Poor Chantal, moving WNW, has I'm afraid lost her definition this morning and is unlikely to survive as a closed system for much longer.

May emerge into the Florida Straights on Friday and regenerate a bit but as it stands she is not a real threat.

Hold your horses... refiring convection now and moving WNW. It appears that the LLC broke free of the old mess of convection and is trying to start anew. The environment is not conducive to development though, so a tropical depression is the most likely result if she holds on as a closed system.

The models now take her south of Haiti and then anywhere from just east of Cuba to just west, with the main cluster going right through the middle. A few cross Jamaica.

The NHC forecast takes her through the middle of Cuba as a TD and then up the east coast of Florida, becoming a tropical storm again just before an eventual landfall somewhere in or just north of Florida.

She is an oddity to say the least.

Looks like Chantal isn't going to last much longer.

Once Junes sst data comes in I'll take another punt at guessing what the final ACE might be, however there has been a large change in the SST pattern since May (especially in relation to SST's) with the tropical Atlantic seeing a marked reduction in it's positive SST anomalies, judging by the IRI anomaly maps.

Will update when the Hadley SST figures for June are available but with La Nina struggling to materialise as well (so far) things don't look as omnious for the Atlantic as what they did 2 months ago.

Soulik in the Pacific is a dangerous typhoon in the Pacific ATM with winds of 140mph and some landfalls likely.

Atlantic quiet at the moment however it's only mid July, still early days.

Chantal is no more - only a remnant mess remains, and it's still in a very unfavourable environment so to be honest all we can do is wait and see if anything emerges from the chaotic remains... puts me in mind of when supernovae leaves behind a nebulae in space - but of course this tropical Atlantic version is far less dramatic!

More and more strong waves are piling off Africa at the moment. While they face a tough future should they be steered into the Caribbean (strong trade winds - one factor of the environment that tore up Chantal), they do serve to moisten up the Main Development Region of the tropical Atlantic - which will greatly aid the Cape-Verde type storms (ones from African tropical waves) in August-October this season.

It remains to be seen how the pattern sets up to steer those systems.

Until then, 'home-grown' developments in the far-western trop. Atlantic, Caribbean and Gulf of Mexico are the main thing to keep an eye on. Chantal's remains could serve as a catalyst for something near Florida.

This morning, TD4 formed not far from the Cape Verde Islands.

The NHC forecast takes it on a steady ENE track across the Atlantic, eventually passing just N. of the Leeward Islands. Nearly all of this is done at tropical storm strength as that is expected to be attained either today or tomorrow.

There's moderate wind shear, marginal SSTs (around 26°C) and some dry air to the N and NW for the storm to contend with, but so far it's done well, keeping itself compact and building decent convection over the central region, with even hints of an eye feature at times.

I wonder if the NWS and Dr Masters were a bit quick in dismissing the GFS last week when it, alone, was showing a strong TS in the basin - Dorian has formed and the 12Z GFS has it as a hurricane a week from now.

http://www.tropicaltidbits.com/analysis/models/gfsfull/2013072412/gfsfull_pres_pcpn_atltropics_61.png  [/quote]

But it's quite isolated. Most models keep Dorian a TS under sheared conditions.

---

Neil
Fareham, Hampshire 28m ASL (near estuary)
Stormchaser, Member TORRO

Still unexpectedly quiet for what was forecast to be an above-average season - it'll have to go some to catch up with expectations.

Meanwhile, a cloud of Saharan dust looks set to suppress activity for yet another week

http://www.weather.com/newscenter/tropical/

 Otherwise a cloud of dry, dusty air from Africa will spread across the Atlantic over the next few days  choking off any thunderstorms that try to organize and keeping the tropical Atlantic quiet for the remainder of the week.

A combination of the Saharan Dust Layer clearing up, the active MJO phase moving into the tropical Atlantic and a relatively flat pattern - driving storms west rather than allowing recurvature - looks to be on the cards for mid-August.

Fair to say that things could become very active and also dangerous in around 10 days time.

Most seasons feature notable lulls in activity, even the active ones; 2010 even didn't get going until Alex formed in August... after which came a torrent of storms.

Some chance of a storm developing in the Caribbean later this week, but little development of the disturbance according to the models. Heavy rain for Florida, but no hurricane yet.

http://www.weather.com/newscenter/tropical/

Could this be the start of the ramp up

Two red circles, high chance of development in both cases

Possibly not hurricane development yet, but signs of ramp up

Could be getting interesting soon

Yes, the Atlantic is showing signs of waking up. Nothing really dramatic yet.

http://www.weather.com/newscenter/tropical/

Yes FIVE is 'alive' but may get wrung-out by dry air in a few days time. Wait and see.

TD5 developed last night, just south of the Cape Verde Islands.

It currently has 35mph max. sustained winds, a minimum central pressure of 1007mb and is SW of the CV Islands, moving WNW at 16mph.

There's some decent convection forming and it looks well organised, with a tight low-level circulation. It could already be a tropical storm and the forecast takes it to moderate TS status with 60mph max. sustained winds at 48 hours range. After that time, some dry air looks to attack the system and cause it to weaken - although the possibility of the system walling off that dry air and holding steady can't be ruled out.

