Atlantic Tropical Action 2013

[phil882]

Note how the GFS has substantially backed off the intensity of the wave as we are getting closer and closer to verification... this is a tale tale sign that the GFS is poorly handeling the convective structure. Even the ECMWF depicts a closed circulation with the wave emerging off the African coast, but it gradually weakens the wave with time. The second feature the GFS depicts breaks off from this same wave and is moving very rapidly westward at the end of the period. 

[bluewave]

It looks like the more favorable MJO moved the needle a little higher in the TA, but the 

conditions were still more stable than normal. This may mean that we will see storms 

wait to really strengthen until they get west of 60 during August and September

where the instability is closer to normal in the EC or Gulf region. The last two

seasons were weighted north of 20 and west of 60 with these conditions.

The subtropical Atlantic is looking less favorable than it was last year.

We could see a westward shift in development this year closer in should

the Western Atlantic Ridge remain as strong as it has been since April.

 

 

 

 

 

 

 

[Ed Lizard]

Now that Chantal is apparently dying, while TC development doesn't really seem likely, several of the global models suggest harmless, not particularly convective upper low in sub-tropics out about 50ºW will start developing a surface reflection as it heads generally Westward towards Florida and South East.

 

GFS shows it trying but failing to close a surface low, Canadian is obviously the most enthusiastic.  Canadian is just a depression or minimal storm near New Orleans in a week, possibly because of the resolution increase.  Perhaps the old Canadian would have predicted a Cat 3

 

I'd say a 30% chance of a lemon in 3-5 days, in my amateur judgement.

 

Other than that, even playing tennis without a net, using 1008 mb as a discriminator, GEFS members suggest a slow tropics next two weeks, 2 of 20 showing a 1008 mb low in MDR at the end of the run, not a ringing endorsement for an active period soon.

[Mike.Ventrice]

Now that Chantal is apparently dying, while TC development doesn't really seem likely, several of the global models suggest harmless, not particularly convective upper low in sub-tropics out about 50ºW will start developing a surface reflection as it heads generally Westward towards Florida and South East.

 

GFS shows it trying but failing to close a surface low, Canadian is obviously the most enthusiastic.  Canadian is just a depression or minimal storm near New Orleans in a week, possibly because of the resolution increase.  Perhaps the old Canadian would have predicted a Cat 3

 

I'd say a 30% chance of a lemon in 3-5 days, in my amateur judgement.

 

Other than that, even playing tennis without a net, using 1008 mb as a discriminator, GEFS members suggest a slow tropics next two weeks, 2 of 20 showing a 1008 mb low in MDR at the end of the run, not a ringing endorsement for an active period soon.

 

#Canadian voodoo

[Ed Lizard]

#Canadian voodoo

 

 

I know, but it is July.

 

Oh, 8 years ago...

 

http://www.youtube.com/watch?v=ZsjLqPL-AdA

[am19psu]

Lol at the thread subtitle

[HurricaneJosh]

Lol at the thread subtitle

[phil882]

 

There is definitely some potential for some GOM mischief in the near future. Both the global and higher resolution model guidance are picking up on a frontal break down over the Gulf of Mexico turning into a relatively small TC in the next 12-36 hours. The circulation is already evident on visible imagery as a mesovort along the frontal axis. The HRRR is picking up on this feature and as the front continues to break down as its modified by the GOM air, a small circulation should develop with some deep convection.

 

 

 

Again this is also being picked up by some of the global models, namely the GFS which develops the system into a weak TC as well. This probably won't get to be anything stronger than a weak TS given marginal conditions and short time period over water, but it bears watching.

 

[metalicwx366]

I was just looking at that also phil882 and I knew you were going to make a post about it soon lol. Needs to be watch, but like you said, probably won't be anything stronger than a weak TS/TD.

[Ed Lizard]

#Canadian voodoo

 

Crazy Uncle persists in turning a cold core low in the Atlantic into a fully warm core high end TS or low end hurricane for the Texas coast end of next week.  It will be right some day.

 

CIMSS steering for weak systems suggests even if a TD forms South of MOB, it'll move slowly and probably towards the Panhandle.  That is ok, the normal Summer sea breeze has been working reasonably well for my yard.

