ATL: FLORENCE - Post-Tropical - Discussion

[Aric Dunn]

must keep a close eye on the motion today.. as is usual with building ridges they often come with more drawn out wsw to west motion.. especially when the are strong as in this case.

Slightly S already...

yeah it has been. NHC went with 24.4 instead of 24.2/24.5..

next recon pass coming. its going to be wobble watching event lol

[toad strangler]

must keep a close eye on the motion today.. as is usual with building ridges they often come with more drawn out wsw to west motion.. especially when the are strong as in this case.

Slightly S already...

yeah it has been. NHC went with 24.4 instead of 24.2/24.5..

next recon pass coming. its going to be wobble watching event lol

 https://twitter.com/TropicalTidbits/status/1038807240898170880

[Aric Dunn]

This next pass is looking farther wsw..

[Hurricaneman]

Just using data from the advisories. Here are the last 10 advisories and the forecasted position closest to 25N

24.9N 59.3W
24.8N 58.3W
24.8N 57.4W
25.0N 58.3W
24.8N 57.5W
24.9N 59.0W
25.0N 57.8W
24.8N 57.0W
24.9N 55.1W
25.0N 54.3W

If Flo hasn't crossed 25N by 60W I would expect to see some moderate model changes. Here's why I think this: 25N isn't just a nice even number, it happens to be where the accelerated northern motion begins.

That’s where North Florida gets a bit nervous too, let’s hope a prolonged 265to270 motion isn’t in the cards

[Aric Dunn]

Slightly S already...

yeah it has been. NHC went with 24.4 instead of 24.2/24.5..

next recon pass coming. its going to be wobble watching event lol

https://twitter.com/TropicalTidbits/sta ... 0898170880

Yes very good advice for those in the cone.. but prolonged wobbles now ( since the models show it turning soon) can have a large effect on tack position 5 days from now.

[Raebie]

Florida folks should already be prepared. In case they haven't noticed, there are 2 systems right behind Florence and October is a long way away.

[chaser1]

I will say this however, the overall appearance "or tilt" of Florence's entire envelope structure does appear oriented in a way that commonly proceeds or even suggests a WNW motion. It's very orientation makes me think it'll begin moving WNW practically immediately. If it were to continue on a steadfast 270 motion into tomorrow you'd have to think there will be more then a few raised eyebrows. Jeeez, i'd love to know how well the FSU Super-ensemble has performed with Flo thus far and how much further west it's projecting landfall

[Rail Dawg]

Am heading to Wilmington, NC (currently) from Houston Tues morning.

Trying to upload image of the New Hanover County (Wilmington) storm surge map.

How do you do this on this site using an image upload service like Google?

As usual going in loaded for bear.

I give a lot of credence to the NHC forecasts these days.

[Highteeld]

982-983 mb or so. Pressure is falling

[floridasun78]

Florida folks should already be prepared. In case they haven't noticed, there are 2 systems right behind Florence and October is a long way away.

look at nw Caribbean look we could see circle that area by 2pm or 8pm twc was talking about it

[chaser1]

Just using data from the advisories. Here are the last 10 advisories and the forecasted position closest to 25N

24.9N 59.3W
24.8N 58.3W
24.8N 57.4W
25.0N 58.3W
24.8N 57.5W
24.9N 59.0W
25.0N 57.8W
24.8N 57.0W
24.9N 55.1W
25.0N 54.3W

If Flo hasn't crossed 25N by 60W I would expect to see some moderate model changes. Here's why I think this: 25N isn't just a nice even number, it happens to be where the accelerated northern motion begins.

That’s where North Florida gets a bit nervous too, let’s hope a prolonged 265to270 motion isn’t in the cards

Great analysis and a very good point regarding the anticipated increase in forward speed. Once Flo bends WNW and accelerates landfall risk should be that much more apperant. Of course if Florence were to continue heading due west with a sudden increased speed of say 20 kt's though.... I might offer to take up a collection for a case of Depends for the kind folks over at NHC as bathroom breaks down there may become suddenly a lot harder to come by lol.

[eastcoastFL]

yeah it has been. NHC went with 24.4 instead of 24.2/24.5..

next recon pass coming. its going to be wobble watching event lol

https://twitter.com/TropicalTidbits/sta ... 0898170880

Yes very good advice for those in the cone.. but prolonged wobbles now ( since the models show it turning soon) can have a large effect on tack position 5 days from now.

