9W 85 KT 100 MPH
24H 23/1800Z 13.8N 135.8W 100 KT 115 MPH
36H 24/0600Z 15.1N 138.9W 100 KT 115 MPH
48H 24/1800Z 16.4N 141.9W 90 KT 105 MPH
60H 25/0600Z 17.6N 145.0W 80 KT 90 MPH
72H 25/1800Z 18.7N 148.0W 75 KT 85 MPH
96H 26/1800Z 20.0N 154.0W 65 KT 75 MPH...NEAR HAWAII
120H 27/1800Z 21.0N 160.0W 55 KT 65 MPH...NEAR HAWAII

$$
Forecaster Berg

The issue here compared to Julio 2014/Ignacio 2015/Lester 2016 is that the models and their ensembles show the ridge filling back in.

This doesn't look good Kingarabian, has ever been a forecast cone including every island before?

You know, now to think of it... I don't recall. This could be a rare occurrence.. Some examples:

Julio 2014:


Ignacio 2015:


Madeline and Lester 2016:
 https://twitter.com/NWSOPC/status/770404921434857472

[Yellow Evan]

Expecting SAB to come up with T4.5. This basically has traded a clearer eye for warmer cloud tops. Should sort itself out within a few hours though.

[Kingarabian]

Current Intensity Analysis


UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.0
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 22 JUL 2020 Time : 235031 UTC
Lat : 12:24:35 N Lon : 131:47:23 W


CI# /Pressure/ Vmax
4.1 / 987.7mb/ 67.4kt


Final T# Adj T# Raw T#
4.1 4.4 5.3

Estimated radius of max. wind based on IR : 17 km

Center Temp : +1.8C Cloud Region Temp : -55.8C

Scene Type : EYE

ADT raws rising but the CI will be slow to come up.

[Kingarabian]

SAB 4.5/5.0.

ADT 4.5/5.3/5.3

[supercane4867]

My current intensity estimate is 95kts

[aspen]

My current intensity estimate is 95kts

https://i.imgur.com/DEtoq8C.jpg

I have a feeling this is going to start exploding into a major in a few hours. Just look at how much better it’s become, with <-70 C convection centralizing around a clearing eye, and it’s not even Dmax yet.

[Yellow Evan]

This just got a B ring and is much more organized. Making a run at major hurricane status now.

[Kingarabian]

ADT closing in on 5.0/90kts.

[Kingarabian]

NHC went with 100mph and a new peak of 125mph.

[EquusStorm]

Will be shocked if we don't hit cat 4. Definitely making up for Cristina

[CrazyC83]

I agree we're probably looking at a cat 4 peak here.