When tropical scales meets other scales: A global view of current Atlantic weather

The major news outlets lately have been completely focused on the threat of hurricane Sandy . Indeed, it has been rumored that it is one of the biggest threats to hit the Northeast [US] in years, and rightly so. The circulation pattern that is leading to this event is rare. It is comprised of a set of events on different scales, both tropical and extratropical, that is leading to this set of events.

The image below shows a hemispheric look of what's currently happening. The most prominent  feature are the two cyclones over the Atlantic ocean. The first one is obviously hurricane Sandy, the second is a not so different looking extratropical cyclone, which has been persisting for several days.

While these two low pressure patterns are quite obvious in satellite imagery, some other strong patterns are ocurring that are not as obvious in a picture.  The figure below shows the forecast of geopotential heighs (and anomalies) within the next couple of days. Geopotential heights are analogous to pressure.

The first and most most interesting pattern in the figure  is the major pattern localized over the Atlantic. Check out how the jet immediately shifts northward near the east coast of the USA. That red bullseye over northeast Canada is an anomalous ridge. That ridging pattern, flanked by two lows (seen above) is often called an "omega" pattern because of its resemblance to the greek capital omega.

Indeed, we are currently in a period where the jet is weaker, and more wavelike features dominate weather patterns. This is very evident in the latest Arctic Oscillation (AO) Index, which has been negative for a while. A negative AO index indicates strong wave features, with potential for Arctic spills over the US, and anomalously warm Arctic temperatures. The pattern, however, is forecast to weaken in the following weeks, thus anomalous blocking patterns like the one seen above may become  less likely.

Typhoon Sanba

Typhoon Sanba has become the object of attention lately, with its characteristic appearance of a robust tropical cyclones.  Below is an animation from NRL of the cyclone during the last couple of hours.

The cyclone strengthened rapidly while it passed an area of high ocean heat content, as seen below (image courtesy of CIMMS and RSMAS).  Although it has gained a lof of strength, reaching the Saffir-Simpson category 5 scale, it will likely not hold it for very long as it is leaving this area of high ocean heat toward one with cooler sea surface temperature.

As an additional sidenotem the cyclone is also dominating the upper-level divergence pattern in the form of velocity potential (divergence is the laplacian of velocity potential). In the plot below, yellow contours denote the velocity potential associated with large-scale upper level divergence, also associated with ascending motion. Green contours denote the opposite. Note the tight contours in the area where the storm lies.  The filled contours denote the upper level streamfunction. Tropical cyclones do not tend to project strongly in the rotation in the upper levels. The contours in that area are likely due to Rossby waves.

In a couple of days, Sanba might become a threat to some land areas in this region.We should keep close attention as this situation unfolds. 

About research money, outreach and people ...

Every once in a while I meet up with people I haven't seen in a while.  When you don't see people for a long time,  they seem to go through a similar routine of questions. Some of the questions include "What are you doing now?", "What's meteorology?" and the infamous "So meteorologists work with [insert something that's wrong but funny]?".  Last week I got asked if I worked with dinosaur bones! 

Sometimes you get thought-provoking questions, the ones that you keep thinking about long after the conversation is over.  For example, a couple of days ago I had another student ask me about funding. His questions were basically "How do you pay for school?", "Why are you getting this funding?" and "What is expected from you with this money. They look like pretty simple questions, and they are. The thing about them is that they make you think about the way that you are using your money,  what do you expect out of yourself, and so on. Naturally I told him about research assistantship, teaching assistantship and the many fellowship opportunities that are out there.  But then I started thinking "What do they want from me with that money?".

The fact is that they want you to do research with that money. Hopefully you will find interesting things, get some papers published, etc. All in all they just want you to add another drop to the cup of advancement of science. It is a topic that I keep mentioning in several blog posts.  In our field, one of the main goals is to improve weather prediction, so we can have better forecasts. 

Take for example what I do:  My research is focused on the MJO. While great progress has been made from it's discovery in the early 70's, there is still so much to get done.  It's complex behavior in the last couple of weeks has been discussed even among experts. All in all, we are still long ways to get a good grip over this big guy. 

It's erratic behavior has not been the only thing that's troublesome. Last year we had a good number of tropical cyclones that came to be, at least in part, due to the enhanced moisture and vorticity provided by the active MJO over the Indian Ocean/ Warm Pool region. Tropical cyclones Keila, Washi ,  Grant and Thane all were generated like this, to name a few.  Some of these storms caused significant damage to the areas they affected. In particular, Washi is responsible for more than a thousand deaths.

Images showing precipitation from TS Washi during the specified dates. The larger swath corresponds to TRMM's Microwave Imager (TMI)  while the smalle swath corresponds to the Precipitation Radar (PR).

These storms did plenty of damage, but what about other events. What about floods that come from prolonged rainfall, not associated with tropical cyclones. What about flash floods from convective precipitation? What about everything else that can be caused by anomalous weather. The truth is that we barely hear about these things. In fact, most people probably don't even know about the damage the tropical cyclones themselves did. The reality is that these events barely ever hit the headlines, and yet they happen on a year to year basis, claiming hundreds to thousands of lives. 

That's one of the reasons behind the heavy funding for research. If we could understand all this better, we could predict it better, hence reducing the likelihood of having a significant weather event claiming lives. But, is this really enough? The answer is inarguably no. 

There is a lot more to the safety of people than proper weather prediction. While it is great that nowadays we count with weather forecasts that are as easy to access as pressing your cellphone's button; it's pretty worthless is the reader has no idea how to interpret the forecast, even less if he/she doesn't know how to act to it. This is where outreaching comes into play.

Just as important as the science itself is spreading the knowledge to the public. But it is not something as simple as writing about it once and leaving it as is. It is a constant process. You have to let it be known with certain frequency, and be persistent about it. You also need enough facts and be convincing when you talk or else you might be shut down. It is a very difficult task. 

Back when I was in high school I was involved in a lot of community service. One of the things I got involved was doing a march against the abuse of elderlies. I directed the march and hundreds attended. It was one of the most fulfilling events of my life! In response to the march I got so much help from different people to help out with the, with people donating checks to wheelchairs. The next year I looked to follow up with a second march, or an event of similar magnitude. Because I was out of town for college I was unable to direct, so a new group emerged to make it happen. Communication between us was low, and the event never happen. That was it for the marches against elderly violence ...

Image from the march against elderly violence. 

That second march could have happened. It just needed more motivation, more persistence and the right attitude. This is what happens fairly often in many of lives situation, you bail on it thinking there's no solution when you can actually seek out an alternative. While this might be too simple with certain scenarios, like climate change, it is generally fairly true for many others. 

So are improvement and outreach all that we need? I don't think so. There's even more to all this than what I have mentioned. People's safety from weather, or other dangerous events depends just as much on each individual and the local government as it does on the other communities that work with it.  In the end it is a multifaceted task, which requires a drop of effort from many people. With the writing of this blog, I hope I do a little bit on the outreaching part. What about you?

Thank you for your time.

Ángel F.