EPAC: OTIS - Post-Tropical

[Kingarabian]

The 70kt intensity on 18z best track is way too low. No way this is only 5kts stronger than Maria right now, likely at least 95kt or higher.

[img]https://i.imgur.com/aYuDBt6.gif[img]

Sheesh... talk about RI... From a tropical depression to a major hurricane in 24 hours. Has this ever happened before? Too bad satellite estimates are playing catch up and ADT can't resolve the eye.

Off the top of my head, Genevieve '14 is the only system that comes to mind.

Part of an exclusive club then.

[1900hurricane]

From GOES-16 band 10. Eye is notably warming with time on the low level water vapor.

[EquusStorm]

[Sciencerocks]

Pin hole eye and -70 convection on ir shows a quickly strengthening system that may become a major if "cooler" sst's to the north don't stop it.

[CrazyC83]

NHC just went 90 kt. Even that may be conservative IMO, but without Recon we will never know.

[1900hurricane]

The eye is pretty deeply off-white per GOES-16. ADT is being ADT and missing the eye this frame, but the previously analyzed one came in at -11.70ºC.

[Kingarabian]

I would say this warrants a T6.0. Clearly a major hurricane.

[CrazyC83]

I would say this warrants a T6.0. Clearly a major hurricane.

I'd put out a Special Advisory with an intensity of 110 kt personally.

[WeatherGuesser]

Otis wandering around making a nuisance but not really bothering anybody ... there must be a Mayberry joke on there somewhere.

[Kingarabian]

Otis wandering around making a nuisance but not really bothering anybody ... there must be a Mayberry joke on there somewhere.

My favorite type of storm.

[Yellow Evan]

W CDO isn't thick enough so T5.5. CDO isn't too symmetrical anyways thought quite circular.

[Kazmit]

Tiny eye!

[Kingarabian]

Tiny eye!

[img]https://i.imgur.com/yafuo28.png[/mg]

Wow great photo!

[1900hurricane]

Now up to 100 kt as of 00Z best track.

15E OTIS 170918 0000 17.6N 127.2W EPAC 100 965

[weathaguyry]

This thing went from a TD that we weren't sure was going to make it to 35kts. to a 100kt. Hurricane

[EquusStorm]

I almost forgot this is a storm that developed from Katia's remnants. What an odd legacy... and a decent bit stronger in its reincarnation than its initial development in the Atlantic, even.

[Cyclenall]

This is the most mind-blowing thing to happen in the EPAC this season . Was there 30 second GOES16 loops when it developed a pinhole eye? The most amazing aspect is this:

Tropical Depression Fifteen-E Discussion Number 19
NWS National Hurricane Center Miami FL EP152017
200 AM PDT Sat Sep 16 2017

An ASCAT pass just before 0600 UTC indicated that the depression
has weakened a little bit. Winds of only around 25 kt were present,
and since the depression lacks a true inner core, I don't believe
that undersampling is a big concern at this time. The initial
intensity has therefore been lowered to 25 kt. It is beginning to
seem unlikely that the depression will become a tropical storm at
any time. The mid-level humidity and SSTs seem sufficient to only
support continued pulsating convection and none of the guidance
really shows significant strengthening.

...

FORECAST POSITIONS AND MAX WINDS

INIT 16/0900Z 15.8N 126.0W 25 KT 30 MPH
12H 16/1800Z 15.7N 126.4W 25 KT 30 MPH
24H 17/0600Z 16.1N 126.6W 30 KT 35 MPH
36H 17/1800Z 16.6N 126.6W 30 KT 35 MPH
48H 18/0600Z 17.0N 126.5W 30 KT 35 MPH
72H 19/0600Z 17.7N 126.6W 30 KT 35 MPH
96H 20/0600Z 18.0N 128.0W 25 KT 30 MPH
120H 21/0600Z 17.0N 130.5W 20 KT 25 MPH...POST-TROP/REMNT LOW

Was thought to be 30 kt TD right when it became a major hurricane!!! 36 hours beforehand!!! 70 knots at least off the maximum intensity. The only thing remotely close to this is Hurricane Kirk a few years ago in the Atlantic and Genevieve as far as going from TD to major in short span. This kind of forecasting error with the advanced models and tools just doesn't happen...unless pinhole/micro-core then anything goes. Kirk also had a very tiny core so the models missed both.

That sentence in the discussion about how unlikely it is that future Otis would become a TS at all...unbelievable. Briefly looking at Genevieve's advisories from the CPHC the strengthening to a hurricane at least was foreseen days in advance before the Wilma-like RI started whereas with Otis...nothing.

[WeatherGuesser]

Hurricane Otis Discussion Number 27
NWS National Hurricane Center Miami FL EP152017
200 AM PDT Mon Sep 18 2017

What goes up must come down -- Otis is a classic example of what can
happen with a small tropical cyclone. After rapidly intensifying
earlier today, the cloud pattern has become rather poorly
organized, with the center on the western edge of an irregular
central dense overcast. The wind speed is reduced to 85 kt, on the
high side of the latest Dvorak estimates, and this could be
generous. Further weakening is likely since Otis has moved over
cool SSTs and increasing shear is expected by tomorrow. Thus,
rapid weakening is forecast, and the official intensity is reduced
from the previous one, lying near the model consensus, although
the corrected consensus models are even lower. Global models
suggest Otis will degenerate into a remnant low within 2 days.

Otis is still moving northward, recently at 5 kt. This northward
motion should turn to the west and southwest over the next 36
hours as it is steered by a low-level ridge over the central
Pacific. The global models are generally showing a stronger ridge,
and the guidance has shifted farther southwest with the track of the
expected remnants of the cyclone. The new NHC prediction follows the
latest guidance, resulting in a faster track that is to the
southwest of the previous official forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 18/0900Z 18.5N 127.3W 85 KT 100 MPH
12H 18/1800Z 19.2N 127.5W 70 KT 80 MPH
24H 19/0600Z 19.3N 127.9W 50 KT 60 MPH
36H 19/1800Z 19.0N 128.6W 40 KT 45 MPH
48H 20/0600Z 18.2N 129.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 21/0600Z 16.5N 132.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 22/0600Z 14.7N 135.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 23/0600Z...DISSIPATED

$$
Forecaster Blake

NNNN

[WeatherGuesser]

BULLETIN
Hurricane Otis Advisory Number 27
NWS National Hurricane Center Miami FL EP152017
200 AM PDT Mon Sep 18 2017

...FICKLE OTIS NOW RAPIDLY WEAKENING...


SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...18.5N 127.3W
ABOUT 1165 MI...1870 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...N OR 355 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...976 MB...28.82 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 200 AM PDT (0900 UTC), the center of Hurricane Otis was located
near latitude 18.5 North, longitude 127.3 West. Otis is moving
toward the north near 6 mph (9 km/h). A slower northward motion
is expected later today, followed by a turn to the west and
southwest by late Tuesday.

Maximum sustained winds have decreased to near 100 mph (155 km/h)
with higher gusts. Rapid weakening is forecast during the next 48
hours.

Hurricane-force winds extend outward up to 25 miles (35 km) from the
center and tropical-storm-force winds extend outward up to 70 miles
(110 km).

The estimated minimum central pressure is 976 mb (28.82 inches).


HAZARDS AFFECTING LAND
----------------------
None.


NEXT ADVISORY
-------------
Next complete advisory at 800 AM PDT.

$$
Forecaster Blake

[Kingarabian]

Wow Otis is almost completely gone. Crazy