Major Hurricane Florence: STORM MODE THREAD

[PackGrad05]

Brad Panovich doing a facebook live.  Just said that he believes it'll have an opportunity to strengthen over gulf stream tomorrow...  Also the core seems to be intact which helps protect it from some shear, etc....

[NJwx85]

The southerly shear is finally gone. You can see how the outflow has finally reestablished itself. Still a good 24 hours or so to ramp back up and probably not enough time to cause another ERC. 

[Amped]

47 minutes ago, Amped said:

Looking at the shear profile, there is a tutt that is progged to dig south of Florence in the next 6-12 hrs.  This will change the 200mb wind trajectory over Florence from a line to a sideways U shape.  I am not sure if this will have a positive or negative impact on Florence.

Appearance has started improving again in the last hour.  It's starting to encounter the gulfstream now too.  Starting to think the last 6hrs may have just been a fakeout. 

[40/70 Benchmark]

Been one of the more interesting evolutions that I can recall..that is for sure.

[zinski1990]

17 minutes ago, NJwx85 said:

Major improvements the last hour or so.

It is starting to reorganize can't deny it. Question is how much will it ramp back up to?

[friedmators]

Pretty big wind field on this thing. I’m on the water in Virginia Beach and it’s a pretty constant 15-20 mph breeze.


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[NJwx85]

2 minutes ago, friedmators said:

Pretty big wind field on this thing. I’m on the water in Virginia Beach and it’s a pretty constant 15-20 mph breeze.


.

It’s already gusting 10-15 on the NJ shore and waves are expected to be 8-12 feet just offshore.

[Eskimo Joe]

 

[NJwx85]

Convection is really starting to fill in on the Southern half now. Once the shear relaxed it appears to be all systems go. It’s amazing how many evolutions she’s gone through, deepening to a cat 4 twice and almost diminishing twice so far.

[WinterWolf]

3 minutes ago, NJwx85 said:

Convection is really starting to fill in on the Southern half now. Once the shear relaxed it appears to be all systems go. It’s amazing how many evolutions she’s gone through, deepening to a cat 4 twice and almost diminishing twice so far.

Very true...she’s been all over the map.

[hazwoper]

10 minutes ago, friedmators said:

Pretty big wind field on this thing. I’m on the water in Virginia Beach and it’s a pretty constant 15-20 mph breeze.


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That is just as much to do with the gradient with the high pressure to the north In Your area

[Hoosier]

Besides being somewhat farther north, Florence seems to be running a tad quicker than what the NHC had.  Curious to see if the 00z runs will have a quicker progression inland.  

[DJnVa]

https://twitter.com/crankywxguy/status/1040051318822449152

Continues to ride north of the 5pm cone. After they adjusted the 5pm cone north because...it was riding north of the 11am cone. Yeah, that's kind of a trend.

[LongBeachSurfFreak]

12 minutes ago, Eskimo Joe said:

 

I know this was posted earlier but I just wanted to mention that Ocracoke is probably the most hurricane prone area of the country. They are likely to be well north of the core winds and surge. Allot of those hardy people have been through over a dozen full fledged canes. If Florence were 100 miles further north we could be talking a Bolivar peninsula repeat. But chances are very high they will be just fine. The OBX in that area have a very small shelf comparatively to the rest of the east coast so they are much less surge prone. They will likely experience washovers and will probably be without power for a few weeks but if your a salty fisherman who’s been there done that it comes with the territory  

[ag3]

14 minutes ago, Hoosier said:

Besides being somewhat farther north, Florence seems to be running a tad quicker than what the NHC had.  Curious to see if the 00z runs will have a quicker progression inland.  

0z Nam has landfall 2am Friday morning as a category 1 type storm.

[ncskywarn]

NAM is NW made landfall near Wilmington at hour 33 moving W at hour 36 & 39 stalled on the NC & SC border at 42 & 45. Edit: still stalled same place hour 51.

[Hoosier]

6 minutes ago, ag3 said:

0z Nam has landfall 2am Friday morning as a category 1 type storm.

I wouldn't use the NAM pressure to extrapolate the strength at landfall. Look what it initialized at compared to what it actually is.  Something like the HWRF may do better but even then it's tricky.  

[olafminesaw]

It may partly be a function of a different part of the eye being exposed, but it appears that Flo has taken a big step to the West over the past few hours.

[Dunkman]

2 minutes ago, olafminesaw said:

It may partly be a function of a different part of the eye being exposed, but it appears that Flo has taken a big step to the West over the past few hours.

Definitely need to use a more long-term motion when dealing with a ragged eye like this. It's gonna wobble all over the place.

[ncskywarn]

20 minutes ago, Hoosier said:

I wouldn't use the NAM pressure to extrapolate the strength at landfall. Look what it initialized at compared to what it actually is.  Something like the HWRF may do better but even then it's tricky.  

Only reason I'm even using it at all is we are within 36 hours and both Reg and 3K NAM are significantly North of 18Z. Not using it for landall strength. Edit after moving maybe 20-30 miles between hours 42-57 it moves SW and parks near Charlestion at hour 66 until 75. Then starts moving W and is on the SC/GA border at the end of it's run at hour 84.

