What is the future of this season?

[dwsqos2]

Regarding seasonal activity, I'm going with persistence at this point.

[Steve]

Any hints here? Heh.

http://www.osdpd.noaa.gov/ml/ocean/sst/anomaly.html

[jtom]

Any hints here? Heh.

http://www.osdpd.noaa.gov/ml/ocean/sst/anomaly.html

Maybe for the Pacific - cooler ocean temps.
For the Atlantic, I think this site may offer some hints:

http://cimss.ssec.wisc.edu/tropic/real- ... k/sal.html

[ConvergenceZone]

I'm starting to believe that there isn't going to be a "switch" that turns on that causes the tropics to become hyperactive.....I'm thinking there will just be the occasional storm from now until the end of the season....

I'm not too sure when the MJO becomes unfavorable again but activity might drop off once that happens...

[Steve]

>>I'm starting to believe that there isn't going to be a "switch" that turns on that causes the tropics to become hyperactive.....I'm thinking there will just be the occasional storm from now until the end of the season....

You might be right short-term- but probably not overall. The 500mb anomalies in the NE are going back to what we've been seeing all along. However, the origins are Pacific instead of polar. The west is about to warm up again, so it's not happening in the next few days. I think that's one of the keys. However, you can see heights building at 200mb, so it's possible that the block is building. However, NAO doesn't look to go positive until after the 1st.

200mb:
http://www.cpc.noaa.gov/products/intras ... anim.shtml

500mb:
http://www.cpc.noaa.gov/products/intras ... anim.shtml

>>I'm not too sure when the MJO becomes unfavorable again but activity might drop off once that happens...

http://www.cpc.ncep.noaa.gov/products/p ... l#forecast

Still, we will probably be to the E or F storm if the Gulf system cranks near Texas by Tuesday a week (8/31/10). That's no longer off the pace.

[Steve]

>>Still, we will probably be to the E or F storm if the Gulf system cranks near Texas by Tuesday a week (8/31/10). That's no longer off the pace.

Storms as of 8/31

1998 -Earl
1995 -Jerry
2005 - Lee
1950 - Dog
1969 - Francella
1999 - Emily

FWIW, European 8-10 day showing positive NAO by the 1st of September and also a surge of heights into the maritimes which would be the strongest block yet to date. Transient? Who knows? Building? Who knows? That's your key to 2010's switch.

[KWT]

Nothing too major though at upper levels Steve, so that high pressure possibly would buckle at the first sight of a low pressure system probably despite looking quite decent on the general maps.

Still I can't see this pattern being quite as strong as it has been, its pretty uncommon for the pattern to hold this long in August IMO.

[Steve]

>>Nothing too major though at upper levels Steve, so that high pressure possibly would buckle at the first sight of a low pressure system probably despite looking quite decent on the general maps.

Agreed that it's nothing drastic, but there is evolution between now and the end of the month. If it sticks, after one or two push-backs, late summer pattern can build in the first week of September. I only have access to 10 day ECMWF, but the average heights are higher than the GFS which pulses back and forth through what we've been seeing through 384. ECMWF ensembles don't bring the NAO as + but are moving toward positive at the end of the month. GFS Ensembles actually go positive. It can go either way or do something else but there isn't a strong enough of a signal yet. That's something else about this season, except for the SOI, there aren't any particularly dominant pattern tip-off signals. La Nina is there, but even that's not super strong. So it's been harder to time blocks, MJO, etc. this year. Weaker signals and weaker systems thus far.

Link to 12Z ECMWF NAO Prediction:
http://raleighwx.easternuswx.com/models ... mwfnao.gif

Link to 12Z GFS Ensemble NAO Prediction:
http://raleighwx.easternuswx.com/models ... ensnao.gif

[ColinDelia]

Assuming we're talking Atlantic...

CSU still forecast 18 named storms on August 4th (vs 9.6 normal). Considerably above average. The third named storm of the year typically comes on Aug 13th, the 4th on Aug 23rd. Assuming we get Danielle in the next two days we have had an exactly normal season this year. Personally I don't think the slower start than expected is for any good reason. Though with global totals so low the past few years I am suspicious. The Pacific is supposed to be slow so that is part of it but to be honest I am not familiar with the other basins. I should really research more on that.

CSU's method explains 50% of the variance in season totals. That still leaves 50% unknown so there is certainly room to be wrong here.

