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Hurricane Dorian (05L)


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Ok, probably my last post for the night. The 11 pm update will probably show a CAT5 hurricane, we shall see. And if you've followed Cranky, then you know we'll have a much better idea in the morning a

My disclaimer... As always, please refer to the latest official forecast from the National Hurricane Center as well as your local NWS forecast offices. 🙂 I'm here to pass along information from a

Posted Images

Let's look at some potential dangers with Dorian as it pertains to the southeast coast. First, waves.

Here's a look at the wave forecast. Also keep in mind this is the time for max tides and also keep in mind that hen I'm talking about specific times and dates, it is "As of now". All of this is very fluid right now and will change, you always have to check back for updates.

 This first image is valid Sunday at 8 pm. Waves offshore are greater than 25 feet and Dorian is piling up water in the curve of the georgia coastline. That natural curve combined with the direction of the wind flow, causes the waves to "pile up" and create a higher surge than it might otherwise do.

ww3-florida-ww3_sig_wave_height_dir-7382400.thumb.png.ed2dae16f65d64c4a3a22fb534c78e8b.png

 

This is 2 am Tuesday. At this point water is being forced up the Savannah River by the wind and serious flooding would be taking place in Savannah and at Hilton Head. Near the center of Dorian the waves are 30 feet. 

ww3-florida-ww3_sig_wave_height_dir-7490400.thumb.png.098266b3cc2c35e5d03378944edf36bb.png

 

Here are 3 NOAA surge maps, the first one is for CAT 1 surges, the next CAT 2, and then CAT 3. This is the color scale for the maps. Notice how far inland the surge can go. There would be MANY areas completely under 3-9 feet of water. 

Snap346062405.jpg.be9125f4e0c4b37e09b82c243b5cde03.jpg

 

CAT 1
231270019_cat1surge.thumb.jpg.0928b8a1436d0f6c787d72c9e58d8eee.jpg

 

CAT 2
708135473_cat2surge.thumb.jpg.93af62091ba12ba7b8dad2ec9350ceb0.jpg

 

CAT 3
Snap346062404.jpg.0f5edb843c74df62ea050b4d931c54ee.jpg

 

This is all well within the realm of possibility, and people living along the Georgia coast need to have a hurricane plan NOW and be able to act on it quickly if necessary. 

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10 hours ago, KingOfTheMountains said:

The NHC, through experience, likely has a really good feel for situations that certain models handle well and situations in which models should be mostly discounted. It can't make the job easy but models are no more than a tool, and like any skilled professional they know when best to utilize certain tools. 

Cantore ask ken graham of the NHC about their wording at the end of the advisory.  As far as lower end of intensity.  He asked him point blank what did he think was the upper end of intensity. He refused to answer.  

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9 minutes ago, RickyD said:

Cantore ask ken graham of the NHC about their wording at the end of the advisory.  As far as lower end of intensity.  He asked him point blank what did he think was the upper end of intensity. He refused to answer.  

Doesn't truly know, but that's not something I would want to say to the public. All they know is that all interest along the southeast US coast should be prepared for a potential hurricane.

It is tough to forecast. Some are cut and dry, some have major obstacles in their way, some act unpredictably. Hurricanes are a different beast. Small changes good or bad, can end up having drastic effects on the size, track, and intensity of a storm. I think that until it gets past PR, the models will struggle a little with all of those parameters. By this time tomorrow morning, we will know much, much more. 

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15 minutes ago, RickyD said:

Cantore ask ken graham of the NHC about their wording at the end of the advisory.  As far as lower end of intensity.  He asked him point blank what did he think was the upper end of intensity. He refused to answer.  

However, if I lived where you live, I would be prepared for possible heavy rain, but again, it's really too soon to know for sure. Prepared is the keyword.

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Dorian is looking nice this morning, all dressed up and ready for the day. 🙂 It's not going to be a fun day for some people in her path though. Things start to get more serious now that Dorin is approaching Puerto Rico, but it does appear that it will go to the ast and north of the island for the most part, and you can see that the winds aren't as strong on that side either. The green line in the middle are Flood Warnings for St. Croix.

Snap346062406.thumb.jpg.4f4fea4077b78e046860aedb3f304bb1.jpg

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Surge on the Georgia Coast is my biggest worry as the more northerly solutions are becoming more common. I know how susceptible that area is but throughout history they've gotten very lucky in terms of avoiding the big storms which means there are a lot of people down there that may not fully respect the power of storm surge. Getting that ridge sampled and modeled correctly is clearly going to be paramount in being able to confidently forecast the track. 

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Wednesday, August 28, 11 am Update

For those people along the coast, your hurricane plans should be rushed to completion. 

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

Tropical Storm Dorian Discussion Number  17...CORRECTED
NWS National Hurricane Center Miami FL       AL052019
1100 AM AST Wed Aug 28 2019

Corrected day 5 intensity forecast in table.

