MikeCAdministrator
(Admin)
Tue Aug 18 2015 10:19 AM
Hurricane Danny forms in the Central Atlantic

11:00 PM EDT 23 August 2015 Update
Tropical Storm watches are now up for Puerto Rico and the US Virgin Islands.

Danny is much weaker today, but seems to be holding at a 50mph tropical storm. The center of circulation is exposed, but convection continues to fire vigorously on the northeast quadrant. An unusually high amount of lightning can also be found in the system. It is still forecast to weaken, but storms of this small size can pull surprises.



8:00 PM EDT 22 August 2015 Update

Above: Danny is being overtaken by very dry air

Shear and dry air are starting to take a very significant toll on Danny. Over the past several hours recon has found no indications of hurricane force winds at the surface, and the 8PM Advisory now shows a - possibly generous - 65MPH tropical storm. Given the current drying trend, Danny will need to take advantage of the cooler atmosphere overnight to hopefully refire convection and build up some defenses, or could become a remnant low by this time tomorrow.

Given that the LLC is now exposed and the cyclone is in the process of becoming decoupled, the track is taking more of a due west if not west-southwest heading. Regardless of the near-term, Danny will likely still bring much needed rains and some blustery winds to the islands ahead.
Ciel

2:00 PM EDT 21 August 2015 Update
Recon has confirmed that Danny became a Major Hurricane today, and NHC has put out a 2PM update with advisory winds of 115MPH and a central pressure of 974mb. Shear and dry air are already starting to affect the micro-sized hurricane, and mostly weakening is now forecast for the next five days.

With luck, Danny's winds decline substantially, but the cyclone still brings much needed rains to the islands ahead.
Ciel

7:00AM EDT 21 August 2015 Update
Danny continues its course, official an 85MPH hurricane (Potentially stronger). It's core is very visible on satellite and very small.





Dry air and shear should begin to affect Danny Saturday afternoon and especially Sunday.

The Leeward islands of the Caribbean should continue to watch this system.

Research aircraft are scheduled to be out there this afternoon and air force recon are scheduled to be out there tomorrow afternoon.

11:00AM EDT 20 August 2015 Update
Tropical Storm Danny has been upgraded to Hurricane Danny.



97L is also being tracked off the east coast, and another wave off Africa has a 20% chance to develop over the next 5 days.

Folks in the northern Lesser Antilles and Puerto Rico and Hispaniola should continue to monitor the progress of Hurricane Danny over the weekend.

9:30AM EDT 20 August 2015 Update
Tropical Storm Danny struggled most of yesterday with dry air intrusion along with a small core. On the flipside the small core allows things like the image below shows:



This is quite a drastic difference in the last few hours as Danny has started intensifying somewhat rapidly. 992 mb is the new estimate, and it appears an eye is developing, all within the last few hours.


Those in the Caribbean islands should watch Danny closely, but the system is still expected to hit a wall of shear once in the Caribbean and greatly weaken or dissipate.


Original Update
The system being tracked as TD4 has become this season's fourth Tropical Storm, and the first Cape Verde system to organize this year.

The National Hurricane Center will be initiating advisories on the system at 5 PM EDT.



The system is forecast to become a category 2 hurricane by Sunday. The name is Danny. And if the forecast is correct, it would be the most southerly hurricane to form since Tomas in 2010.

93C near Hawaii is also worth watching there.

flhurricane Antilles Radar Recording of Danny approach

flhurricane East Caribbean Radar Recording of Danny approach

{{StormLinks|Danny|04|4|2015|04|Danny}}

{{StormLinks|98L|98|5|2015|98|Invest 98L}}

Since Danny is a long track storm, make sure to check out the Danny Forecast Lounge for talk about long range model runs and guesses at where and when it may go along with how strong.

{{StormCarib}}

Info for Kilo near Hawaii

{{HawaiiStorm}}


cieldumort
(Moderator)
Tue Aug 18 2015 10:37 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

The most recent ASCAT pass suggests Four may already be nameable, with regions of solid 30-35 knot winds.

