Slow Season?

[MWatkins]

Anyone wondering if the 2010 hurricane season is off to a slow start should consider these two facts:

Alex was the first category 2 hurricane (or stronger) in the month of June, since 1966.

Bonnie was the first July tropical storm to affect South Florida...from the east...since 1936.

I wonder what firsts August will bring.

MW

[Stormcenter]

Hey in my opinion it's not the quantity but the quality of the storms
that matters the most. We could have 25 named TS in 2010 but if
they are all Cat. 1 or less then most people would be happy.

[sandyb]

i think they jumped the gun...the season is not going to be as active as they have said it is they will revise in Aug wait and see if numbers are not down a lot

[StormClouds63]

i think they jumped the gun...the season is not going to be as active as they have said it is they will revise in Aug wait and see if numbers are not down a lot

I agree completely. The forecasted numbers were far too high. Expect numbers to be lowered (not drastically, but lowered) for the August updates.

[barometerJane61]

It always seems like the actua numbers are the opposite of the intial forecasts. Barring a sudden surge of named storms in August,I see maybe a total of 10 systems

[rockyman]

It always seems like the actua numbers are the opposite of the intial forecasts. Barring a sudden surge of named storms in August,I see maybe a total of 10 systems

Any evidence to support your idea that "actual number are the opposite of initial forecasts"? Have you actually analyzed initial forecasts for the past 10 years and compared them to actual numbers? I would be interested in your findings.

[MWatkins]

There are two ways to look at seasonal activity...either in terms of the number of named storms, or the ACE (total energy released by a storm over its lifetime).

I tend to be a big fan of the ACE, because it controls for short lived systems that might get a name (oh, say like Bonnie) vs. long track hurricanes that can hog the basin for a period of time.

2004 and 2005 illustrate those differences. 2005 had a lot of close in to the US development, and a lot of storms. Many were short lived though, including Katrina and Rita, both of which developed very close to where Bonnie spun up.

However, 2004 featured several long, long, long track hurricanes like Frances, Jeanne and Ivan.

Steering features were very different in those years...but in terms of the ACE, they were both hyper active seasons with almost the same total on that index.

Given the pattern that has evolved so far this year, it looks like 2010 is going to be more like 2004 than 2005. So while I expect we may not see 20+ named storms, the ones that do develop are going to be moving westward for a long time.

At the end of the season we can look back and see what happens, but I would not at all be surprised to see an ACE value at 180+.

The fact that we saw a July tropical cyclone come out of the southwest Atlantic is not a good sign for the rest of the year. July is the most hostile month of them all for westward moving tropical waves, and we would have seen two develop last week if 98L wasn't so close to land when it tried to get going.

Heck, 98L last week and Alex in June both looked like westpac typhoons in the development stage, just kind of developing out of the equatorial trough.

When you see that in the Atlantic from westward moving waves...in June and July...that's not a good sign for an inactive season.

MW

[wxman57]

I'd add a third way to evaluate seasonal activity - impact. It won't matter to most folks that we hit 18 or 20 named storms if they're all forming and tracking out to sea or into less-populated regions of Central America. Doesn't matter if the ace is 300. The general public equate activity with impact. It'll just take a couple of major hurricane impacts (and I don't mean Cat 3-4-5, Ike was a Cat 2) in key areas (Florida, East Coast, New Orleans) for the public to conclude it was a very bad season, even if there are only 10 named storms in 2010.

[shell70]

No, I don't think we are having a slow season. Actually with Bonnie forming like she did I would think it is ahead of schedule. I have seen busy season not start till the mid of August.

[lonelymike]

This is Ed Dunham's take over at CFHC:

"I’ve observed some comments about the lack of tropical cyclone activity so far this season when compared against the high pre-season storm total forecasts. While I was one of the few that felt that this season would not be hyperactive (and I haven’t changed my thoughts on that), the season is far from over – in fact it has barely begun.

In the past (1880-2009), by July 25th only 13.3% of the total number of storms (1 May – 30 Nov) had been observed. That means the season still has about 87% to go, thus it is premature to suggest that the season is over. However, it is not premature to suggest that a hyperactive season of 18 or more named storms may not occur. Conditions in the Atlantic Basin are still quite hostile with significant areas of subtropical windshear, evidence of an active Saharan Air Layer (although it looks like it could finally be starting to wane), and a equatorial easterly low-level tradewind that continues to dive to the west southwest off the west African continent. Until these negative factors modify, the likelihood of having a new storm every week is pretty slim.

