ATL: FLORENCE - Post-Tropical - Discussion

[TheDreamTraveler]

NHC says its moving west lol

BULLETIN
Tropical Storm Florence Advisory Number 35
NWS National Hurricane Center Miami FL AL062018
1100 PM AST Fri Sep 07 2018

...FLORENCE FORECAST TO RESTRENGTHEN LATER THIS WEEKEND...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...24.8N 53.2W
ABOUT 780 MI...1260 KM NE OF THE NORTHERN LEEWARD ISLANDS
ABOUT 875 MI...1405 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...W OR 265 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES

[Highteeld]

[BobHarlem]

The NHC kept the latitude at 24.8N (Same as 5PM) for the 11PM, even though SSD showed 24.5. I guess visible will help here.

[Aric Dunn]

NHC says its moving west lol

BULLETIN
Tropical Storm Florence Advisory Number 35
NWS National Hurricane Center Miami FL AL062018
1100 PM AST Fri Sep 07 2018

...FLORENCE FORECAST TO RESTRENGTHEN LATER THIS WEEKEND...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...24.8N 53.2W
ABOUT 780 MI...1260 KM NE OF THE NORTHERN LEEWARD ISLANDS
ABOUT 875 MI...1405 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...W OR 265 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES

Yeah they often do that for continuity as well as making sure of accuracy. they will wait to first visible to make and position or motion adjustments.

[SouthFLTropics]

Technically it is moving a hair south of due west. Due west would be 270, they are showing it at 265.

[TheDreamTraveler]

Tropical Storm Florence Discussion Number 35
NWS National Hurricane Center Miami FL AL062018
1100 PM AST Fri Sep 07 2018

Florence remains a sheared tropical cyclone. Satellite images
indicate that the low-level center is partially exposed on the
southwesterly edge of a large convective mass, with the overall
circulation somewhat elongated from southwest to northeast.
A blend of the latest Dvorak wind speed estimates from TAFB/SAB and
the CIMSS SATCON gives a value of 50 kt for this advisory.

While the winds at 200 mb are already from an easterly direction
near the center of Florence, there is significant shear from
northwesterly winds from 300-500 mb, undercutting the outflow layer.
This shear is forecast to relax by the global models over the next
36 hours as an anticyclone builds to the north of the storm, which
should promote some strengthening by Sunday. After 48 hours, the
deep-layer flow becomes easterly near the cyclone, with very little
shear while the system is over very warm waters. This pattern
favors significant intensification, and most of the guidance brings
Florence back to a category 4 hurricane in 4 or 5 days. The
intensity forecast is very similar to the last one, and is raised
slightly at days 3 and 4 to come into better agreement with the
guidance. It is interesting to note that even with a lower initial
intensity, the guidance is higher than the last cycle, which speaks
to the strength of the signal for intensification in the long range.

The initial motion estimate is 265 degrees at 6 kt. Florence is
expected to continue moving slowly westward for the next 48 hours
under the influence of a weak mid-level ridge over the western
Atlantic. By days 4 and 5, an exceptionally strong blocking ridge
is forecast to develop between Bermuda and the Northeast U.S. and
build westward, keeping Florence on a west-northwestward trajectory
with a notable increase in forward speed by the end of the forecast
period. It feels like a broken record to mention that the overall
guidance envelope keeps shifting southwestward, and the official
forecast is moved in that direction. Unfortunately with such a
large well-defined steering current from the ridge becoming likely,
the extended-range risk to the United States keeps rising, which is
confirmed by the majority of the latest ensemble guidance.

Key Messages:

1. Regardless of Florence's eventual track, large swells are
affecting Bermuda and will begin to affect portions of the U.S.
East Coast this weekend, resulting in life-threatening surf and rip
currents.