Hawkeyewx
(Weather Analyst)
Tue Aug 18 2015 11:33 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

I didn't expect the NHC to be quite so bold with the intensity forecast. Hurricane-strength systems approaching the islands from the east have been pretty rare over the last ten years.

doug
(Weather Analyst)
Tue Aug 18 2015 12:19 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

This little puppy will blow right past depression stage...visible imagery is indicative of storm now IMO.

rmbjoe1954
(Weather Master)
Tue Aug 18 2015 12:30 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

I do not know what The NHC is seeing. I thought the Carib was a 'no go' zone. Danny may be born later today but it may also see its demise once it passes the Leeward Islands.

And hello to all.


MikeCAdministrator
(Admin)
Tue Aug 18 2015 01:50 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

Quote:

I do not know what The NHC is seeing. I thought the Carib was a 'no go' zone. Danny may be born later today but it may also see its demise once it passes the Leeward Islands.

And hello to all.




It's mostly the outflow and the shield from the dry area to the north being created. I can see the strengthening in the near term (NHC forecast looks good, and the GFDL is on board with that strength also), but once it gets closer to the Caribbean it may weaken. Right now the outflow is VERY good, and this system is already looking like a Tropical Storm.


scottsvb
(Weather Master)
Tue Aug 18 2015 02:12 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

I agree with everyone here. It should be named by 5pm or 11pm. Dry air center has filled in and evening humidy increasing the T-Storms near the center. Probably 40mph with recent build up and sat apperance. I expect this also to be a hurricane in 2 days (say by Thurs night). It's still to far out to tell what lies ahead with upper level windflow in the caribbean next week.

danielwAdministrator
(Moderator)
Tue Aug 18 2015 04:37 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

Scott nailed it. They upgraded to Danny, no relation, for the 4 PM Advisory

Dual outflow channels, one toward the Equator and one toward the north pole are allowing the storm to tap moisture and maintain a steady state.

The outflow that I've been watching is the one toward the West. Appears to be shielding Danny from the SAL to a degree


craigm
(Storm Tracker)
Tue Aug 18 2015 07:27 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

Quote:

I do not know what The NHC is seeing. I thought the Carib was a 'no go' zone. Danny may be born later today but it may also see its demise once it passes the Leeward Islands.

And hello to all.



Agree with the no go through the Carib - values are lower just north of the Islands and the real test will be between 50 and 60 west. Higher shear and dry air as Danny moves out of the Monsoon trough. Stronger storm will mix the dry air more efficiently. Shear, depending on amount, is more damaging to a developing system. IMO


MikeCAdministrator
(Admin)
Wed Aug 19 2015 07:09 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

Danny pulled in some dry air overnight which slowed down the intensification run, but it will likely hit another spike later today if it can get out of the dry air. A few days out conditions get a bit worse, so should weaken a bit. I think the possibility of it rapidly intensifying is pretty low at this point.

MikeCAdministrator
(Admin)
Wed Aug 19 2015 11:28 AM
Re: TD#4 is now Tropical Storm Danny in the Eastern Atlantic

Recon flights are scheduled to start around Friday.

LoisCane
(Veteran Storm Chaser)
Wed Aug 19 2015 12:46 PM
Re: TD#4 is now Tropical Storm Danny in the Eastern Atlantic


shame can't get recon in there now, would be so good to have solid data

for that matter Gulfstream Jet would be nice too

seems like this storm has a very slim window to pull itself back together and i keep wondering if the original Euro was right and weaker storm travels west into Carib... tho think tangling w Haiti is less a possibility than possibly PR getting rainfall...

if it gets over the Gulfstream (days and days away..........recon is days away)

IF..


doug
(Weather Analyst)
Wed Aug 19 2015 03:26 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

The storm has moistened the environment immediately around the core, and does not show the degree of dry air intrusion from the east and south that affected it earlier. It also seems to be taking more control of the large convective area east of the core, and the west side seems to be moistening up a bit...overall I would say the system should intensify within the parameters of the forecast...

