Tropics Active Worldwide
As the title of my blog suggests, the tropics are very active across the world right now. The main feature right now in the Atlanitc is an area of disturbed weather in the northwest Caribbean Sea. This area, dubbed invest 94L by the National Hurricane Center, is currently very broad and elongated, and the NHC is giving the system a near 0% chance of development over the next 48 hours as it fights moderate to high wind shear which will prevent it from consolidating and developing.
Figure One: Invest 94L is seen in the Caribbean as nothing more than a disorganized region of convection
94L is currently a heavy rain threat to several islands in the Caribbean. Things may get more interesting for 94L when it gets out of the Caribbean and moves into an environment more conducive for development off the Southeast US coast.
Figure Two: Current Atlantic Ocean shear map
As Figure Two shows, 94L is embedded in an area of 20-30 knots of shear. However, once it crosses over into the open Atlantic, it will enter a region of lower shear as the pocket of high shear there now moves out. I question exactly how favorable these conditions will be, however, particularly because 94L has such a long way to go to organize that it would need near perfect conditions to have a chance at development. So, I agree with the NHC that this has a near 0% chance of developing within the next 48 hours, and I give it about a 35-40% chance of developing beyond that time.
Bud Not As Strong As Forecast
Meanwhile, in the East Pac, tropical storm Bud continues to churn in the open waters of the Pacific as it moves slowly towards Mexico. Initially Bud was forecast to be a potentially major problem for Mexico by many, and the NHC initially forecast the storm to be a strong Cat 2 at peak and make landfall in Mexico as a hurricane. I was never optimistic on Bud and forecast him to peak as a 65mph tropical storm, which happens to be his current intensity. Under fairly favorable conditions Bud will probably strengthen a little more over the next couple days and may peak as a low end hurricane, meaning my original forecast may be a bit low. I think at this point a peak of 75-80 mph may be more likely. It also appears at this point that Bud will not make landfall in Mexico but instead only approach the coast before turning back out to sea.
Figure Three: Current official forecast track for Bud.
The only way Bud could potentially be a problem for Mexico is if it approaches closer to the coast than forecast, because since it is growing in size and slow moving, this would bring a major flood threat. I currently do not anticipate that happening, but it should be watched.
First Typhoon of the Season in the West Pac
On the other side of the world, the West Pacifc has its first typhoon of the season, named Sanvu. Sanvu currently has winds of 75 mph and is forecast to strengthen some by the Joint Typhoon Warning Center as it is under fairly favorable conditions for further strengthening. Sanvu provided some heavy rains to Guam Monday night but is now over the open ocean and should not threaten any land areas.
Figure Four: Typhoon Sanvu
I had to get my thoughts out on the tropics tonight as I will be on Cape Cod this Saturday and Sunday without my computer so I won't be able to monitor the tropics. It's looking like great weather for my first swim of the year down there: High temperatures should be around 70 with water temperatures in the mid to even upper 50s!! That is unheard of this time of year up here, all thanks to the mild winter.
Thank you as always for reading and have a great rest of your week and a great long weekend!
Alberto Spinning Down, 92E Should Be Watched
Tropical storm Alberto is currently meandering off the Southeast US coast. He is located about 105 miles southeast of Savannah, Georgia. The current intensity is estimated at 45mph by the National Hurricane Center with a pressure of 1006mb. The pressure has steadily risen throughout the day, indicating Alberto is weakening as it battles dry air to its south and some shear.
Tiny Alberto is seen battling a lot of dry air to its south and east
All Tropical Storm Watches have been discontinued as it appears Alberto will remain far enough offshore to not provide tropical storm force conditions to South Carolina. The wind field of Alberto is tiny, with tropical storm force winds barely extending 50 miles from the center. Under weak steering currents, Alberto has drifted southwest over the past day and is now turning more to the south. It should begin a move to the northeast soon, which will cause it to accelerate and become extratropical if it has not already dissipated by that time. After a convective burst near the center earlier today, Alberto once again seems to have weakening convection, leading me to believe it will dissipate in 24 hours or so.
Alberto is seen nearly void of deep convection
An air force recon mission earlier today found some winds of near 60mph but due to possible contaminations as well as the storm's worsened satellite presentation the intensity was kept at 45mph.
92E Organizes In The East Pac
Meanwhile, in the East Pacific, long lived invest 92E appears to finally be organizing. The National Hurricane Center gives it a 60% chance of developing within the next 48 hours as it drifts slowly to the northwest. Some models intensify 92E into a hurricane and bring it close to the Mexican coastline. My intenisty forecast is less agressive, as I expect a peak of around 60-65mph. I do think that it is likely 92E will at least track close to Mexico, so people there should be on guard. I will have more updates on 92E later this week as it continues to develop.
92E has quite a bit of deep convection and an improving satellite signature.
Looking long range, it appears we will be entering a quiet spell in the tropics for the next week or two, but as always, storms can spin up out of nowhere so we should remain vigilant.