[NJwx85]

She just took a big wobble almost due North.

[Windspeed]

Old mid-level eye clouds and cirrus canopy on satellite can be deceiving versus actual center fix of core surface circulation. Also, concentric outer banding may be closer to actual recon fix and progressive evolution for tracking, regardless if the NW banding becomes a new eyewall. It's certainly more difficult in degraded presentation to follow on satellite. Simply put, focusing on the cloud pattern of that old eye may mislead you versus actual recon center fix.

 

 

 

 

[Buddy1987]

The satellite is showing all 4 quadrants beginning to look healthy once again I’m curious to see what this thing looks like when most of us wake up tomorrow morning.

whatever shear was impeding the western and southern portion of the storm has completely stopped now 

[Hoosier]

4 minutes ago, ncskywarn said:

Only reason I'm even using it at all is we are within 36 hours and both Reg and 3K NAM are significantly North of 18Z. Not using it for landall strength.

That would seem to match up with track trends.  This is kind of obvious but the farther north it gets, the more unlikely it would be able to get back over the water on the way to SC. 

[Hoosier]

957 mb and 110 mph on new advisory.

[Windspeed]

874 
WTNT41 KNHC 130249
TCDAT1

Hurricane Florence Discussion Number  55
NWS National Hurricane Center Miami FL       AL062018
1100 PM EDT Wed Sep 12 2018

Satellite data and reports from Hurricane Hunter aircraft indicate
significant changes in the structure of Florence and the
environment near the storm since the last advisory.  Microwave
satellite imagery shows that the convection on the southern side of
the storm has been disrupted, and reports from an Air Force Reserve
Hurricane Hunter aircraft indicate the eyewall now wraps less than
50 percent of the way around the center.  The aircraft also reports
that the hurricane again has concentric wind maxima, the inner at a
radius 20-30 n mi and the outer at 50-60 n mi.  The convection seems
to have been affected by 20-25 kt of southerly vertical wind shear,
most of which appears to be due to strong winds between 200-250 mb
seen in dropsonde data from the NOAA G-IV jet.  The central
pressure has risen to 957 mb, and the maximum 700-mb flight-level
winds reported so far are 103 kt.  Based on the latter data, the
initial intensity reduced to a probably generous 95 kt.

The initial motion is 315/15.  During the next 12-36 hours, the
hurricane is expected to turn toward the west-northwest and west
with a decrease in forward speed as it moves into an area of
weakening steering currents near and over the southeastern United
States.  The new forecast track now brings the center onshore in
southern North Carolina near the 36 h point.  After landfall, the
cyclone should move slowly westward to west-southwestward through
the 72 h point, then it should turn northwestward to northward by
the end of the forecast period as it moves through the Appalachian
Mountains.  The new forecast track lies between the HCCA corrected
consensus model and the other consensus aids, and it is nudged just
a little to the north of the previous track.

The dynamical models forecast the current shear to subside after
6-12 h as Florence moves farther from an upper-level low currently
near northeastern Florida.  This, combined with sea surface
temperatures near 29C, would allow a last chance for strengthening
before landfall.  However, the storm structure, particularly the
large outer wind maxima, would likely be slow to respond to the
more favorable environment.  The pre-landfall part of the intensity
forecast thus calls for little change in strength, but given the
uncertainties the confidence in this is low.  After landfall,
Florence should gradually weaken during the 36-48 h period while
the center is near the coast, then weaken more quickly when the
center moves farther inland.

While Florence has weakened below major hurricane intensity, the
wind field of the hurricane continues to grow in size.  This
evolution will produce storm surges similar to that of a more
intense, but smaller, hurricane, and thus the storm surge values
seen in the previous advisory are still valid.  The threat of
rainfall has also not diminished, and these impacts will cover a
large area regardless of exactly where the center of Florence moves.


Key Messages:

1. A life-threatening storm surge is now 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.  All
interests in these areas should complete preparations and follow any
advice given by local officials.

2. Life-threatening, catastrophic flash flooding and prolonged
significant river flooding are likely over portions of the Carolinas
and the southern and central Appalachians late this week into 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, 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  13/0300Z 32.0N  73.7W   95 KT 110 MPH
 12H  13/1200Z 33.1N  75.3W   95 KT 110 MPH
 24H  14/0000Z 33.9N  76.7W   95 KT 110 MPH
 36H  14/1200Z 34.2N  78.0W   80 KT  90 MPH...INLAND
 48H  15/0000Z 34.1N  78.7W   60 KT  70 MPH...INLAND
 72H  16/0000Z 33.5N  80.5W   40 KT  45 MPH...INLAND
 96H  17/0000Z 34.0N  83.0W   25 KT  30 MPH...INLAND
120H  18/0000Z 37.5N  83.5W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven

 

[Windspeed]

New 11 PM graphic:

 

[NycStormChaser]

2 minutes ago, Windspeed said:

New 11 PM EDT graphic:

says 8pm

[BlueRidgeFolklore]

[ncskywarn]

ICON is West at 21. Edit: makes landfall near North Topsail at 33 and is moving West inland at 48. Edit: Looks like Northern model trends continue next up GFS