Thoughts on 2013 Atlantic Hurricane Season

[Ptarmigan]

I have a graphic here that probably doesn't apply to hurricane season at all, but I found it interesting since some have been comparing the start of this season to 2004 or 2009.

http://img43.imageshack.us/img43/5144/7u36.jpg

Yes, the number of 90+ days up here in Cincy, and the fact that we seem to be done with the 90's for the year, putting us in 2004 and 2009 territory. Both 2004 and 2009 experienced el nino's, and right now we are heading into what looks to be a week la nina.

El Nino seasons tend to end early, La Nina tend to end late.

What does it all mean?

2004: Modoki El Niño
2009: (Full-Blown) El Niño
2013: Nuetral to weak La Niña

Just summing up the facts.

2004: Active
2009: Least Active Since 1997
2013:

Both 2004 and 2009 were Modoki El Nino.

[wxman57]

Here's a graphic from that website I posted on the previous page. I clicked "Individual Forecast" in the left frame and the "All Map" for the map. It plots all 12 model forecasts of mean sea level pressure anomaly for August-October. Blue = low pressure, red = higher pressure. CPTEC is the Brazil model. Exeter is the UK model. The individual models are listed on their "home" page. Any listing "ASO" have not updated since July. Euro is from July on that web site. the "Pretoria" model is from South Africa, it's quite bold with the low pressure forecast. The Melbourne model was the only one forecasting significantly higher pressure last month (with the Euro). Now the Euro has abandoned that idea.

https://www.wmolc.org/



You can also see how badly the Euro has performed with its forecast of Nino 3.4 temps. Blue dotted line is the verification. Looking at the May forecast (below), almost every single member was too warm.

[sunnyday]

Will someone please explain why all systems are now go for a big season? It seems as if one day things are a no go, and now they are all ready to go. Thank you.

[Alyono]

1997 had no August storms

[WeatherEmperor]

1997 had no August storms

True...however, 1997 also featured one of the strongest if not the strongest El Nino ever recorded.

Sent from my HTC EVO 4G LTE

[Bocadude85]

1961 had not August storms.

[CalmBeforeStorm]

http://www.youtube.com/watch?v=lIm6rcQGggQ
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Levi Cowen has a great video here showing why activity should really ramp up in late August and into September and why the U.S. is at a greater risk this year.

[galaxy401]

Can anyone post the MJO graph to show where it's supposed to be going in the next week?

[WeatherEmperor]

1961 had not August storms.

And the first ever weather satellite was launched into orbit just 1 year before that. How many systems could have been there that by todays standards would have been named?

I think many people are over reacting. High numbers were forecast during the preseason up until recently and there is no real activity so far and it frustrates people because they got involved in the so called hype.
Sent from my HTC EVO 4G LTE

[wxman57]

Can anyone post the MJO graph to show where it's supposed to be going in the next week?

There's no MJO signal out there. Typically, the MJO develops in the Indian Ocean and takes about 45 days to track eastward to the East Pacific. About 2 weeks later there tends to be an increase in development in the Gulf or Caribbean. With no signal present, don't expect any MJO "help" for weeks and weeks.

http://www.cpc.ncep.noaa.gov/products/p ... r_wh.shtml

Weekly MJO Outlook/Discussion:
http://www.cpc.ncep.noaa.gov/products/p ... update.ppt

[ninel conde]

http://models.weatherbell.com/news/nasa ... ex_atl.gif

looks to be more SAL to contend with.

['CaneFreak]

Not really. Its weakening with time.

http://models.weatherbell.com/news/nasa_2013080800_dustex_atl.gif

looks to be more SAL to contend with.

[ninel conde]

Not really. Its weakening with time.

http://models.weatherbell.com/news/nasa_2013080800_dustex_atl.gif

looks to be more SAL to contend with.

http://tropic.ssec.wisc.edu/real-time/s ... vmid&time=

it looks like another surge of very dry mid level air is getting ready to surge off africa. will have to see if it does the next few days.

['CaneFreak]

Its moistening with time. Dry air is not the problem.

Not really. Its weakening with time.

http://models.weatherbell.com/news/nasa_2013080800_dustex_atl.gif

looks to be more SAL to contend with.

http://tropic.ssec.wisc.edu/real-time/s ... vmid&time=

it looks like another surge of very dry mid level air is getting ready to surge off africa. will have to see if it does the next few days.

[beoumont]

Will someone please explain why all systems are now go for a big season? It seems as if one day things are a no go, and now they are all ready to go. Thank you.

Below is from today's NOAA season outlook,

<<<<<<Our confidence for an above-normal season is still high because the predicted atmospheric and oceanic conditions that are favorable for storm development have materialized,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, a division of the National Weather Service. “Also, two of the four named storms to-date formed in the deep tropical Atlantic, which historically is an indicator of an active season.”

The conditions in place now are similar to those that have produced many active Atlantic hurricane seasons since 1995, and include above-average Atlantic sea surface temperatures and a stronger rainy season in West Africa, which produces wind patterns that help turn storm systems there into tropical storms and hurricanes.>>>>>

The full press release can be read here:

http://www.noaanews.noaa.gov/stories2013/20130808_atlantichurricaneupdate.html

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The above post is an official NOAA outlook; and may be used as such. It is not the opinion of the poster and is backed by sound meteorological data.

[Ntxw]

Dry air may not be a problem but sinking air is. There is a kelvin wave over in the EPAC, I think once we get a storm or two going near the Mexican west coast shortly after the W Carib or southern Gulf may get active. Models should slowly (some already have) get optimistic in this region for development, I would bet this area first and the MDR later in the month with the progression of the Kelvin wave. Problem with a Kelvin wave by itself is that opportunity for development with enhanced lift is rather short vs MJO enhancement.

[Hammy]

By the looks of it comparing with earlier maps it looks like the instability is gradually increasing over Africa as well.

[Ntxw]

It is remarkable how pretty much nonexistent the MJO is. This since mid-late July. It's a known fact the MJO is weaker during the summer than other seasons but still. It is usually at it's strongest during ENSO neutral or weak Ninas <- perhaps some correlation to neutral years being active, and weakest during Nino's which makes it weird that it's clear across the board.



Empty since mid July.

[ConvergenceZone]

One thing people have to be careful not to assume is that just because there have been a few seasons where it got busy even after super slow August that it automatically means that it will be the case this season as well...Because those seasons could have had overall better atmospheric conditions than we have this year. .

It could get busy, or it could remain a slow season if the conditions don't change.

['CaneFreak]

Thermodynamically, the Atlantic is primed and ready for an active season. The waters easily support a major hurricane throughout most of the basin. The general problem so far and continues to be an overall lack of tropical disturbances with strong pre-existing vorticity. With the MJO being forecasted to remain in the circle of death for the foreseeable future, we are going to have to get some strong tropical waves to move off of Africa soon. I just don't see much else that will instigate tropical cyclones right now throughout the Atlantic domain. I must say I am pretty shocked at the lack of disturbances that we have seen so far but take heart little ones. This season is far from over. The peak is still 4 weeks away and we have all of September and October as well. A lot can happen in 12 weeks time.