Saturday, May 26, 2012

Tropical Storm Beryl (2012)

Storm Active: May 25-30

On May 21, a low pressure system developed near the eastern coast of the Yucatan Peninsula. From there, it slowly moved northeast, and accumulated some more significant cloud cover on May 23. Initially, conditions were very hostile for development, but as the low tracked farther northeast, the upper-level winds slowly abated, and the circulation became better organized. On May 24, the system moved over Cuba, bringing some rainfall to it and neighboring Caribbean islands. Later that day, the western edge of the system passed over the Florida keys.

The center of the low became much better defined late that night and into May 25, and the convection increased markedly, though mainly in the northern and eastern quadrants. The system continued to move northeast, but its motion slowed as it encountered strong ridges of high pressure to its north and east. Late that evening, thunderstorm activity flared up near the center, and the low was upgraded to a tropical cyclone. However, due to its proximity to an upper-level low and its relatively broad circulation, it was designated Subtropical Storm Beryl.

Beryl's motion reversed early on May 26 as it adopted a west-southwest track. Its convection remained limited, as dry air was invading the center from the southeast, but the cyclone became more symmetrical in appearance as it moved toward the U.S. coastline. Over the following day, Beryl became slightly more organized, and experienced modest intensification late that night. The system veered more to the west early on May 27 and accelerated somewhat. More powerful rain bands developed that same morning, but the center remained broad as the cyclone approached the Florida coastline.

Later that day, the windfield contracted and intense thunderstorm activity appeared near the center of circulation, meriting a reclassification of Beryl as a fully tropical cyclone. Despite its proximity to land, Beryl was rapidly strengthening during the afternoon of May 27. It nearly reached hurricane strength, achieving its peak intensity of 70 mph winds and a minimum central pressure of 992 mb late that night before making landfall near Jacksonville Beach, Florida very early on May 28.

The convection quickly deteriorated over land that morning, but the circulation remained intact, and the rainbands near the coastline still caused heavy rain, as they tapped into Atlantic moisture. The winds fell quickly, however, and Beryl was downgraded to a tropical depression by late morning. Over the following day, Tropical Depression Beryl tracked further inland, crossing into Georgia, and then slowed in forward speed as the ridge to the north weakened. Soon, the typical steering patten emerged, and Beryl turned to the northeast.

On May 29, the convection associated with the tropical depression began to be entangled with a front to the north. As the depression crossed over land into South Carolina, all of the remaining rain bands were displaced significantly poleward. Despite this, Beryl's circulation deepened, but this was probably due to the beginning of extratropical transition. During the afternoon of May 30, as Beryl regained tropical storm intensity near the North Carolina coast, it became post-tropical. Soon after, it was absorbed by a front.

Beryl was the strongest preseason cyclone since 1972, and, since it was the second named storm to form before the start of the official hurricane season (begins June 1), 2012 was only the third Atlantic hurricane season in history to have two preseason storms, after 1887 and 1908.

Beryl near peak intensity, just before making landfall in Florida. Beryl was one of the strongest U.S. landfalling off-season storms in history.

Track of Beryl.

Sunday, May 20, 2012

Tropical Storm Alberto (2012)

Storm Active: May 19-22

On May 17, a cold front moved off of the U.S. East Coast. The southern end of the front stalled off of the coast of South Carolina, and a low pressure trough developed. Over the following two days, the area of low pressure remained nearly stationary, and began to acquire tropical characteristics, which, during the afternoon of May 19, were enough to classify it as Tropical Storm Alberto, the first tropical cyclone of the 2012 Atlantic Hurricane Season.

The system drifted slowly to the southwest and west-southwest over the following day, and the devtelopment of modest convection near the center late on May 19 allowed the system to reach its peak intensity of 60 mph winds and a minimum central pressure of 995 mb. Early on May 20, the shear from a low pressure system to its northwest intensified, and the circulation became exposed mid-morning, weakening Alberto. As the day went on the blocking pattern that was in place over the U.S. northeast and the northwest Atlantic Ocean receded, and Alberto quickly shifted its motion from southwest to south to east and then northeast.

Accelerating as it did so, the system weakened further to a minimal tropical storm and then a tropical depression on May 21. By May 22, the convection was strongly displaced from the circulation center, and Alberto became extratropical later that morning, while southeast of Cape Hattaras, North Carolina. The next day, it merged with a front coming off of the U.S. Alberto was the earliest forming cyclone in the Atlantic basin since Ana in 2003, and 2012 was the first year on record such that a preseason cyclone formed in both the Atlantic and East Pacific Basins.

Alberto near peak intensity on May 19.

Track of Alberto.

Professor Quibb's Picks-2012

My personal prediction for the 2012 Atlantic Hurricane Season is (written May 16, 2012):

15 cyclones attaining tropical depression status
13 cyclones attaining tropical storm status
5 cyclones attaining hurricane status
3 cyclones attaining major hurricane status

These predictions are near normal for an Atlantic Hurricane Season, with the number of predicted tropical storms slightly above average and the numbers of predicted hurricanes and major hurricanes near their respective long-term averages.

Despite being near the average, this prediction is low relative to recent years, in which 7 out of the last 10 seasons have had 15 or more named storms, and have included some of the most active on record. This active period reflects a theoretical phenomenon called the Atlantic Multidecadal Oscillation (AMO), a cycle involving sea surface temperatures that has a period of about 60 years. The whole of the 2000's was in the "active" period of the oscillation, which is expected to persist for at least another five years.

