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NHC will issue advisories from 4pm. .. Still lacks significant convection but it has persisted over a fairly well defined center.. Track is pretty clear cut with a likely eventual path somewhere west of the Azores.. Strength guidance looks pretty straight forward too, likely to become a hurricane. 6z operational from GFS suggested something around a strong category 1, weak category 2.

After a worldwide lull in tropical activity, a new tropical depression has developed in the Atlantic ocean, in the bay of Campeche. Aircraft recon was able to close of a well-defined center, and so TD 05 is born with an initial intensity of 25 kt. Below is the NHC foecast track on TD 05: Track forecast of TD 05 from NOAA. Source: http://www.nhc.noaa.gov/

We finally have it. Updates to follow. Recon have just found 1002mb. Large size means slow development but wind field of strong winds should be large. Large track spread. Once convection fires over the LLC the environment looks good.

Convection increased near the well defined LLC of invest 93L overnight, and winds from recon were found to be at 40kts, so NHC upgraded 93L to Tropical Storm Bertha. Shear and dry air continue to affect Bertha as it heads west-northwestwards into the eastern Caribbean. Shear isn't expected to significantly ease anytime soon, so Bertha will probably continue to struggle. Bertha is expected to affect the eastern Caribbean before lifting northwestwards into the northeast Caribbean Sea. A recurve to the northeast is then expected east of the USA.

The season's second tropical depression has formed in the central tropical Atlantic to the east of the Lesser Antilles, with winds of 30kts. A well defined low pressure system has managed to generate some fairly shallow but persistant convection over the LLCC, prompting NHC to upgrade the system to a tropical depression. However, 02L is not long for this world. Convection has already began to wane after the upgrade (at 9pm) as it begins to run into significantly drier air to the west. NHC forecast degeneration into a remnant low in 72hrs time, but I would not be surprised if this happened sooner. Depression's in this area at this time of year often don't prosper, as conditions generally don't become favourable here until later in the year. 02L is no exception.

After a lull of about a month in TC activity, a new subtropical storm has developed in the Central Atlantic, and it has been named Melissa. The system is quite large, and seems to have a quite large range of tropical storm winds, but in the last few hours, convection has also built at the center of Melissa, which is a characteristic of a (sub-)tropical cyclone. Current OSCAT data shows the large radius of tropical storm winds associated with the system (winds of at least three and a half flag suggest tropical storm force winds) Current water vapor imagery shows a tongue of dry air curving toward the center of Melissa, likely impeding in development. Shear analysis by CIMSS (not shown here) shows the system is currently in a sharp shear gradient, with values ranging from 20 kt to the east, to 50 kt to the west of the system, providing, along with the dry air, only marginal conditions for development. The NHC is currently forecasting Melissa to get close to hurricane strength, as shear values are expected to drop to values below 10 kt, and SSTS are about 27 degrees Celsius. Thereafter, extratropical transition is about to begin. The storm is forecast to move northward during most of its lifetime, with a recurve toward the northeast afterward. Behind that time, it is yet uncertain if the system will turn back toward Greenland, or continue its recurve toward Spain. The NHC is currently forecasting a backward curve toward Greenland, on which an increasing amount of models seem to agree upon. The track of Melissa as forecast by the NHC. Although the model spread has been reduced in the past 24 hours, there remains a considerable amount of uncertanity about the angle of the recurve. An image of the different forecasts of different models, showing the current spread at the medium to long range. It will be interesting to see how the models handle this system now it has been qualified as a subtropical storm, and especially the effects on the forecasted blockade west of Ireland. It is likely that there will be quite some model-hopping in the medium to long term time frame. It is also very nice to see how tropical cyclones could have a significant impact on the weather in Europe, directly or indirectly. To illustrate the model-hopping of the various models on the handling on the storm, some output of the GFS and ECMWF models at T96hr below: GFS: EC: While the GFS suggests a very pronounced southern part of the complex low pressure area (extreme left, remnants of Melissa), the ECMWF shows a much more pronounced northern part of the system (in this case, the remnants of Melissa would be absorbed). The different handle could easily result in very different outcomes at bigger timeframes. And finally (to get back to the storm itself), a visible image of the subtropical cyclone.

