EPAC: DOUGLAS - Remnants

[Extratropical94]

12Z Best Track

08E DOUGLAS 200721 1200 12.6N 123.6W EPAC 55 998

[cycloneye]

Tropical Storm Douglas Discussion Number 5
NWS National Hurricane Center Miami FL EP082020
500 AM HST Tue Jul 21 2020

A recent SSMIS microwave pass indicated that Douglas's low-level
center is located very near the head of a broken band of convection
which curls around the southern, western, and northern side of the
circulation. This center is also now embedded beneath a Central
Dense overcast in infrared imagery, near an area of cold
overshooting cloud tops. TAFB and SAB Dvorak classifications have
both risen to T3.5, and Douglas's initial intensity is therefore
raised to 55 kt.

Douglas continues to dip west-southwestward, or 255/13 kt, due to
strong mid-level ridging to its north. A mid- to upper-level low
located northeast of the Hawaiian Islands is forecast to retrograde
westward over the next few days, which will allow the ridge to take
on a more east-west orientation. As a result, Douglas is expected
to turn westward later today and then move west-northwestward
beginning overnight Wednesday into the weekend. The track guidance
all agrees on this scenario, but there are some speed differences,
bookended by slower GFS and HWRF solutions and a faster ECMWF
solution. Overall, however, the new NHC forecast remains very
close to the multi-model consensus aids, and no significant changes
were made compared to the previous forecast, except maybe a slight
northward adjustment on days 4 and 5.

The low-shear, warm sea surface temperature environment within
which Douglas is moving is a recipe for continued strengthening,
potentially at a rapid rate, for the next 48 hours. The intensity
guidance has been trending higher, and the latest SHIPS Rapid
Intensification (RI) indices are highlighting the increased chance
of RI. For example, there is currently a 50/50 shot that Douglas's
winds will increase by 25 kt within the next 24 hours, and a 40-50
percent chance of a 30-kt increase during that period. Based on
this guidance, the new HCCA and Florida State Superensemble
solutions, and the intensity consensus, the NHC intensity forecast
has been increased from the previous cycle and now shows Douglas
becoming a hurricane later today with a higher peak occurring in
about 2 days. Since oceanic heat content falls to zero along
Douglas's path by day 3, some gradual weakening is shown in the
latter stages of the forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 21/1500Z 12.4N 124.2W 55 KT 65 MPH
12H 22/0000Z 12.1N 126.0W 70 KT 80 MPH
24H 22/1200Z 12.1N 128.5W 80 KT 90 MPH
36H 23/0000Z 12.6N 131.0W 85 KT 100 MPH
48H 23/1200Z 13.6N 133.7W 90 KT 105 MPH
60H 24/0000Z 14.9N 136.5W 85 KT 100 MPH
72H 24/1200Z 16.1N 139.4W 75 KT 85 MPH
96H 25/1200Z 18.0N 145.5W 65 KT 75 MPH
120H 26/1200Z 18.5N 151.5W 55 KT 65 MPH

$$
Forecaster Berg

[aspen]

Still developing an eyewall:

[Sciencerocks]

[Kingarabian]

After last nights dry air intrusion I'm impressed it held itself together with no problems.

06z model suite continues the trend of a stronger peak.

[cycloneye]

Kingarabian There is Recon for Saturday.

PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. ADDITIONAL DAY OUTLOOK: BEGIN 12-HRLY FIXES ON TROPICAL STORM
DOUGLAS FOR 25/0600Z.

[Yellow Evan]

21/1730 UTC 12.3N 124.3W T3.5/3.5 DOUGLAS -- East Pacific

[Kingarabian]

Kingarabian There is Recon for Saturday.

PACIFIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.
3. ADDITIONAL DAY OUTLOOK: BEGIN 12-HRLY FIXES ON TROPICAL STORM
DOUGLAS FOR 25/0600Z.

Yeah I figured. Hopefully they can get a synoptic mission in as well.

[Kingarabian]

12z Euro rakes Maui and Oahu with 60kt winds @ 991-994mb.

12z UKMET hits eastern Big Island/Puna as a minimal TS.
12z/July 20 GFS Parallel is a 55kt Puna landfall. GFS Parallel is currently running a day late.
The rest of the global models show this decaying enough and dipping south of Hawaii.