Yup. I've admittedly been watching the motion a lot and according to dvorak fixes its continued to have rather decent jumps to the wsw. I still don't think models have a full grasp on when the motion will turn wnw until the ridge actually gets in place. I don't know if they are over or underestimating the motion from the ridge but I doubt they are spot on yet.

[GCANE]

[Rail Dawg]

OK figured out how to post images.

Storm surge map for Wilmingon, NC:

[AJC3]

Just throwing this out there to clarify that all Atlantic ridges, weak and strong, are not created equally. Storm motion has just as much to do with the position and orientation of the ridge axis, as it does its strength.

This is idealized, or course, but a stronger ridge will generally send a TC farther westward at a faster rate of speed, however, this assumes a mostly zonal (W-E) orientation to the ridge. The more meridional (N-S) component there is, or develops, the more poleward a TC can and will move. Even a weaker Atlantic ridge will continue to send a TC generally westward (let's not get into beta-effect or drift ) , just at a slower forward speed, and that motion will continue just as long as there isn't a breach or significant weakness in said ridge.

[GCANE]

Product: NOAA Vortex Message (URNT12 KWBC)
Transmitted: 9th day of the month at 15:45Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Lockheed WP-3D Orion (Reg. Num. N42RF)
Storm Number & Year: 06 in 2018
Storm Name: Florence (flight in the North Atlantic basin)
Mission: Second flight of a sequence of non-tasked research missions into this system
Observation Number: 16 ( See all messages of this type for this mission. )

A. Time of Center Fix: 9th day of the month at 15:21:43Z
B. Center Fix Coordinates: 24.34N 56.37W
B. Center Fix Location: 747 statute miles (1,202 km) to the ENE (57°) from San Juan, Puerto Rico (U.S.).
C. Minimum Height at Standard Level: Not Available
D. Minimum Sea Level Pressure: 984mb (29.06 inHg)
E. Dropsonde Surface Wind at Center: From 265° at 14kts (From the W at 16mph)
F. Eye Character: Open from the east to the southeast
G. Eye Shape & Diameter: Circular with a diameter of 20 nautical miles (23 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 64kts (73.6mph)
I. Location & Time of the Estimated Maximum Surface Wind Inbound: 19 nautical miles (22 statute miles) to the N/NNE (11°) of center fix at 15:16:52Z
J. Maximum Flight Level Wind Inbound: From 95° at 68kts (From the E at 78.3mph)
K. Location & Time of the Maximum Flight Level Wind Inbound: 16 nautical miles (18 statute miles) to the NNE (13°) of center fix at 15:17:45Z
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 62kts (71.3mph)
M. Location & Time of the Estimated Maximum Surface Wind Outbound: 9 nautical miles to the SSW (192°) of center fix at 15:23:51Z
N. Maximum Flight Level Wind Outbound: From 279° at 65kts (From the W at 74.8mph)
O. Location & Time of the Maximum Flight Level Wind Outbound: 8 nautical miles to the SSW (193°) of center fix at 15:23:38Z
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 16°C (61°F) at a pressure alt. of 2,441m (8,009ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 18°C (64°F) at a pressure alt. of 2,490m (8,169ft)
R. Dewpoint Temp (collected at same location as temp inside eye): 13°C (55°F)
R. Sea Surface Temp (collected at same location as temp inside eye): Not Available
S. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
S. Fix Level: Other - Not surface, 1500ft, 925mb, 850mb, 700mb, 500mb, 400mb, 300mb or 200mb
T. Navigational Fix Accuracy: 0.01 nautical miles
T. Meteorological Accuracy: 2 nautical miles

Remarks Section:

Maximum Flight Level Wind: 70kts (~ 80.6mph) which was observed 12 nautical miles (14 statute miles) to the ENE (60°) from the flight level center at 14:16:40Z
Maximum Flight Level Temp: 19°C (66°F) which was observed 8 nautical miles to the NNE (17°) from the flight level center

[jlauderdal]

Every wobble matters as to the end result of the eyewall landfall

must keep a close eye on the motion today.. as is usual with building ridges they often come with more drawn out wsw to west motion.. especially when the are strong as in this case.

Slightly S already...

yeah it has been. NHC went with 24.4 instead of 24.2/24.5..

next recon pass coming. its going to be wobble watching event lol

[GCANE]

Recon reports 20nm eye
984mb.
Moving due west
2C Core Temp

[LarryWx]

Per visible loops, I think Flo is now ~24.35N and I’m guessing she’s moving about due W.

[toad strangler]

 https://twitter.com/NWSCharlestonSC/status/1038819027882311681