ATL: JOAQUIN - Post-Tropical - Discussion

[Chris_in_Tampa]

Here is something I posted previously for another storm:

See this page here:
http://www.aoml.noaa.gov/hrd/Storm_page ... ormat.html

"The second type of operational data that HRD provides is the actual raw dropsonde observations from the Airborne Vertical Atmospheric Profiling System (AVAPS). Measurements of pressure, temperature, relative humidity, and wind are obtained at 0.5 s [2 Hz] resolution (for certain dropsonde models the wind measurements are only available at 1.0 s [1 Hz] resolution)."

You are talking about a half second wind gust perhaps, very, very momentary.

See here for the definition of wind gust:

http://www.nws.noaa.gov/ndfd/definitions.htm

"WIND GUST is the maximum 3-second wind speed (in knots) forecast to occur within a 2-minute interval at a height of 10 meters"

So a sonde might be over a period of less than even a wind gust.

A program called Aspen might average it over several seconds though, the program that creates the raw text data and then releases it to the public. But since they give a specific level, perhaps not, or perhaps it is over a very small interval of seconds. Regardless, the sonde is definitely not reflective of the 1 minute sustained wind speed. It may not even be truly reflective a three second gust, but it would certainly be closer.

[Iknownothing]

I could be wrong but it appears that the eye has moved very little and that the lack of cleared eye may be from a new round of bursting convection.

I may be wrong but it seems those graphics show it finally slightly nudging WNW, maybe starting it's Northward track.



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[northjaxpro]

75W looks like the line in the sand for the start of the North turn. Lets see what happens.

At the rate this is moving it won't be long until it reaches 75 west

The eye is approaching 74 degrees Longitude currently. Still moving southwest.

[Hammy]

Inching down a bit more - pressure likely 949 right now.

Close, VDM came in at 950. Also supports 120mph, which tells me it may be even higher by 2am advisory.

75W looks like the line in the sand for the start of the North turn. Lets see what happens.

At the rate this is moving it won't be long until it reaches 75 west

The eye is approaching 74 degrees Longitude currently. Still moving southwest.

73.1 right now as of last fix. The eye is east of the warm spot, under the deepest convection.

[NDG]

I could be wrong but it appears that the eye has moved very little and that the lack of cleared eye may be from a new round of bursting convection.

I may be wrong but it seems those graphics show it finally slightly nudging WNW, maybe starting it's Northward track.



The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

Recon's last fix just around 40 minutes ago it still shows a SW movement.

[Yellow Evan]

Based on the dropsonde data after doing some research, thinking this is around 110 knots.

[Chris_in_Tampa]

3:15Z satellite.

[TimeZone]

Intensity seems to be leveling off now based on recon.

[txwatcher91]

CDO and outflow finally starting to expand some on the north side of the system. Usually this is an early sign, usually 12-24 hours in advance, before a turn begins. All the high res models seem to indicate it moving over San Salvador or just south of it before turning.

[ConvergenceZone]

Intensity seems to be leveling off now based on recon.

it may "temporarily" level off for a few hours.

[NDG]

Here are the recon's 3 fixes so far.

23.93N 72.93W
23.78N 73.03W
23.65N 73.15W

[blp]

75W looks like the line in the sand for the start of the North turn. Lets see what happens.

At the rate this is moving it won't be long until it reaches 75 west

Yea that is what I am seeing will be close.

[NDG]

Intensity seems to be leveling off now based on recon.

On the last pass it found the strongest flight level winds so far, 117 knots and the pressure down a couple of more mb.

[WilmingtonSandbar]

0Z GFS run is way east of previous run! Looks like it bows to the Euro!

[floridasun78]

Here are the recon's 3 fixes so far.

23.93N 72.93W
23.78N 73.03W
23.65N 73.15W

that still sw movement?

[terstorm1012]

0Z GFS run is way east of previous run! Looks like it bows to the Euro!

Keep watching. Hook comes later and farther north around hour 108.

[northjaxpro]

The cyclone is moving around 7 mph to the SW, I say it is closer to 73.5 W currently as we reach just past the stroke of midnight here on the East Coast.

[Chris_in_Tampa]

Mission over.

In this case 85% of the boundary layer wind (mean wind in the lowest 500 geopotential meters of the sounding) of 118 knots would be 100 knots, the advisory intensity. Vortex went with 105 knot SFMR for surface. (SFMR is 10 second average) Higher values had been flagged around it. That particular ob had 3.07 in/hr of rain in the eyewall and lower rain values were flagged.

[AutoPenalti]

Here are the recon's 3 fixes so far.

23.93N 72.93W
23.78N 73.03W
23.65N 73.15W

that still sw movement?

Still moving to the SW. By tomorrow, if models are correct, this should be already moving up north?

[windnrain]

0z GFS sends it to NYC...