As for the track, see for yourself:

http://www.nhc.noaa.gov/storm_graphics/AT05/refresh/AL0513W5_NL+gif/084939W5_NL_sm.gif

I wonder if it will become a 'sleeper' that slides through the Caribbean as a weak feature before waking up again once in the W. Caribbean.

Interestingly, the NHC track is to the south of nearly all model tracks.

Meanwhile, invest 92L, just east of the Yutacan Peninsula (W. Caribbean), lost nearly all convection last night and is only just starting to rebuild. There's a notable swirl at the mid-levels but it's struggling to work down to the low levels due in part to competing vortices.

Thought I would throw in a little forecast of mine reviewing a load of factors which I believe have an influence on accumulated cyclone energy (ACE).

SST's

Here I pay particular attention to the SST's to the coast of West Africa (this is the area were SST's relate to hurricane activity in the Atlantic basin most).

Through May they were especially high but they eased off a bit in June and July but have still been substantially above in June and July. Still they are some way off the levels seen in 2005 and 2010.

Also worth watching are the temperature gradients, the difference in anomaly between the tropical North Atlantic and South Atlantic is a very positive gradient (above normal in tropical north and below normal in tropical South). This is linked to more storms being formed around Cape Verde, one to watch over the next month for sure).

ENSO

This has been stuck in neutral La Nina for a while now, La Nina's can boost activity, but el Nino's almost always reduce it as it usually increases wind shear in the Carribean. Wind shear severly limits the formation of hurricanes. There are exceptions to this rule though. An El Nino Modiki is where ENSO conditions are limited to the central Pacific (2004 a very good example of this).

Nethertheless I expect neutral La Nina conditions to persist here perhaps developing into La Nina in October maybe. No El Nino to hold back hurricane activity this year.

Drought Indices

A lack of rainfall across Sahel Africa can limit hurricane activity substantially as less storms are able to move out of Africa and merge to form tropical storms. Rainfall has been near average though so no impact there I don't think.

US drought has eased substantially this year. It's speculation at the moment but I think substantial drought over US can supress hurricane activity also. In 2011 and 2012 few hurricanes developed into majors (Sandy was a Cat 2 I think), despite the fact many storms formed, leading to limited ACE. Interestingly the quiet seasons of 1934, 1939, 1954 and 1956 for example all occured in major US droughts.

Forecast

Given the US drought has eased off I fear we may see more cat 4 and maybe our first cat 5 hurricane since 2007 forming. The similar years to 2013 I have found are (with ACE listed next to them):

Since 1950

1961 - 201

1989 - 133

1995 - 229

1996 - 166

2005 - 251

2008 - 144

1996 is very similar - From this analysis I would expect ACE to come in between 130 - 170. Long term average is 96 so a hyperactive season is in store. Expect activity to increase considerably in the next month.

Thanks for that Yorkshirelad, a sound forecast in my opinion

Erin formed today to the SW of the Cape Verde Islands. He's a small storm with not a lot to boast about at the moment except for some nice organisation to his structure. Forecast still says moderate TS before weakening due to dry air and marginal sea surface temperatures starting in a couple of days time. GFS dissipates him well before reaching the Leewards.

92L is hard to figure out - a disorganised mess of thunderstorms with signs of spin in varous places, capable of spawing a system of some sort over the next day or so somewhere in the Gulf of Mexico.

Still very quiet

"Meanwhile dry air in the eastern Atlantic is keeping the lid on thunderstorm growth as storm clusters move westward from Africa."

http://www.weather.com/newscenter/tropical/

Does anyone know if this notable presence and persistence of dry air in the eastern Atlantic has been observed in previous years?

Still very quiet

"Meanwhile dry air in the eastern Atlantic is keeping the lid on thunderstorm growth as storm clusters move westward from Africa."

http://www.weather.com/newscenter/tropical/

Does anyone know if this notable presence and persistence of dry air in the eastern Atlantic has been observed in previous years?

It was a major issue in 2007 but quite a few seasons go through quiet phases for a substantial amount of time... even 2005. I would expect activity to increase in Spetember unless this year ends up being similar to 2007.

Usually, when the run up to the season has been average or above for rainfall across the Sahel region, dry air and dust is less of an issue in the eastern Atlantic.

We've had the prerequisite, but for some reason, the response this year is different

IIRC 2007 had a coule of 'sleepers' which sneaked across into the Caribbean and then exploded into Cat. 5 monsters.

Usually, when the run up to the season has been average or above for rainfall across the Sahel region, dry air and dust is less of an issue in the eastern Atlantic.

We've had the prerequisite, but for some reason, the response this year is different

IIRC 2007 had a coule of 'sleepers' which sneaked across into the Caribbean and then exploded into Cat. 5 monsters.

Yup there was in fact two Cat 5 hurricanes, despite this the ACE for the season was only 72 so it was the 3rd quietest hurricane season since the AMO turned positive in 1995, maybe 2013 could be one of those years, I don't think it will persist for too long though. If Saharan dust does clear I would expect hurricane activity to ramp up significantly.