Archive for Atlantic Basin

Bertha closing in on Lesser Antilles

Visible satellite photo of Bertha showing the deeper thunderstorm activity displaced to the east of the center

Visible satellite photo of Bertha showing the deeper thunderstorm activity displaced to the east of the center

Tropical storm Bertha has more convection with it this morning but it is displaced to the east of the low level center as seen in early morning satellite imagery. This is due to the fact that upper level winds are running in to the storm instead of going with it – thus the deep thunderstorms are pushed off to the east while the storm travels westward.

Top winds are still 45 mph and the pressure is not falling much at all. Unless Bertha can wrap the deep thunderstorms around the center and develop a more organized core, it will not strengthen much. There is a chance this could happen as forecast by many of the intensity models. In fact, the statistical SHIPS model makes Bertha a hurricane but well after it passes through the Caribbean Sea.

Today, the main issue will be heavy rain and brief squally weather for portions of the eastern Caribbean as Bertha closes in from the east. The worst of the weather will be felt where the deep convection is located. It is impossible to tell with such a poorly organized system how this will play out in the coming hours. Local radar from the Caribbean will help but people in the region need to be ready for the potential of tropical storm force winds, rough seas and very heavy rain – again, mainly where the deep convection is located. Outside of that, the lighter rain bands will not have much impact other than an increase in wind and rain.

For Puerto Rico and the Dominican Republic, again, a lot has to do with how well organized Bertha becomes. Water temps are only going to rise along its path but if the shear and dry do not relent much, then Bertha could remain more of a rain maker than anything else. This is still a problem, especially for mountainous terrain but the rain itself is much needed for the region – hopefully just not too much at one time.

Once Bertha tracks out of the Caribbean, it should remain just to the east of the Bahamas as it nears the western edge of the Bermuda High and begins to turn northward. At this point, it could begin to strengthen and may have a shot at becoming a hurricane before turning out to sea. This could bring a couple of days of increased swells and coastal rip currents to parts of the Southeast coast. Surfers will love this but swimmers, especially children and those who are not used to such conditions, may be at risk from the rougher than normal surf. Check your local NWS site for more details on this potential hazard next week.

Elsewhere in the Atlantic, all is quiet on this first day of August.

As I mentioned yesterday, the east Pacific remains quite busy overall but everything is remaining well away from land and will remain that way for the time being.

I’ll post more on Bertha early this evening.

M. Sudduth 9:02 AM ET Aug 1

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Not the best looking tropical storm but there it is – NHC upgrades 93L to TS Bertha

NHC 5-day track map showing Bertha moving thorugh the Caribbean and then off the Southeast coast

NHC 5-day track map showing Bertha moving thorugh the Caribbean and then off the Southeast coast

The NHC has begun issuing advisories on TS Bertha as of 11pm ET tonight. While deep thunderstorms are very limited, the circulation is well defined and an Air Force plane confirmed winds to tropical storm force earlier today.

While some may wonder why on earth something so weak looking would get an upgrade, consider this: a tropical cyclone is a large and unusual weather phenomenon when compared to everyday weather. The Lesser Antilles are a series of islands and there are many people who live or otherwise use boats and other water craft in the region. A tropical storm, no matter how ragged, can impact an area with strong winds, rough seas and heavy rain. Just because it is rather poorly organized from a convection stand point, doesn’t mean it lacks the potential to cause issues for the area that it will pass through.

Speaking of that – the forecast track takes Bertha through the eastern Caribbean before turning northward and across the Dominican Republic and in to the Bahamas. Here too, rain and related issues are a concern, especially in the mountainous areas of Puerto Rico and of course Hispaniola. Hopefully the circulation will remain rather bare of deep convection but as I have said many times, hope is not a planning tool, knowing the hazards that could affect you is. We can hope that Bertha remains weak but this only pertains to the wind speeds. It could still dump copious amounts of rain, even if in a limited area, and that could cause issues for people.

After passing through the Caribbean Sea, Bertha is expected to turn northward just off the Southeast coast. How close it tracks to, say, the Carolinas or points north, remains to be seen. Let’s see how the storm fares over the next day or two before worrying too much about the longer term outcome. Needless to say, we will be watching this closely as we move through the weekend but for now, it looks to be a wave maker perhaps for parts of the East Coast and that’s it as far as impacts. Things can change so stay tuned.

I will have more here tomorrow morning.

M. Sudduth 11:52 PM ET July 31

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Bertha by mid-week? Seems likely at this point

NHC graphic showing potential path of developing system in the Atlantic, designated as 93L

NHC graphic showing potential path of developing system in the Atlantic, designated as 93L

The tropics are about to get active and this time, it could stick.

The NHC is monitoring a tropical wave, now designated as invest area 93L, far out in the deep tropics. While this region has been quite hostile up until now, it appears that the tables are about to turn and we will likely get the next named storm, Bertha, within a few days.