12z EPS:

[Kingarabian]

Tropical Storm Douglas Discussion Number 6
NWS National Hurricane Center Miami FL EP082020
1100 AM HST Tue Jul 21 2020

Douglas appears to have been trying to scour out a little bit of
dry air on its western side during the day, although recent visible
images suggest that deep convection is attempting to wrap entirely
around the center. Because the convective pattern didn't change
much from earlier, Dvorak classifications from TAFB and SAB remain
T3.5/55 kt, so the initial intensity is held steady on this
advisory.

Strong ridging to the north of Douglas continues to impart a
west-southwestward motion of the cyclone, or 255/13 kt. As
mentioned this morning, the ridge is likely to take on a more
east-west orientation as a mid-/upper-level low northeast of the
Hawaiian Islands retrogrades westward, and this pattern evolution
will allow Douglas to turn westward by tonight and then
west-northwestward by late Wednesday. That general motion is
forecast to continue for the remainder of the 5-day forecast
period. The track guidance still showcases a faster ECMWF and
slower GFS and HWRF solutions, and the overall envelope and
model consensus aids have again nudged northward. The updated
track forecast is therefore a little north of the previous one,
mainly after 48 hours through day 5.

Once deep convection can isolate Douglas's center from the
ambient environment, low shear and warm sea surface temperatures of
28-29 degrees Celsius should allow intensification to resume.
Despite this morning's hiatus in strengthening, the SHIPS Rapid
Intensification (RI) guidance continues to key in on a significant
chance of RI during the next day or two. Therefore, the intensity
forecast from this morning has been left unchanged, and it still
generally lies between the HCCA and Florida State Superensemble,
closer to the higher end of the guidance envelope. Douglas should
reach its peak intensity in about 48 hours, after which time
oceanic heat content values drop to zero, which should cause some
gradual weakening.

Based on a partial ASCAT-A pass, Douglas's tropical-storm-force
wind radii were increased on the northern side.


FORECAST POSITIONS AND MAX WINDS

INIT 21/2100Z 12.1N 125.4W 55 KT 65 MPH
12H 22/0600Z 11.9N 127.1W 70 KT 80 MPH
24H 22/1800Z 12.1N 129.5W 80 KT 90 MPH
36H 23/0600Z 13.0N 131.9W 85 KT 100 MPH
48H 23/1800Z 14.4N 134.5W 90 KT 105 MPH
60H 24/0600Z 15.7N 137.3W 85 KT 100 MPH
72H 24/1800Z 16.9N 140.2W 75 KT 85 MPH
96H 25/1800Z 18.5N 146.0W 65 KT 75 MPH
120H 26/1800Z 19.0N 151.5W 55 KT 65 MPH

$$
Forecaster Berg

[aspen]

I agree with the NHC. Douglas already has some good convection; once it’s able to fend off the dry air and fully establish its eyewall, it’ll probably undergo a significant burst of intensification.

It’s already more impressive than 80% of everything in the EPac this season, so I still call it a win.

[Kingarabian]

18z GFS has a moderate TS landfall, SE Big Island.

[Kingarabian]

Continues to gulp dry air:


Still has a lot of time to become a hurricane.

[Kingarabian]

18z Euro stronger and peaks this with major hurricane pressure @ 966mb.

[aspen]

Still has a lot of time to become a hurricane.

We all said that about Cristina, and look how she turned out.

(Yes, she likely was a hurricane, but she continued to struggle for the entire timeframe where RI could’ve commenced).

[Kingarabian]

Still has a lot of time to become a hurricane.

We all said that about Cristina, and look how she turned out.

(Yes, she likely was a hurricane, but she continued to struggle for the entire timeframe where RI could’ve commenced).

While it wouldn't surprise me if this craps out, the thing this has over Cristina is location and that it's entering a sweet spot. Cristina started off in a sweet spot and was moving away when it stopped struggling.

Last couple of hours it has increased its size and the CDO has grown. This could help maintain itself better.

[Kingarabian]

 https://twitter.com/DerekOrtt/status/1285712871217913856

[Yellow Evan]

Too soon to start cancelling but I'm not thrilled with Douglas right now either.

[Chris90]

Cristina actually built a nice core right out the gate really fast, but it also fell apart really fast and then struggled continuously.

Douglas has been building and maintaining a nice structure for awhile now. It's not a complete eyewall or anything, but it's been maintaining and fighting off those dry air entrainments admirably. He's impressed me more than Cristina so far.

[supercane4867]

Probably won't be much left when it reaches Hawaii. I highly doubt it will be stronger than Olivia and Darby in terms of wind speeds.