ATL: FLORENCE - Post-Tropical - Discussion

[chaser1]

GOES-16 is the best weather invention since the barometer. <3

http://rammb.cira.colostate.edu/ramsdis/online/loop.asp?data_folder=loop_of_the_day/goes-16/20180910000000&number_of_images_to_display=400&loop_speed_ms=25

See that small flock of pelicans down there? There's a lot of pressure on the one flying point to keep the right vector going

[seahawkjd]

Sorry for the off topic post but I just realized that as of today I have been a member on the board for 15 years. You all really didn't need to send a major hurricane my way in celebration lol.

[WAcyclone]

Looks like there are instantaneous windspeeds well above the Cat 5 threshold in the lower parts of the southern eyewall:

[plasticup]

Does this dropsonde show 143 kt surface-level winds in the southern eyewall? I am reading that correctly?

[cheezyWXguy]

Florence is making some pretty solid progress of developing a ring of -69C to -75C cloud temps around its eye. Im not all that familiar with the dvorak technique, but isn't that closing in on 6.0?

This seems like a decent page for Dvorak updates.

http://tropic.ssec.wisc.edu/real-time/adt/odt06L.html

You have recon, i suggest using that.

So you're saying there is no point in becoming familiar with the dvorak technique for future use cases, because we have recon available for this one?

[Exalt]

viewtopic.php?f=30&t=119915

Can someone give me some evacuation advice? Am in the W&M campus, considering evacuation tomorrow night. Thanks.

[plasticup]

Looks like there are instantaneous windspeeds well above the Cat 5 threshold in the southern eyewall:

I just posted that in the Recon Discussion thread. It is so incongruous with other measurements, although there was that one 123 kt SFMR flagged reading.

[NotoSans]

The eyewall dropsonde suggests that the SFMR winds may actually be valid. I personally would have go with 120 knots right now.

[chaser1]

I'm really doubting that we're even seeing a "stair-stepping" going on at this point. Seems to me that Flo's motion is far less erratic and looking pretty steady. If an increase in forward speed were to be beginning to occur then I'd guess this train(wreck) might have finally read NHC's script.

[plasticup]

We may get another Update Statement. If the NHC find this data credible, Florence is already a Category 5. And firmly in that range, too.

[Hypercane_Kyle]

Dropsonde found 143 knots at the surface, with Cat 5 winds all the way to the 910mb level.

Could be a gust, but wow.

http://tropicalatlantic.com/recon/recon ... 49-152-143

[Ken711]

I'm really doubting that we're even seeing a "stair-stepping" going on at this point. Seems to me that Flo's motion is far less erratic and looking pretty steady. If an increase in forward speed were to be beginning to occur then I'd guess this train(wreck) might have finally read NHC's script.

Was it suppose to have started moving wnw by now according to the NHC forecast?

[NotoSans]

We may get another Update Statement. If the NHC find this data credible, Florence is already a Category 5. And firmly in that range, too.

Dropsonde winds are more representative of gust instead of sustained winds. Definitely not a category 5 right now, although Florence has a chance to become one.

[plasticup]

We may get another Update Statement. If the NHC find this data credible, Florence is already a Category 5. And firmly in that range, too.

Dropsonde winds are more representative of gust instead of sustained winds. Definitely not a category 5 right now, although Florence has a chance to become one.

Fair point, thanks.

[KWT]

I'm really doubting that we're even seeing a "stair-stepping" going on at this point. Seems to me that Flo's motion is far less erratic and looking pretty steady. If an increase in forward speed were to be beginning to occur then I'd guess this train(wreck) might have finally read NHC's script.

Was it suppose to have started moving wnw by now according to the NHC forecast?

Broadly yes and I think it's pretty much on track right now. Wobbles will start to count more soon enough.

[Gustywind]

Hurricane Florence Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL062018
1200 PM AST Mon Sep 10 2018

...FLORENCE BECOMES A CATEGORY FOUR HURRICANE...

Data from a NOAA Hurricane Hunter aircraft indicate that Florence
has continued to rapidly stregthen and has maximum sustained winds
near 130 mph (195 km/h). The latest minimum central pressure based
on data from the aircraft is 946 mb (27.93 inches).


SUMMARY OF 1200 PM AST...1600 UTC...INFORMATION
---------------------------------------------------
LOCATION...25.0N 60.2W
ABOUT 575 MI...925 KM SSE OF BERMUDA
ABOUT 1230 MI...1985 KM ESE OF CAPE FEAR NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...130 MPH...195 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...946 MB...27.93 INCHES

$$
Forecaster Blake

Just a remark, i think that they make a mistake by writing 130 mph ( 195km/h). Given my poor and untrained eyes 130 mph equals to 210 km/h and not 195km/h as the NHC mentionned ( surely they're busy and a bit stressfull! i understand why)...°meaning by extension a cat 3 cane and not a cane 4 with 130 MPH like Florence now.

[clambite]

Sorry for the off topic post but I just realized that as of today I have been a member on the board for 15 years. You all really didn't need to send a major hurricane my way in celebration lol.

Did you used to work for Leroy at the Sea Hawk ?

[CrazyC83]

Based on a blend of the dropsonde, SFMR and satellite, I would go with 125 kt right now.

[WAcyclone]

We may get another Update Statement. If the NHC find this data credible, Florence is already a Category 5. And firmly in that range, too.

Dropsonde winds are more representative of gust instead of sustained winds. Definitely not a category 5 right now, although Florence has a chance to become one.

Yes, but isn't the lowest 150 meter mean wind more representative of the actual max sustained wind speed? However, it's definitely strange there weren't any flight level winds above 107 knots in the southern eyewall...

[NotoSans]

We may get another Update Statement. If the NHC find this data credible, Florence is already a Category 5. And firmly in that range, too.

Dropsonde winds are more representative of gust instead of sustained winds. Definitely not a category 5 right now, although Florence has a chance to become one.

Yes, but isn't the lowest 150 meter mean wind more representative of the actual max sustained wind speed? However, it's definitely strange there weren't any flight level winds above 107 knots in the southern eyewall...

Need to multiply that by an adjustment factor of ~0.85.