MikeCAdministrator
(Admin)
Wed Aug 14 2013 01:16 AM
Erin Forms, West Caribbean Wave Struggles

Update 8:00AM EDT 15 Aug 2013
Tropical Storm Erin formed from TD#5 in the far east Atlantic, of the options talked about in the earlier one, it's leaning toward moving more west and possibly dissipating rather than the northerly route. It will have a lot of hostile conditions to go through to hang on, and the main watch for this is to see how much it persists through it.



The wave in the west Caribbean is very much elongated this morning, and will likely remain weak, as some energy moves to the west, and parts stream to the north. If it does form, it will likely remain weak due to an upper area of low pressure in the central Gulf.

Update 10:30PM EDT 14 Aug 2013
Still a bit of disagreement in the forecast for 92L if it moves west, more northerly, or splits/elongates. The latter is the most likely. Which would, along with shear and other poor conditions, keep it relatively weak. Still worth watching over the next few days, but it looks unlikely to develop before it reaches the Yucatan at this point.

Updated 2:30PM EDT 14 Aug 2013
After a few quiet weeks post Dorian, the usual ramp up of storm activity in mid to late August is nearly upon us, and this year seems to be no exception.

There are two waves worth watching this week, 92L in the west Caribbean which may form toward the weekend, but likely will remain weak. This will be worth watching as it moves into the Gulf of Mexico. Those in the Yucatan peninsula may have to do with rain and stormy conditions Thursday and Friday. Future track depends on what occurs in the short term, odds favor it moving into Mexico, but there is a chance that it could veer more northerly and enter the central Gulf. There is a chance the storm will split or be elongated, which would likely keep it weaker. Either way most of the Gulf will want to watch this over the next few days, in particular the Northeast Gulf from LA to the Florida Panhandle basic on the forecast trends that have occurred since this morning.

Recon is scheduled to check out this area tomorrow. It is mid August and things can change rapidly with systems in this area this time of year, so check in on it often, and this system is an extremely difficult forecast with evidence to support both west and northerly movement of the system.

The other is 93L well in the east Atlantic, which will have time to be watched as it moves generally westward, odds favor it it staying out to sea or dissipating, but persistence is the key on these waves. Since earlier this system indeed has become better organized and may develop within the next few days, if not later tonight.

{{NorthGulfRadar}}

{{NortheastGulfRadar}}

{{StormLinks|Erin|05|5|2013|05|Erin}}}

{{StormLinks|92L|92|6|2013|92|Yucatan Wave (92L)}}


berrywr
(Weather Analyst)
Wed Aug 14 2013 07:07 AM
Re: Watching Waves in Caribbean and East Atlantic

I will cover 92L on our Facebook page for the time being. 93L is so far out there it might as well be in the Indian Ocean. I will focus on 92L only until at least GOES East has eyes on it. As of this typing there is no model consensus.

Wingman51
(Weather Guru)
Wed Aug 14 2013 05:24 PM
Re: Watching Waves in Caribbean and East Atlantic

What is the FB page so we can link - - Thanks

Tazmanian93
(Weather Master)
Wed Aug 14 2013 05:57 PM
Re: Watching Waves in Caribbean and East Atlantic

https://www.facebook.com/pages/Flhurricanecom/91063554398?ref=stream&hc_location=timeline

MikeCAdministrator
(Admin)
Wed Aug 14 2013 06:52 PM
Re: Watching Waves in Caribbean and East Atlantic

Bill handles most of the facebook updates, but some information gets pasted from this site automated. And others we add ourselves.

That said, watch 92L, this time of August is ripe for unexpected and rapid changes in the tropics in this area. The entire Gulf (especially Northeast Gulf) should be checking in on this every 6 hours or so. Things are flipped flopped from last night, and now it forecast favors the more northerly track. It's likely to be a sheared tropical system, if so.


Joeyfl
(Weather Guru)
Wed Aug 14 2013 07:17 PM
Re: Watching Waves in Caribbean and East Atlantic

92L in western Caribbean really coming to life now. Looks to be very close to TD/TS status. I would really keep an eye on this one especially those from New Orleans to Big bend of FL. Like Mike said this area has to be watched this time of year for quick development especially given low shear, and abundant oceanic heat in this area. Will be interesting to see if we get a TD or TS sooner rather than later given its rather impressive organization it has undertaken this afternoon...