Despite this, an El Nino event is expected to develop in the coming months, characterized by a stronger jet stream, and areas of strong wind shear across the Atlantic basin. El Nino tends to inhibit cyclone development, and this is reflected in the forecast. The exact intensity of the season is dependent on how quickly the El Nino develops and its intensity, but, even in the case of a strong El Nino event, there will be portions of the season where wind shear temporarily abates, possibly allowing strong cyclones to form.

Below, my anticipated risk factors for four major regions of the Atlantic basin are listed. The risk index runs from 1 meaning very low potential to 5 being very high potential.

U.S. East Coast: 2
Despite high sea surface temperatures off of the U.S. coast following a mild winter, the risk is low for an East Coast landfall this year. With a strong jet stream and a weak Bermuda, the steering currents will strongly push cyclones out to sea, which for the most part will miss the East Coast. Bermuda might not be so lucky, however. The greatest risk for East Coast states is from a system on the Gulf side tracking over land and then up parts of the east coast. Though this minimizes the risk of strong winds, flooding may still be the result if such a system combines with an existing front or extratropical system (for example, Tropical Storm Lee of 2011).

U.S. Gulf Coast/Northern Mexico: 3
The Gulf coast has not experienced a hurricane landfall since 2008, but this may change in the 2012 season. The Gulf waters will again be very warm, and the blocking pattern across the Gulf will not be as strong as in previous years. Also, as is characteristic with the El Nino, any troughs across the Gulf are likely to be impermanent, and it is likely that at least a few cyclones will enter the Gulf.

Yucatan Peninsula and Central America: 4
Central America has been hit by a number of cyclones over the past few years, and this shows few signs of abating as we enter the 2012 Atlantic Hurricane Season. With mountainous terrain over much of Nicargua, Honduras, and Belize, flash flooding is a major concern, and the warm and moist southwest Caribbean is a prime location for tropical cyclone formation. I expect at least two landfalls, though they may be by weak storms.

Caribbean Islands: 3
The Caribbean Islands are always at risk for hurricane damage, as they lie in the center of many common tropical cyclone paths. However, the risk for damage is not as high as last year, as any cyclones will probably be more fast moving in areas of the Caribbean, and the scenario of a Cape Verde type hurricane is not as likely as in the previous few years.

Overall, 2012 will be a moderate season in terms of formation, but there is still a fair likelihood for a devastating hurricane, which would most likely effect Mexico and the U.S. Gulf coast.

Wednesday, May 16, 2012

Hurricane Names List-2012

For the Atlantic Basin, the hurricane names list for 2012 is as follows:

Alberto (used)
Beryl (used)
Chris (used)
Debby (used)
Ernesto (used)
Florence (used)
Gordon (used)
Helene (used)
Isaac (used)
Joyce (used)
Kirk (used)
Leslie (used)
Michael (used)
Nadine (used)
Oscar (used)
Patty (used)
Rafael (used)
Sandy (used)
Tony (used)

This list is the same as that of the 2006 Atlantic Hurricane Season, as no cyclone names were retired that year.

Tuesday, May 8, 2012

Spinors and Applications

Spinors are a type of mathematical quantity that expand on the notion of regular vectors and vector rotations. In the case of regular vectors in a space, it is a basic property that rotating a vector about any axis 360º will bring it back to its starting point. In other words, if we apply any 360º rotation r to a vector v, then

rv = v,

which can be simplified to r = 1, expressing the fact that the application of an arbitrary 360º rotation r will leave a vector unchanged. However, the key property of a spinor, or a space of spinors, is that a 360º rotation does not transform a spinor into itself, but rather its negative. Only a rotation of 720º, corresponding to two full rotations, will correspond to leaving a vector unchanged. Therefore, if s is a 360º rotation in a spinor space, then

s = -1, and
s2 = 1, i.e. the application of s twice returns any spinor to its original state.

To clarify, the mathematical objects that are actually spinors are elements, not rotations (strictly speaking), of a certain space. The above spinor rotation s expresses the way through which spinors are transformed into their respective negatives, and is not itself, in this context, a spinor. However, in reality, the set of possible rotations on a space often is itself a space, and the example provided below falls under this category.

One geometrically accessible example of a spinor is a quaternion. As discussed elsewhere, quaternions are an extension of the complex numbers to four dimensions, with four basis elements 1, i, j, and k.

The confusion arising from whether spinors are elements or rotations is related to the dual interpretation of quaternions: either as elements of a four dimensional space, or as rotations of three-dimensional space. However, the full "meaning" of i, j, and k, are not captured by the three-dimensional rotation analogy. As the orientation of the three-dimensional space is shifted through, for example, i2, returning to its former position, the space "remembers" that there has only been one rotation, and the orientation now is the negative of what it was before. In this sense, there is an added complexity to the ambient three-dimensional space-it has a way of "knowing" how many rotations have been performed.

The mathematical properties of spinors find a physical application in the area of quantum physics. It happens that the rotational properties of some particles are identical with those of spinors, in that a rotation of 360° produces not the same quantum state, but a "conjugate"-many properties are the same, but some are opposite to what they originally where. In the same way as spinors, they are restored to their former state through only a 720° rotation.

The family of particles that exhibit the properties of spinors are those with spin 1/2. One example is the electron. The electron, of course being very common, is then important to modeling particle interaction phenomena, and the knowledge of its properties is thus equally important. Thus spinors find an application in the study of subatomic particles.

Sources:, The Road to Reality by Roger Penrose, Chapter 11