ATL: DORIAN - Post-Tropical - Discussion

[hipshot]

Nice 96 frame with Fl and Dorian showing general w/nw motion near the end?

https://weather.cod.edu/satrad/?parms=s ... orbar=data

Yep, it sure looks like a WNW motion in that video. Not a radical jump but a slow movement in that direction for sure,
it doesn't look like a "wobble".

[1900hurricane]

114kts unflagged

9583 +164 +155 132091 111 114 017 00

948-950mb and 115kts is reasonable.

Matches with KZC pretty well.

>>> l = 25.2
>>> c = 10
>>> r34 = 85
>>> oci = 1012
>>> roci = 100
>>> p = 950
>>> KZCV(p, c, r34, l, oci)
112.19999999999789
>>> KZCVroci(p, c, roci, l, oci)
113.5999999999978

[johngaltfla]

114kts unflagged

9583 +164 +155 132091 111 114 017 00

948-950mb and 115kts is reasonable.

Give it 24 hours. I'll bet 115 kts versus 130 kts will seem very reasonable....

[ScottNAtlanta]

Current, not future. The steering currents will have to be substantially stronger than currently indicated, in my opinion, to divert or steer a major hurricane like this once it becomes a strong Cat 4 or stronger.

Thats not how steering currents work, but sure thats your opinion.

I'll quote the paper from the US Naval Observatory, Section One, Influences on Tropical Cyclone Motion:

1.3 Tropical Cyclone Winds Affecting Steering

Large TC s have strong winds out to 5-7 miles radially that could affect steering flow computations. Super Typhoon Abby (1983) was large enough (a 30 knot wind radius of over 350 nm or 650 km) that TC winds were included in steering flow computations (Chan, 1986). There is evidence that the steering flow concept may not be as applicable in large size TCs as it is for small size TCs.

The debate at the academic level continues to this day, but I've always referenced the papers which tend to support deviations in storm paths away from steering currents once storms approach what would be considered "Super Typhoon" type status, which this storm might well peak at before it settles down. Everything is about the timing but I will not dismiss out of hand your theory about the steering currents, nor the scientific research about storms creating their own "paths" or environments ahead of impacts on land.

https://www.usno.navy.mil/NOOC/nmfc-ph/ ... /se100.htm

From what I have read, I've been lead to believe that really intense hurricanes can create parts of their own environment, but I think computer models take that kind of info into account. Perhaps the hurricane models take more of this into account, but with the last 2 intense storms I can recall, the HWRF nailed them.

[Nancy Smar]

TXNT28 KNES 310012
TCSNTL

A. 05L (DORIAN)

B. 31/0001Z

C. 25.4N

D. 71.0W

E. ONE/GOES-E

F. T5.5/5.5/D1.0/24HRS

G. IR/EIR/SWIR

H. REMARKS...WESTERN EYEWALL IS WARMING IN RECENT EIR IMAGERY. WMG EYE
IS EMBEDDED IN AND SURROUNDED BY LG RESULTING IN A DT OF 5.5. AFTER 0.5
IS ADDED FOR AN EYE ADJUSTMENT. MET AND PT AGREE. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...TURK

[MacTavish]

I'll quote the paper from the US Naval Observatory, Section One, Influences on Tropical Cyclone Motion.

And that is why we now have area average soundings to account for the cyclone.

[Yellow Evan]

Thats not how steering currents work, but sure thats your opinion.

I'll quote the paper from the US Naval Observatory, Section One, Influences on Tropical Cyclone Motion:

1.3 Tropical Cyclone Winds Affecting Steering

Large TC s have strong winds out to 5-7 miles radially that could affect steering flow computations. Super Typhoon Abby (1983) was large enough (a 30 knot wind radius of over 350 nm or 650 km) that TC winds were included in steering flow computations (Chan, 1986). There is evidence that the steering flow concept may not be as applicable in large size TCs as it is for small size TCs.

The debate at the academic level continues to this day, but I've always referenced the papers which tend to support deviations in storm paths away from steering currents once storms approach what would be considered "Super Typhoon" type status, which this storm might well peak at before it settles down. Everything is about the timing but I will not dismiss out of hand your theory about the steering currents, nor the scientific research about storms creating their own "paths" or environments ahead of impacts on land.

https://www.usno.navy.mil/NOOC/nmfc-ph/ ... /se100.htm

From what I have read, I've been lead to believe that really intense hurricanes can create parts of their own environment, but I think computer models take that kind of info into account. Perhaps the hurricane models take more of this into account, but with the last 2 intense storms I can recall, the HWRF nailed them.

In theory they do but they're not always the best at it AFAIK.

[Hammy]

TXNT28 KNES 310012
TCSNTL


H. REMARKS...WESTERN EYEWALL IS WARMING IN RECENT EIR IMAGERY. WMG EYE
IS EMBEDDED IN AND SURROUNDED BY LG RESULTING IN A DT OF 5.5. AFTER 0.5
IS ADDED FOR AN EYE ADJUSTMENT. MET AND PT AGREE. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...TURK

DMIN affects?

[supercane4867]

No signs of an outer eyewall yet

[SFLcane]

John Morales from nbc6 seems a bit concerned now that Dorian is rapidly intensifying might it head further west.

[ScottNAtlanta]

It is stunning to look at, and how quickly it came together



...and before anyone starts...no its not annular.

[johngaltfla]

Thats not how steering currents work, but sure thats your opinion.

