Snow_Miser Posted August 3, 2012 Share Posted August 3, 2012 Ugh. satellite looks pretty bad. i have some doubts any of it will even survive to regenerate later. I think it will survive, but certainly the satellite presentation is poorer than expected this morning, and the winds have responded to this decrease in convection and are now down to 45 mph. Link to comment Share on other sites More sharing options...
bluewave Posted August 3, 2012 Share Posted August 3, 2012 Hurricane forecasters have long been puzzled (e.g., Henry 1924) by the apparent tendency of nascent tropical cyclones to cease development or weaken as they traverse the eastern Caribbean Sea. Given the low latitude of this region, most of these tropical disturbances are those that develop from African easterly waves that are embedded in the deep, tropical easterlies over the North Atlantic Ocean. tropical cyclones and their associated convection unexpectedly decrease in intensity over the eastern Caribbean, only to redevelop once they enter the west- ern Caribbean, posing a dilemma for forecasters. A map (Fig. 1) of the points of origin of all named tropi- cal cyclones from June through November 1851–2008 reveals a distinct minimum of origin points from 10° to 20°N and from 75° to 60°W (the eastern Caribbean Sea) relative to locations east and west of this region http://journals.amet.../2009BAMS2822.1 Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 3, 2012 Share Posted August 3, 2012 Just has to survive the day. SHIPS has a large decrease in shear in the very near future. Back up to 50 mph at 11am? AL, 05, 2012080312, , BEST, 0, 136N, 615W, 45, 1002, Link to comment Share on other sites More sharing options...
isohume Posted August 3, 2012 Share Posted August 3, 2012 Pretty much everything you need to know about the next 48 hours is right here: Looks like crap. Link to comment Share on other sites More sharing options...
Superstorm93 Posted August 3, 2012 Share Posted August 3, 2012 12z Models were initialized at 50 mph and 1002mbs Just looks like a small TS (Banding is really improving) Link to comment Share on other sites More sharing options...
Srain Posted August 3, 2012 Share Posted August 3, 2012 Link to comment Share on other sites More sharing options...
Ed Lizard Posted August 3, 2012 Share Posted August 3, 2012 I can always find a silver lining. L. Open North Link to comment Share on other sites More sharing options...
Srain Posted August 3, 2012 Share Posted August 3, 2012 Link to comment Share on other sites More sharing options...
am19psu Posted August 3, 2012 Share Posted August 3, 2012 At the risk of looking like a fool, the HWRF intensity guidance looks reasonable. Link to comment Share on other sites More sharing options...
Gibbsfreeenergy Posted August 3, 2012 Share Posted August 3, 2012 I am kinda of surprised by NHC bullish intensity stance through the weekend Link to comment Share on other sites More sharing options...
Derecho! Posted August 3, 2012 Share Posted August 3, 2012 I am kinda of surprised by NHC bullish intensity stance through the weekend I think I take the careful anti-weenie-ing around here with more of a grain of salt now than NHC. Link to comment Share on other sites More sharing options...
wxmx Posted August 3, 2012 Share Posted August 3, 2012 I am kinda of surprised by NHC bullish intensity stance through the weekend Out of respect of the statistical guidance (LGEM and SHIPS), which are the best performers usually, IMO...plus the GFDL... Should make them uneasy looking at the GFS and Euro though. Link to comment Share on other sites More sharing options...
am19psu Posted August 3, 2012 Share Posted August 3, 2012 Out of respect of the statistical guidance (LGEM and SHIPS), which are the best performers usually, IMO. But are often wrong when 850-200mb shear is not indicative of the true shear environment Link to comment Share on other sites More sharing options...
phil882 Posted August 3, 2012 Author Share Posted August 3, 2012 At the risk of looking like a fool, the HWRF intensity guidance looks reasonable. But are often wrong when 850-200mb shear is not indicative of the true shear environment What appears to be the problem though are that the models aren't handeling the current shear. The Netherlands Antilles show westerly flow at 200 hPa that has recently switched from the last sounding. In addition its exceptionally dry in the mid-levels. Not a very good environment at all. Another developing problem. The kelvin wave that pass over the storm 24-36 hours ago is gone, and is now being replaced by a subsiding phase which is currently moving overhead of the storm. The raw velocity potential anomalies (without any wave filtering) show convergent flow aloft which is typically not favorable for convective development. Link to comment Share on other sites More sharing options...
Ed Lizard Posted August 3, 2012 Share Posted August 3, 2012 In a way, it doesn't look terrible at all on visible imagery. Except for the arc clouds it is spitting out, suggestive of the dry mid-levels mentioned above... Link to comment Share on other sites More sharing options...
QVectorman Posted August 3, 2012 Share Posted August 3, 2012 What appears to be the problem though are that the models aren't handeling the current shear. The Netherlands Antilles show westerly flow at 200 hPa that has recently switched from the last sounding. In addition its exceptionally dry in the mid-levels. Not a very good environment at all. Another developing problem. The kelvin wave that pass over the storm 24-36 hours ago is gone, and is now being replaced by a subsiding phase which is currently moving overhead of the storm. The raw velocity potential anomalies (without any wave filtering) show convergent flow aloft which is typically not favorable for convective development. Appears the CCKW preformed as you said it would. Help strengthen it to a TS and now leaves it to fend for itself. Link to comment Share on other sites More sharing options...
PSUBlizzicane2007 Posted August 3, 2012 Share Posted August 3, 2012 12Z GFS weakens Ernesto even more, keeping it weak throughout the Caribbean, strengthening it a bit as it approaches Chetumalish, then moving it agonizingly slowly into the BoC where the remnants stall for days before moving north. FWIW, it also shows a weaker 90L as well and a less favourable environment across the Atlantic. Link to comment Share on other sites More sharing options...
