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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

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Wednesday, August 28 - 8 PM Update

Hurricane Dorian Intermediate Advisory Number 18A...Corrected
NWS National Hurricane Center Miami FL       AL052019
800 PM AST Wed Aug 28 2019

Corrected NNW to NNE of San Juan in summary section


LOCATION...19.2N 65.7W

At 800 PM AST (0000 UTC), the eye of Hurricane Dorian was located
by an Air Force Reserve Unit Hurricane Hunter aircraft near latitude
19.2 North, longitude 65.7 West.  Dorian is moving toward the
northwest near 13 mph (20 km/h), and this general motion is expected
to continue through Friday.  On this track, Dorian should move over
the Atlantic well east of the southeastern and central Bahamas on
Thursday and Friday.

Maximum sustained winds are near 80 mph (130 km/h) with higher
gusts.  Dorian is forecast to strengthen into a powerful hurricane
during the next few days over the Atlantic waters.

Hurricane-force winds extend outward up to 15 miles (30 km) from
the center and tropical-storm-force winds extend outward up to 80
miles (130 km).

The minimum central pressure estimated from Hurricane Hunter
observations is 990 mb (29.23 inches).


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Just now, KingOfTheMountains said:

Big pressure fall from 997 to 990. That's quite a bit ahead of that 18z Euro which isn't showing that til past hour 36.

The model data ingest initialization happens about 6 hours before the model run... the models are playing catch up, and another reason I think a low end CAT 4 is what we'll see at some point. There will be a little interaction with the upper level low that's been hanging out around the path, but it will only help to limit the intensity for a little while.  

We shall see. 

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Thursday, August 29 2019 - 5 AM Update

Hurricane Dorian Discussion Number  20
NWS National Hurricane Center Miami FL       AL052019
500 AM AST Thu Aug 29 2019

Soon after the previous advisory was issued, Dorian appeared to
have a bit of a hiccup in its structure.  A dry slot was noted
penetrating into the southeastern portion of the circulation, with
the eye becoming cloud- and rain-filled.  In fact, dropsonde data
from the Air Force Reserve mission indicated that the central
pressure had come back up a bit to around 991 mb.  That being said,
the plane still measured maximum SFMR winds between 70-75 kt, so the
initial intensity is being held steady at 75 kt for this advisory.

Dorian continues northwestward, or 325 degrees at 11 kt.
Confidence in the track forecast is fairly high for the first 48
hours, with Dorian expected to continue moving northwestward and
then begin to turn west-northwestward between mid-level ridging to
the north and a mid- to upper-level low retrograding westward
across the Straits of Florida.  The models, and their ensembles,
continue to diverge after 48 hours and have not really budged from
their respective solutions compared to yesterday.  The GFS
is a northern outlier from the rest of the guidance, showing a
weaker ridge and bringing Dorian close to the Florida/Georgia
border, while the UKMET and ECMWF models show stronger ridges
and remain the southernmost solutions near South Florida.  Given the
spread in the guidance, the new NHC forecast blends the previous
forecast with the simple multi-model consensus aids and the HCCA and
Florida State Superensemble aids, and it actually ends up in a
position very close to the tightly clustered global model ensemble
means.  The most notable change in the new forecast is that it's a
little bit slower than the previous one as Dorian approaches

Various shear analyses are indicating 10-15 kt of southwesterly
shear over Dorian at the moment, but the global models show this
shear diminishing within 12-24 hours.  With lower shear and very
warm waters, all of the intensity models forecast Dorian to begin
strengthening again soon, and rapid intensification could occur.

The updated NHC intensity forecast has been increased from the
previous one and most closely follows the HCCA and Florida State
Superensemble aids during the first day or two.  After 48 hours, the
official forecast is near or just above the intensity consensus, but
it's still lower than the solutions shown by the HCCA, Florida State
Superensemble, and the HWRF.
 Dorian is likely to reach major
hurricane strength in the next day or two and is forecast to
maintain that status until it reaches land.

Key Messages:

1. The risk of dangerous storm surge and hurricane-force winds later
this week and this weekend continues to increase 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 they have their hurricane plan in place
and not focus on the exact forecast track of Dorian's center.

2. 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.


