Monday, October 24, 2011

Hurricane Rina Strengthening Rapidly; Likely a Major Hurricane by Tomorrow...

Hurricane Rina has become very strong in a relatively short period of time today. The latest infrared satellite image above shows strong outflow from all directions within the storm, which is an important ingredient in developing and maintaining the overall intensity of the system ("old" air gets exhausted out at the top, and fresh, unstable air gets drawn in at the bottom).

A high resolution, close-up visible satellite image shows what looks to be an eye feature (near the tip of the red arrow), surrounded by developing thunderstorms on all sides:

The Air Force hurricane hunter aircraft that flew through the system shortly before 4pm CDT found a maximum surface wind of about 70 mph, just to the South/Southeast of the center of the hurricane:

Rina is currently situated over some of the warmest water in the Atlantic Basin, as shown on the Sea Surface Temperature (SST) analysis below (I've drawn a white circle on the map showing the approximate coverage area of the most organized part of the system at this time):

This, along with a favorable middle and upper-level wind flow pattern suggests that further strengthening of Rina is likely for at least the next 24 hours, with the system likely to become a "major" hurricane during the day on Tuesday.

Rina will likely continue at a rather slow pace toward the West/Northwest through Tuesday, being steered by a high pressure ridge that is building over the northern Gulf of Mexico.  The ridge will slide Eastward in 2-3 days, likely resulting in a Northward to even Northeastward turn toward the end of the week.

The latest run of the HWRF model, a short to medium range model specializing in hurricanes, depicts the system moving across far southern Florida by this weekend:

Another model specializing in the tropics, the GFDL, offers a similar solution:

The GFS model shows the system nearing the Western tip of Cuba by 5pm EDT on Friday:

...but then turns the system back Southward, hinting that it will never make a run at Florida this weekend (image below valid 11am EDT Saturday):

The ECMWF model, which has historically been reliable in dealing with tropical matters, is completely out to lunch on this one, showing the system to completely dissipate by Thursday morning along the coast of the Yucatan peninsula:

The only thing I can tell you for sure is to completely discount the ECMWF projection, as it is not going to happen...

Otherwise, I am confident in both the GFDL, HWRF and GFS model projections of the system reaching the Western tip of Cuba by the end of the work week.  From that point forward, I am less confident.

I think the GFS solution taking the system back Southward is a bit too extreme in that direction.  At this time, my gut feeling is that the system will do one of two things over the weekend:  (1).  make a run at the Florida Keys or extreme south Florida, or (2). remain just South of the state, traversing Eastward across much of Cuba.

The key factor in determining which of these tracks take place will be the exact timing and placement of a surface cold front and mid-level trough of low pressure that is expected to move in from the West at about the same time.  If the hurricane "beats" the arrival of the front and trough, it will move further Northward.  If the front and trough beat the hurricane to the region, they will push it back toward the South and East, away from Florida.

Residents across the region should keep an eye on Rina throughout the week and watch for the latest updates and forecasts.  We should have a much more solid idea as to the end of the week track of the system by Wednesday, as additional aircraft reports are fed into the computer models, etc.

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