Have you ever noticed that for every rule it seems that there is at least one exception? The exception may or not be legal or right but it is taken anyway.
We have a good example of that right here in Oregon. If you drive at all you have seen a deer crossing sign or even two fairly close together indicating where deer are expected to be crossing the road. The problem is that the deer can’t read and in my experience they cross where ever they want. The most dangerous places where they seem to cross most often are just as you are coming out of a curve or coming up and over the top of a hill. The signs are there to warn us to be careful, but who tells the deer that’s where it would be safest to cross the street?
There are plenty of other examples of where lines are drawn but circumstances overrule them. Severe thunderstorm and tornado watch boxes from the National Weather Service encompass the area most prone to have severe weather. Those storms have occurred outside of the boxes many times. The subject I am comparing to all of these is the Atlantic/Caribbean tropical cyclone season. It officially starts on June 1st each year and ends November 30th.
The case in point is Tropical Storm Ana which recently developed and struck the U.S. coastline and moved inland. It developed as what is called an Extratropical cyclone . That means it has a colder core without the typical tropical characteristics.
The National Hurricane Center issued the first advisory on Subtropical Storm Ana at 11 PM EDT (8 PM PDT) on Thursday May 7, 2015 (nearly a month before the official start of the season). The storm’s maximum sustained winds were measured at 45 mph and it was located at 31.5N latitude and 77.6 W longitude which is about 170 miles SSE of Myrtle Beach, SC. The storm became Tropical Storm Ana with advisory six with highest sustained winds to 60 mph. It had moved to 32.4 N and 77.6 W or 115 miles SE of Myrtle Beach, SC. The highest sustained winds remained at 60 mph as the storm headed to the NNW at 3 mph.
Anna made landfall between Myrtle Beach and North Myrtle Beach, SC at about 6 AM EDT (3AM PDT) Sunday May 10th. Not too long after landfall the winds dropped Ana back down to a tropical depression and the last advisory was issued at 5 PM EDT (2PM PDT) with the center of the storm located at 34.4 N and 78.6 W which is 10 miles NNE of Whiteville, NC with highest sustained winds dropping down to 35 mph.
We know that we can use radar to see where a tropical storm or hurricane is located when they are close to land and satellite imagery lets you lookout over the oceans. The question is how do they get the data like sustained wind speeds around the eye of the storm and farther away or the barometric pressure to see if the storm is getting stronger or weaker?
You may have heard of the Hurricane Hunters who fly over and around these massive storms to gather the data necessary to follow these storms and figure out where they are going to go. The storm tracking missions are preformed by The United States Air Force Reserve’s 53rd Weather Reconnaissance Squadron and the National Oceanic and Atmospheric Administration’s (NOAA) Hurricane Hunters. The Air Force crews the WC-130J aircraft for their missions while the NOAA crews fly the WP-3d Orion aircraft for their work.
As an aside note: At an American Meteorological Society meeting I attended in Memphis, TN in the 1980s our group got a tour of one of those C-130s. It was just the empty plane without all of their equipment in it because the plane they were supposed to show us got called out for a hurricane reconnaissance flight the day before our tour.
Why do they use the older 4-propeller driven planes instead of the newer, sleeker, and faster jet aircraft available today? There are two main reasons. The first is that the propeller driven planes are tougher and more stable in the high winds and heavy rains that they have to fly through. Secondly they need to be able to fly at a slower speed to be able to get the necessary data.
They use a dropsonde which is also called a sonde. It is a package of equipment that measures the barometric pressure, temperature, etc. above and in the storm after it is dropped from the airplane. It has a parachute attached to slow it down as it passes through the various layers of the storm and even the eye of a hurricane. They have to make multiple passes through very turbulent air to drop them in specific locations. It is a dangerous job that is absolutely necessary to enable pinpointing where the storms are, how strong the winds are, and the direction in which they are going in order to plot where they will have an affect on landmasses and people.
According to Wikipedia Ana was the only tropical storm on record in the North Atlantic Basin to exist in the month of April. It was also the 5th earliest start to the Atlantic Tropical Storm/Hurricane season since 1851. Anna was also the first preseason tropical storm or subtropical storm since Beryl in 2012.
In a recent article in my column published on April 27th called “Why Should We Care?” I explained that Colorado State University’s Department of Atmospheric Sciences stated “We anticipate that the 2015 Atlantic Basin hurricane season will be one of the least active season’s since the mid 20th century.” Just because Ana formed so early you might think that goes against the prediction. That is not necessarily true. Ana may have come very early, but as of now we don’t know how long it will be before the next storm forms and how many will follow it throughout the whole season. Only Time will tell.
Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].