A record quiet start to the 2010 Northern Hemisphere tropical cyclone season

By: Dr. Jeff Masters , 3:42 PM GMT on August 12, 2010

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The remnants of Tropical Depression Five have re-organized this morning, and the storm is pounding Southeast Louisiana with heavy rains. Radar imagery out of New Orleans shows that the remains of TD 5 have have formed some respectable low-level spiral bands that have brought heavy rains in excess of five inches in some areas. However, with the circulation center now moving over land, not much further development can occur.


Figure 1. Morning radar image of TD Five's remains.

Why so quiet in the Atlantic?
The Tropical Atlantic is quiet, and there are no threat areas to discuss today. The Invest 93 system we were tracking has been destroyed by dry air and wind shear. There are a couple of long-range threats suggested by some of the models--the GFS model predicts a tropical depression could form off the coast of Mississippi six days from now, and the NOGAPS model thinks something could get going in the Gulf of Mexico's Bay of Campeche seven days from now. Neither of these possibilities are worthy of concern at present. Overall, it's been a surprisingly quiet August, considering the pre-season predictions of a hyperactive season. According the National Hurricane Center, this hurricane season has been exactly average so far. There have been three named storms and one hurricane as of August 12. The average date of formation of the third named storm is August 13. One hurricane typically forms by August 10. One reason for this year's inactivity may be an unusual number of upper-level low pressure systems that have paraded across the tropical Atlantic. These lows, also called Tropical Upper Tropospheric Trough (TUTT) lows, tend to bring high wind shear that inhibits tropical cyclone formation. The other major factor appears to be that vertical instability has been unusually low in the Atlantic over the past month. Instability is measured as the difference in temperature between the surface and the top of the troposphere (the highest altitude that thunderstorm tops can penetrate to.) If the surface is very warm and the top of the troposphere is cold, an unstable atmosphere results, which helps to enhance thunderstorm updrafts and promote hurricane development. Since SSTs in the Atlantic are at record highs, enhancing instability, something else must be going on. Dry air can act to reduce instability, and it appears that an unusually dry atmosphere over the Atlantic this month is responsible for the lack of instability.


Figure 2. Vertical instability (in °C) over the Caribbean (left) and tropical Atlantic between the Lesser Antilles Islands and coast of Africa (right) in 2010. Normal instability is the black line, and this year's instability levels are in blue. The atmosphere became much more stable than normal in both regions at the end of July. This lack of instability also extends to the Gulf of Mexico and North Atlantic Ocean between Europe and North America, as well as the Western Pacific east of the Philippines, and the South Indian Ocean. Image credit: NOAA/CIRA.

A record quiet start to the 2010 tropical cyclone season in the Northern Hemisphere
What is really odd about this year, though, is the lack of tropical cyclone activity across the entire Northern Hemisphere. Usually, if one ocean basin is experiencing a quiet season, one of the other ocean basins is going bonkers. That is not the case this year. Over in the Eastern Pacific, there have been five named storms and two hurricanes. The average is seven named storms and four hurricanes for this point in the season. This year's quiet season is not too surprising, since there is a moderate La Niña event underway, and La Niña conditions usually supresses Eastern Pacific hurricane activity. But over in the Western Pacific, which usually generates more tropical cyclones than any ocean basin on Earth, it has been a near-record quiet season. Just four named storms have occurred in the West Pacific this year, and the average for this date is eleven. Only one typhoon season has had fewer named storms this late in the season--1998, with just three. The total number of named storms in the Northern Hemisphere thus far this year is fifteen, which is the fewest since reliable records began in 1948. Second place belongs to 1983 and 1957, with eighteen named storms. According to an email I received from NOAA hurricane researcher Gabe Vecchi, the lack of tropical cyclones so far this year in the Northern Hemisphere is between a 1-in-80 and 1-in-100 year event.

So, what is causing this quiet tropical cyclone season? One possibility is that since Northern Hemisphere land areas have heated up to record temperatures this summer, this has created strong rising motion over the continents. This rising motion must be compensated by strong sinking motion over the adjacent oceans in order to conserve mass. Sinking air causes drying and an increase in stability. Another possibility is that the unusual jet stream configuration that is responsible for the Russia heat wave and record flooding in Pakistan is also bringing dry, stable air to the Northern Hemisphere's tropical cyclone breeding grounds. It is also possible that climate change is causing the reduction in tropical cyclone activity, for a variety of complex reasons. Computer simulations of a future warmer climate generally show a reduction in global number of tropical cyclones (though the strongest storms get stronger), and it is possible we are seeing a preview of that future climate. Or, this year's quietness may simply be natural variability. It will be interesting to see when the Russian heat wave breaks if vertical instability over the Atlantic increases back to normal levels. Current forecasts from the GFS and ECMWF models project the Russian heat wave to break late next week.

