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Tropical Major Hurricane Florence

If anyone wants to see a funny run look at the FV3. It still has Florence in the Atlantic up to hour 384 only finally on its way out then. It just keeps getting shoved south and back along its initial track.
 
looks like it avoids landfall by about 30 miles on this run :confused:

not that it matters the coast would be wiped out if it stalls there for days
 
That was an interesting run for sure. Ridge does break down late, so obviously further north this run...Sits forever, as y'all have said.
 
Florence has become a category 4 hurricane based on the latest ATCF message, making it the furthest north a category 4 hurricane has formed in the Atlantic east of 50W (according to Sam Lillo).
 
Interestingly, average member is a fair bit weaker on the 12Z EPS vs 0Z. Tracks are similar so far.
 
Blue_Ridge_Escarpment said:
For some early afternoon entertainment, toggle the euro run from 12Z yesterday to 12Z today. One more jump like that and this thing is in the gulf. I think OTS is pretty much off the table now.
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The reason for the huge "jump" is whether or not this feels the weakness and interacts with the shortwave energy digging down. It's a very fluid and sensitive situation. Interaction with that shortwave will tug this north and closer to the weakness making it hard for this to make it to the US even if the ridge builds back in to block it. If it takes a track further south then it will miss that weakness and have a much better chance of hitting the US.

IMO here is the key to watch. There is significant divergence with the models between 50-55w. The models that are further south with stronger ridging like the UK diverge around 50W and by 55W the gap is fairly significant. In 2 days we will know a lot more about potential threats to the US once we see which path this takes and how much of a weakness there is.
06L_tracks_18z.png
 
Good news fwiw. The 12Z EPS has fewer members than the 0Z EPS hitting the SE US with Hs along with weaker average members. So, good vs the very bad 0Z EPS. But still quite threatening.
 
GaWx said:
Good news fwiw. The 12Z EPS has fewer members than the 0Z EPS hitting the SE US with Hs along with weaker average members. So, good vs the very bad 0Z EPS. But still quite threatening.
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Larry, I'm pretty darn good keeping up with testimony, but right now you have my head spinning ... keep up the great work! The more facts, the better for evaluating ... ;)
 
Good news vs the horrible 0Z EPS anyway. Out of 51 members, the 12Z EPS has only ~6 TS+ hits on the SE US vs the insane ~23 hits on the 0Z EPS, all on 9/13-4:
- 2 on NC, 1 far S GA, 3 N 1/2 of FL
 
The tracks that come close to the US or landfall stay much further south the next 48 hours hence the greater landfall threat due to less trough interaction and a stronger ridge building in to the north whereas the recurve solutions take it well north of 25N the next 48 hours. We will know a lot based simply on what happens the next 24-48 hours.
 
snowlover91 said:
The tracks that come close to the US or landfall stay much further south the next 48 hours hence the greater landfall threat due to less trough interaction and a stronger ridge building in to the north whereas the recurve solutions take it well north of 25N the next 48 hours. We will know a lot based simply on what happens the next 24-48 hours.
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This run look like the EPS from 2 runs ago (bigger spread and many fewer SE US hits). If there had not been that very threatening 0Z EPS, this run would have been thought of as equally threatening. But compared to the 0Z, it is way less threatening.
 
GaWx said:
This run look like the EPS from 2 runs ago (bigger spread and many fewer SE US hits). If there had not been that very threatening 0Z EPS, this run would have been thought of as equally threatening. But compared to the 0Z, it is way less threatening.
Click to expand...
Agreed, the EPS has been back and forth quite a bit and probably will be until we see which track verifies the next 48 hours as that will have significant implications on whether the threat increases or not. Notice the 18z suite below and how the divergence starts around 50W and then really expands by 55W. When we are dealing with the potential of trough interaction models will have widely diverging scenarios as we get close to the timeframe in question. By 55W if this is at or below 26N I think the chances of a US impact go up considerable whereas a track at 55W and north of 27N will allow this to have a chance for trough interaction. Shear appears to be affecting the core of Florence now and how much she weakens will play a big role as well.

06L_tracks_18z.png
 
GaWx said:
This run look like the EPS from 2 runs ago (bigger spread and many fewer SE US hits). If there had not been that very threatening 0Z EPS, this run would have been thought of as equally threatening. But compared to the 0Z, it is way less threatening.
Click to expand...

Agree, compared with the 0z run it appears like it backed off but when you look at this it looks troubling still. There is a weak trough digging into the SE at day 7. I bet if we plotted past SE/MA hurricanes that hit land it would look somewhat like the 5h map below.

14-km EPS Global Tropical Atlantic 500 hPa Height Anom 168.png eps_mslp_lows_atlantic_168.png
 
Kylo said:
Agree, compared with the 0z run it appears like it backed off but when you look at this it looks troubling still. There is a weak trough digging into the SE at day 7. I bet if we plotted past SE/MA hurricanes that hit land it would look somewhat like the 5h map below.

View attachment 5854 View attachment 5853
Click to expand...
Just need a little more of a closed ull over the western SE and that's a carolinas hit look

Sent from my SM-G955U using Tapatalk
 
SD said:
Just need a little more of a closed ull over the western SE and that's a carolinas hit look

Sent from my SM-G955U using Tapatalk
Click to expand...

Kind of what I was thinking, but I guess it could also kick it out too. The Bermuda ridge builds/retrogrades.
 
