It’s been a while since I’ve written, but the last week in the meteorological enterprise was a blur of “Polar Vortex,” frozen Chicago posts, boiling water turning to snow videos, and the freezing of a half-dozen different fruits and vegetables. At times, the hashtag #PolarVortex was even trending above #FSU and #Auburn during the BCS National Championship…a personal jab in the side for a FSU meteorologist. I am not going to explain the phenomena that happened last week since it happens all the time, but instead I’ll point you toward a post NWS New York (below) made three days ago about the phenomenon that has become more phenomenal that need be. After all, it’s been in the glossary of the AMS for more than 50 years.
Now, what I will comment on is the practice of naming winter systems. Known to most by now, the Weather Channel has been naming winter storms for a year and a half. The idea behind naming weather systems has been around, in terms of a government function, for 60 years. As anyone on the street in Miami if they remember Andrew, and they won’t be talking about their cousin or father. The same goes for Katrina, Wilma, and Camille….all of which were monstrous storms. The same also goes for Zeta…a storm that affected few, but that name makes it recognizable.
The goal of TWC’s naming of storms was to get a collective name behind a certain storm, and that I support. Before their practice, the social mediasphere were coming up with names like snowmaggedon and snowpocalypse. Attach a few letters after snow, and you had a storm.
What I don’t support is the naming of a system with no criteria. The naming of tropical cyclones worldwide is done with meticulous criteria set forth by a number of well thought out organizations. In a quick google search, I was still unable to find any hard and fast requirements for naming a winter storm. With mention that the shape, size, precipitation type, and temperature regimes are much more variant than in tropical cyclones, I still believe that the practice of naming winter storms should be much more scientific in the meteorological sense. In fact, I believe criteria should be developed over the next decade with help from both meteorologists and social scientists. To go one step further, I would suggest that the Weather Prediction Center pick up the naming practice in a decade.
Now, the question is whether or not the practice was successful with this recent storm. By far, twitter activity seemed to weigh heavily toward the term “Polar Vortex” rather than the TWC’s name of “Ion”. I have to wonder if this storm has been named Hercules, the previous name on the list (used a week ago), would have garnered more attention from the 1950′s glossary term of the AMS phenomena. In other words, if scientists created a new list of names for winter storms, would the public use it?
The effects of this storm were the same with or without a name. To those of you in the Midwest: I hope warmth, power, and the sight of a less snowy front yard returns soon. I couldn’t imagine what you all went through earlier this week.
A few interesting things happened today with Invest 97L as 96L fell apart. As I mentioned last night, we would have to see the ULL pull away from 97L in order for any development to occur, and that in fact…sort of happened. I put it in that context because we saw the ULL split into two areas, one that is falling apart north of Puerto Rico and another more robust area near Hispaniola. The two areas have allowed upwelling to occur on the northern side of 97L, which is a good thing.
Generally when someone talks about upwelling, it is often in an oceanic context where something atmospheric feeds off of the surface layer of the ocean and drains it of heat. In the atmospheric context, as used here, two areas of low pressure ventilate the area of low pressure in the lower levels of the atmosphere. Here, we have a couple upper level lows whisking away mass and heat from the “center” of 97L at the mid and upper levels. This is a case where shear is favorable over a tropical system.
This evening, that effect seemed to wear out as convection near the center of 97L has waned since early evening. The “center” of 97L is north of Barbados, and continues to move generally toward the west. Earlier today, the island of Barbados had a semi-reliable westerly wind, which to me signifies that 97L took a run at trying to become a tropical depression earlier today before thunderstorm activity fell apart. 97L has winds of 30-35 mph and a pressure of 1008 mb. Most thunderstorm activity tonight is well to the east of the center of 97L.
The track of this system in the long term will nearly entirely depend on the intensity of the system. Currently, the system is being guided toward the west at the surface by the subtropical ridge, which is aligned east to west from the Bahamas eastward. There is a trough in the picture, but I believe this will be a case where the train will miss the station for the most part. The models are in two camps right now with a splitting tropical wave or a more centralized spin in the Caribbean.
Scenario #1: GFS/Euro solution: As the tropical wave reaches Puerto Rico, it produces two areas of spin (or vorticity) north and south of that island. What I think will actually happen with the second piece of energy is that it comes from a wave following 97L. This will likely take a weakness that may or may not be present north the NW. This solution takes 97L toward the west as a struggling mess, and eventually makes landfall in central America. I am much more inclined to take scenario #2:
Scenario #2: UKMET: This scenario keeps a stronger subtropical ridge and a more centralized vorticity toward the WNW over the next few days. This more centralized vorticity will form in about 24-48 hours in the central Caribbean. I believe that some of the hurricane a barotropic models are taking this scenario a little too quickly. For instance, the GFDL spins up this circulation, which currently is stretched out (Below), within 24 hours and quickly intensifies it before moving into Hispaniola.
