This thing developed when? Rare Hurricane Jimena exploding

I can’t recall one hurricane off the top of my head that became a category two within 24 hours of being upgraded to a tropical depression.  Even Hurricane Alicia in 1983 didn’t develop this fast.  I honestly cannot recall of the top of my head any Atlantic or East Pacific storm that has gone from being classified a tropical depression to a category two hurricane within 24 hours.  If anyone knows an example, please let me know.  So, why is Jimena doing this?

Size Does Matter

To get with the basics, Jimena is a tight system.  In fact, hurricane-force winds only extend about 20 miles from the center.  Add in the tropical storm-force winds and the estimated diameter of the eye and Jimena is only 120 miles wide.  In comparis, Hurricane Katrina covered that same distance with hurricane-force winds alone.  Another rapidly intensifying hurricane, Bret, was 165 miles wide (tropical storm-force wind radii) after it’s intensification cycle.  Charley was 175 miles wide.  Seeing a pattern?

Hurricane Jimena Visible - Credit NRL MontereyHurricane Jimena Visible – Credit NRL Monterey

This isn’t to say a storm must be small to intensify rapidly.  But, it helps.  The smaller the storm, the faster it can strengthen.

What’s Your Thermocline?

Jimena is currently located over water temperatures above 30°C (celsius) or 86°F (farenheit).  That is extremely warm for tropical development.  Consider the minimum sea surface temperatures supportive of tropical cyclones is 26°C or 80°F.  Six degress may not sound like much.  But, for a tropical system that lives on the release of heat energy, that’s tremendous – like spinach to Popeye.  Even more incredible is that Jimena will be passing over or very near water temperatures pushing 32°C or 89°F.

Would you like steroids with that spinach?

Hurricane Jimena SST - Aug 29, 2009 - Credit CIMSSHurricane Jimena SST – Aug 29, 2009 – Credit CIMSS

Would you like some water with that spinach?

How about thousands of square miles of over 50mm of h20/in2.  In essense, it’s humid.  Very humid.  And it won’t dry up anytime soon.  Jimena has more than enough moisture to work with.  And the moisture, thanks to the water temperatures and air temperatures, is over 85°F.  Hurricane Jimena is drawing in all of this warm abundant moisture and processing it into energy, dropping pressures and increasing wind speeds.  As you can see from the image below, there’s plenty of it around for the next several days.

Hurricane Jimena - Total Precipitable Water - Aug 29, 2009 - Credit CIMSSHurricane Jimena – Total Precipitable Water – Aug 29, 2009 – Credit CIMSS

What goes up must go out

Jimena is beneath an anticyclone or an upper-level high pressure system.  This leads to upper-level winds that are more than enough to pull the used energy from the center of Jimena.  Yet, the winds aren’t too strong to pull the convection away from the system.  This system will remain over Jimena for the next several days – possibly up until landfall.  As long as this anticyclone stays over Jimena the hurricane will be able to draw in ample amounts of energy, process the energy to help strengthen the storm, and dispose the energy through the upper levels.

Surely, there’s a catch

The catch is Jimena can destroy itself.  Not to the point of dissipation, but certainly the system can trip up over itself.  Primarily, this comes in the way of eyewall replacement cycles.  The more intense a hurricane is, the more likely the eye collapses under the pressure of the storm itself.  These are unpredictable and could happen at anytime.

Hurricane Jimena - Visible - Aug 29, 22:00 UTC - Courtesy NASAHurricane Jimena – Visible – Aug 29, 22:00 UTC – Courtesy NASA

Don’t be surprised at all if this thing gets to cat 5 status.  The hurricane, however, will likely go through a “calming” phase where all equal parts of the hurricane try to catch up to each other.  Once the system becomes in-sync with itself then it will continue to grow until:

  • an upper-level trough approaches the storm as expected in a few days and increases shear over the system;
  • the storm approaches a drier air mass – possible in a few days;
  • the storm makes landfall – likely in a few days.

In the meantime, watch Jimena grow.  This is a truly rare occurence.