If you look at all of the storms since 1880 (all 1,223 of them) you don’t reach the halfway point in the season until September 16th. NHC defines that midpoint date as September 10th, but they only examine the totals during the satellite era (starting in 1966, although the era actually started in mid 1964). Twelve of the most active seasons (75% of the total) and one of the least active seasons (5% of the total) have occurred during the satellite era. Of the 130 seasons from 1880 – 2009, 12% had a seasonal total of 14 or more storms and 14% had a seasonal storm total of 5 or less. Since highly active seasons are just as uncommon as highly inactive seasons, the forecast skill for predicting either extreme is rather poor.

The average number of storms for the entire period (1880-2009) is 9. Using that long-term period, the average date for the first storm was July 3rd, the average date for the second storm was August 1st and the average date for the third storm was August 18th, so currently we are still ahead of the average based on the activity thus far this season. From 1965 – 2009 (that satellite era again) there have been exactly 500 storms in 45 years – and that’s where the current average of 11 named storms per year comes from.

The most active seasons were: 2005 (28), 1933 (21), 1887 and 1995 (19), 1969 (18), 1936, 2003 and 2008 (16), 1916, 2000, 2001, 2004 and 2007 (15), and 1953, 1990 and 1998 (14).

The least active seasons were: 1914 (1), 1930 (2), 1929 (3), 1883, 1884, 1890, 1917, 1925 and 1983 (4), and 1902, 1904, 1905, 1907, 1910, 1919, 1920, 1922, 1939 and 1962 (5).

Its interesting to note that low activity seasons can cluster into periods of multi-year inactivity just like active seasons can cluster into periods of multi-year increased activity – which does lend some support to the notion of a 25 year cycle (or a 20 year cycle, or whatever it turns out to be). In the long-range forecasting weather business, patience prevails.
ED "

[Stormcenter]

Most of the experts predicted 18 plus named storms and so far on July 26 you only have 2 then I think you're behind schedule. Not saying your can't reach it but only saying now it's an uphill battle in my opinion. We shall see.

[SeminoleWind]

I may not know a whole lot about predicting storm formation but i do know we are just really getting started.
For example in 2004 Bonnie didn't form until august 3rd and we all know the rest of the story.

[Vortmax1]

I have never allowed myself to get in the "game" of predicting storm totals.
And I won't do it now. August is already upon us with only two named storms. Four months remain so that leaves us with 16 weeks to make 16 more named storms if we had one per week.
This would bring the season in on the low side of most of the preseason forecasts at 18.

Personally I'm just tossing out November because I don't have the confidence in this season to believe anything much will happen that month.

So now there's three months left (12 weeks) to get 16 more named storms.
You see how this is looking?

Yeah, yeah...it could happen...but the odds of it happening are getting astronomically higher as each day passes.

[Fego]

It took only one hurricane (Georges 1998) to impact Puerto Rico and make people believe that 1998 was very active season. Just one.

[StormClouds63]

Most of the experts predicted 18 plus named storms and so far on July 26 you only have 2 then I think you're behind schedule. Not saying your can't reach it but only saying now it's an uphill battle in my opinion. We shall see.

I agree.

1 in June
1 in July
3 in August (prediction)
6 in September (prediction)
3 in October (prediction)
1 in November (prediction)

Even with a generous total for September, the ultimate number of named storms would be 15, short of most preseason forecasts. Looks like a fairly hostile environment in tropical Atlantic for the next 2-3 weeks. Long-range models showing nothing of significance. Looks like it might be mid-August until the switch is turned on. We'll wait and see.

[Macrocane]

1998 was a very active season indeed, but there are other seasons that have had deadly storms but have been inactive like 1992, deadly is not equal to active we should not think in that way.

[dixiebreeze]

Looks pretty ripe across the entire basin:

http://www.ssd.noaa.gov/goes/east/tatl/flash-rb.html

[hurricaneCW]

Some interesting convection between 30-40W at around 8-10N. The overall shear isn't too strong either, the persistent TUTT in the Atlantic has weakened and SAL has decreased. I don't see why something couldn't form in the next 5-10 days.

[Agua]

It always seems like the actua numbers are the opposite of the intial forecasts. Barring a sudden surge of named storms in August,I see maybe a total of 10 systems

Sounds like duck hunting. Wonder if the NOAA forecasters work for USF&W in the offseason.

[MWatkins]

Couple of quick notes:

1. To WX's point, 1 storm in 1992 made a very active season for Miami.

2. I am not forecasting 18 named storms or any number in between 0 and 100 (I tend not to do deterministic seasonal forecasts...except for my day job, when I do deterministic revenue forecasts every month...and even then I hate doing them).

3. I think ACE is a much better measurement of overall activity...so while we may not see 18 or more storms, I struggle to see how forecast conditions across the Atlantic in Aug/Sept/Oct won't support an above average ACE of 150 or more.

4. Counting storms so far and pacing that out is the statistical analog to the XTRAP model. In 1969, the second named storm didn't form until August 11th (Blanche) and the Atlantic basin produced 18 named storms that year.

MW