Global model runs discussion

[Hurricane Alexis]

The 00Z ECMWF shows a large wave emerging off of Africa in 10 days...just in time for the start of the Cape Verde season which generally starts in mid August.

http://i59.tinypic.com/ev77ec.jpg

I guess it's one thing if the good 'ol Euro shows it since it's been gold so far this season, and the GFS has literally snooped down to the Crazy CMC's level.

But IT WILL LIKELY CHANGE and probably towards a much weaker solution similar to the fate of 93L.

GFS has been like it's always been, over agressive. The Euro, while it did great with Arthur, doesnt do good with systems in the MDR. A good example of it was Isaac of 2012. Isaac was already a tropical storm and the Euro had a weak low at initialization. So let's just say both models need improvements.

[tolakram]

The GFS is no longer predicting a moistening of the environment through 180 hours.

Frankly it looks to be getting much worse at 180 rather than improving.

[tropicwatch]

The GFS is no longer predicting a moistening of the environment through 180 hours.

Frankly it looks to be getting much worse at 180 rather than improving.

Well that's no good. Puerto Rico and other islands need moisture to help end the drought. Hope the GFS is wrong.

[tolakram]

Source for that pic: http://moe.met.fsu.edu/cgi-bin/gfstc2.cgi?time=2014073106&field=700mb+Relative+Humidity&hour=Animation

If you turn on the animation you can see all the dry air pushing off of Africa. At least the way the GFS models it.

[ninel conde]

high over the atlantic is set up perfectly to pump out record amounts of dry air.

[WPBWeather]

high over the atlantic is set up perfectly to pump out record amounts of dry air.

I was wondering when the "massive dry air" and "too much SAL" talk would reappear.

[blp]

The CFS is still advertising and active August and September. Despite all the hostile conditions we are just starting August. Plenty of time to go. June and July don't typically produce MDR based storms so let's see what the next two months bring.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=noat&MODELL=cfs&MODELLTYP=1&BASE=-&VAR=pslv&HH=396&ZOOM=0&ARCHIV=0&LOOP=1&RES=0

[gatorcane]

12Z GFS and CMC out through 384 and 240 hours respectively show NADA.

[ninel conde]

high over the atlantic is set up perfectly to pump out record amounts of dry air.

I was wondering when the "massive dry air" and "too much SAL" talk would reappear.

july set a record for desert conditions and the massive dry air has been firmly established for years now. im hoping one season water molecules will appear in the deep tropics.

[baytownwx]

Levi Cowan has been tweeting some interesting stuff concerning the rest of the Atlantic hurricane season:


@TropicalTidbits: MJO to Phase 2 while ridge builds over western Atlantic is a dangerous combination, one we haven't seen in a while: http://t.co/8z73c0adea
https://twitter.com/tropicaltidbits/status/495626291396091905

@TropicalTidbits: Warm SSTA off NW Africa is big deal...starts moderating dry SAL outbreaks. Atlantic may turn more favorable just in time for season peak.
https://twitter.com/tropicaltidbits/status/495638379527012352

@TropicalTidbits: More signs of life: Gulf of Guinea cooling over last few months just in time to support Cape Verde waves. http://t.co/USz6sauDPq
https://twitter.com/tropicaltidbits/status/495641057225228288

Edited to add link to video LC tweeted talking about Bertha and rest of season
https://twitter.com/tropicaltidbits/status/495661325431758851

[Sambucol]

Levi Cowan has been tweeting some interesting stuff concerning the rest of the Atlantic hurricane season:


@TropicalTidbits: MJO to Phase 2 while ridge builds over western Atlantic is a dangerous combination, one we haven't seen in a while: http://t.co/8z73c0adea
https://twitter.com/tropicaltidbits/status/495626291396091905

@TropicalTidbits: Warm SSTA off NW Africa is big deal...starts moderating dry SAL outbreaks. Atlantic may turn more favorable just in time for season peak.
https://twitter.com/tropicaltidbits/status/495638379527012352

@TropicalTidbits: More signs of life: Gulf of Guinea cooling over last few months just in time to support Cape Verde waves. http://t.co/USz6sauDPq
https://twitter.com/tropicaltidbits/status/495641057225228288

Would this first tweet imply the GOM would be open for business?

