ATL: FLORENCE - Post-Tropical - Discussion

[Hammy]

Looks like some easterly shear and dry air entrainment going on--if you watch the outer bands to the east, there's no outflow but it looks like the cloud tops are being blown back to the west.

[otowntiger]

Dry slot still to the west, superimposed with a strong shear axis.
No sign of an outflow channel yet.
Would be a game changer if it could tap into 95L's convective debris.

When you say ‘game changer’- exactly what do you mean in this case? Thanks.

[jlauderdal]

Looks liked they bumped the path a little to the left at the 5 am advisory

yes, they are discounting(not ignoring or throwing it out) the right biased gfs, its a real issue with that model..obx and a little south look to take an eyewall..a chasers dream cape lookout if that track holds on the NE quad, morehead city all seems good now, fine tuning closer to landfall..btw, can we stop with the its going to be wiped off the face of the earth, this region has been taking major hurricanes for a very long time, damage of course but the strong stuff survives even a surge...that said, if you are in an evacuation zone, get out

[Nimbus]

Looks like Florence picked up a little dry air during the EWRC.
Models showing a slowdown off the coast of North Carolina which is probably due to that ridging from the south bridging up over, since there doesn't seem to be a trough in the forecast.
The narrow cyclonic outflow channel to the west is really getting squeezed and should fill as the ridge builds over.
Perhaps there will then be too much shear from the west for Florence to go sub 930 mb?

[1900hurricane]

Florence actually looks remarkably well walled off from dry air to me.

[NDG]

[p1nheadlarry]

Emerald Isle NC on the coast

I will come on wed and find a staging area nearby. However, the coast is the not a good idea. looking at your elevation of 10 feet. the estimated surge is 15 plus.. then wave action.. even if it weakens the surge will still be the same as a 4 or 5..

Wilmington, NC is the nearest place with parking garages I think,

They're all downtown by the river, UNCW will not let you use theirs. Some hotels have already told people that they have to cancel reservations if mandatory evacs started.

[SconnieCane]

To me on that and the SSD floater loop the CDO looks quite robust and the new eye about ready to take off. Convection definitely much deeper and more symmetrical than when I went to bed. Any dry air entrained has been/will soon be mixed out.

[GCANE]

Dry slot still to the west, superimposed with a strong shear axis.
No sign of an outflow channel yet.
Would be a game changer if it could tap into 95L's convective debris.

When you say ‘game changer’- exactly what do you mean in this case? Thanks.

The moisture of the convective debris, if it gets ingested by Flo, would be very conducive for additional strengthening.
Something to keep a close eye on.

[1900hurricane]

It's worth noting that Florence is crossing a subsident background environment, but this actually isn't a bad thing for the system. Instead of having massive outflow channels, Florence really only has an ok poleward one. That's because the rest of the (rather good) radial outflow is being taken care of by the surrounding subsidence. None of it is impinging on the circulation due to the low shear environment, and it is removing mass. This is a case where subsidence isn't always a bad thing for a tropical cyclone. This actually is a similar setup to many of the powerful El Nino WPac Typhoons, and was also seen in the NAtl last September, particularly with Irma.

[HurricaneFrances04]

Pressure up to 951 mb according to the recon pass.

[eastcoastFL]

Photos from buoy cam near Florence reporting 45kt winds and 27ft waves

https://www.ndbc.noaa.gov/station_page. ... tion=41049

[wxman57]

Looking more likely Florence will slow its forward speed considerably as it nears the NC coast. Landfall may be delayed until around sunrise Friday. It would then turn westward and track very slowly west across southern NC, possibly all the way to northeast SC (as a remnant low by then). This could mean 2-3 days of a slow-moving hurricane to TS tracking west across southern NC. Hurricane force winds would lash the NC coast for a long time, and the threat for extremely heavy rain would go up. Think Harvey with wind and surge. I wouldn't want to be living there.

Oh, and looks like max winds are down to about 100 kts now (115 mph), but don't fret, as the new larger eye contracts it should regain Cat 4 strength this evening. However, it's core of stronger winds will expand a bit, making it even worse when it reaches the coast. Have to go now. We are working 8 active storms around the world now. Might check in after work this evening.

[artist]

Floater loop
http://www.ssd.noaa.gov/PS/TROP/floater ... imated.gif

[GCANE]

Preliminary Recon
112 knots peak SFMR (clear)
103.9 knots avg SFMR (Cat 3)
951.5mb
26.350N 64.400W
10:47:30Z
Rain Rate 58mm/hr

Lots of Latent Heating still underway.
Likely to ramp back up.

[1900hurricane]

Looks like Florence is down to about 110 kt at the moment to me, but I suspect it will rebound fast.

[otowntiger]

Dry slot still to the west, superimposed with a strong shear axis.
No sign of an outflow channel yet.
Would be a game changer if it could tap into 95L's convective debris.

When you say ‘game changer’- exactly what do you mean in this case? Thanks.

The moisture of the convective debris, if it gets ingested by Flo, would be very conducive for additional strengthening.
Something to keep a close eye on.

Ok, gothcha thanks! I was wondering if it would affect its track as the NHC was alluding to regarding the possible ridge erosion that 95l was causing- but that was confusing me a bit.

[GCANE]

Much bigger eye. EWRC at or near completion.


Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 11th day of the month at 11:10Z

A. Time of Center Fix: 11th day of the month at 10:47:30Z
B. Center Fix Coordinates: 26.35N 64.40W

F. Eye Character: Open in the north
G. Eye Shape & Diameter: Circular with a diameter of 34 nautical miles (39 statute miles)
H. Estimated (by SFMR or visually) Maximum Surface Wind Inbound: 98kts (112.8mph)
L. Estimated (by SFMR or visually) Maximum Surface Wind Outbound: 112kts (128.9mph)
P. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 11°C (52°F) at a pressure alt. of 3,046m (9,993ft)
Q. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 15°C (59°F) at a pressure alt. of 3,053m (10,016ft)

Maximum Flight Level Wind: 113kts (~ 130.0mph) which was observed 22 nautical miles (25 statute miles) to the NW (317°) from the flight level center at 10:40:30Z

CENTER DROPSONDE TERMINATED AT 13M WITH WINDS 140 DEGREES 12 KNOTS

[GCANE]

[GCANE]

Close in gravity waves on the cirrus trailing off the eyewall convective burst.
Sure sign of strengthening.