OrlandoDan
(Storm Tracker)
Thu Aug 20 2015 02:27 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

Seems the western side has reduced the dry air a bit in latest satellite imagery. Danny seems to be holding. Time will tell a few days out as the storm gets into a more hostile shear environment.

doug
(Weather Analyst)
Thu Aug 20 2015 09:15 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

This morning there is some evidence of drier air intruding from the west, and south, and being drawn up on the east side which has caused the moisture envelope to shrink a bit, actually quite a bit, IMO. However, it is still in an overall moist envelope as it moves toward the islands and its future in the immediate depends on how it maintains that envelope.
The future depends on the dynamic that will develop with the sharp trough moving SE off Conus and the strength and position of the upper level high pressure that Danny will need to maintain as it enters the Caribbean. All this can be followed by viewing the HD water vapor loops.


MikeCAdministrator
(Admin)
Thu Aug 20 2015 09:25 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

Danny hit a sweet spot recently this morning and has gone into a rather drastic intensification mode.



Not sure how long this will last, but it is a bit surprising.

Best track has the pressure down to 992.


MikeCAdministrator
(Admin)
Thu Aug 20 2015 09:56 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

Yeah looking at the microwave imagery from earlier, the structure was very good this morning, it's a safe bet for a hurricane upgrade at 11AM.

scottsvb
(Weather Master)
Thu Aug 20 2015 10:05 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

What a increase in the past 8hrs. I saw 200 miles west of Danny last night on sat imagry that T-Storms fired up... so I did assume he would be better organized this morning and say have pressure of around 995-997 and winds near 60mph...but I didn't expect this. Danny looks like a solid hurricane..infact, he looks like he could be as strong as a Cat 2. My guess is that the pressure could be as low as 982 or lower with a small compact system and eye now. These compact and small systems can really get going. Usually it does take the winds 3-12hrs to catch up to the pressure drop depending on how fast the pressure drops.

I'm really curious on what the NHC will say and put as the winds and pressure. This will be a good example of us not having Recon in to determine the actual pressure and wind speed. Sat helps but since this is so rapid, the scan might of been in the earlier stages and not give us the "Current" pressure. Now comes the educated guess of what it is "Now" by also looking at current sat. Closest Bouy won't give a exact pressure cause of the small compact system.


danielwAdministrator
(Moderator)
Thu Aug 20 2015 11:24 AM
Re: Tropical Depression Four Forms in Eastern Atlantic

Closest buoy is 41041. Pressure was 1012.6 mb and falling at 1050 EDT or 30 minutes ago.
Winds NE at 14 mph
Seas 8 feet


Ed DunhamAdministrator
(Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017))
Thu Aug 20 2015 11:37 AM
Re: Hurricane Danny forms in the Central Atlantic

The early morning wrap-up of Danny was quite impressive. At 1045Z, CIMSS microwave imagery still had the intensity at 45 knots but the central core and eye feature were already starting to form. Although the hurricane is small, the outflow is quite good.
ED


scottsvb
(Weather Master)
Thu Aug 20 2015 02:30 PM
Re: Hurricane Danny forms in the Central Atlantic

GFS over the past few years has had a hard time keeping a very small Atlantic system Recognized. I think this 1 is included. It will always show a weaker system after the first 12-24hrs unless the system grows in size. I do think Shear will be a problem by Sunday thus weakening this...but question will be...decoupling? or just keeping the system in check before land (if there is) interaction with PR and DR.

Steve H1
(Storm Tracker)
Thu Aug 20 2015 03:03 PM
Re: Hurricane Danny forms in the Central Atlantic

Think Danny will be walking a fine line after day 2. Although latest Visible imagery suggests that his envelope is expanding, and a bigger system will stand a better chance of not decoupling, especially if he can manage to stay just north of the islands. Ridge should build in after 97L moves north. Don't know if the trough in the eastern US will be moving out as (if) Danny gets closer.