[stormlover2013]

Whew! That means a straight shot into the gulf.

[gatorcane]

A look at all the global models today show nothing of significance as far a new tropical development for the next 10+ days.

So I took a look at this past week's long-range CFS model runs. This is a model that goes way out into the long-range out to 1092 hours. Needless to say it is not always accurate since it projects so far out into the future but can sometimes accurately pick up on areas to look for way in advance.

It's picking up on two areas for possible development to watch for in the coming few weeks. One area is in the general area 93L form which eventually formed Bertha. It forms around two weeks from now and heads WNW

Another one is near the Cape Verde islands around Aug 20-23 range.

CFS Aug 19th:


CFS Aug 22nd:

[stormlover2013]

Just my opinion but I think we will have 3-4 names storms in August and 3-4 in sept, conditions are slowly getting favorable!!!

[TheStormExpert]

Just my opinion but I think we will have 3-4 names storms in August and 3-4 in sept, conditions are slowly getting favorable!!!

Yes conditions have gotten very very very slightly better. Lol!

But in the season the Atlantic is expected to have this year, we will be lucky to see 3-4 named storms for both August and September combined IMO.

[Hammy]

But in the season the Atlantic is expected to have this year, we will be lucky to see 3-4 named storms for both August and September combined IMO.

I haven't seen any season forecasts below 10 storms so unless we end up with an extremely active October we'll likely have at least 6 between Aug/Sep combined if the forecasts hold.

[Ntxw]

In terms of modelling there's nothing too imminent on the horizon. Bertha was one, if we get something beyond the 7 day period we'll be in mid August, so another storm or two for August looks reasonable. At the higher end if we get one a week we'll be at 3. Sept another 2-3 during peak is also reasonable to me statistically.

[Alyono]

Lats wee, I took a look at the IOD vs CV storms (forming east of 40). IOD calculations were made using the JAS mean value. Data calculated from the following dataset

http://www.jamstec.go.jp/frcgc/research ... onthly.txt

If you include all years (1980-2013, a 34 year sample size), yes, a negative IOD is SLIGHTLY favorable (correlation was about -.14... so it explains about 3% of the variance)

However, if we exclude the el niño years, it is a POSITIVE IOD that favors CV storms, with the correlation about .3, or explaining 10% of the variance.

Some of the very strong el niño years has a very high positive IOD. The el niño signal overwhelmed the IOD signal, throwing the statistics off

The negative IOD is going to be a slight hindrance based upon the statistics

[blp]

July 2014 has had more extreme mid level dry air than even July 2013 if you compare the two months. Now if you break it down by week they tell a different story. 2013 started the month and got dryer toward the end and that only got worse into Aug & Sept and shutdown the season but if you look at 2014 started out much worse but got better. What you see is that toward the end of July 2014 you start to notice a dent being made in the dry air starting with a push of moisture from the East. There is still extremely dry air from 40W to 60W but it looks to be shrinking some. It is like to seperate regions in the MDR with 10W-40W somewhat favorable and 40W-60W not favorable. So it will be interesting to see how this plays out in Aug and Sept and if this trend continues.

Looking at the future with the CFS I see an agressive set of waves rolling off Africa but they seem to open up or lose strength right around the area of this extreme dry air. An indicator that this dry air may stay entrenched in the middle of the MDR. So my amateur take is that we may see more activity coming up this month but there will be many good looking waves that will not make it across the Atlantic, more than normal. We may see a few more Bertha's that struggle in the middle of the MDR and then become sleepers that we need to keep on eye on. So Bertha might be the blueprint for the season but the only difference being conditions getting a little better as we head into the peak months.

July 2013


July 2014


July 24-31 2013


July 24-31 2014

[tolakram]

GFS 700MB RH showing more and more dry air entering the tropics. The pattern continues, at least as far as the GFS is concerned.