Moscow's air remains clear; coolest temperatures in two weeks
Moscow's winds remained favorable for keeping smoke away from the city today, and temperatures "cooled" to at Moscow's Domodedovo airport to 33°C (91°F)--the lowest maximum temperature since a high of 32°C (90°F) was recorded on July 30. Moscow's airport has reached a maximum temperature of 30°C (86°F) or higher for 35 consecutive days now (at Moscow's official observing site, the Moscow Observatory, this string is 30 days.) Moscow's average high temperature for August 12 is 20°C (68°F). Moscow's high temperatures have averaged 15°C (27°F) above average so far this August--a truly extraordinary anomaly for a country so famous for its notorious cold weather. The latest forecast for Moscow calls for high temperatures of 30 - 33°C (86 - 91°F) Thursday through Monday. This is still 23°F above normal, but will be a welcome change from the extreme heat of the past two weeks. Long range forecasts from the ECMWF and GFS models continue to suggest that a series of troughs of low pressure will begin to attack the ridge of high pressure anchored over Russia beginning on Wednesday, bringing cooler temperatures just 5°C (8°F) above average to Russia late next week. By ten days from now, the ECMWF model shows a strong trough of low pressure over Moscow, and a end to the Great Russian Heat Wave of 2010.

Next update
I'll have an update Friday morning.

Jeff Masters

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1488. centex
Quoting alfabob:
I don't understand why anyone would question global climate change. Not to be a "doomcaster", as I consider real evidence key to any discussion; but our actions have in fact caused some deviation from the "norm". It is not possible to look into the past and make any real conclusions about the future, at least with current technology. What can be concluded is that the possibility for increased natural disaster damage is only going to rise in the future. So making decisions based on this assumption is key, because all factors currently point to it. Even more so with this seasons predictions and the current state of the Gulf.

As with predicting hurricane seasons, I don't understand how a prediction can already be under criticism. Those who are not professionals in the field need to understand that predictions are based upon defined principles. Regardless if something occurs or not, our current understanding of nature allows a prediction to be produced. If incorrect then another "prediction" is produced. Chances are, this is going to be an over average hurricane season. So go flip a coin 10 times, and if you get heads 8/10 times then it is just as likely that this season will be uneventful.
Many are stupid on this site but may know some about the tropics. Most don't understand the science behind GM and only react negatively. I would suggest asking all your questions directly to JM and not this blog. More than half of the stupid bloggers do not follow JM, go figure. Just shows how ignorant they are. They still think political issue which is a decades old dead argument.
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1487. pottery
Quoting msphar:
Perseid Meteor shower tonight in the NE sky. Best late.

Too many clouds here.
Tomorrow, all.
TXS Keeper.
Member Since: October 24, 2005 Posts: 0 Comments: 24390
Models +72 hrs = Little to No Skill.
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1485. msphar
Perseid Meteor shower tonight in the NE sky. Best late.
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1484. KEEPEROFTHEGATE (Mod)
night pottery
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1483. pottery
It is Raining!
Again!!
I am going to bed>>>>>>>>>>
G/N all.
Thanks for the good discussions.
Member Since: October 24, 2005 Posts: 0 Comments: 24390
1482. Drakoen
Quoting Levi32:


Rather significant northward shift from the 18z.


Yea. Still plenty of time to watch it though. The GEFS ensembles show the NAO heading positive after the 16th so that could be the reason why.

Member Since: October 28, 2006 Posts: 57 Comments: 30563
1481. pottery
Good Post, Alfabob.
Member Since: October 24, 2005 Posts: 0 Comments: 24390
1480. KEEPEROFTHEGATE (Mod)
Quoting weatherbro:
Nevermind the record head, floods and cool British Summer. But the Southern hemisphere has been dealing with an anomalously freakish cold Winter(especially South America)!
don't worry our turn is coming in a 110 days
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Quoting Drakoen:
GFS still showing development off the African coast


Those specs indicate a good possibility of a MID, N-Atl storm.
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1478. pottery
Quoting weatherbro:
Nevermind the record head, floods and cool British Summer. But the Southern hemisphere has been dealing with an anomalously freakish cold Winter(especially South America)!