Satellite and radar images indicate that the cloud pattern has
become better organized during the past several hours. This was
confirmed by data from an Air Force reconnaissance plane currently
investigating Dorian, which reported a flight-level wind of 72 kt
and a peak SFMR value of 60 kt.  The estimated central pressure was
999 mb in the last fix.  On this basis the initial intensity has
been adjusted upward to 60 kt.
 Only a slow strengthening is
anticipated today while Dorian is moving through the U.S. and
British Virgin Islands.  However, once the cyclone reaches the
western Atlantic well east of the Bahamas, it will encounter a
favorable environment of low shear and warm waters, resulting in a
more marked intensification. The NHC forecast is more aggressive than
the previous one, and brings Dorian to category 3 intensity by the
end of the period.
This forecast very closely follows the intensity
consensus, the HCCA model, and the SHIPS guidance.

Fixes from the reconnaissance plane indicate that Dorian has been
moving toward the northwest or 315 degrees at 11 kt. The cyclone is
heading toward a weakness in the Atlantic subtropical ridge, and
this motion should continue for the next 2 to 3 days. However, after
that time, all global models build a robust ridge over the western
Atlantic, and this flow pattern should force Dorian to turn more
to the west-northwest toward Florida and the southeast coast of the
United States. All indications are that by this Labor Day weekend, a
powerful hurricane will be near the Florida or southeastern coast of
the United States. The new NHC track forecast is not significantly
different from the previous one, and it very closely follows the
multi-model consensus TVCA and the HCCA
. Users are reminded not to
focus on the exact forecast track, as the average 5-day track error
is around 200 miles.

Key Messages:

1. Hurricane conditions are expected in the U.S. and British Virgin
Islands, Culebra, and Vieques today. Tropical storm conditions are
expected in Puerto Rico today with hurricane conditions possible.

2. Heavy rainfall over portions of Puerto Rico and the U.S. and
British Virgin Islands could produce flash flooding during the next
couple of days.  Heavy rains are expected to occur over portions of
the Bahamas, Florida, and elsewhere in the southeastern United
States later this week and into early next week.

3. The risk of dangerous storm surge and hurricane-force winds is
increasing in the central and northwestern Bahamas and along the
Florida east coast, although it is too soon to determine where these
hazards will occur. Residents in these areas should ensure that
they have their hurricane plan in place and not focus on the exact
forecast track of Dorian's center.


FORECAST POSITIONS AND MAX WINDS

INIT  28/1500Z 17.5N  64.5W   60 KT  70 MPH
 12H  29/0000Z 18.7N  65.7W   65 KT  75 MPH
 24H  29/1200Z 20.5N  67.0W   65 KT  75 MPH
 36H  30/0000Z 22.4N  68.4W   70 KT  80 MPH
 48H  30/1200Z 24.2N  69.9W   75 KT  85 MPH
 72H  31/1200Z 26.5N  74.0W   90 KT 105 MPH
 96H  01/1200Z 27.7N  77.7W  100 KT 115 MPH
120H  02/1200Z 28.6N  80.3W  100 KT 115 MPH

 

 

151450_5day_cone_with_line_and_wind.png

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Dorian is trying to fight off the intrusion of dry air on the southwest side of the storm, and is seeing somme disruption in the wind flow due to the mountains of Puerto Rico, but this little storm is a fighter,  and no doubt will shake this off as it has every other obstacle that has gotten in the way. Another 6-8 hours and Dorian is free and clear. At that point, it has everything it needs to ramp up with quickly.

 

Snap346062409.jpg

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Bastardi (with grammar and spelling corrections... not that I'm not any expert... but it's Joe. 🙂 )

Quote

Betting the Ridge

In years gone by, this is a no brainer The GFS will break down the ridge too much and you bet the west track. However, we are dealing with the new GFS and the problem here is:
 

  •  it's not quite as strong with the ridge so it moves slowly to the west
  • this leads to it being in a position to stall near the FLA east coast

And we all saw from Matthew how hard if is it to drive a storm in from that angle. So this is a big test, I gotta believe tho, given the warmth of the water off the east coast, the Euro is on to this ( it's control is even further west)

This is a potential 10's of billions disaster. It's bad enough the storm will likely be near a major at landfall, but the slow movement near the coast whether its inland or not mean excessive rains. This is more like Harvey, not Florence, as the trapping is brought about by the WEAKNESS IN THE RIDGE not the kind of strong ridge that steered Florence the way it did. That was to the north, but the slowing to the coast was byproduct of what Climate change people are pushing, the abnormally strong ridge. Harvey would have kept moving if not for the trough that caught it, and the trapping here will likely be because of a ridge breakdown.

However before that ever happens, I like the Euro over the GFS as its control is even further west, though its ensembles are further east.

 

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16 minutes ago, NorthGeorgiaWX said:

It's possible, but all dependent on the final track. We just don't have that answer yet. That and heavy rain would be the two major impacts.

 

The slow forward speed on that GFS run would help with the winds as well I'm assuming? Really don't want another Ivan/Irma... Not fun to ride out and cleanup was rough. 

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