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Major Hurricane Florence: STORM MODE THREAD

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Probably not. I don't think the NE flow of water is fast enough/deep enough to counteract upwelling. But I agree that the inner core has actually gotten its act together rather well. I doubt it intensifies much, but it'll probably at least hold serve
 
The flow at the surface would get stalled but that would not stop the fresh supply of warm waters at deeper layers which will get mixed out via upwelling.

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Nope, maybe closer to 960? Looks terrible.


To be fair, this is the best radar presentation Florence has had since coming into range. But Florence probably will still be steady state unless it continues with the deep convection and the eyewall continues organizing.74a1867ccf5ddf52e0dd9965c4a23378.jpg

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Looks like a flareup of convection around the southern and eastern eyewall on the last half hour of visible satellite.

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Just now, mempho said:

The flow at the surface would get stalled but that would not stop the fresh supply of warm waters at deeper layers which will get mixed out via upwelling.

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But the point I was trying to make is I don't think that happens at a fast enough rate such that it outpaces the speed of upwelling, especially for a storm the size of Florence.

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25 minutes ago, NJwx85 said:

I'm really amazed at how good she looks on radar. Not only are the moats filling in, but the entire rain shield looks to be expanding as well.

Surprised yet not surprised at the same time. Some of the hi res guidance showed this reorganizing fairly well. Not good news at all.

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*This is not a free pass to derail the thread again with talk about other storms.*  That being said, Diana in 1984 could be somewhat useful to keep in the back of the mind for what is possible with intensity since it meandered around the same area also in mid September.  After weakening from category 4, it was able to maintain category 2 status for a full day before weakening to category 1 at landfall.  Of course no two storms are exactly the same and water temps/OHC are just part of the puzzle.

 

image002.jpg

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But the point I was trying to make is I don't think that happens at a fast enough rate such that it outpaces the speed of upwelling, especially for a storm the size of Florence.
Fair enough. I can see your point as well and it is debatable. Are there any buoys moored directly in the Gulf Stream close to the eye that would enable us to see what actually happens?

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2 minutes ago, salbers said:

Convection is now appearing on the north side of the eye as well...

 

Yup almost completely wrapped around, with a very apparent eye becoming visible. 

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4 minutes ago, EastKnox said:

Looks like a little southerly shear at the moment.

goes16_vis_06L_201809132013.jpg

Been a small amount of shear all day but it's been relatively weak and not having a huge impact.

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11 minutes ago, Angrysummons said:

This is classic map watching bias. There is always bursts of convection at different points. Your so desperate, your willing to believe anything.

?

The radar presentation is improving.

The satellite presentation is showing intense convection wrapping around the core.

The satellite estimated intensity (ADT) numbers are starting to rise.

 

Might be a short term trend and it goes to crap when it gets over the shallower waters but anyone looking at this objectively would agree that it is currently strengthening.

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1 minute ago, KPITSnow said:

I mean, it does look fairly good on visible, but when you look at IR images it is still pretty ragged looking. 

The IR images show the skeleton and this hurricane is not doing well.  Still ingesting dry air it looks like.  From the north.

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2 minutes ago, KPITSnow said:

I mean, it does look fairly good on visible, but when you look at IR images it is still pretty ragged looking. 

that's why i love that new GOES 17 viewer.  throw on the cirrus band and you can see through the emperor's new clothes in a way that traditional visible channels obscure.

798507471_cirrusband.thumb.PNG.99c9c5cc7a8f72f7f6aa860bfa491d6c.PNG

 

 

 

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On the first recon pass through the core, extrap central pressure was down to around 952. Wind speeds show a very broad field of hurricane force, ~60 knots in the SW side, 70s kt on the NE side w/ 90s at flight level, waiting for dropsondes to provide more details.

 

Edit: Corrected the winds, accidentally had flight level winds

Dropsonde shows 956 mb, so more or less holding steady state in terms of pressure and wind, basically confirming this is a giant category 1 cane.

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2 minutes ago, mattb65 said:

On the first recon pass through the core, extrap central pressure was down to around 952. Wind speeds show a very broad field of hurricane force, 60-70 knots in the SW side, 90-95 kt on the NE side, waiting for dropsondes to provide more details.

Those are FL winds.

Highest surface winds were around 75kts but again need dropsondes to confirm. 

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We're not going to see wind speeds increase with the system so broad and so close to shore. Pressures may end up dropping some, but you'd need a significant pressure drop to have much increase in winds with such a large wind field. The only difference a strengthening system versus a weakening one at landfall is you'll be able to mix down FL winds more efficiently. With a dropsonde showing 956 MB we can also confirm there has been little change in pressures over the last several hours. 

