Beryl now fully tropical, closing in on Florida 5/27/2011
Good afternoon and welcome to my tropical weather update for Sunday, May 27th, 2011. Our main story remains now fully Tropical Storm Beryl, located at 30.1°N 79.9°W. Maximum sustained winds have increased to 65mph with higher gusts, and Beryl is forecasted to make landfall sometime tonight. Satellite shows a well organized, tight tropical cyclone with gradual organization, mostly in spiral banding. Beryl is unlikely however to gain strength after this, and the intensification has already halted. Beryl is beginning to pass over a cool shelf of water off the coast of Florida, that will cause convection to weaken throughout the day. It is slightly possible though before that, Beryl could become a 70mph Tropical cyclone but it is virtually impossible in my opinion of Beryl becoming a hurricane.
(figure 1. Tropical Storm Beryl approaching Florida's coastline)
(figure 2. Tropical Storm Beryl's forecasted track)
I will have an updated forecast tomorrow.
Subtropical Storm Beryl develops 5/26/2012
Good morning and welcome to my tropical weather update for Saturday, May 26th, 2012. The tropics are awake and for the first time since 1908, we now have our second pre-season named storm. Subtropical Storm Beryl as of the 11 a.m. EDT advisory was located at 31.6°N 76.3°W, maximum sustained winds are at 45mph and the minimum pressure is at 1001mb. Satellite reveals a system with minimal convection, with most of it confined to spiral banding around a very tight and vertically stacked center of circulation. This system on satellite is very reminiscent of Subtropical Storm Andrea.
(figure 1. Subtropical Storm Beryl as of 11 AM EDT)
Where will Beryl go and how strong will it get?
Beryl is stuck between two highs that is causing a very unusual direction, this is the same setup that caused Alberto to come back towards the US coast as a minimal system. Instead of being ejected out to sea, the ridge is causing Beryl to stall out then move back SW towards the SE United States - a place that is in absolutely desperate need for rainfall. Beryl should make landfall on late Sunday evening or early Monday morning around Jacksonville, Florida. After that, things get tricky. The majority of the models are predicting that a trough will force Beryl after moving inland to retrograde back over Florida and head out over the Atlantic and out to sea. This is being reflected in the latest NHC path.
(figure 2. 06z dynamic model forecast)
The intensity forecast is a little bit more problematic, right now Beryl is not organized as the deep convection is limited and confined to outer bands. However, Beryl is going to be moving over the warmer waters of the Gulf stream shortly, that and with the reduced windshear, Beryl could be able to gain some more convection to allow for a stronger system later. The NHC is predicting a 50mph TS at landfall in N. Florida. I would say that is a fair bet, the real problem for real intensification is if Beryl decides to become a fully Tropical Storm or not. If Beryl decides to re-emerge over the Atlantic, it is possible that it could obtain a higher intensity as shear will be lower and dry air less of an issue.
(figure 3. Latest intensity forecast for Subtropical Storm Beryl)
I will be back later today or tomorrow with another update.
94L in the Atlantic a threat to become a historic 2nd named storm in May - 5/25/12
Good afternoon everyone and welcome to my tropical weather update for Friday, May 25th, 2012. We are currently looking at in the tropical Atlantic at Invest 94L, currently off the Florida east coast. 94L is a very broad low but with a very good chance of development. Model support is unanimous at this time that 94L will develop into Sub-Tropical or Tropical Storm Beryl. If 94L does become Beryl, it would be unprecedented in the last 125 years since the 1887 Atlantic Hurricane season to have two named storms develop in the month of May. The National Hurricane Center is currently giving 94L a 70% chance of becoming Beryl.
(figure 1. Invest 94L in the Tropical Atlantic)
Where will 94L go and how strong will it get?
At this time as I earlier mentioned, 94L has nearly unanimous model support to develop into a tropical cyclone. The general consensus in track is that 94L will begin to slow down in a forward NE speed today then begin to retrograde back towards the US coast line anywhere from South Carolina to North Florida. The ECMWF is predicting that 94L will make landfall in North Florida, however the model consensus at this time is leaning more towards the East Coast, South Carolina to be more specific. It is too early really to say where 94L will hit exactly, other than it's probably not going out to sea and might stick around for a while bringing beneficial rainfall to the SE United States.
(figure 2. Current model track for 94L)
Wind shear over 94L is as expected for the month of May very high, 40kt plus, however this shear is predicted to lessen but still will be prudent over it. That will limit peak intensity to more than likely only 45mph and nothing higher. The main threat with 94L will be rainfall, with potential flooding.
(figure 3. Model intensity forecasts for 94L)
Is 94L's formation a sign of an active season?
Unlike Alberto, if we do end up with Beryl before the month of June then the answer is possibly. It is unlikely that 2012 will be as inactive as 2009 and 2006, but will be no where near as active as 2011 and 2010. Most seasonal forecasts are specific to the time period of June 1st - November 30th, and not so much anything before and after those dates. UKMO for example is only prediction 10 named in that time period, however if we do get Beryl before June 1st and the UKMO proves correct, the total will be 12 named storms obviously.
In short, these are my seasonal totals.
12 named storms.
I will have an update tomorrow.