 

 

ETA:  I will not mention NAM supports Canadian, lest bendy mod five post me until August.

[wxtrackercody]

The GFS and UKMET send the MJO, which has been well-behaved so far this year, back into Octants 8 and 1 by the end of this month. The ECMWF is slower...and probably more accurate as a result. Maybe some implications on enhanced Atlantic activity during the first half of August, even though the effects of these pulses mean a lot less when compared to early in the season.

 

[wxmeddler]

There is definitely some potential for some GOM mischief in the near future. Both the global and higher resolution model guidance are picking up on a frontal break down over the Gulf of Mexico turning into a relatively small TC in the next 12-36 hours. The circulation is already evident on visible imagery as a mesovort along the frontal axis. The HRRR is picking up on this feature and as the front continues to break down as its modified by the GOM air, a small circulation should develop with some deep convection.

 

I posted this in the Chantal thread, but the 4km NAM also has support for this.

http://www.meteo.psu.edu/~fxg1/NAMSFC4SE_12z/comploop.html

[Superstorm93]

RAP Meso-analysis has some kind of weak LLC 150 miles south of PCOLA

 

Could be mildly interesting 

 

[Srain]

Stalled frontal boundaries along the Gulf Coast in summer tend to raise an eyebrow regarding potential TC Genesis.

[Ed Lizard]

Stalled frontal boundaries along the Gulf Coast in summer tend to raise an eyebrow regarding potential TC Genesis.

 

Those graphics tend to be, optimistic, not a single GEFS member at 12Z shows a 1008 mb low anytime in the ATL tropics the next almost 15 days.

 

 

 

 

30 years since the last major to landfall in the HGX CWA, and that developed from a decaying frontal trough in the Gulf, but I'm more concerned about a 35 knot name waster killing me in July contest.  Especially since it looks like a Panhandle threat.

 

Playing around here, West winds aren't hard to find around and South of the area of apparent interest, but East winds North of it don't seem to exist.  http://www.ndbc.noaa.gov/maps/WestGulf.shtml

 

Pressures seem to be falling looking at the 5 day plots of the various buoys.

[Mike.Ventrice]

Hi all, 

 

Just had a young met's (or weather lover's) dream come true where I got to hang out a couple days at the weather channel with the guys from the expert desk. First off, I can't tell you all how nice everyone is there and how down to earth they all are (especially dr. greg postell and carl parker). Anywho, I have been helping them develop an extended medium range genesis graphic, where Bryan Norcross can easily show it to the viewers. I'd like to hear some comments if anyone has sometime, as the tropics are beginning to shift to more of a suppressed state over the Atlantic (with exception of ex-Chantal and the baroclinic pv-streamer in the gulf). 

 

First plot is MJO-filtered VP200 anomalies (The data that goes into here will NEVER go back to the west as RMM tends to do so in the forecast). Blue shading is "more favorable" conditions, especially after the passage, where orange shadings are "less favorable" conditions for genesis.

 

 

Second plot is the same, but with Kelvin filtered VP200 anomalies overlaid at the time where the mid-point in the period occurs (i.e., week 1 is the Day 1-6 aggregate for MJOfiltered anoms, but the KW is put at Day 3).

 

 

This way, we can get a rough ideas of times when there may be a 2-3 day window for favorable conditions produced by a CCKW in a locally suppressed MJO state.  Anyway, thought I'd share this as it is publicly available on my website and the main-purpose is to make it easier for viewers to monitor Atlantic TC activity. Thanks in advance.

[Eyewall2005]

This is great stuff mike thanks again

[QVectorman]

Mike thanks for posting this. I have been watching this CCKW for the past week while it has been over 120-150E and been expecting it to make it to around 75W on July 22. I was thinking the CCKW might have a chance to work some kind of magic and it's great to see this in graphical forecast now and we are thinking along the same line about this CCKW. Also the GWO signals are pointing to a peak in temps across the eastern US July 25-27 and the pattern back in the winter with this signal was the Bermuda high backing west posting up off the eastern seaboard. So as this CCKW traverses the Atlantic anything that does form could be suppressed south and then curved into the GoM towards gulf states. That's IF anything forms. 