Even though it is now September, I am not buying the rapid intensification story that numerous models are trying to sell. The truth is that this storm is elongated, and it will take a night or two for this system to centralize and develop. Only once it does that, can it tap the better than all season conditions. Note that I did not say favorable conditions. In 4-5 days we will see more favorable conditions, but in the short term there will be 15-25 kt shear around this system and a bit of dry air to work out. If this system is to get a name, it will be in 3-5 day or beyond.
This system struggles over the next 24-48 hours before showing signs of organization in the central Caribbean. 97L will keep a WNW heading until roughly 75W when it should be in the rough proximity of Jamaica as a developing system.
Scattered moderate thunderstorms to isolated strong thunderstorms will move through the central and lower lesser antilles overnight into tomorrow night. Gusty winds are probable. Seas will be choppy at times, especially in the passes between islands as the system passes through. Any localized torrential rainfall may lead to mudslides in mountainous areas of the Caribbean over the next 5 days. Stay prepared!
As we start September, we inch closer to the peak of the Atlantic Hurricane Season. During the first 10 days of the season, most storms form in the Gulf of Mexico or the Mean Development Region, which stretches from the Lesser Antilles to the coast of Africa. Hurricanes form this time of year more than any other time of year because water temperatures are the warmest and winds in the layer of the atmosphere where clouds reach their peak heights are the weakest.
The Atlantic is heating up as we reach the peak month for activity in the basin. There are currently two invests in the Mean Development Region (MDR) with a low chance of development in the short term. After Fernand made landfall last week, the basin went pretty quiet with the exception of the African wave train. A steep increase in instability, a drop in dry air, and an increasingly favorable MJO should resuscitate the Atlantic over the next week.
The first of two invests (96L) is fresh off the coast of Africa and seems to be undergoing poofogenesis before even making it to the Cape Verde Islands. The current spaghetti models show a general trend toward the northwest with a decent gain in latitude over the next few days. With environmental conditions (dry air, shear) becoming prohibitive for development, the time for this system is quickly running out.
Impact: Expect heavy rainfall in the Cape Verde Islands over the next day or two with higher than normal wave activity.
The second of two invests in the Atlantic, Invest 97L, has much more of my interest at the moment. The Hurricane Hunters showed a broad circulation 350 miles east of the lesser antilles last afternoon, and convection has been on the increase since their departure from the system. With dropsonde data in the models, the current thinking is that 97L will trend toward the west through the lesser antilles as a weak disturbance with gaining organization. An Upper Level Low is exhibiting shear in the area of 15-25 knots on the northern side of 97L, which combined with slightly less than favorable mid level moisture should keep 97L weak for the time being. The forecast challenge beyond 48 hours become whether or not the ULL disengages with 97L or not. Currently, I liken the situation to two people running down a pair of lanes toward a finish line of some sort with a tree in the middle which will obstruct both paths. That tree, is of course the island of Hispaniola. In order for any organization to take place, the ULL must either weaken or gain latitude at a faster rate than 97L. After 2 days, 97L will be out of the eastern Caribbean death zone (a climatological anomaly in the basin that prohibits growth), into warmer SST’s and ocean heat content, in slightly more humid atmospheric columns, and should be temporarily far enough from land that chances of development are decent.
Thus far, this has been one of the most climatologically “normal” systems we have tracked. The others being Fernand and Andrea. Climatology would suggest slow development over the next few days, and some of the models show enhanced development after 3 days.
Impact: Expect heavy rainfall in the central lesser antilles over the next 36 hours and enhanced rainfall chances in the Caribbean over the next 5 days. Waves should be in the 6-9 foot range in close proximity to the tropical wave as it passes, with higher waves in the open Atlantic north of the islands. Gusty conditions are possible. This may become a threat to the Greater Antilles and the Bahamas in the days to come…be prepared for tropical weather as we head into the peak of the season. More than half of the season is still ahead of us activity wise.
Special Note: This was the first post created in part using a mobile device. I should able to initiate posts and respond to twitter (@JonathanBelles) with more ease with this new capability. Expect more frequent posts over both medium.