INIT  29/0900Z 20.5N  66.6W   75 KT  85 MPH
 12H  29/1800Z 21.9N  67.6W   85 KT 100 MPH
 24H  30/0600Z 23.7N  69.0W   95 KT 110 MPH
 36H  30/1800Z 25.1N  70.6W  100 KT 115 MPH
 48H  31/0600Z 26.0N  72.5W  105 KT 120 MPH
 72H  01/0600Z 27.0N  76.4W  110 KT 125 MPH
 96H  02/0600Z 27.5N  79.5W  110 KT 125 MPH
120H  03/0600Z 28.0N  81.5W   75 KT  85 MPH...INLAND


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Good morning everyone!

Dorian supposedly got a little out of sorts last night, but you can't tell it on the radar loop, she looks healthy this morning.

One little piece of information I find important this morning is this:

5 minutes ago, NorthGeorgiaWX said:

With lower shear and very
warm waters, all of the intensity models forecast Dorian to begin
strengthening again soon, and rapid intensification could occur.
The updated NHC intensity forecast has been increased from the
previous one and most closely follows the HCCA and Florida State
Superensemble aids during the first day or two.  After 48 hours, the
official forecast is near or just above the intensity consensus, but
it's still lower than the solutions shown by the HCCA, Florida State
Superensemble, and the HWRF.

Looking at the intensity forecast from the various models, the thing that stands out to me are the number of members now calling for a CAT4.  Intensity is one thing that needs to be watched closely as intensity errors are generally greater than track errors.  Right now I'd call the consensus a solid CAT3 but given the conditions that Dorian will face, the fact that she will be slowing down as she approaches land, I still tend to favor a high CAT3/low end CAT4. But it's stupid to split hairs on this, the damage is the same. 




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Let's hope that the HWRF American hurricane model is a little amped up like it use to be. The problem is the HWRF is using the new GFS for initialization so it should have a better grasp of the situation than in the past. That being said...

The HWRF brings a 930 mb CAT4 Hurricane to the Florida coast. Should this come to pass, this would be a devastating storm for Florida.

Sea Level Pressure


10 meter wind speeds


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The WPC Model discussion


...Hurricane Dorian...

Preference: Blend of 00Z GFS/ECMWF/CMC closest to 03Z NHC advisory
Confidence: refer to NHC

...07Z update...

Shifts in the 00Z UKMET/CMC were slower compared to their previous
cycles while the 00Z ECMWF only made minor adjustments. A blend of
the 00Z ECMWF/CMC/GFS places a position nearest to the 03Z NHC
advisory track for Hurricane Dorian.

...previous discussion follows...

The 00Z GFS, 12Z ECMWF and 12Z UKMET are closest to the 03Z NHC
advisory track regarding Hurricane Dorian through about Saturday
morning. After this point in time, the 00Z GFS deviates north and
west of the NHC forecast positions but the 12Z ECMWF/UKMET remain
close to the NHC track. The 12Z CMC is a faster outlier with
Dorian while the 00Z NAM is slower with the track.


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One thing to be wary of is the Euro going a little wacky around 4 days away. It had issues last year with Florence in that range, almost like it gets distracted and doesn't know what to do. It self corrects, but something to watch for going forward. Maybe that was why some of the ensemble members did what they did, not sure yet. 

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I think that we've starting to see a general consensus of the track. You can tell from the ensembles combined with the operational, that the landfall will be somewhere around  the central Florida coast. After that, just about all the models now keep Dorian over land and recurve her to the NE. That exact placement varies still, but by tomorrow that too will be in better focus.

This shows the pressure change over the last 24 hours. To me the colors are backwards but what do I know.... the blue means the pressure is increasing, the yellows mean it's decreasing. Notice the blue area to the north of Dorian. That is the area that in theory, should continue getting "bluer", the pressure should be increasing there and that is what will steer Dorian to the left, or west.  We watch and wait.



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Here are examples as to why the southeast coast is still in jeopardy... not from a direct hit, but from storm related coastal flooding.

72 and 96 hour wave forecast. Notice how the waves are "funneled" into the natural curve of the coastline. The coast is going to take a battering.




Here are two gauges, one from Charleston Harbor and one for Ft. Pulaski in Savannah. Both in major flood stage.





As Dorian approaches, this will only get worse and worse. This will not be good for the Georgia and South Carolina coast no matter how you look at it.


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