18 storms would still be the 5th highest total ever. I find it difficult to forecast a top 5 season despite the incredible known conditions. How many storms were lost to the season with no storms from August 4th to 21st? I can see shaving 2 or 3 off the total. I'll take 15 named storms for the year. Still tied for 9th all time. Still way above normal.

[KWT]

Despite what I said about this being a 12-13NS type season there is still in theory time for a 16NS type season if things do really explode like the ECM long range expects...

Probably will see a hyperactive season in terms of ACE still, I was onboard with a 160-200 type season and I think despite probably lower NS September will probably provide a large ramp-up to the ACE....

[ConvergenceZone]

Despite what I said about this being a 12-13NS type season there is still in theory time for a 16NS type season if things do really explode like the ECM long range expects...

Probably will see a hyperactive season in terms of ACE still, I was onboard with a 160-200 type season and I think despite probably lower NS September will probably provide a large ramp-up to the ACE....

Okay, I have a stupid question, what the heck does ACE mean, and why is it significant? I've seen the threads here on ACE, but I've been too ashamed to ask what the heck it means...

[KWT]

Accumulated Cyclone Energy...

Its a much better measure of how busy a season is then just pure numbers.

For example 2007 had higher NS then say 1950, but 1950 had stronger systems that lasted longer and thus notched up more ACE then 2007.

http://en.wikipedia.org/wiki/Accumulated_cyclone_energy

Its also a large part of what defines a hyperactive season.

[ConvergenceZone]

Accumulated Cyclone Energy...

Its a much better measure of how busy a season is then just pure numbers.

For example 2007 had higher NS then say 1950, but 1950 had stronger systems that lasted longer and thus notched up more ACE then 2007.

http://en.wikipedia.org/wiki/Accumulated_cyclone_energy

Its also a large part of what defines a hyperactive season.

Thanks KWT, I'll have to read up on that link you posted....

[Ptarmigan]

Accumulated Cyclone Energy...

Its a much better measure of how busy a season is then just pure numbers.

For example 2007 had higher NS then say 1950, but 1950 had stronger systems that lasted longer and thus notched up more ACE then 2007.

http://en.wikipedia.org/wiki/Accumulated_cyclone_energy

Its also a large part of what defines a hyperactive season.

I made a post about ACE per a storm. Some seasons like 1950, 1961, 1998, and 1999 have high ACE per a storm, while seasons like 2005 have about average ACE per a storm, while 2007 had a low ACE per a storm.

[Steve]

GFS Ensembles trending more positive for NAO in a week (6z 8/21). Let's see if it holds for a while.
http://raleighwx.easternuswx.com/models ... ensnao.gif
00Z

[ColinDelia]

In the short to mid-term:

"MJO CONDITIONS REMAIN FAVORABLE ACROSS THE
FAR EASTERN TROPICAL ATLANTIC/AFRICA...WITH THE EWP MODEL SHOWING
THIS PERSISTING INTO THE END OF THE MONTH. THE CFS IS MORE
OPTIMISTIC...SHOWING FAVORABLE TO NEAR NEUTRAL CONDITIONS TO
PERSIST INTO THE MONTH OF SEPTEMBER. THUS FAR...THE CFS HAS BEEN
DOING A BETTER JOB THAN THE EWP MODEL. "

http://www.hpc.ncep.noaa.gov/discussions/fxca20.html

[ConvergenceZone]

I believe that Joe Bastardi is going to be eating a large plate of crow with his outlandish 18 to 21 storm prediction he still believes is going to happen....

Danielle may still be the last storm we get in August...Too early to tell, but we will know in about 3 or 4 days....

[KWT]

I'd still bet the ACE will get us close to the hyperactive range though CZ, esp if we get a couple of storms like Danielle and say a 4/5 in the Caribbean in October as well thrown in for good measure.

We'll see, too early to know whats going to happen!

[ConvergenceZone]

I'd still bet the ACE will get us close to the hyperactive range though CZ, esp if we get a couple of storms like Danielle and say a 4/5 in the Caribbean in October as well thrown in for good measure.
We'll see, too early to know whats going to happen!

I know some make a big deal of ACE, but when an active season is called for usually they don't disclose ACE to the public. Usually they equate an active season to how many storms form, so that's what I'm doing s well.....

If they want to start using ACE fine, but they should also stop calling for a specific amount of storms if high ACE is the only thing that defines a hyperactive season.

[KWT]

True but they do mention ACE and usually that is whats used offically to define a normal/above/below and a hyperactive season usually, though really its a combo of all those factors.