Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

TS Emily: 215 Miles SSE Of San Juan, PR


Recommended Posts

  • Replies 984
  • Created
  • Last Reply

Mike Montgomery's pouch site a dividing streamline analysis for each pouch, although admittedly it's difficult to interpret. What's easier to interpret for me are the wind vectors, which I believe are the ones that are used for calculating the streamlines. The description of the product is here.

The original paper associated with this is here: Riemer and Montgomery (2010)

What Riemer and Montgomery (2010) show is that the pouch is distorted in the presence of shear, which make the TC vulnerable to dry-air intrusions. In their simulation, they had a TC undergoing easterly speed shear, so easterly storm-relative upper-level winds with westerly storm-relative low-level winds. Hence, you get inflow into the western quad, and doing back trajectories (Fig. 6 in the paper) shows that the dry air intrusion is *most effective* when it originally located downshear-right. However, the magnitude of the dry-air intrusion into the TC depends on moisture gradient, the vertical profile of moisture, and the vertical profile of winds...so it *can* come from elsewhere.

My interpretation of this is that it doesn't necessarily contradict Dunion's work. The dry air doesn't just travel inwards towards the TC, but it also gets advected counterclockwise around the TC. It may be that if you see dry air upshear of the TC, the Riemer and Montgomery processes described above may have already been underway for some time.

I do think it's either inaccurate or misleading to say that the shear vector is "advecting" the dry air into the TC. From what I've read on the topic, it's more complicated than that.

I found this to be very interesting reading. I have a coffee stained copy on my desk that I printed out not to long ago. I was thinking that all the talk of rapid development might be overly optimistic after looking at the GFS "dividing" streamlines on the site this morning. That combined with the SOI spike and the NAO had me quietly leaning towards a more southerly route and not a slam dunk out to sea.

Link to comment
Share on other sites

Models may be sensing some kind of weakness in the Berrmuda high allowing it to escape north.

at201191_model.gif

Only problem with most of the NHC tropical models is initialization and boundary conditions off the GFS. I do not know if the GFDL outermost grid is large enough to make it semi-independent of what the GFS is doing toward Day 4 and 5 of the run. If the GFS ridge and trough speeds and strengths are off, a lot of the tropical guidance will follow.

Link to comment
Share on other sites

Between the Euro non-developing Caribbean to Gulf cruiser, and the GFS recurve, I'm tempted to make the old S2K Canada to Nicaragua bears watch comment.

But I won't.

It's 240 hours... but with that said, you can see some clues through a consensus of these two models. Prior, the Euro was way too excited for development, and the GFS wasn't excited much at all... now the trend has reversed with the GFS going back to its typical intense recurve scenario, and the Euro going west and weak.

The key to the future of track of this will be the Greater Antilles. If it manages to stay away from them and get/stay stronger, look more towards a GFS style solution. On the other hand, if it tries to hit several of them and loses strength, look for more of a Euro-style solution.

Link to comment
Share on other sites

Gaining convection and has circulation. Think 40 or 50% at 8 PM.

http://www.ssd.noaa..../flash-avn.html

Sun is still up. On the vis loop, looks like more than one center, easternmost one may have West winds to the South of it, but overall, still somewhat lacking in organization.

40% sounds about right in my amateur opinion.

First visible loop images tomorrow could be very interesting.

Link to comment
Share on other sites

Sun is still up. On the vis loop, looks like more than one center, easternmost one may have West winds to the South of it, but overall, still somewhat lacking in organization.

40% sounds about right in my amateur opinion.

First visible loop images tomorrow could be very interesting.

I agree with both points. I noted two distinct centers earlier today but was too lazy to post about them.

Link to comment
Share on other sites

Interestingly enough the 12Z GFDL, which was developing this into a hurricane, has completely reversed and now looks like the 12Z Euro, weak LP into the Islands in about 4 days.

almost as though the system got in between the initializaion points for that part of the Atl Basin grids -

Link to comment
Share on other sites

18z GFS plows this through the central caribbean. There is a massive weakness in the ridge.

The current and projected pattern is one that would cause 91L to recurve well east of the U.S. east coast (just as occurs in the 18Z gfs) unless it stays weak/further south and gets into the GOM. There is a lack of high pressure either near the NE US or in the typical Bermuda high position to drive it either into the SE or up the east coast. Until this pattern changes, the east coast above S FL (with the possible exceptions of the Outer Banks and Cape Cod) shouldn't be threatened with a direct landfall from any TC. So, complete rainstorming is the way to go at least FOR THE TIME BEING..say through ~8/10.

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...