944
WTNT31 KNHC 052032
TCPAT1

BULLETIN
Hurricane Florence Advisory Number 26
NWS National Hurricane Center Miami FL AL062018
500 PM AST Wed Sep 05 2018

...FLORENCE STRENGTHENS INTO A CATEGORY 4 HURRICANE...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...22.7N 46.6W
ABOUT 1110 MI...1790 KM ENE OF THE NORTHERN LEEWARD ISLANDS
ABOUT 1295 MI...2080 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...953 MB...28.15 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the eye of Hurricane Florence was located
near latitude 22.7 North, longitude 46.6 West. Florence is moving
toward the northwest near 13 mph (20 km/h), and this general motion
is expected to continue through Thursday. A turn toward the
west-northwest with a decrease in forward speed is forecast to begin
Thursday night, followed by a turn back toward the northwest early
next week.

Maximum sustained winds have increased to near 130 mph (215 km/h)
with higher gusts. Florence is now a category 4 hurricane on the
Saffir-Simpson Hurricane Wind Scale. Some weakening is forecast
during the next couple of days, but Florence is expected to remain
a powerful hurricane through early next week.

Hurricane-force winds extend outward up to 15 miles (30 km) from the
center and tropical-storm-force winds extend outward up to 90 miles
(150 km).

The estimated minimum central pressure is 953 mb (28.15 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Florence will begin to affect Bermuda on
Friday. These swells are likely to cause life-threatening surf and
rip current conditions. Please consult products from your local
weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Berg/Rhome
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107
WTNT41 KNHC 052033
TCDAT1

Hurricane Florence Discussion Number 26
NWS National Hurricane Center Miami FL AL062018
500 PM AST Wed Sep 05 2018

Florence has continued to intensify during the day, with colder
cloud tops completely encircling a clearer eye. Both subjective and
objective Dvorak estimates have unanimously increased to T6.0/115
kt, and on this basis, the initial intensity is raised to 115 kt,
making Florence a category 4 hurricane.

Florence appears to be right along the southern edge of a zone of
stronger vertical shear and continues to defy the intensity
guidance, which has consistently been predicting weakening. That
said, the last few satellite images indicate that the eye may be
becoming slightly disrupted by the shear. Since the shear is
anticipated to increase during the next day or so, gradual weakening
is shown in the short-term official forecast, which lies along the
upper end of the guidance through 48 hours. Beyond 48 hours,
vertical shear is anticipated to weaken, which would allow Florence
to intensify and potentially regain major hurricane status. However,
Florence will need to thread the needle between areas of stronger
shear for this to happen, and there is significant uncertainty in
the intensity forecast. The new official intensity forecast is
little changed from before except to adjust upward to account for
the higher initial intensity.

The initial motion estimate remains northwestward, or 305/11 kt.
Strong upper-level ridging is forecast to strengthen north of
Florence over the next few days, forcing the hurricane to turn
toward the west-northwest through about 48 hours. Track guidance is
good agreement during this period, and the official forecast is
essentially an update to the previous one. Beyond day 2, a break
forms in the ridge, which results in a weakening of the steering
currents, a slowdown in Florence's forward speed, and a turn back
toward the northwest. The new official forecast is shifted south a
bit on days 3-5 to account for recent model trends and is closest to
the TVCN consensus.

It should be noted that there is considerable model ensemble spread
and run-to-run variability for Florence's track beyond day 5. Given
the large uncertainty at these time ranges, it is far too soon to
speculate what, if any, impacts Florence may have on the U.S. East
Coast next week. Regardless of Florence's eventual track, large
swells emanating from the hurricane will reach Bermuda beginning on
Friday, resulting in life-threatening surf and rip currents on the
island. Swells from Florence could also reach the U.S. East Coast by
early next week.
Click to expand...
 
Brent said:
969wmf.png
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Those that don’t recurve, look ominous for many on here! Even if just rain, but if it was a Cat 4 with those SE hits:eek::eek::eek:
 
Kylo said:
Agree, compared with the 0z run it appears like it backed off but when you look at this it looks troubling still. There is a weak trough digging into the SE at day 7. I bet if we plotted past SE/MA hurricanes that hit land it would look somewhat like the 5h map below.

View attachment 5854 View attachment 5853
Click to expand...
Many fronts the last few weeks, have not made it as far SE or been as strong as modeled! Just a thought
 
89D34F64-0A98-4FFD-BAE7-B11592E16E2B.jpeg The image above of the 12Z EPS members shows an accurate 12Z initialization. The 5PM location of 22.7N, 46.6W, is where the two lines cross. As you can see, the lines cross to the north of the mean near the northernmost members. I estimate the lines cross 0.5 degrees or 35 statute miles north of the mean. If Flo continues to track on the N edge of the members all other things being equal, that would be encouraging for a better chance for a safe recurve next week. I’d prefer she track on the northern edge over the middle and certainly over the southern edge. But that’s about as much as I can say about that as there is way too much uncertainty regardless of how it is now tracking with regard to the 12Z EPS.

Edited for typo (longitude)
Edit: So, Flo has moved NW since 12Z vs the WNW of the 12Z EPS mean.
 
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ridge looks crazy on the GFS, stronger than last run at 156 hours

174 hours looks headed for NC/VA
 
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SD said:
Just need a little more of a closed ull over the western SE and that's a carolinas hit look

Sent from my SM-G955U using Tapatalk
Click to expand...

That is what I was joking about yesterday. Even though it's a higher latitude, this is where modeling went with Irma in the mid range with the weakness over the SE capturing it and sending into SC/NC after tge OTS solutions. Of course it was wrong, but it's crazy the similarities.
 
Kylo said:
Good grief.
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Yup, but it is 8 days out ...
Go here, pick a storm or two or three, any year(s), and see how close even NHC typically is @ day 8 ... much less looking at an 18Z GFS run with no human input ... https://www.nhc.noaa.gov/archive/
Sure ... NHC gets them right sometimes, but just sayin', 18 Z modeling (or any) is not a poker table I'd sit at (yet) ... :confused:
 
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