ATL: DORIAN - Post-Tropical - Discussion

[Michele B]

Those IDIOTS! Well, it did nearly fall apart...

Hundred+ miles to the W and he woulda been a gooner via the shredder

That center reformation yesterday was key to makin this such a formidable threat

AND missing the high mountains of PR and Hispaniola.

[jdjaguar]

tropical cyclones with pinhole eyes are associated with rapid intensification

Folks, Dorian has a pin hole eye.

Just because you see a small clearing on visible does not mean it's a pinhole eye. Pinholes surrounded by very cold, symmetric CDO are something to behold. Not the case here.

It was IR, no need for the eye roll

[Michele B]

Ventilation anyone?

https://weather.cod.edu/satrad/?parms=g ... =undefined

How in the hell does this son of a gun, stay in check.....

https://ocean.weather.gov/shtml/A_96hrsfc.gif

https://ocean.weather.gov/Atl_tab.php

What do you mean?

All I see is a very large "Bermuda high" which will COMPEL Dorian to move to the west.

[Aric Dunn]

One can also check TJUA radar to see eye structure

https://cdn.discordapp.com/attachments/485132024949112855/616365101192052801/Screenshot_20190828-151409.png

and then have a little fun with this too lol

[ScottNAtlanta]

https://imgur.com/MTpGGeb

That looks to me like an eye trying to clear out. I wouldnt say "pinhole", but its an eye just the same

[xironman]

Another hot tower on the NE side

[Dave C]

One can also check TJUA radar to see eye structure

https://cdn.discordapp.com/attachments/485132024949112855/616365101192052801/Screenshot_20190828-151409.png

Classic banding eyewall forming.

[jdjaguar]

Vero Beach, FL here. Walmart is packed. Home Depot is packed. That weird feeling in the air is here now. Those who have been in a Hurricane know what I'm talking about. Just driving around, I was asking, what will our city even look like in a week from now? It's get very eerie here, now that everyone is expecting a Major hurricane at landfall somewhere on the Florida EC, seemingly Central. Praying for everybody in Dorians path.

My 86 mom lives in vero on the barrier island.
Trying to figure out a game plan while I Prep up the coast.
Nerve wracking

[wx98]

Up to 80 mph now

[KC7NEC]

Florida State of Emergency

https://twitter.com/GovRonDeSantis/stat ... 4325210112

[USVIKimmie]

On the east end of St Thomas... that sucked. On a boat, same as my neighbors. For a protected harbor that faces east, that was gnarly seas!

Watching the satellite loops last night, I had a gut feeling Dorian was heading right for us.

My Cocorahs rain gauge looks like maybe 6 inches or so. The outside container is almost half full. It's still raining, too.

[MGC]

Dorian missing the Greater Antilles could prove disastrous in the coming days. The Hurricane looks to be wrapping up this afternoon per San Juan radar. Looks like some dry air is still being entrained into the circulation preventing the eye wall to close. Dorian should continue to intensify, I'm afraid the NHC intensity forecast might be conserative.....MGC

[aperson]

SHIPS probabilities indicate a modest chance for Cat 4+ conditions with 22% chance of 65kt/72hr RI.


(from: https://twitter.com/AlexJLamers/status/1166814147054571520)

Code: Select all

                        INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
                         6   12   18   24   36   48   60   72   84   96  108  120
                        ----------------------------------------------------------
  SAMPLE MEAN CHANGE     1.   2.   3.   4.   6.   8.   9.  10.  11.  11.  12.  12.
  SST POTENTIAL          1.   3.   4.   4.   5.   5.   6.   6.   6.   6.   7.   6.
  VERTICAL SHEAR MAG     0.   0.   0.   1.   2.   4.   7.   8.   9.  11.  11.  11.
  VERTICAL SHEAR ADJ     0.   0.   0.   1.   2.   3.   4.   5.   5.   5.   4.   3.
  VERTICAL SHEAR DIR     0.  -1.  -1.  -1.  -2.  -2.  -2.  -2.  -2.  -2.  -2.  -1.
  PERSISTENCE            3.   3.   3.   3.   2.   1.   1.   1.   1.   0.   0.   0.
  200/250 MB TEMP.       0.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -1.  -2.  -2.
  THETA_E EXCESS         0.   1.   1.   1.   1.   1.   1.   1.   1.   1.   1.   0.
  700-500 MB RH          0.   0.   0.   0.   0.   0.   0.  -1.  -1.  -2.  -2.  -2.
  MODEL VTX TENDENCY     0.  -1.  -1.  -1.   0.   1.   3.   5.   6.  12.  11.  13.
  850 MB ENV VORTICITY   0.   0.  -1.  -1.  -1.  -2.  -3.  -3.  -3.  -3.  -3.  -3.
  200 MB DIVERGENCE      0.   0.   0.   0.  -1.   0.   0.   0.   0.   0.   0.   1.
  850-700 T ADVEC        0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  ZONAL STORM MOTION     0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  STEERING LEVEL PRES    0.   0.   0.   0.   0.   0.   0.  -1.  -1.  -1.  -1.  -1.
  DAYS FROM CLIM. PEAK   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.   0.
  GOES PREDICTORS        0.   0.   0.   0.   1.   1.   1.   1.   1.   1.   1.   1.
  OCEAN HEAT CONTENT     0.   0.   0.  -1.   0.   0.   0.   0.   0.   0.   0.   0.
  RI POTENTIAL           1.   2.   4.   7.   9.   8.   6.   3.   1.  -2.  -4.  -5.
                        ----------------------------------------------------------
  TOTAL CHANGE           5.   9.  13.  16.  23.  28.  32.  33.  33.  36.  33.  33.
 