Hawkeyewx
(Weather Analyst)
Wed Aug 14 2013 08:54 PM
Re: Watching Waves in Caribbean and East Atlantic

92L has had some nice persistent convection today, but the surface flow is still disorganized with the wave axis being out ahead of the convection.

berrywr
(Weather Analyst)
Wed Aug 14 2013 10:11 PM
Re: Watching Waves in Caribbean and East Atlantic

West moving Tropical Waves always have their negative vorticity out in front of the axis and positive vorticity behind the axis. In the upper level and dynamic systems moving west to east...generally positive is out ahead of the trough/front axis and negative behind...so looking at it; negative is always on left side of any trough axis, positive on the right regardless of what direction it is moving but that's not always the case especially in higher latitudes where upper lows generally rotate around a broader low. Just remember in the tropics, the action is behind the wave, not in front....

berrywr
(Weather Analyst)
Wed Aug 14 2013 10:23 PM
Re: Watching Waves in Caribbean and East Atlantic

I just updated the Facebook page...yesterday the GFS was the outlier; today it's 50-50 and the ECMWF has shifted further north. Keep an eye on the upper level trough situated over the eastern US and look for it to retrograde westward; Currently there is an upper low in the South Central Gulf of Mexico squarely centered between the upper ridge over South Central US and another upper ridge over Central Cuba...at 300 millibars there is a clear trough axis in the extreme southern GOM and excellent upper air difluence between it and the upper ridge over Cuba that has enhanced convective elements of 92L. I didn't post that low in my discussion but the GFS has had a good handle on it now for a few days; it can't be dismissed and the CIMMS Tropical website is down so I don't have access to the shear analysis but I'm not convinced that down the road this will be a pure tropical cyclone given the upper air environment.

danielwAdministrator
(Moderator)
Wed Aug 14 2013 11:54 PM
Re: Watching Waves in Caribbean and East Atlantic

I find it rather interesting that the Canadian model 12Z run of today is a hard left turn from yesterday's 12z run.
Yesterday's projected landfall was in the Pensacola,FL area and today's projected landfall from the same model is Tampico,MX / Brownsville,TX.
That's a miss the trough solution to me.

But the model today also does a small loop-de-loop in the BOC before moving toward Tampico / Brownsville.


Random Chaos
(Weather Analyst)
Thu Aug 15 2013 01:20 AM
Re: Watching Waves in Caribbean and East Atlantic

Both invests are now up to 80% chance of development over the next 5 days (Gulf invest is 70% for the next 2 days, the other 80%). The season sure got off to a slow start, but it now looks to be giving itself a kick. MJO is shifting strongly toward the Atlantic in virtually all forecast models.

Ref: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml


ralphfla
(Weather Watcher)
Thu Aug 15 2013 01:26 AM
Re: Watching Waves in Caribbean and East Atlantic

the latest runs are now showing going to mexico and not really becoming much. I think this is a no event

danielwAdministrator
(Moderator)
Thu Aug 15 2013 01:34 AM
Re: Watching Waves in Caribbean and East Atlantic

Quote:

the latest runs are now showing going to mexico and not really becoming much. I think this is a no event




Just remember.
1. Don't turn your back on a tropical system until it is Onshore.... somewhere.

2.Or north of your latitude.

3.Second rule doesn't always work.


ralphfla
(Weather Watcher)
Thu Aug 15 2013 02:02 AM
Re: Watching Waves in Caribbean and East Atlantic

when it becomes a event as of now it is a wave that is it. Nobody said look away just no need to over do it

Random Chaos
(Weather Analyst)
Thu Aug 15 2013 03:09 AM
Re: Watching Waves in Caribbean and East Atlantic

There is one more to add to Daniel's list:

4. Any model run before it becomes at least a Tropical Storm is more than likely the wrong track. Throw it out and roll the dice instead.

Models just don't initialize tropical cyclones well until they have formed. Therefore there is a statistical chance a model track "could" be correct, but that will be more than likely coincidence, not model accuracy, at this point. Once it becomes a Tropical Storm, plus 6-12 hours for model run data ingest, and you will start having somewhat reliable tracks. Add in a few hurricane hunters, and then you have a fairly reliable track.

One problem with early models is that a tropical wave is a semi-normal low pressure system steered by shallow layers of the atmosphere in a regional dynamic. A tropical cyclone, however, is a much deeper storm, and in addition to affecting the regional dynamic directly, gets steered by deeper layers of the atmosphere. Unless the model correctly models the depth of the storm (which I have almost never seen them do), they will be highly inaccurate.


ralphfla
(Weather Watcher)
Thu Aug 15 2013 03:11 AM
Re: Watching Waves in Caribbean and East Atlantic

I know these things and i also know right now it is much ado about nothing. It is not a depression even yet let alone a storm and the models most do not show it making it so again it is a non event till it even becomes something to be a event about.

weatherguy08
(Weather Hobbyist)
Thu Aug 15 2013 03:22 AM
Re: Watching Waves in Caribbean and East Atlantic

Don't forget also that recon is flying AL92 tomorrow, and that data will be ingested into the models (maybe starting with the 16/00Z runs?), so that'll make a big difference.