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207 
WTNT41 KNHC 132052
TCDAT1

Hurricane Florence Discussion Number  58
NWS National Hurricane Center Miami FL       AL062018
500 PM EDT Thu Sep 13 2018

The satellite and radar presentations of Florence have changed
little this afternoon with a 20-25 nmi wide eye waxing and waning
as intrusions of dry air have occasionally eroded the southern and
eastern eyewall. Despite the occasional ragged appearance of
Florence's eye, reconnaissance aircraft data indicate that the
central pressure has remained steady at 955 mb. The last reports
from the Air Force Reserve hurricane hunters support an intensity
of 85 kt, and this is corroborated by average Doppler velocity
values of near 105 kt at 2500-3000 ft ASL. A report of a 10-minute
average wind of 59 kt and a gust to 74 kt was recently received from
the Cape Lookout C-MAN station (CLKN7). The 59-kt 10-minute wind
speed is roughly equivalent to a 65-kt 1-minute wind.

Florence has continued to slow down, and radar fixes over the past
couple hours suggest that Florence has possibly stalled due to a
re-organization of the eye/eyewall. Smoothing through the fixes
over the past 6 h yields an initial motion estimate of 295/04 kt.
There is no change to the previous forecast reasoning. The ridge to
the north and east of Florence remains intact over the Atlantic
Ocean, but water vapor imagery and special upper-air observations
indicate that a shortwave trough has weakened that portion of the
ridge along the U.S. mid-Atlantic coast, resulting in a weakening
of the steering currents. The ridge is forecast by all of the
latest model guidance to remain intact, albeit weak, for the next 72
hours, which will nudge Florence on a slow westward to west-
southwest track into central South Carolina. On days 4 and 5,
Florence is expected to become an extratropical low as it interacts
with a front while moving northward and northeastward along the
Appalachian Mountains. The official forecast track is similar to,
but slightly south of the previous advisory track through 72 hours,
with little change indicated on days 4 and 5. This scenario closely
follows the simple consensus model TVCN/TVCA, which is north of the
corrected-consensus models HCCA and FSSE, which are heavily weighing
the southernmost model, ECMWF, which keeps Florence over or near the
Atlantic through about 48 hours.

Radar data indicate that Florence may be developing an outer
eyewall. If this trend continues, then little change to the
intensity is likely until landfall occurs in about 24 hours due in
part to the low vertical wind shear conditions and the warm, deep
waters of the Gulfstream current. Florence is expected to weaken
after landfall, but the rate of weakening may be tempered somewhat
due to much of the hurricane's circulation remaining over the warm
waters of the Atlantic Ocean and Gulfstream. Once Florence moves
farther inland over central South Carolina, rapid weakening of
the inner-core wind field should occur due to land interaction and
the cyclone's slow forward speed of 5 kt or less. However, intense
rainbands are expected to continue developing over the Atlantic
waters and keep moving along the coast and inland, likely producing
strong wind gusts through Saturday night.

Aircraft and satellite wind data show that Florence remains a large
hurricane.  Life-threatening storm surge, heavy rainfall, and
damaging wind will cover a large area regardless of exactly where
the center of Florence moves.

Key Messages:

1. A life-threatening storm surge is highly likely along portions of
the coastlines of South Carolina and North Carolina, and a Storm
Surge Warning is in effect for a portion of this area. The greatest
storm surge inundation is expected between Cape Fear and Cape
Hatteras, including the Neuse and Pamlico Rivers and western Pamlico
Sound.

2. Life-threatening, catastrophic flash flooding and prolonged
significant river flooding are likely over portions of the Carolinas
and the southern and central Appalachians through early next week,
as Florence is expected to slow down as it approaches the coast and
moves inland.

3. Damaging hurricane-force winds are likely along portions of the
coasts of South Carolina and North Carolina beginning this evening,
and a Hurricane Warning is in effect. Strong winds could also spread
inland into portions of the Carolinas.

4. Large swells affecting Bermuda, portions of the U.S. East Coast,
and the northwestern and central Bahamas will continue this week,
resulting in life-threatening surf and rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT  13/2100Z 33.7N  76.2W   85 KT 100 MPH
 12H  14/0600Z 34.1N  77.2W   85 KT 100 MPH
 24H  14/1800Z 34.2N  78.2W   75 KT  85 MPH...INLAND
 36H  15/0600Z 33.9N  79.0W   50 KT  60 MPH...INLAND
 48H  15/1800Z 33.8N  79.9W   35 KT  40 MPH...INLAND
 72H  16/1800Z 34.8N  82.3W   25 KT  30 MPH...INLAND
 96H  17/1800Z 37.9N  82.6W   20 KT  25 MPH...POST-TROP/INLAND
120H  18/1800Z 42.7N  76.3W   20 KT  25 MPH...POST-TROP/INLAND

$$
Forecaster Stewart

 

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And just like that the Southern half of the storm has nearly completely dried up again with a large moat now wrapping itself about 2/3rds of the way around the core.

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