(from ftp://ftp.nhc.noaa.gov/atcf/stext)

[drewschmaltz]

If atmospheric conditions are prime, why then are intensity forecasts not cat 4 winds? I'm sincerely interested, what conditions did say Andrew have that Dorian does not? Are the SSTs not high enough? Does it not have enough ventilation? Too high of shear? I thought with the setup these are all expected to be favorable... What's capping only a 35mph increase from right this minute.

[jasons2k]

Here is an update from Houston Met Jeff Lindner about an hour ago:

Dorian becomes a hurricane over the US Virgin Islands

***Major hurricane threat to FL this weekend***

Discussion:
Dorian has undergone intensification today with recent radar images from San Juan and satellite images showing the formation of an eyewall. While the surface pressure has not fallen much per USAF fixes, wind observations from ST Thomas of sustained winds of 82mph at an elevated observation site support hurricane intensity at the surface and Dorian has been upgraded to a hurricane. Dorian is moving toward the NW and this motion is expected to continue with the hurricane now completely missing Puerto Rico and the Dominican Republic to the east. This answers one of the big questions…of will Dorian survive those landmasses and the answers is…yes. With that a troubling trend has developed in the intensity guidance with several models now indicating a significant hurricane approaching the Bahamas and FL this weekend.

Track:
Dorian is moving NW into a weakness in the sub-tropical ridge to the north and this overall motion will continue for the next 48 -60 hours followed by a turn toward the WNW and then likely the W. How fast Dorian turns toward the west will be a function of the upper low level moving west over the Bahamas toward the Gulf of Mexico and a building ridge of high pressure over the SW Atlantic toward the SE US. While the center of Dorian reformed yesterday well to the N of the previous center and had required some adjustments to the short term forecast track, the longer term track reasoning has not changed. Additionally, today there is increasing agreement that Dorian will turn toward the west and potentially cross the state of FL and enter the eastern Gulf of Mexico. There is still some potential that the building ridge of high pressure is slightly weaker than forecast and this would allow Dorian and escape route to the NE along the SE US, but this potential appears to be closing. The more west trend in model guidance today opens the potential for a second US landfall along the US Gulf coast after Dorian impacts FL.

The official forecast brings a potentially dangerous hurricane to the FL east coast late this weekend or Labor Day.

Intensity:
As mentioned above, Dorian will miss the tall terrain of Puerto Rico and the Dominican Republic and will find nearly ideal conditions ahead for intensification. With the formation of an eyewall, Dorian will be able to protect the inner core structure more easily from dry air intrusions which will become less and less as the hurricane moves into a more moisture rich environment east of the Bahamas. Dorian is forecast to move over very warm waters in a low shear environment with likely outflow channels to the NW and SE of the hurricane. This all support significant intensification over the forecast track and a major hurricane is forecast to be approaching the FL east coast this weekend. Based on the intensity guidance, additional increases in the intensity forecast may be required. It is becoming increasingly likely that a significant hurricane event will be approaching and potentially making landfall in some portion of FL this weekend or early next week.

Note:
It is too early at this time to make any significant track or intensity forecasts for Dorian after crossing FL. The track forecast will hinge on the position and intensity of the sub-tropical ridge over the SW Atlantic into the SE US as well as a mid latitude short wave trough that will move across the Midwest this weekend and early next week. Most models show Dorian slowing the forward speed significantly while approaching and crossing FL indicating Dorian will be reaching the western extent of the ridge and trying to turn toward the right (north) toward a weakness being created in the ridge by the Midwest trough. I strongly caution drawing any conclusions at this time from individual model runs beyond the 4-5 day time period as there can be significant changes.

[HurricaneBelle]

Surprised nobody's seemed to notice the 5PM advisory has been out for about ten minutes, it's now being taken across Vero, hooking up with I-4 in the central part of the State.

Here in Tampa our probabilities went up from 36/11/5 to 62/31/17 in the space of one advisory interval.

[Highteeld]

If atmospheric conditions are prime, why then are intensity forecasts not cat 4 winds? I'm sincerely interested, what conditions did say Andrew have that Dorian does not? Are the SSTs not high enough? Does it not have enough ventilation? Too high of shear? I thought with the setup these are all expected to be favorable... What's capping only a 35mph increase from right this minute.

hwrf sees it. same issue happened with michael last year. most models are initiated it wayyyyy too weak right now

[northjaxpro]

Dorian missing the Greater Antilles could prove disastrous in the coming days. The Hurricane looks to be wrapping up this afternoon per San Juan radar. Looks like some dry air is still being entrained into the circulation preventing the eye wall to close. Dorian should continue to intensify, I'm afraid the NHC intensity forecast might be conserative.....MGC

Yeah MGC, I agree.

[CronkPSU]

If atmospheric conditions are prime, why then are intensity forecasts not cat 4 winds? I'm sincerely interested, what conditions did say Andrew have that Dorian does not? Are the SSTs not high enough? Does it not have enough ventilation? Too high of shear? I thought with the setup these are all expected to be favorable... What's capping only a 35mph increase from right this minute.

the discussion addresses that and seems to be saying, their forecast intensity right now may be too low

[SoupBone]

Surprised nobody's seemed to notice the 5PM advisory has been out for about ten minutes, it's now being taken across Vero, hooking up with I-4 in the central part of the State.

Here in Tampa our probabilities went up from 36/11/5 to 62/31/17 in the space of one advisory interval.

Has Tampa ever been hit by a major coming from East to West like this?