Tropical Depression 18L has formed in the Caribbean, a few hundred miles south of Jamaica. Intensity is 25kts currently, and 18L should strengthen quickly over the next few days as shear is low and waters very warm. 18L could approach hurricane strength as it moves towards Jamaica, so this cyclone needs to be watched closely. 18L is currently in a weak steering environment but models are consistant in bringing 18L across Jamaica and Eastern Cuba over the next few days, then possibly on to the Bahamas.

It looks like the Atlantic has briefly awoken from it's slumber. But don't get too excited, because it looks like we may be in for a weak tropical storm at best with this system. 13L is located in the open waters of the central Atlantic, well east of Bermuda. Convection blossomed over the LLCC this afternoon, but already westerly shear is partially exposing the LLCC to the west of the convection. 13L could become a tropical storm over the next day or so whilst waters remain warm enough, but shear will cap any significant intensification. After a couple days, shear will rise further and waters cool along the east-northeast track, which will put an abrupt end to 13L's brief life.I still can't believe there have only been two hurricanes in the Atlantic, and they were only cat 1's!

Tropical Depression 09L has formed south of the Cape Verde islands in the Eastern Atlantic. Intensity is 30kts. The depression will move westwards initially on the south side of a ridge to the north until a trough creates a weakness and turns the cyclone abruptly towards the northwest. Low shear, warm sea temps and fairly moist air (for the first time this season it seems) should allow 09L to strengthen, and this cyclone actually has a shot at becoming the season's very late first hurricane.

THIS SYSTEM HAS A LOW CHANCE...10PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48HOURS...AND A HIGH CHANCE...60 PERCENT...OF BECOMING A TROPICALCYCLONE DURING THE NEXT 5 DAYS.http://www.nhc.noaa.gov/gtwo_atl.shtml

70% during the next 48 hours and 90% during the next 5 days http://www.nhc.noaa.gov/gtwo_atl.shtml

This is the topic for invest area HS27 and the possible tropical storm or hurricane in the next days. The chance is still 30 % (according national hurricane center)? THIS SYSTEM HAS A MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A MEDIUM CHANCE...40 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. http://www.nhc.noaa.gov/gtwo_atl.shtml From this position, is there chance for this system to come in western Europe?

Former invest 95L has been raised to TD 6 in the southern bay of campeche, Gulf of Mexico, but is highly likely to reach landfall on the Mexican shore within 12hrs given Westerly heading but current recon may provide data to raise to TS status prior.

The fifth tropical depression of the season has formed south of the Cape Verde Islands, in the Eastern Atlantic. Intensity is 30kts. 05L appears close to tropical storm strength, as very deep convection is expanding near the LLCC and good banding features are taking shape in the southern quadrant of the cyclone. For the next 48hrs, shear is set to remain light and waters warm, so intensification should occur as 05L moves generally west-northwestwards along the south side of a narrow ridge. After this time, sea temperatures cool along track, and 05L should also run into the Saharan Dust Layer (SAL), which should cause 05L to begin to weaken. The weaker cyclone is then expected to turn more towards the west in the low level flow. By day 4/5, waters warm up along track again, but the SAL could still be plaguing the system by this point, so further weakening appears to be the most likely outcome at this stage, but this is uncertain.

The fourth tropical depression of the Atlantic season has formed in the Eastern Atlantic. Winds are at 30kts. Strengthening is expected initially, but dry air, increasing shear and marginal sea temps are expected to dampen significant strengthening on the west-northwest track.

Invest 93L in the NW Caribbean has developed a closed LLC and enough organised convection to be designated a 30kt tropical depression, the second of the Atlantic season. 02L is very near the coast of Belize so doesn't really have time to strengthen any further. After landfall, 02L will obviously weaken but is expected to emerge into the southern Bay Of Campeche; as the upper level environment is expected to remain favourable then 02L might become a tropical storm before a second landfall, this time on the Mexican coast. Heavy rains are the primary concern from this cyclone.