Thank you as always for reading, and have a great week!
Updated: 9:17 PM GMT on May 20, 2012
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Aletta No Threat To Land; Bud Likely Within Days
Today, May 15, marks the first day of the 2012 Eastern North Pacifc Hurricane Season. For my thoughts on the season as a whole you can look at my last blog entry. Yesterday saw the formation of TD One E, a day ahead of the start of the season. The depression strengthened some and was upgraded to Tropical Storm Aletta early on May 15 (UTC) meaning it was not named in the preseason. According to the National Hurricane Center Aletta is located about 810 miles south of the tip of Baja California. She is moving slowly westward at around 10 mph. The storms's current intensity is 45 mph with a pressure of 1003 mb. Aletta is probably peaking in intensity right now if she has not done so already. There is a significant amount of dry air to the south, west, and north of Aletta. Also, a powerful upper level trough will soon pass north of Aletta, greatly increasing wind shear over the system. Finally, Aletta is also heading for cooler waters. These three factors will combine to cause Aletta to disipate. The NHC is forecasting the storm to be dissipated by 72 hours. I think it will occur sooner than that because of how many factors will soon be working against Aletta. Also, Aletta is a very small system so this will make it difficult for her to resist the influences of shear and dry air.
This image reveals that dry air and shear seems to be already taking their toll on the system's west edge. The storm's convective pattern remains quite good overall though.
This image reveals the significant amount of dry air surrounding Aletta.
An area of disturbed weather several hundred miles from shore in the East Pac is being monitored for development. The NHC is giving this system a 10% chance of development within 48 hours, however beyond that time it appears likely that this system will become a tropical storm and be named Bud. Several models have shown this with the ECMWF being the most aggresive. The GFS model has also shown the system but to a lesser degree of intensity. Due to the poor handling of Aletta by the ECMWF and the excellent handling of the storm by the GFS, I do not see this becoming a major storm. I think it is likely to peak as a mid strength tropical storm with 55-60mph winds. I will likely have another update this week.
Regarding my "blogging schedule" for hurricane season, there really isn't one. I will post entries when time allows me to and when there is interesting tropical weather to discuss. I will blog on tropical activity in the Atlantic, East Pacific, and West Pacifc.
Thank you as always for reading and enjoy the rest of your week!
Updated: 9:29 PM GMT on May 15, 2012
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East Pacifc Hurricane Season Preview
As we all know, it's getting to be that time of year... In less than a month we will begin the 2012 Atlantic Hurricane Season! However we are less than 2 weeks away from the start of the 2012 East Pacific Hurricane Season. The main factor that will drive the Atlantic Season this year will also be the driving force in the East Pacifc, and that is of course the ongoing transition from La Nina conditions into neutral conditions and likely heading for at least weak El Nino conditions by late season. Many, including myself, expect this year's Atlantic season to have the majority of its storms for by the end of August before we transition to El Nino conditions which increases shear across the Atlantic basin.
This recent Sea Surface Temperature anomaly map indicates that waters in the East Pacific where storms are most likely to form this year are very warm, increasing the chances of an active season. Many other areas in the Pacifc remain cooler than average, however.
El Nino conditions that inhibit development in the Atlantic aid in storm development in the East Pac, so I expect a lot of this basins' storms to occur from September to November. Two good analogues for this year in the East Pac seem to be 2006 and 2009.
Map of storms and storm tracks during the active 2006 East Pac season
I think 2006 is a better analogue becuase that year had more storms form closer to the coast than in 2009, and I'm expecting a lot of coastal development in that area this year because of the warm waters. 2009 is a good analogue in terms of number of storms, but many storms that year formed farther away from shore because El Nino conditions were present for the full 2009 season. This year, however, waters further from shore are not as warm because we are coming out of a La Nina, meaning it may not be until late in the season until these waters are more favorable for storm development. All things considered, here are my official numbers:
* 19 named storms
* 10 hurricanes
* 6 major hurricanes
I am willing to bet that my the end of July people will be calling the East Pac season a bust and my numbers will look totally impossible to reach. Just remember what I said though: Many of our storms in the East Pac this year will happen towards the end of the season as we reach El Nino conditions.
The final aspect of the East Pac season I'll look at in this post will be potential land impacts. Because tropical cyclones generally move from east to west, it is rare for storms in the East Pacific to impact land since storms that move west as most do move away from shore. Still, there are exceptions. Just last year Hurricane Jova struck Mexico. In 2009, extremely powerful Major Hurricane Rick put a serious scare into Baja California as it charged towards the peninsula at Cat 5 strength before rapidly weakening prior to reaching Baja. Becuase I expect a lot of storms to form close to shore in the East Pacific this year, I think there is a higher than normal chance of impacts in Mexico, so people there should be on guard.
We're almost there!
Thank you for reading, and enjoy the rest of your week!