Pattern probably not set up for U.S. hurricane hit right now

The same amount of caution must be used when discussing the possibility of a non-hurricane hit as when we talk about one that could hit a particular location, no matter how general. This is one of those cases and my aim here is to point out the reasons why I believe that 96L or what ever it becomes will turn away from the United States. Of course, this is how things look now, obviously the weather is subject to change but sometimes you get clues that are pretty large and cannot be ignored.

First, the here and now.

96L is a large, sprawling low pressure area without a well defined center of circulation. Such large envelopes of energy in the tropics often take time to consolidate and close off a low level center.

96L is not in an ideal location for upward motion which helps to aid in organized deep thunderstorm development

96L is not in an ideal location for upward motion which helps to aid in organized deep thunderstorm development

Dry air continues to impede development to some extent but the overall lack of upward motion or, to put it another way, sinking air, seems to be a big issue, perhaps more so than dry air. As you can see in the graphic I have posted, 96L is located in an area that is only marginal for rising motion. Sure, there are worse conditions elsewhere around the globe but it is not located in a prime area for divergence aloft which would allow for more efficient upward motion and thus convection.

The motion is currently WNW and this should continue for the next day or so. At this track and heading, showers and squally weather will spread over portions of the Lesser Antilles today and tomorrow. Eventually, Puerto Rico and parts of Hispaniola could feel the effects with heavy rain and gusty winds possible. For now, it’s the eastern most islands of the Caribbean Sea that are having to deal with this slowly developing system.

So what about the future? Some of it is complicated but overall, I think the pattern is showing us what should ultimately happen.

Right now, 96L is being driven west by a ridge of high pressure to its north. It acts like a ceiling keeping a helium balloon from escaping in to the sky while a fan blows it laterally along the plane of the ceiling. If you were to open a hole in that ceiling, up, up and away the balloon would go. The same is generally true for tropical cyclones. High pressure at the steering layers keeps them moving more or less westward. As the pressure eases off, the cyclones literally gain latitude or move poleward (north). If the Atlantic were dominated by one large area of high pressure, like we saw in 2008 with Ike, then tropical waves that develop could travel from Africa to Texas without any chance of turning north and out to sea. This does happen but has not been the case for quite some time. The reason? Troughs of low pressure that erode the Atlantic ridge down and create the hole needed for a hurricane to escape through.

500 millibar forecast from the GFS model showing the position of various large (and small) scale weather features

500 millibar forecast from the GFS model showing the position of various large (and small) scale weather features

Check out the second graphic I have posted. It is the 500 millibar forecast from the most recent GFS model run (valid 5 days out). Notice where 96L (or what ever it may be at the time). Also note the two well defined areas of high pressure on the map. One is over the eastern portions of the USA. The other is located over the central Atlantic. These massive domes of air will not allow a tropical cyclone to penetrate them. Instead, they have to go around like a blob of jello navigating around more dense blobs of jello. They each react to one another in subtle ways but the end result is that the smaller blobs (hurricanes) cannot go through the larger, more dense blobs (high pressure areas).

Now notice the trough over the Atlantic between the two ridges – this is the opening between the continental ridge and the Atlantic ridge. If the two were connected, then we’d be talking about a system cruising through the Caribbean Sea right now. Instead, a through of low pressure has carved out enough of an opening in in the Atlantic ridge to allow a possible escape for what ever 96L evolves in to – be it a tropical storm or a hurricane. It will “feel” that weakness or hole and likely turn away from the Southeast U.S.

The GFS global model and the ECMWF global model both show this scenario right now. Can it change? Yes it can but the overall pattern is not likely to change enough to affect the outcome and that is to send 96L packing and out to sea.

There is one glaring issue that needs to be considered. We are talking about computer model data that is days away from becoming reality. These are computer projections of the weather almost a week out in time. I am wanting to explain the situation as it appears today. This also strongly emphasizes the issue of posting graphics that show a hurricane knocking on the door of some coastal location in seven to 10 days. It’s nonsense. Especially without any explanation beyond “this is just one model run and it could be wrong”. Anyone can say that – I wanted to point out the actual players, so to speak, and explain the process in a way that I hope you can understand.