True.
And Brazil recorded some incredible rainfalls earlier this year as well.
Floods killed many...
Member Since: October 24, 2005 Posts: 0 Comments: 24390
1477. Levi32
Quoting Drakoen:
GFS still showing development off the African coast


Rather significant northward shift from the 18z.
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Have a blessed night TxSweetPea and all.
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1474. help4u
One great benefit of global warming according to Dr. Masters less hurricanes which would lead to less loss of life. Great news!
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Nevermind the record head, floods and cool British Summer. But the Southern hemisphere has been dealing with an anomalously freakish cold Winter(especially South America)!
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1472. JLPR2
Quoting BahaHurican:
SLU, we've had 94 in Nassau, which was unheard of in the Bahamas before the last few years. Our summer has been remarkably cool by comparison w/ 2006 -2009 because we kept having ULLs parked in our vicinity, giving rise to unseasonable rainy periods lasting days at a time [rather than the more traditional pop up afternoon shower]. The last few July's have been severely hot with high humidity but little rain. Seems that is becoming more the norm than the anomaly.


Only 94*F? O.o
My area hit 98*F once in 1981, I dont even want to imagine what the heat index was with that one. XD
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1471. Drakoen
GFS still showing development off the African coast
Member Since: October 28, 2006 Posts: 57 Comments: 30563
Quoting Drakoen:
The CMC does the same thing with the strengthening over land



wish storm?
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Tropical storm Erin in Oklahoma is not nominated?
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1468. centex
The next system in 3 or 4 days at most is not even a gleam your eyes. Granted I don't know either, but I admit it.
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1467. Drakoen
Member Since: October 28, 2006 Posts: 57 Comments: 30563
Quoting Levi32:


1357.

La Nina is just having a small blip. It happens.



ok
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Quoting BahaHurican:
I'm sticking with mine, but starting to feel a bit pressured about it .... lol. I'm expecting something that manifests itself around the 20th to start showing up by Sunday. But we shall see, won't we...


Just thinking I may be wrong is all. Looking at what was and looking at what is right now, it's going to be close. It's a mess in the E&Mid ATL right now.
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1464. pottery
Quoting pottery:

What image are YOU looking at?????

SORRY!!
I read your comment wrong.
Thought you said "clear sailing across Africa"
The Atl is clear, Africa looks, well, wet!
Member Since: October 24, 2005 Posts: 0 Comments: 24390
1463. smuldy
Quoting help4u:
Sounds like DR. Masters thinks this seaon is dead,could it be slower than the season Andrew hit with 6 named storms.I think he is right in thinking the season is a bust.
Maybe it will be slow. Could be too hot too far north for differential to allow a great number of storms. Get ready for another wicked snowy winter DC and north if that is the case. Lots of warm energy left for storm formation from the gulf to maine then.
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1462. JRRP
that's funny
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1461. Drakoen
The CMC does the same thing with the strengthening over land
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1459. Drakoen
Quoting Levi32:


Lol, same thought.


:)
Member Since: October 28, 2006 Posts: 57 Comments: 30563
1458. Levi32
Quoting Drakoen:
GFS 00z showing TD5 pushing south over the Florida Panhandle and organizing as it does so.



Lol, same thought.
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1457. pottery
Quoting KerryInNOLA:
Clear sailing clean across to Africa. Could this be the season without CV storms?

What image are YOU looking at?????
Member Since: October 24, 2005 Posts: 0 Comments: 24390
1456. SLU
Quoting BahaHurican:
SLU, we've had 94 in Nassau, which was unheard of in the Bahamas before the last few years. Our summer has been remarkably cool by comparison w/ 2006 -2009 because we kept having ULLs parked in our vicinity, giving rise to unseasonable rainy periods lasting days at a time [rather than the more traditional pop up afternoon shower]. The last few July's have been severely hot with high humidity but little rain. Seems that is becoming more the norm than the anomaly.
Quoting JLPR2:


Talking about temps I seem to be from 2-4 degrees above normal.
The normal temp for my area during August is 87-88*F
Today it got up to 93*F and most days we are reaching low 90s with the occasional mid 90s. And with seabreeze and everything. :|


Based on our interesting discussion tonight, one can deduce that the temperatures in the Caribbean have skyrocketed in the last 2 decades or less.
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Anyhoo, I'm leaving u ECar crew to it. I want to be up in the a.m. in case anybody else nominates a Blog Legend overnight... lol That and my first cup of coffee will be calling me LOL.