[wxtrackercody]

Retrograding MJO pulse should help with the intensity of the waves coming off Africa by the end of July. The CMC and GFS agree for a very vigorous wave to emerge off the coast in about 10 days. The CMC run ends there obviously, so we don't know what becomes of it, but the latest 18z GFS runs tracks it over Puerto Rico and positions it just northeast of Hispaniola as a 974 millibar hurricane at the end of the run.

 

We'll see. Bottom line is we should be watching the eastern Atlantic in a while.

[N. OF PIKE]

Retrograding MJO pulse should help with the intensity of the waves coming off Africa by the end off August. The CMC and GFS agree for a very vigorous wave to emerge off the coast in about 10 days. The CMC run ends there obviously, so we don't know what becomes of it, but the latest 18z GFS runs tracks it over Puerto Rico and positions it just northeast of Hispaniola as a 974 millibar hurricane at the end of the run.

We'll see. Bottom line is we should be watching the eastern Atlantic in a while.

End of july or end of august?

[metalicwx366]

End of july or end of august?

End of July.

[hurricaneman]

End of july or end of august?

 

The first option end of July

[wxmeddler]

Good, the lack of bendy trees in the Atlantic is taking a toll on my metal health.

[wxtrackercody]

End of july or end of august?

End of July as stated, sorry. Corrected my post...and the spelling error. 

[Eyewall2005]

Good, the lack of bendy trees in the Atlantic is taking a toll on my metal health.

 

We skip this year if the ECM is correct ..

 

[Superstorm93]

ECMWF has the MJO swinging back into Phase 2 possibly by the end of the month. The ensembles also show a more favorable MDR with trades relaxing just in time for a possible uptick in activity (and saving my hide for the tropical contest) 

 

[am19psu]

There is no such thing as a retrograding MJO.

[Ed Lizard]

Everyone knows I'm no anti-weenie (get an 18Z GFS 288 snow fall forecast for IAH, its full bore weenie), but a post-resolution GFS run, when most recent GFS runs have been quiet, well...  July is supposed to be slow, anyhow,

 

0Z GEFS at the end of the run show a couple of sub-1008 members, not a ringing endorsement for tropics gone wild.  You can see from the spread the places individual ensembles are enthusiastic about.  Again, 240 hour Canadian and GFS runs, well, curbing enthusiasm. 

 

Now, different story if the GFS starts repeating itself, especially when it gets within 192 hours.

[Mike.Ventrice]

Guys Adam is correct in saying that there is no such thing as a retrograding MJO event. To begin and to maintain my current them, do not trust model forecasts of the MJO because on most occasion, they are wrong. That being said, the MJO is currently pushing over the Maritime Continent region. At times, the models struggle with propagating the MJO across the Maritime (or Africa, or S. America) and instead, they reflect the eastward propagating MJO signal back to the West. A lot of research has been done with regards to this problem and folks call the Maritime Continent "a barrier" to the eastward propagation of the MJO. Take a look at the time-longitude plot of 850 VP... nice eastward propagating signal but as soon as it goes into forecast mode (GFS op), it hits a wall and gets reflected back towards the West.

 

 

I cringe everytime I see the models do something like this. Now what I anticipate to occur is we will continue to see the MJO push over the West Pacific, which typically favors large-scale subsidence over the atlantic and low AEW activity. I'm not buying the AEW in the GFS in the 11-15 day time frame. In fact, no one should be looking at a dynamical model in the medium range to see if there are any AEWs. Models can only skillfully predict an AEW up to 5 days. That's about it. These waves grow from baroclinic and barotropic processes, but also have a diabatic energy conversion. Models that use convective parameterization schemes always butcher the AEW forecast. I do see some small chances of a developing tropical cyclone over the East Pacific or Caribbean in 5-8 days. A strong (2 sigma in amplitude) atmospheric Kelvin wave will likely cross the Pacific, then Atlantic ocean and could cause some activity. However, it will be superimposed with the convectively suppressed phase of the MJO, so there will only be a small window of opportunity here. I think the better chance is for a spinup over the East Pacific instead of the Atlantic but its tough to tell.

 

 

Take home message: DON'T TRUST MODEL FORECASTS OF THE MJO UNLESS ITS A CLOUD RESOLVING MODEL!

[am19psu]

What Mike said.