For today, we know that there is a slowly organizing tropical wave and low pressure area which is affecting parts of the eastern Caribbean Sea. Recon is currently investigating the system now and we’ll know more about its structure, etc. soon enough. From there, we will see what happens as each model cycle gives us more clues as to the eventual outcome.

In the eastern Pacific, busy is not strong enough of a word to describe the activity there. We have TS Karina along with hurricane Lowell. In addition, another large low pressure area is about to become the next depression well off the coast of Mexico. It too should strengthen in to a hurricane but is forecast to track parallel to the coast and not bring any significant impacts to the region.

I’ll have another update here late tonight.

M. Sudduth 2:25 PM ET Aug 21

 

 

 

0
0
0
0

Beware the hurricane trolls

The official NHC 5-day graphical Tropical Weather Outlook

The official NHC 5-day graphical Tropical Weather Outlook

As we get in to August, especially late August, the tropics begin to spring to life as conditions become more favorable across the Atlantic Basin.

This time of year also sees a marked increase in what I like to refer to as Hurricane Trolls. These are the people who like to post images, paths, swaths, cones of death – what ever – showing a snap shot of some distant model time period that conveniently has a strong hurricane parked off of some poor, unsuspecting city.

The result? Lots and lots of “shares” and “likes” of said graphic and a few moments of glory for the person who posted it.

What good did it do? How many people have any clue as to what they are looking at? Does it raise awareness or just make people nervous? These are all issues that we have to deal with in the age of instant information and global model output readily – and freely – available to the masses.

The National Hurricane Center now has an experimental five day graphical Tropical Weather Outlook that highlights any areas of concern out to five days. It never, ever shows a single frame from any particular model run to try and drum up interest or increase Facebook likes. Instead, a well thought-out discussion of what players there are on the field is written up and illustrated to outline any potential formation areas in the tropics. Beyond five days is just too uncertain and has little merit to even discuss with any degree of accuracy.

The same hype machine is fired up during winter when a similar group of Snow Trolls comes out of the wood work to post snap shots of day 10 ECMWF snow accumulation graphics which depict some region of the I-95 corridor buried in “The Day After Tomorrow” type snow. Funny, I never see this done when that much snow is forecast for a swath of real estate extending from Montana to Kansas. Wonder why? Again – the more people who could be impacted, the more likes and shares the trolls accumulate.

There is no question that people are interested in the weather, especially when it turns ugly. It’s inherently exciting to think about the possibility of a cat-3 hurricane bearing down on you. It doesn’t mean it’s a good thing but it is exciting by definition. What the Hurricane Trolls fail to consider is how this excitement can lead to anxiety and fear. Posting an image of something that may not happen has more negatives associated with it than positives. It does not help the cause and that is to spread awareness and useful information. While there is a chance that a tropical cyclone could be somewhere in the Gulf of Mexico within the next seven to ten days, there is no way to know how strong it might be. It’s getting towards late August – there’s a chance within any 10 day window that something could pop up. The global models are good but putting faith in a seven, eight or ten day forecast to point of sharing it with fans of your website or Facebook page is doing them a disservice. There’s no education behind the image, only some ill-fated attempt to become the hurricane go-to guy, if only for a brief time.

Now, as far as what is really going on out in the tropics today? Nothing to be alarmed about, just something to keep an eye on as we would any suspect area brewing this time of year. It’s not like hurricanes are something new that we are still adjusting to. They’ve been around ever since the oceans could support them. What we need to get used to is the idea that information put in the wrong hands can be detrimental – always check the source. When ever in doubt, use the ole reliable: hurricanes.gov. No traffic-driven agenda to worry about there, just hard working, dedicated government employees giving you the facts and a wealth of educational info to go with it. Be smart and remember: don’t feed the trolls…they may bite and are known to be aggressive.

I’ll have more here tomorrow.

M. Sudduth 11:10 AM ET Aug 20

0
0
0
0

Quiet time coming to an end for Atlantic?