Edited: should be Not decoupling and trough moving out, not in


LoisCane
(Veteran Storm Chaser)
Thu Aug 20 2015 03:35 PM
Re: Hurricane Danny forms in the Central Atlantic

Historically models have a hard time with very small hurricanes.

This was a problem in 2001 with Iris.

http://www.nhc.noaa.gov/archive/2001/dis/al112001.discus.013.html

Just one example.d

Most models have problems with such small systems. Perhaps one is better than others and would like to know..if so.

Can't wait to get dropsondes in and data back for better reliable model runs.


OrlandoDan
(Storm Tracker)
Thu Aug 20 2015 09:10 PM
Re: Hurricane Danny forms in the Central Atlantic

It is going to be a rough ride for Danny after he passes the Leewards. Sheer and potential interaction with PR will be tough to overcome.

LoisCane
(Veteran Storm Chaser)
Thu Aug 20 2015 09:31 PM
Re: Hurricane Danny forms in the Central Atlantic

Suppose in the end it depends on which track he takes.

Through the islands or clipping PR on the NE side?

Intensity affects everything and not sure they have the intensity forecast down pat.

Tonight it appears Danny is growing in size some.

http://weather.unisys.com/satellite/sat_wv_east_loop-12.gif

I like to be able to see all the various players on the larger loop. Floaters are wonderful, but sometimes we miss suble changes.

Will know when recon gets there.

This loop shows a larger Danny

http://www.ssd.noaa.gov/goes/east/catl/flash-ft.html

Not a lot larger but it's a process I think. Possibly bulking up before the islands?


cieldumort
(Moderator)
Thu Aug 20 2015 10:35 PM
Re: Hurricane Danny forms in the Central Atlantic

While a (somewhat) larger Danny might be able to influence his immediate environment a touch more, an increase of wind field could also increase the odds that the cyclone bumps into and ingests the very dry air that surrounds the small cocoon of moisture the presently still small TC has been benefiting from.

Threading the needle, so to speak. Danny is a very small hurricane by global standards, and intensity changes both up and down could be rapid, with any downward intensity changes also possibly fatal, given the synoptic environment.


MikeCAdministrator
(Admin)
Fri Aug 21 2015 10:36 AM
Re: Hurricane Danny forms in the Central Atlantic

The NOAA P-3 aircraft will be leaving around 10am EDT with some ocean based surveys and then a fly through of Danny in the afternoon.

MikeCAdministrator
(Admin)
Fri Aug 21 2015 11:26 AM
Re: Hurricane Danny forms in the Central Atlantic

Looks like a last minute decision to head towards Danny first was made for Recon.

scottsvb
(Weather Master)
Fri Aug 21 2015 11:34 AM
Re: Hurricane Danny forms in the Central Atlantic

I think Danny peaked around 115-125mph this morning. Sat estimates are usually under done by 5% and given such a small size..a even hard reading would of been possible. By time recons head out there, Danny will be Dir Min and shear will start to pick up some tonight.So it's too bad they weren't there early this morning when I think he peaked out. I will note that that shear 15-20kts will hamper Danny but not tear him apart. I think the shear will decrease some to 12-15kts as the Tutt moves out...but then a very dry pocket is in his way around 53W-60W and 16N-19N...directly in his path thus weakening him down to a TS by later Saturday afternoon or by Sunday. Like the NHC said...Land interaction will be the next faze. Will he go thru D Rep, or just north of it by Tuesday. We have time to see..and any talk of the U.S. right now can be put on hold till Monday to see how Danny is and what conditions will look like by next weekend.

MikeCAdministrator
(Admin)
Fri Aug 21 2015 12:15 PM
Re: Hurricane Danny forms in the Central Atlantic




TropicalAtlantic is showing P3 radar updates if you have google earth installed.

Radar image link (Req. Google earth) http://tropicalatlantic.com/recon/recon....ar&latest=1




MikeCAdministrator
(Admin)
Fri Aug 21 2015 12:26 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

Recon's first brush Pressure ~968mb but not if that's the lowest.

