Hurricane Gonzalo Part 1: The Buoy

19 10 2014

Our first major hurricane of the 2014 was Hurricane Gonzalo.  The replacement for Gustav since it was retired in 2008, Gonzalo has proven to as powerful as the meaning of its name which is “battle”.  Gonzalo first traveled between islands in the eastern Caribbean, but it was not a powerful storm.  Once it finally left the Caribbean and went into the open waters of the Atlantic it took advantage of it and exploded.  Becoming a very powerful storm, we had only satellites to help determine how strong it was becoming until Oct. 15.  Gonzalo was heading straight towards a NDBC buoy and it was determined to go directly over the buoy.  A perfect situation for the NHC and other meteorologists as the NHC can adjust it’s forecast and other meteorologists can observe what is really going on inside the storm.

What was caught by the buoy?  Everything most people search for.  Pressure, winds, air temperature, dew point, and waves.  Wonder what it looked like?  We have the graphs from the NDBC site itself on what it looked like when Gonzalo passed directly over the buoy.  These graphs can show so many things about the storm and we will point out all of the details we found.

First, we will start off with one of the most obvious measurements and that is the pressure.  BARO


You can see where the air pressure started to drop dramatically on the 15th at 1400Z, which is 9 AM CDT.  The eye of Hurricane Gonzalo began passing over the buoy around 1830Z, 1:30 PM CDT, and left the buoy about 2000Z, 3:00 PM CDT where the air pressure was at it’s lowest.  As a matter of fact, the lowest pressure recorded from the buoy was 954.9 millibars at 1915Z, 2:15 PM CDT.  Keep the times of when the eye wall was passing over the buoy because for the remaining graphs it will play a critical roll.  Next, we will look at the winds.



This graph is continuous winds which are winds reported by the buoy every 10 minutes.  You can really see where Hurricane Gonzola was approaching the buoy, when eye passed over it, and when the hurricane was leaving the buoy.  The winds were actually stronger where the buoy was once it passed it reaching as high as 56 knots, which is equivalent to 64-65 MPH.  The lowest winds shown on the graph were reported at 1930Z, 2:30 PM CDT.  With this in mind and the time of the lowest air pressure reported by the buoy, that tells us that the dead center of the storm passed over the buoy sometime between 2:15 PM and 2:30 PM CDT.  Think that’s cool?  It gets better!  image8


Here is a graph of the peak gusts in knots reporting every hour.  The highest gust reported after the eye passed and was 80.5 MPH.  This gust was measured about the same time as the highest wind speed reported in the previous graph.  To really show that the hurricane passed over the buoy we have this next graph.  image10

The wind direction began changing about 2:10 PM CDT from the Northeast and came completely from South Southwest at about 2:50 PM.  Pretty neat huh?

What about the waves?  This storm had to have produced some gnarly waves right?  You are definitely right.  image3

This is the significant wave height which is primarily from wind generated waves.  Waves reached as high as about 33 ft at this buoy at 1:00 PM CDT.  You can again see the effects of the eye as it passed over the buoy as the waves dropped to about 17 ft at 3:00 PM and 4:00 PM CDT and came back up again.

Now we can go to the last graph that show the effects of Hurricane Gonzalo.  image4

Here is the air temperature from the buoy throughout the storm.  The air temperature dropped as Gonzalo approached it.  With this you could see drops in air temperature due to the rain from the storm and the rise in air temperature in the middle of the eye as well as another rise in air temperature afterwards which could possibly indicate a gap between the main eyewall and a second eyewall.  If this is true, then that means Gonzalo was possibly undergoing an eyewall replacement where it will later become stronger.  This is a very strong theory because Gonzalo, during this time, was estimated to have winds of 130 MPH and shortly afterwards dropped to 125 MPH and stayed there until the morning of the 16th where they jumped up to 140 MPH and continued to increase that day.