Looking at the forecast, take a gander at the 15/00Z 500 mb analysis from SPC: http://www.spc.noaa.gov/obswx/maps/500_130815_00.gif

There is a series of shortwave troughs over the northern CONUS: one over eastern Nebraska and the other over eastern Montana. These shortwave troughs will act to amplify the longwave trough over the east coast and allow the ridge over the western CONUS to build, which will result in a col (a saddle point in the wind/pressure field) being set up over the Gulf of Mexico. These tend to result in two things: (1) weak steering currents, and (2) low model predictability. Since the aforementioned longwave trough amplification will result in large-scale height falls over the eastern half of the US with height rises over the western/central US, my thinking is that the northern models will win the day in the end, meaning people from Corpus Christi to Pensacola are probably the most under the gun. This general idea is what the GFS and ECMWF have been suggesting for the past few runs.


berrywr
(Weather Analyst)
Thu Aug 15 2013 04:16 AM
Re: Watching Waves in Caribbean and East Atlantic

This is the 500 millibar analysis chart with plots that one hasn't changed in 40 years and two, is the best of the best tool in the meteorologist or forecaster's arsenal. The plot analysis is the one you want.

http://weather.noaa.gov/fax/barotrop.shtml


doug
(Weather Analyst)
Thu Aug 15 2013 11:22 AM
Re: Watching Waves in Caribbean and East Atlantic

Brief comment based on the morning view from space. An upper level cyclonic flow is to the NW of this system and that seems increasing. A TUTT may be forming. There is no question that this has impacted the system and split the moisture envelope as the northern and eastern portion are now being shifted northward and the rest continues toward Belize. This type of set up has killed the previous two surface features coming up out of the Caribbean. The key today will be the influence of this dynamic on the future path and development of that surface low. Frankly I give it a low chance if that upper feature continues and virtually no chance if it strengthens.

MikeCAdministrator
(Admin)
Thu Aug 15 2013 03:07 PM
Re: Watching Waves in Caribbean and East Atlantic

The Recon scheduled to investigate 92L today was cancelled.

LoisCane
(Veteran Storm Chaser)
Thu Aug 15 2013 03:26 PM
Re: Watching Waves in Caribbean and East Atlantic

Canceling recon just about says it all. I wouldn't say it's dead in the water but definitely not developing any time soon. I've always felt the timing was off with this system. The environment is not very favorable and surprisingly the Atlantic is friendlier suddenly than the caribbean. More on hold if or can wait out the negative conditions it might flare up in the BOC.

berrywr
(Weather Analyst)
Fri Aug 16 2013 04:46 AM
Re: Watching Waves in Caribbean and East Atlantic

I think as a single tropical entity 92L is not likely going to develop any further; I don't think one can rule out the system splitting but as I posted yesterday on our Facebook page and given the upper air pattern in place over the US; you can't rule out a hybrid; you're right timing matters; take care!

doug
(Weather Analyst)
Fri Aug 16 2013 01:03 PM
Re: Watching Waves in Caribbean and East Atlantic

Re: the TO for this morning: it is a puzzle for me to understand the high degree of probability for development of this system based on the current environment. It must be cautionary because there is definitely a low level circulation in the GOM. However, it is under very dry air aloft which should supress otherise norma convective activity...it is a stretch for 50-60% IMO.

Ed DunhamAdministrator
(Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017))
Fri Aug 16 2013 01:38 PM
Re: Watching Waves in Caribbean and East Atlantic

I think that it is indeed a small dose of 'cautionary' and a large measure of 'continuity' from the earlier forecasts. The Gulf certainly has its reputation as a breeding ground for hybrid systems - and 92L could quickly fit into that category. Although the circulation is quite weak, convection has started to redevelop to the east of the center. Movement to the west = dry air; to the north, not so much.
ED


berrywr
(Weather Analyst)
Fri Aug 16 2013 06:52 PM
Re: Watching Waves in Caribbean and East Atlantic

Ed, check out the RAMBIS page and visible imagery - the low level center is completely exposed and moving due west. I looked at the water vapor and as the models have been forecasting the upper level low to fill and be absorbed by the larger longwave trough which its axis is now extended as far south as Houston, TX. Last night, the GFS at 850 millibars took one piece of energy into the Northern Gulf Coast and the other west. There wasn't enough at 500 millibars for me to gauge anything moving west. 92L is likely too shallow for any of us to rely on the global models for the time being. The evolving longwave trough over the southern tier of the United States makes anything tropical approaching the US one unlikely and two, not likely to be pure tropical not with winds aloft in excess of 70 knots. A system moving west still could be absorbed by the main trough if it becomes more vertically deep otherwise, it has a date with the Mexican coast but not likely anything more than a weak storm. I was not aware of the page NHC mentioned in the discussion but I did look it up and here it is: http://rammb.cira.colostate.edu/ramsdis/online/tropical.asp


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