atlantic hurricane season Hurricane Arthur

[Vorticity0123]

The 2014 Atlantic hurricane season has finally gotten into business. Tropical depression One has developed out of a low pressure area (formerly 91L), which has been meandering of the northeastern coast of Florida during the past few days.

 

Current organization

 

Current satellite imagery (as of 07:30 UTC) shows that Tropical depression One is under impact of significant northerly shear, which is blowing the convection southward away from the LLCC (low level circulation centre). In fact, the LLCC is still partially exposed (according to CIMSS).

 

Visible satellite loop of Tropical depression 01 (Courtesy: NHC)

 

Forecast

 

Despite the seemingly disorganized appearance, the NHC forecasts gradual strengthening of the cyclone, reaching a peak intensity of 60 kt near the Eastern Seaboard. This is caused by a trough which forces the cyclone to recurve toward the northeast after a slow southwestward drift in a few days. The forecast track from the NHC can be seen below:

 

Forecast track of Tropical depression 1.

 

Sources:

http://www.ssd.noaa.gov/PS/TROP/floaters/01L/01L_floater.html

http://www.nhc.noaa.gov/

http://tropic.ssec.wisc.edu/real-time/storm.php?&basin=atlantic&sname=01L&invest=NO&zoom=4&img=1&vars=11111000000000000000000&loop=0

Edited July 1, 2014 by Vorticity0123

[be cause]

why abandon the original discussion of this low ??

[Vorticity0123]

why abandon the original discussion of this low ??

 

It is to avoid the Atlantic hurricane/invest thread from getting too crowded and confusing. In other words, the policy is to create a separate thread on each new tropical cyclone developing. The general threads for each individual basin (for example, the East-Pacific and the West-Pacific/North Indian invest threads) only discuss tropical disturbances up to and including invests. So, when a system gets classified as a tropical cyclone by an agency (for example: NOAA or JTWC), a new thread is started.

 

The same occured with tropical storms Douglas and Elida, which were discussed in the East Pacific thread when they were still invests, but got a separate thread when they were designated as tropical cyclones by the NHC.

 

I hope this answers your question satisfactory  .

Edited July 1, 2014 by Vorticity0123

[Somerset Squall]

That's right Vorticity

Also it works vice versa. The main threads are there to discuss the many disturbances across the basins, many of which fail to become tropical cyclones, instead of starting a thread for each one. This stops the forum being littered with threads of "non-events" so to speak

The newest advisory indicates 01L reaching minimal hurricane strength. A little fairly useless piece of trivia: if future Arthur does reach hurricane strength, it'll be the first storm named Arthur to do so in the Atlantic basin (all previous Arthur's have only reached tropical storm strength).

Edited July 1, 2014 by Somerset Squall

[Vorticity0123]

Good addition Somerset Squall, I hadn't yet thought about the other side of the reasoning  .

 

On a more serious note: Tropical Depression One has been upgraded to Tropical storm Arthur, the first of the 2014 Atlantic hurricane season. Although convection still appears to be sheared, the convection has increased in areal coverage and depth (judging from satellite imagery). This could have prompted the aforementioned upgrade.

 

Arthur also appears to be on the influence of some dry air. Water vapor imagery shows that a pocket of relatively dry air is located to the north and northwest of Arthur. This was possibly also a contributor to the relative lack of convection of the cyclone in the northern semicircle.

 

Water vapor satellite imagery of Arthur (Courtesy: NOAA)

 

However, now that convection appears to be on the increase, it might indicate that the northern half of Arthur will soon also be covered (if the northwesterly shear also abates, as indicated by the NHC). This could initiate a period of more steady strengthening of the system.

 

Sources:

http://www.nhc.noaa.gov/text/refresh/MIATCDAT1+shtml/011502.shtml

http://www.ssd.noaa.gov/PS/TROP/floaters/01L/01L_floater.html

Edited July 1, 2014 by Vorticity0123

[Cookie]

 

Finally we are off! 

[summer blizzard]

Looks to be strengthening quickly on satellite.

 

Recon reporting 1003mb, 42mph. 

[summer blizzard]

[Cookie]

[summer blizzard]

Nhc went with 50mph.

Unconfirmed reports go for 998mb and 60mph, looks like its strengthening.

Nhc goes for 90mph in 72 hours.