Large area of general low pressure in the central tropical Atlantic looks like it has potential to develop over the coming days

Large area of general low pressure in the central tropical Atlantic looks like it has potential to develop over the coming days

There are indications that we might be getting in to a more active period across the Atlantic Basin in the coming days. While nothing is imminent and there are no threats to land, the potential for development is steadily going up.

Right now, the main area to watch is associated with a rather large and elongated region of low pressure in the central tropical Atlantic. The NHC has two distinct areas outlined in their outlook but I think that we will eventually see one take over and begin to develop.

Water temps are plenty warm and the upper level winds seem to be favorable for gradual development once the moisture content increases in a few days as the low(s) track westward.

Computer models suggest that one of these low pressure areas could organize enough to become at least a tropical depression over the next five days – probably somewhere in the Caribbean Sea. In fact, there is apparently enough interest from the NHC so that a tentative recon mission has been planned for the area east  of the Windward Islands on Thursday. Stay tuned, things might be about ready to pick up as we end the week.

Meanwhile, the east Pacific remains very active with two tropical storms and a new area developing further south well off the coast of Central America on the Pacific side. So far, none of the systems threaten land but we’ll have to watch this new system as it could track closer to Mexico than any previous one thus far this season.

I will have more here tomorrow morning.

M. Sudduth 11:36 AM ET Aug 19

 

0
0
0
0

Atlantic quiet for the time being while east Pacific remains very active

Dry, dusty air continues to put a lid on development in the Atlantic

Dry, dusty air continues to put a lid on development in the Atlantic

The Atlantic Basin is quiet as we begin the week. Dry air continues to dominate the deep tropics and in fact, some of the African dust has made its way across the Atlantic to show up in the skies over Florida (and adjacent land masses). This has resulted in a milky, hazy color to the sky which should persist for the next few days at least.

So far, the global models are not indicating any significant areas of development over the coming week or so in the Atlantic. Water temps are plenty warm in most areas, tropical waves are emerging from Africa and shear is generally a non-issue. The main inhibiting factor continues to be the stable conditions that have taken up residence across the deep tropics in recent hurricane seasons. I see little evidence that this pattern will change anytime soon and it is possible that August will end without any more named storms – something that would be highly unusual but not unexpected for this season.

Meanwhile, the east Pacific continues to crank out tropical cyclones on a regular basis. A new depression formed last night (12-E) and is forecast to become a tropical storm later today. Fortunately, no impact to land is forecast as the track should keep the system well off the coast of Mexico and eventually in to cooler Pacific waters later this week.

To the west of TD 12-E, a weak tropical storm Karina continues to churn slowly in the open waters far from land. There is no threat of impact to land from Karina over the next five days.

I’ll have more here tomorrow.

M. Sudduth 10:40 AM ET Aug 18

0
0
0
0

East Pacific remains very busy while Atlantic not so much

The busy east Pacific hurricane season continues

The busy east Pacific hurricane season continues

The eastern Pacific has been very busy this hurricane season and now we can add another name to the list: Karina. The NHC began issuing advisories on the newly designated storm last night. Fortunately, it is located well off the coast of Mexico and is moving westward and away from land.

Meanwhile, farther to the west, near the central Pacific region, another area of low pressure is expected to develop and move westward to west-northwest over the next few days. Interests in Hawaii should keep an eye on this feature as there are indications that it could track towards Hawaii in the longer term.

In the Atlantic, all is quiet still as dry, stable air continues to dominate the pattern over the tropical Atlantic. Sea surface temperatures are plenty warm just about everywhere but this alone is not enough to generate hurricanes. I believe we will begin to see a shift in the overall pattern in about a week to 10 days that could favor more development potential. This would also coincide with the normal climatological increase in activity that begins this time of year. So far, we’ve seen very little activity since Arthur back in early July and most recently, Bertha. The Gulf and Caribbean have not even had an area of interest develop as of yet. Will the coming weeks see a change in that? Hard to know for sure but one would think that considering that lack of El Nino would at least reduce the negative influences a little bit – possibly allowing for a busy end of the month and in to September. We’ll see.

I’ll have more here tomorrow.

M. Sudduth

2:04 PM ET Aug 13

0
0
0
0