Updated: 01:01 GMT le 28 mai 2012
A A A
Alberto meandering off the US Coast - 5/20/12
Good morning and welcome to my tropical weather update for Sunday, May 20th, 2012. The main story today is Tropical Storm Alberto, currently located at 31.7°N 79.3°W. Maximum sustained winds are at 50mph with higher gusts, and Alberto is moving west-southwest at 6mph. Satellite shows that Alberto is a fragile and small system, which last night out of no where became a 60mph Tropical Storm. That can happen often with these small storms, even in an unfavorable environment, they can wind up fast and they can also loose steam fast as Alberto also did overnight.
(figure 1. Current satellite image of Alberto)
Where will Alberto go?
Alberto is currently moving WSW, but that direction is expected to change as Alberto interacts with a non-tropical low and a front oncoming towards the system. It's forward speed should decelerate and become stationary by 2pm or so as a deep-layered ridge of the United States weakens, after that Alberto should generally begin to move in a more northerly direction by later today and should eject to sea with only a novice to shipping.
(figure 2. Current NHC track of Alberto)
How strong will Alberto get?
Alberto has probably peaked in intensity. It is rare to get May storms as it is, but Alberto was in terms of pressure yesterday at 995mb the strongest May tropical cyclone since Hurricane Alma in 1970. Alberto is a small system however, and it is more acceptable to things such as slight increase of wind shear which is quite prudent over the Atlantic in May. Alberto's intensity will also be hampered by two non-tropical lows to the north and soon to be the east of the system that will begin to interact with Alberto.
(figure 3. Intensity model forecast of Alberto)
Is Alberto's formation a signal of an active hurricane season?
In short - not really. Alberto is a one-off cyclone, as 2009 also had a tropical cyclone off the East Coast in May (unnamed) and that season did not have active season at all. These freak systems that develop non-tropically are hard to get and can really happen anytime of the year. If Alberto had developed in the Caribbean, this would be a different story as it would show that shear in the Caribbean would be far below average than it should be for this time of year. Alberto does only to boost the final count this year.
I will have an update tomorrow afternoon.
Updated: 12:48 GMT le 20 mai 2012
A A A
SPECIAL UPDATE Tropical Storm Alberto. 5/19/2012
Good afternoon and welcome to my SPECIAL TROPICAL WEATHER UPDATE for Saturday, May 19th, 2012. Throw out your calendars, Hurricane Season is here! Tropical Storm Alberto has developed at 323N, 776W. Maximum sustained winds are at 45 mph. Alberto developed off a trough split that managed to align itself with an Upper Level low in order to protect itself in a more favorable environment, and was very unexpected but with no surprise was predicted to happen for several days by the ECMWF. Satellite reveals that Alberto is a well organized and small tropical cyclone, with the center of circulation just on the edge of the central dense overcast.
(figure 1. Satellite image of Alberto)
Where will Alberto go and how strong will it get?
Alberto is currently centered just off the coast of South Carolina in a relatively stationary motion. The majority of the models predict that Alberto will skirt the outer banks with no real threat for a serious landfall. The environment around Alberto is semi-favorable, and further strengthening to a stronger system is possible as long as Alberto remains over the warm gulf stream. However, as a trough approaches Alberto shear will increase as it ejects out to sea. Alberto however has until Tuesday AM to attain its peak intensity before weakening.
(figure 2. Model track forecasts for Alberto)
(figure 3. Model intensity forecasts for Alberto)
I will have a much more in-depth update later today or tomorrow morning,
Odd 92L in the Atlantic - Another Grace situation? 5/12/12
Good afternoon and welcome to my tropical weather update for Saturday, May 12th, 2012. I wasn't expecting to write up a tropical update - but as always, who does with these kinds of systems? Today we're dealing with 92L out in the North Atlantic by the Azores. 92L is surprisingly well organized for this time of year and this far north, but it shouldn't really surprise everyone that this is happening. SST anomalies are already 1-2C above average in that area, so it's more typical of July as it is. Satellite reveals a tight, well organized core with great spiral banding, and showing a system that is already detaching from the front that it has been associated with for the past few days. It's sudden uptick in convection though is very unnatural, and it looks well on it's way to become Sub-Tropical or Tropical Storm Alberto perhaps as soon as early tomorrow.
(figure 1. 92L in the Northern Atlantic)
Sub-Tropical or Non-Tropical?
Determining whether or not this is a warm-core system or a hybrid is difficult, but most if not all the of the phase-diagrams indicate that this system is transitioning from a symmetric cold core system to a symmetric warm core system, which is what a tropical cyclone is. However, given that the wind-radius and surface pressure is so far spread out, plus it's association with the front near by (similar to Sean in 2011), it would be sub-tropical in nature.
(figure 2. Sea Surface Temperatures in the area)
Polar Low or a Tropical Cyclone - the Grace and Vince dilemma.
These systems are very rare in the Atlantic. It was first seen in 2005 with the infamous Hurricane Vince, but was once again seen in a very similar fashion to 92L - Tropical Storm Grace. In both cases, our basic understanding of tropical formations where both defied when both of these systems developed in highly unusual locations, generally considered too hostile for formations, and thrived in those environments. The dilemma exists however on how to name it. These systems are similar to Polar Lows, so determining the difference between the two is difficult. However, 92L does not meet the requirement exactly for a Polar Low, so what it is? For now, the NHC settles on it being a sub-tropical cyclone.
In any case, the NHC will be waiting for consistency to name 92L. If it continues to look like this in say 6 hours, it is probable that it could be named as soon as tonight and as late as tomorrow. 92L does not have long to live in either case, as hostile wind shear should overcome this system in 48 hours or so.
I will release a special update if 92L is named Alberto.