Global computer models are coming in to agreement that the tropical wave will develop steadily in the coming days as it moves generally west to west-northwest.

Water temps are okay for development but are certainly not running above normal in the region. This might keep the system from developing faster, we’ll see. The presence of dry air all across the deep tropics may also inhibit development even though there are indications that this pattern is about to let up some.

The track appears to be generally westward with a gradual bend to the west-northwest with time. Keeping this in mind, interests in the Lesser Antilles should be monitoring this feature closely. The NHC’s five day outlook graphic suggests a path towards the islands. After that point, it is just too soon to even begin speculating on where this might end up. We know the drill by now: it could turn north and eventually away from the United States or it could continue west enough to eventually affect land somewhere after a potential encounter with the Caribbean islands.

One thing that interests me quite a bit is the fact that, if this system develops, it would be several weeks ahead of the usual time frame that we look this far east. It would also signify a change in the overall hostile pattern for the deep tropics. In short, this could indicate that we are in for a different hurricane season than originally forecast. The El Nino failed to develop thus far and now that we are seeing development in the deep tropics, it may be that the forecast of a below average season is in jeopardy. I do not want to put too much in to this but considering just how hostile the region between Africa and the Caribbean has been for the past year at least, I do wonder if we are seeing a change that could lead to more long-track systems that do not fall apart.

The rest of the Atlantic Basin is quiet as we start the week. I see nothing to worry about anywhere outside of 93L.

In the east Pacific, things remain quite busy with weakening TS Hernan moving away from the Mexican coastline. Other areas to monitor dot the Pacific but none pose any significant threat to land right now.

I will post another update on 93L later this evening after more information comes out from the global models and the NHC.

M. Sudduth 9:27 AM ET July 28

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Slowly but surely, it looks as though development potential is there

The GFS model showing a tropical cyclone approaching the Lesser Antilles in about five days. How strong it could be remains to be seen.

The GFS model showing a tropical cyclone approaching the Lesser Antilles in about five days. How strong it could be remains to be seen.

A tropical wave over the eastern Atlantic continues to move westward without much convection or organization associated with it. Dry air and a general lack of upward motion in the atmosphere are keeping the system in check for now.

Despite the lack of organized thunderstorms, the NHC has increased the potential for development over the next five days to 40%. This is due to the fact that the overall environmental conditions are expected to improve in the favor of gradual development of this system.

So far, there is not a lot of global computer model support for the area. This is not too uncommon over the deep tropics when marginal conditions are in place. The GFS model seems to have the most consistency, showing a gradually developing tropical storm moving towards the Lesser Antilles within a week. Whether or not this actually happens remains to be seen but we are heading in to a more favorable time period and as such, interests in the region should keep an eye on this system.

It will be very interesting to see if this tropical wave actually develops. If it does, considering it is still only late July, then it will show me that the deep tropics are not quite as hostile as we’ve seen in recent weeks and even dating back to last year. The plethora of dry air dominating the tropical Atlantic tends to make me skeptical about any significant development but time will tell, that much is for certain.

In the east Pacific, tropical storm Hernan, which formed yesterday, is gaining strength and could become a hurricane before it moves over cooler water and begins to weaken. It poses no threat to mainland Mexico as its track is away from land.

I will have more here tomorrow morning.

M. Sudduth 2:25 PM ET July 27

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Deep tropics the place to watch this coming week

Tropical wave over the far eastern Atlantic has potential to develop next week

Tropical wave over the far eastern Atlantic has potential to develop next week

It’s not much to look at now, but the NHC has mentioned a tropical wave over the far eastern Atlantic that has some potential for development over the next few days.

Right now, the environment is not very suitable for anything to get going but that may change as indicated by some of the global computer models. A more favorable upward motion pattern, coupled with less dry air (perhaps) just might allow for a tropical low and eventually a depression to develop. It is close enough to August that this scenario seems plausible, especially considering the fact that TD2 formed within this general region just a few days ago. Even though that depression literally dried up, it is still a sign that this part of the deep tropics is becoming more and more favorable.

On the other hand, there has been an overwhelming amount of dry air across this region for a good part of the hurricane season to date. If this pattern does not ease up, it will be extremely difficult to believe that much will come out of the area south of 20N between Africa and the Lesser Antilles. All it takes is a few weeks of less hostile conditions and the lid could come off but for now, I am skeptical of seeing much – we’ll see what happens in the coming days.

Elsewhere, the Atlantic Basin is quiet this weekend.

In the east Pacific, things remain very busy with several systems on the map this morning. However, none pose any threat to land areas and that looks to remain the case over the next several days at least.

I’ll have more here tomorrow.

M. Sudduth 11 AM ET July 26

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