Jump to content
  • Member Statistics

    17,607
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

Tropical Storm Isaac, Part 1: Moving Through The Eastern Caribbean Sea


Recommended Posts

  • Replies 1.1k
  • Created
  • Last Reply

Well, the sample set isn't that large, really. There just aren't that many examples of hurricane landfalls in this region. I don't see any physical reason why a cyclone would be less likely to move due N just offshore of FL's W Coast (compared with a cyclone farther W in the Gulf).

Yup! Here's a look at the Tropical Storms or Hurricanes that passed within 100 miles of St Marks, FL (figured that was a good marker for the Big Bend...) since 1950. Like you said, there aren't a ton of examples. However, what I noticed, and made me pause, was none of them really paralleled the west coast of Florida and into the Big Bend. Most of the landfalls originate from the Central Gulf or western Caribbean, as I'm sure you know being the historian for the tropics! :D

It only gave me pause because it doesn't happen too often. I'm not saying it can't, but rarely occurs because of the incredible timing/orientation/strength of the ridges & troughs to set up a run up the West Coast of Florida.

post-1807-0-39588100-1345652730_thumb.jp

Link to comment
Share on other sites

I hate to mention who I first heard this from, so I won't. But storms into the Big Bend produce offshore winds, and with fairly shallow warm water depths, tend to upwell cooler water ahead of them, making major hurricane landfalls into the Big Bend difficult. Panama City Beach being sort of an Eastern limit to better landfalls.

I will say, I don't buy everything unnamed source says the way I did a decade ago. BUt it seems to make sense.

2012233god26.png

Link to comment
Share on other sites

I hate to mention who I first heard this from, so I won't. But storms into the Big Bend produce offshore winds, and with fairly shallow warm water depths, tend to upwell cooler water ahead of them, making major hurricane landfalls into the Big Bend difficult. Panama City Beach being sort of an Eastern limit to better landfalls.

I will say, I don't buy everything unnamed source says the way I did a decade ago. BUt it seems to make sense.

You should find a bathymetry map to compare to your 26C isotherm depth map.

Link to comment
Share on other sites

You should find a bathymetry map to compare to your 26C isotherm depth map.

You're saying the places where the 26º water is less than 25 meters deep, the bottom is less than 25 meters from the surface?

Like I said, I don't trust that degreed met quite the way I did around 2001...

Link to comment
Share on other sites

You should find a bathymetry map to compare to your 26C isotherm depth map.

Yup. The main reasons why major landfalls in the big bend are rare are that usually storms on that path are later in the season, so there is more shear/dry air/cooler water from cold fronts, the land interaction often prevents too much strengthening, and the fact that it is such a small area, there often isn't going to be a lot of storms making landfall there (the last one I can remember was Josephine 1996, but I wouldn't be surprised if I'm missing one since).

Link to comment
Share on other sites

So after looking at the 12Z GFS, it seems my earlier theory was about half right... though the track shifted east ever so slightly (wrong on it shifting west), the ridge did end up being stronger (correct), but other dynamics cause Isaac to have a slightly more to the right track.

Actually looking at the UKMET at well there seems to be a "left" early trend, but a more "right" trend in the later part of the track.

If that trend continues Isaac could pull off the almost impossible Windward Passage dodge missing signficant time over high terrain.

Link to comment
Share on other sites

So many times, when it comes down to how deep the northern stream trough is, and how far south a shortwave digs, it's the GFS that is over zealous, and it's the GFS that is wrong. I expect the Euro to win that synoptic battle.

I could see the Hispaniola "pulling" in a storm argument, as the wxmann has said, but I ultimately lean much more towards the Euro at this time. I think the Euro will correct east, but not by much, IMO.

This is the thought process I've been working with. If Euro holds serve (or goes full tilt with a monster into upper Tx coast) then some serious evaluation of the mid-level wind field needs to be performed vs. previous runs of the Euro vs. GFS/others to see which suite is handling the steering currents correctly up to this point (DUH!).

Link to comment
Share on other sites

A NOAA flight with the new 3D doppler radar is set to take off at 3 this afternoon from Barbados.

Can you provide a link to this if you can. I'm intrested in the science behiend it. I know the P-3 by itself has 3 radars already, the belly radar, the tail (vertical cross section) and the regular nose cone radar.

Link to comment
Share on other sites

Yup. The main reasons why major landfalls in the big bend are rare are that usually storms on that path are later in the season, so there is more shear/dry air/cooler water from cold fronts, the land interaction often prevents too much strengthening, and the fact that it is such a small area, there often isn't going to be a lot of storms making landfall there (the last one I can remember was Josephine 1996, but I wouldn't be surprised if I'm missing one since).

Opal hit St. George Island in Oct. 1995 which is just a bit west of St. Marks. It completely undermined

the lighthouse near the beach to the point you could walk under the foundation.

Link to comment
Share on other sites

Opal hit St. George Island in Oct. 1995 which is just a bit west of St. Marks. It completely undermined

the lighthouse near the beach to the point you could walk under the foundation.

Actually Opal made landfall at Pensacola Beach, FL, much further to the west. St George was on the far east side of the system, so they felt some rough effects.

Link to comment
Share on other sites

The UKMet results are misleading due to a bias, but otherwise that is spot on.

The only problem is that the skill doesn't necessarily translate to skill from one year/season to the next, due to :

1. Seasonal dependent biases/errors

2. Model changes (we've shown that the hybrid EnKF/Var-based GFS did relative to the operational GFS for historical cases)

Link to comment
Share on other sites

12Z GGEM/CMC has shifted way west and now is a lot more in line with other guidance- skims eastern FL with a landfall JAX/SAV then right over me in ATL. Probably not correct, very unusual track to be sure but the key takeaway is that it is now not a big outlier.

Euro just casting it's hooks on the stray models....yanking them in....next it'll bring out the net, and pull them all westward! ;)

Link to comment
Share on other sites

The only problem is that the skill doesn't necessarily translate to skill from one year/season to the next, due to :

1. Seasonal dependent biases/errors

2. Model changes (we've shown that the hybrid EnKF/Var-based GFS did relative to the operational GFS for historical cases)

I kinda meant operationally. In my mind, I view the models as ECM-GFS-TVCA-UKM-everything else

Link to comment
Share on other sites

Big FWIW

Just note the ECM and GFS difference after 48 hours.

2011 National Hurricane Center Forecast Verification Report

Great link... not surprised to see the ECMWF was superior in most cases.

The center location of Isaac is very interesting today. Recon is flying in to get a closer look, but it looks like the center has become more broad over the past 24 hours, and its very difficult to see if its still south of 16N.

Isaac_22Aug12_Martinique.gif

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...