I'll quote the paper from the US Naval Observatory, Section One, Influences on Tropical Cyclone Motion:

1.3 Tropical Cyclone Winds Affecting Steering

Large TC s have strong winds out to 5-7 miles radially that could affect steering flow computations. Super Typhoon Abby (1983) was large enough (a 30 knot wind radius of over 350 nm or 650 km) that TC winds were included in steering flow computations (Chan, 1986). There is evidence that the steering flow concept may not be as applicable in large size TCs as it is for small size TCs.

The debate at the academic level continues to this day, but I've always referenced the papers which tend to support deviations in storm paths away from steering currents once storms approach what would be considered "Super Typhoon" type status, which this storm might well peak at before it settles down. Everything is about the timing but I will not dismiss out of hand your theory about the steering currents, nor the scientific research about storms creating their own "paths" or environments ahead of impacts on land.

https://www.usno.navy.mil/NOOC/nmfc-ph/ ... /se100.htm

From what I have read, I've been lead to believe that really intense hurricanes can create parts of their own environment, but I think computer models take that kind of info into account. Perhaps the hurricane models take more of this into account, but with the last 2 intense storms I can recall, the HWRF nailed them.

Until the season is over, the statistical variations at 96 hours + can not be taken into account regarding the path or intensity forecasts by the models, aka, evaluation. I'm skeptical because of all the tinkering with the EURO and GFS this year until a chance to review the total statistical output can be reviewed. It is impossible, IMHO, to impute the future influences of a hurricanes own "super environment" based on projected intensity until it achieves said intensity, IMHO. I just do not think our math wizards nor the super computers can provide a proper formula for the millions of variables which could influence the output; yet.

[johngaltfla]

John Morales from nbc6 seems a bit concerned now that Dorian is rapidly intensifying might it head further west.

That is concerning. He's one of the better ones.

[Nancy Smar]

AL, 05, 2019083100, , BEST, 0, 253N, 710W, 115, 950, HU

[HurricaneEric]

John Morales from nbc6 seems a bit concerned now that Dorian is rapidly intensifying might it head further west.

I was under the same impression. I remember Levi Cowan’s discussion video a couple days back talking about how a stronger Dorian would feel the ridge more and likely be positioned more west (and potentially west-southwest). Are the models taking into account this rapid intensification or are they behind the 8 ball with intensity?


Sent from my iPhone using Tapatalk

[Monsoonjr99]

I won't rule out Dorian pushing cat5 in the near term, but I doubt a cat5 landfall. Since NHC expects Dorian to slow down before landfall, I think it will likely deal with upwelling and weaken quite a bit. I don't think it will weaken as much as Florence did before landfall, however, since Florence also had shear problems.

[miami33]

Well we can all feel a little less guilty marveling over this intensifying storm now that a US landfall looks unlikely. However, the Bahamas are still UTG so don't completely forget about them.

You really need to stop this, sounding the all clear and saying a US threat is unlikely is way off from one set of model runs when many of those runs/ensembles still show it over FL.

Sounds to me like TWC mets are also now "hedging" and saying - or showing - that several models are now keeping it near the shoreline, both onshore and off shore.....rather than right across the state, or up the "spine" - like they thought Irma would do for a long time last year.

I'm NOT calling an "all clear" but it looks like we really might see a storm that turns north sooner rather than later. It would be a good thing, or course, and it's not just "wishful thinking" on my part, but it looks like this thing doesn't WANT to meet up with the Bermuda high....which seems poised to pull away before Dorian gets in position.

Thank you for the clarification. I hope that Dorian heads North sooner than predicted by NOAA.
Meanwhile, the Grand Bahama International Airport is closing at 10 p.m. tonight.
https://www.local10.com/travel/grand-ba ... iday-night

[Nancy Smar]

Data from the NOAA Hurricane Hunters indicate that Dorian has
strengthened to an extremely dangerous category 4 hurricane with
maximum sustained winds near 130 mph (215 km/h). This increase in
intensity will be reflected in the forecast issued at 1100 pm EDT
(0300 UTC).

[Highteeld]

..DORIAN STRENGTHENS TO A CATEGORY 4 HURRICANE...
.
Data from the NOAA Hurricane Hunters indicate that Dorian has

strengthened to an extremely dangerous category 4 hurricane with

maximum sustained winds near 130 mph (215 km/h). This increase in

intensity will be reflected in the forecast issued at 1100 pm EDT

(0300 UTC).

SUMMARY OF 830 PM AST...0030 UTC...INFORMATION

----------------------------------------------

LOCATION...25.3N 71.0W

ABOUT 400 MI...645 KM E OF THE NORTHWESTERN BAHAMAS

ABOUT 575 MI...925 KM E OF WEST PALM BEACH FLORIDA

MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H

PRESENT MOVEMENT...WNW OR 300 DEGREES AT 10 MPH...17 KM/H

MINIMUM CENTRAL PRESSURE...950 MB...28.05 INCHES

$$

Forecaster Cangialosi/Latto

[WeatherEmperor]

John Morales from nbc6 seems a bit concerned now that Dorian is rapidly intensifying might it head further west.

I remember hearing him on TV right when Dorian became classified as a Tropical Storm that he is not concerned about it because it will be approaching our area as a weak TD/TS at best. He sure has changed his tune today. This just goes to show you how little we still know about tropical meteorology and how much more we have to learn.