MikeCAdministrator
(Admin)
Fri Aug 21 2015 12:36 PM
Re: Tropical Depression Four Forms in Eastern Atlantic

111knots, Danny's a cat 3.

cieldumort
(Moderator)
Fri Aug 21 2015 12:43 PM
Re: Hurricane Danny forms in the Central Atlantic

It does appear that Danny probably did max out within the past few hours somewhere in the 115-135MPH range*, within a very tight core, à la Marco (2008). Recon is finding some very stout winds and much lower pressure than has been estimated, despite the fact that the cyclone appears to be interacting some with the increasing shear.

What lies ahead for Danny could be very challenging for the microcane. The research mission flying in and around it has been finding dewpoint depressions on the order of 70 degrees. With increasing shear ahead, it looks supremely difficult for the cyclone not to begin ingesting this phenomenally dry air, and rapid weakening could ensue.

* And arguably on the high end of that range, for as Mike just mentioned above, recon has found 111 knots at flight level (12k ft), which would normally translate to around 100 knots +/- at the surface.



MikeCAdministrator
(Admin)
Fri Aug 21 2015 01:06 PM
Re: Hurricane Danny forms in the Central Atlantic

Vortex message, highlights 965mb presure and the 111knot flight level winds. I'd expect the NHC to issue a special update.

URNT12 KWBC 211655
VORTEX DATA MESSAGE AL042015
A. 21/16:20:00Z
B. 14 deg 08 min N
048 deg 19 min W
H. EXTRAP 965 mb
I. 6 C / 3690 m
J. 21 C / 3321 m
K. 2 C / NA
L. OPEN S
M. C12
N. 12345 / NA
O. 1 / 4 nm
P. NOAA3 WA04A DANNY OB 06
SLP EXTRAP FROM 12000 FT
MAX OUTBOUND FL WIND AND MAX FL WIND 111 KT 026 / 04 NM 16:20:40Z


doug
(Weather Analyst)
Fri Aug 21 2015 01:34 PM
Re: Hurricane Danny forms in the Central Atlantic

The shearer is just ahead and on sat. is visible at about 55W.

Ed DunhamAdministrator
(Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017))
Sun Aug 23 2015 12:05 AM
Tropical Storm Danny Hanging On As It Approaches the Leeward Islands.

After getting clobbered on Saturday, Tropical Storm Danny seems to be more robust than I thought that it would be with convection now refiring over the center again this evening.
ED


craigm
(Storm Tracker)
Sun Aug 23 2015 07:37 AM
Re: Tropical Storm Danny Hanging On As It Approaches the Leeward Islands.

Quote:

After getting clobbered on Saturday, Tropical Storm Danny seems to be more robust than I thought that it would be with convection now refiring over the center again this evening.
ED



Feeling the same way. Danny looked pretty bad yesterday. I am noticing in one of the loops this morning Danny seems to be having some effect on the shear environment near him. If you watch the attached loop closely the high cirrus clouds, in the lower left corner of the image ahead of Danny, embedded in the upper level flow seem to be having their direction altered from the NE to the NNE and affecting the shear environment above as Danny approaches (to some extent that I can't quantify). I heard this explained in an earlier video blog by Levi Cowan,at Tropical Tidbits, but he expected this type of interaction with a stronger storm. This could explain why Danny is refiring even though the LOC is still partially exposed. Obviously this link is time sensitive and may not reflect what I am talking about in a couple of hours. SSD RBtop loop


MikeCAdministrator
(Admin)
Sun Aug 23 2015 08:06 AM
Re: Hurricane Danny forms in the Central Atlantic

Added radar recording of Antilles radar for danny at flhurricane Antilles Radar Recording of Danny approach

MikeCAdministrator
(Admin)
Sun Aug 23 2015 10:05 AM
Re: Hurricane Danny forms in the Central Atlantic

Added another radar recording of an Eastern Caribbean radar composite for Danny at flhurricane East Caribbean Radar Recording of Danny approach


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