2. The risk of other direct impacts associated with Florence along
the U.S. East Coast next week has increased. However, there is
still very large uncertainty in model forecasts of Florence's track
beyond day 5, making it too soon to determine the exact location,
magnitude, and timing of these impacts. Interests near and along
the U.S. East Coast should monitor the progress of Florence through
the weekend and ensure they have their hurricane plans in place.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0300Z 24.8N 53.2W 50 KT 60 MPH
12H 08/1200Z 24.7N 54.1W 50 KT 60 MPH
24H 09/0000Z 24.7N 55.2W 55 KT 65 MPH
36H 09/1200Z 24.7N 56.3W 60 KT 70 MPH
48H 10/0000Z 25.0N 57.8W 70 KT 80 MPH
72H 11/0000Z 25.8N 62.3W 95 KT 110 MPH
96H 12/0000Z 27.5N 68.5W 115 KT 130 MPH
120H 13/0000Z 30.5N 74.5W 115 KT 130 MPH

$$
Forecaster Blake

[SouthFLTropics]

That error cone is starting to look real ominous on approach to the SE Coast.

[JaxGator]

NHC says its moving west lol

BULLETIN
Tropical Storm Florence Advisory Number 35
NWS National Hurricane Center Miami FL AL062018
1100 PM AST Fri Sep 07 2018

...FLORENCE FORECAST TO RESTRENGTHEN LATER THIS WEEKEND...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...24.8N 53.2W
ABOUT 780 MI...1260 KM NE OF THE NORTHERN LEEWARD ISLANDS
ABOUT 875 MI...1405 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...W OR 265 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES

Yes, it is per NHC. Though at the 5pm Disco, they mentioned Florence was moving south of due west.

"Florence has been moving south of due west (260 degrees) at 7 kt,
located south of a low- to mid-level ridge."

[meriland29]

I think this was a very interesting bit quoted from NHCs last advisory:


It is interesting to note that even with a lower initial
intensity, the guidance is higher than the last cycle, which speaks
to the strength of the signal for intensification in the long range.

[Bocadude85]

I guess the NHC does not agree with the ADT estimate of 24.5

[SouthFLTropics]

The other interesting part was when he spoke of sounding like a broken record referring to the consistent SW shifts of the models.

[TheDreamTraveler]

I think this was a very interesting bit quoted from NHCs last advisory:


It is interesting to note that even with a lower initial
intensity, the guidance is higher than the last cycle, which speaks
to the strength of the signal for intensification in the long range.

Yeah I thought so too. Very ominous. But we know that due to the intensity models showing it strengthening and how the environment its moving into is going to be. If this thing gets powerful it might stay like that until landfall since there won't be much in the way to weaken it.

[Hurricaneman]

I guess the NHC does not agree with the ADT estimate of 24.5

And my guess of 24.25 so maybe the NHC May be a little off with this but without visible imagery it’s really hard to tell

[Hurricaneman]

I think this was a very interesting bit quoted from NHCs last advisory:


It is interesting to note that even with a lower initial
intensity, the guidance is higher than the last cycle, which speaks
to the strength of the signal for intensification in the long range.

Yeah I thought so too. Very ominous. But we know that due to the intensity models showing it strengthen and how the environment its moving into is going to be. If this thing gets powerful it might stay like that until landfall since there won't be much in the way to weaken it.

I wouldn’t be shocked to see a cat 5 approaching the coast, I would be prepared for that anywhere from Norfolk to Melbourne even if it doesn’t happen but prepare for the worst and hope for the best

[toad strangler]

The other interesting part was when he spoke of sounding like a broken record referring to the consistent SW shifts of the models.

Certainly didn’t sound like he expected this to end.

[floridasun78]

now cone east north fl before was like east of GA so more south will cone go or will stop were now models? i hear been sifting more south last day or two

[Blinhart]

All I can say is keep watching and hope for the best like the recon doing upper air data finds a weakness or something to send it out to sea

That's why we need to figure out how to do dropsondes straight across the whole Atlantic Basin from Galveston or Corpus Christi, to Miami, to Southern part of Caribbean to North Africa.

[SFLcane]

From NHC at 11pm ...It feels like a broken record to mention that the overall guidance envelope keeps shifting southwestward, and the official forecast is moved in that direction.

[hurricaneCW]

Extremely ominous discussion, we just have to hope the storm entrains some dry air like Isabel as it approaches the coast.

Does anyone know what the worst case landfall spot would be for Georgia and the Carolinas.

[floridasun78]

you all think sw moving stop?