Mike.Ventrice Posted August 3, 2012 Share Posted August 3, 2012 What appears to be the problem though are that the models aren't handeling the current shear. The Netherlands Antilles show westerly flow at 200 hPa that has recently switched from the last sounding. In addition its exceptionally dry in the mid-levels. Not a very good environment at all. Another developing problem. The kelvin wave that pass over the storm 24-36 hours ago is gone, and is now being replaced by a subsiding phase which is currently moving overhead of the storm. The raw velocity potential anomalies (without any wave filtering) show convergent flow aloft which is typically not favorable for convective development. Hi all, I've noticed this morning that in my Kelvin filtered VP200 maps that I was over laying filtered anomalies from the raw total VP200 field. While this is not a large problem, it won't catch the complete Kelvin wave signal. The next update will have the kelvin filtered VP200 anomalies using filtered data from the VP200 *Anomaly* field. This should highlight the suppressed phase of the Kelvin wave currently propagating across the Atlantic. You can see my point in the below time-longitude plots of unfiltered VP200 total values and anomalies (shading), with the corresponding kelvin filtered VP200 anomaly contours. The Kelvin filtered anomalies using the total VP200 field doesn't highlight the suppressed phase of the Kelvin wave as nearly as much as the Kelvin filtered anomalies using the anomalous VP200 field! Link to comment Share on other sites More sharing options...
bluewave Posted August 3, 2012 Share Posted August 3, 2012 Does anyone think that the GFS upgrade may be impacting the intensity guidance? Link to comment Share on other sites More sharing options...
HurricaneJosh Posted August 3, 2012 Share Posted August 3, 2012 Wow, this thread is a hatefest. Link to comment Share on other sites More sharing options...
Analog96 Posted August 3, 2012 Share Posted August 3, 2012 I don't know why anyone would be using a global low-resolution model for intensity of a tropical storm. Link to comment Share on other sites More sharing options...
phil882 Posted August 3, 2012 Author Share Posted August 3, 2012 Appears the CCKW preformed as you said it would. Help strengthen it to a TS and now leaves it to fend for itself. For the most part... I had hopes that the CCKW would spin up Ernesto more than it did but the result is just a weak tropical storm. Most of the global dynamical models (except the Canadian) now show a weak system throughout its journey in the Caribbean. Link to comment Share on other sites More sharing options...
am19psu Posted August 3, 2012 Share Posted August 3, 2012 I don't know why anyone would be using a global low-resolution model for intensity of a tropical storm. Because it works? Link to comment Share on other sites More sharing options...
andyhb Posted August 3, 2012 Share Posted August 3, 2012 For the most part... I had hopes that the CCKW would spin up Ernesto more than it did but the result is just a weak tropical storm. Most of the global dynamical models (except the Canadian) now show a weak system throughout its journey in the Caribbean. In other words, say goodbye to your chase ambitions Josh. Link to comment Share on other sites More sharing options...
Ed Lizard Posted August 3, 2012 Share Posted August 3, 2012 For the most part... I had hopes that the CCKW would spin up Ernesto more than it did but the result is just a weak tropical storm. Most of the global dynamical models (except the Canadian) now show a weak system throughout its journey in the Caribbean. 12Z Canadian Link to comment Share on other sites More sharing options...
phil882 Posted August 3, 2012 Author Share Posted August 3, 2012 I don't know why anyone would be using a global low-resolution model for intensity of a tropical storm. They are not low resolution. The ECMWF is run at 12km while the GFS sits at 35km resolution. Yes they are low resolution in comparison to the HWRF and GFDL, but they models only run very high resolution in a small domain around the tropical cyclone. They also tend to be less accurate than the global models. Link to comment Share on other sites More sharing options...
Analog96 Posted August 3, 2012 Share Posted August 3, 2012 Because it works? WHEN? Link to comment Share on other sites More sharing options...
CoastalWx Posted August 3, 2012 Share Posted August 3, 2012 I don't know why anyone would be using a global low-resolution model for intensity of a tropical storm. The globals imo are pretty good at indicating or at least hinting at the life cycle or development of a TC. If they start showing a black hole in the MSLP fields, or barely keep a few closed isobars around the center...it may be trying to tell you something. Link to comment Share on other sites More sharing options...
CUmet Posted August 3, 2012 Share Posted August 3, 2012 What appears to be the problem though are that the models aren't handeling the current shear. The Netherlands Antilles show westerly flow at 200 hPa that has recently switched from the last sounding. In addition its exceptionally dry in the mid-levels. Not a very good environment at all. Another developing problem. The kelvin wave that pass over the storm 24-36 hours ago is gone, and is now being replaced by a subsiding phase which is currently moving overhead of the storm. The raw velocity potential anomalies (without any wave filtering) show convergent flow aloft which is typically not favorable for convective development. I don't doubt that Ernesto is under some shear currently, but I'd be very cautious about using a single sounding to illustrate this. It's not necessarily reflective of the shear or winds that the TC is feeling (which is why an area-average is used for TC shear calculations), and it's not surprising to find westerly winds/shear aloft to the north of a TC given the anticyclonic outflow. That said, it can be useful to look at observed soundings to diagnose what the models might be missing with regard to shear, but at least so far, I haven't found much that's stuck out. Link to comment Share on other sites More sharing options...
am19psu Posted August 3, 2012 Share Posted August 3, 2012 WHEN? Pretty much always. I'd rather have the Euro and the GFS as intensity guidance than anything else. Link to comment Share on other sites More sharing options...
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