[Somerset Squall]

Arthur certainly seems to be insulating itself from the dry air currently, perhaps shear is reducing? As has been said, winds are up to 45kts, and NHC expect a peak of 80kts, just shy of cat 2 on the SS scale. Looks like it might pack some punch to the eastern seaboard later this week.

[knocker]

GFS 00z has 985 mb prior to North Carolina landfall for #Arthur Positive-trough interaction will help intensify. pic.twitter.com/EAxgcgIQM9

[Sainsbo]

Arthur doesn't look very impressive on satellite, but that could easily change throughout the day.

 

 

NHC stating windspeeds are at 60mph right now.

Edited July 2, 2014 by Sainsbo

[Vorticity0123]

Arthur doesn't look very impressive on satellite, but that could easily change throughout the day.

 

Latest visible satellite images (as of 18:00 UTC) show a clear banding type eye developing:

 

Visible satellite image of Arthur (courtesy: NOAA)

 

Banding featuers have also become nicely defined to the south and west of the system. 

 

However, visible satellite imagery can be misleading. Judging from Dvorak satellite imagery, one would classify this system as a rather disorganized one, with only some deep convection present in the eastern semicircle (though it is present in a banding pattern).

 

Dvorak satellite image of Arthur (courtesy: NOAA)

 

It will be interesting to see what NHC will do with the mixed satellite appearance. What do you think about this?

 

Source:

http://www.ssd.noaa.gov/PS/TROP/floaters.html

Edited July 2, 2014 by Vorticity0123

[Buriedundersnow]

some pics from ryan maue and joe b from twitter

 

 

joe b talking possibility of a cat 2-3 hitting the outer banks at 48 hours

 

heres a few radar images which show the eye feature

 

Edited July 2, 2014 by Buriedundersnow

[Sainsbo]

 

Latest visible satellite images (as of 18:00 UTC) show a clear banding type eye developing:

 

Visible satellite image of Arthur (courtesy: NOAA)

 

Banding featuers have also become nicely defined to the south and west of the system. 

 

However, visible satellite imagery can be misleading. Judging from Dvorak satellite imagery, one would classify this system as a rather disorganized one, with only some deep convection present in the eastern semicircle (though it is present in a banding pattern).

 

Dvorak satellite image of Arthur (courtesy: NOAA)

 

It will be interesting to see what NHC will do with the mixed satellite appearance. What do you think about this?

 

Source:

http://www.ssd.noaa.gov/PS/TROP/floaters.html

 

 

 

It definitely looks more organised than it did when I posted the message 9 hours ago.

 

But yeah, I agree with everything you've said. With satellite images being so decieving, a recon would be quite handy. Personally I would take the increasingly prominent banding features as a sign as intensification, and ignore the rather disorganised nature of the system, I think that's something that will change slowly with time.

 

Edit: The eye is definitely becoming moe defined, and the latest ECMWF has it down to 966mb when next to NC.

Edited July 2, 2014 by Sainsbo

[Sainsbo]

Latest NHC Advisory puts windspeeds at 70mph. Satellite images show the system becoming increasingly organised, with a CDO forming. Not too long before we have the first Hurricane of the season!

[Buriedundersnow]

Hurricane Central â€@twc_hurricane 29m

Tropical Storm Arthur: 5 PM ET, 70 mph winds, 992 mb, moving at 7 mph. http://wxch.nl/r1tYL6

 

updated track and hurricane warnings now issued for parts of the Carolinas

 

 

looking good on animation

 

[summer blizzard]

987mb reported. Open eyewall.

[Buriedundersnow]

you can see how its really wrapped up in the last 18 hours on the 10m wind charts

 

 

most of the precipitation looks to be on the eastern flank so unless this changes and with the current forecast path it might not be too much of a soaker

 

[Cookie]

http://darecountyem.com/mandatory-evacuation-ordered-for-hatteras-island/

 

Mandatory Evacuation for Hatteras Island 

[summer blizzard]

Recon recording 984mb, 79KT I think.

[Cookie]

Now a hurricane

[Somerset Squall]

Arthur is now the season's first hurricane, with winds of 65kts. Arthur has about another 24-36hrs to strengthen before shear rises causing weakening. If there are any more dry air intrusions, strengthening will be capped. NHC forecast a peak of 75kts.

 

We have already had half the number of hurricanes of the whole 2013 season

[Cookie]

Haha love that