NHC to issue an advisory on Tropical Storm Andrea within the next hour based on a "well defined circulation" as per Recon. (NHC) Amazing turnaround from initial 0% forecasts of formation?

Another tropical depression has formed in the Atlantic, well northeast of the Lesser Antilles. Convection is persisting near the LLC. 19L has about 48hrs to strengthen before shear rises and waters cool on the northward track. Over the next couple of days, 19L should move northwards on the east side of a low, and then move northeastwards as the depression hits the mid-lattitude westerlies. These westerlies should be the main cause of weakening beyond 48hrs.

The sixteenth tropical depression of the season has formed just east of the Bahamas. 16L is located in a region of strong shear ahead of a cold front. The depression could strengthen into a tropical storm before it merges with the cold front in the next day or so- however, the environment is far from favourable for significant intensification at this time. Current intensity is 30kts. EDIT: Just been upgraded to Tropical Storm Patty, with sustained winds now at 35kts.

The fifteenth tropical depression of the season has formed midway between the Cape Verdes and the Lesser Antilles. The depression is not all well organised, with multiple circulations and the majority of the convection located in a loose band. Shear and dry air are affecting 15L, preventing strengthening. 15L has a small chance of becoming a tropical storm prior to dissipation in the next 48hrs. 15L is moving northwestwards but will accelerate northeastwards over the next day ahead of a large extatropical low to the west which will ultimately bring 15L to an early death.

Tropical Depression 14L has formed midway between the Eastern Caribbean and the Cape Verde Islands. The depression has a well defined LLC but convection is not looking to healthy as present as 14L is ingesting a large amount of the dry air from the west. 14L is eventually expected to overcome this, especially as shear is low which will prevent the dry air making significant intrusions into the centre once the depression has formed an inner core. Sea temps support strengthening too, and NHC expect 14L to become a hurricane in a few days time. 14L looks to move northwestward, then north then northeastward around a the subtropical ridge to it's northeast. 14L should not be a threat to land.

The twelfth tropical depression of the Atlantic season has formed roughly midway between the Cape Verde Islands and the eastern islands of the Caribbean. Intensity is 30kts. The depression appears to be in a favourable environment characterised by low shear and very warm sea temps. There is a fair amount of dry air to the northwest of 12L, but the cyclone should be able to overcome this IMO if the shear remains low. Looks to be a fish at present with a northwestward then northward track out to sea, but this is still uncertain. If 12L overcomes the drier air to the north then we could well be looking at a strong hurricane here; NHC forecast 12L to be an 80kt hurricane in 3 days time with the potential for further strengthening after that if the environment remains favourable. That, of course, depends on just where 12L ends up.

The tenth tropical depression of the Atlantic season has formed mid-way between the west coast of Africa and the eastern Caribbean. Intensity is 30kts. The depression does not look at all healthy this evening as convection has decreased over the LLC. Nevertheless, NHC forecast some steady intensification as the cyclone heads wes-northwestwards. Later, a turn towards the northwest is expected as 10L rounds the ridging to the north. The track at this point depends on how strong 10L gets; a weaker cyclone will head to the west, a stronger cyclone will feel the weakness in the ridge that bit more and turn northward.

After moving off the west coast of Africa a week ago, invest 93L has developed little due to very dry air and cool waters. It has journeyed northwestwards and is out in the open Atlantic. Today, convection has increased over an increasingly well defined LLC. NHC give 93L a 50% chance of becoming a TC in the next 48hrs as the air is now more moist and sea temperatures are increasing. Models are forecasting 93L to recurve well east of Bermuda but potentially threaten the Azores Islands eventually. SHIPS is keen on making 93L a hurricane. We may need to watch 93L too- although it's a long way off, 93L may reach our shores as an extratropical storm next week.