NIght all...
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1454. Levi32
GFS still starts trying to feedback TD 5 again before it's even back out over the water.

90 hours:

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1453. Drakoen
GFS 00z showing TD5 pushing south over the Florida Panhandle and organizing as it does so.

Member Since: October 28, 2006 Posts: 57 Comments: 30563
1452. pottery
Quoting Levi32:


According to some sources....

Daily Mean Arctic Temperature verse Climatology from the Danish Meteorological Institute:


Nice one. Thanks .
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1451. KEEPEROFTHEGATE (Mod)
Quoting help4u:
Sounds like DR. Masters thinks this seaon is dead,could it be slower than the season Andrew hit with 6 named storms.I think he is right in thinking the season is a bust.
there really is nohelp4u
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1450. pottery
Quoting SLU:


So true ..

Anyway man. Nice chat as always. I'm signing out now. So take care. Heading your way pretty soon :) (Y)

Keep Good.
Member Since: October 24, 2005 Posts: 0 Comments: 24390
Quoting CyclonicVoyage:


Re thinking my 15th claim here. 3 days to clear out a big mess is looking rather slim.
I'm sticking with mine, but starting to feel a bit pressured about it .... lol. I'm expecting something that manifests itself around the 20th to start showing up by Sunday. But we shall see, won't we...
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1448. pottery
Quoting help4u:
Sounds like DR. Masters thinks this seaon is dead,could it be slower than the season Andrew hit with 6 named storms.I think he is right in thinking the season is a bust.

I think you need to read his Blog!
Member Since: October 24, 2005 Posts: 0 Comments: 24390
1447. SLU
Quoting pottery:

Absolutely Right.


So true ..

Anyway man. Nice chat as always. I'm signing out now. So take care. Heading your way pretty soon :) (Y)
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1446. help4u
Sounds like DR. Masters thinks this seaon is dead,could it be slower than the season Andrew hit with 6 named storms.I think he is right in thinking the season is a bust.
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1445. Levi32
Quoting pottery:

Very good point.
The poles are also heating (not so much the South), so the northern Gradient is not as great as it seems.


According to some sources....

Daily Mean Arctic Temperature verse Climatology from the Danish Meteorological Institute:

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1443. JLPR2
Quoting pottery:

Keep in mind that Climatology is basically a Historic Record.
We have never been in this situation before.......
The heat records that have been set, over land and sea, this year, make a mess of all that.


Talking about temps I seem to be from 2-4 degrees above normal.
The normal temp for my area during August is 87-88*F
Today it got up to 93*F and most days we are reaching low 90s with the occasional mid 90s. And with seabreeze and everything. :|
Member Since: Posts: Comments:
SLU, we've had 94 in Nassau, which was unheard of in the Bahamas before the last few years. Our summer has been remarkably cool by comparison w/ 2006 -2009 because we kept having ULLs parked in our vicinity, giving rise to unseasonable rainy periods lasting days at a time [rather than the more traditional pop up afternoon shower]. The last few July's have been severely hot with high humidity but little rain. Seems that is becoming more the norm than the anomaly.
Member Since: October 25, 2005 Posts: 19 Comments: 22322
1441. pottery
Quoting Levi32:


Well, the total amount of energy contained in the earth's atmosphere can vary....that's how we get global temperature swings. Lower that total energy and you generally get weaker storms. Hurricanes are used to balance the earth's heat budget, so you can also get a reduction of storms simply by decreasing the difference in temperature from the equator to the poles, which also routinely goes through swings.

Very good point.
The poles are also heating (not so much the South), so the northern Gradient is not as great as it seems.
Member Since: October 24, 2005 Posts: 0 Comments: 24390
1439. centex
There was a long diatribe how we would not see tropical development for over 7 days. Many of the so called experts who just recently predicted 94L wrong where willing to speculate how there forecast would somehow be better if more than a week out. Beware of those who know some science but have not learned how to apply it. Many on this site blindly follow them and go out of the way to KTB. We are nearing peak of season and only a couple of days can change things, so don’t believe them.
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Quoting BahaHurican:
I'll repeat for those who might have missed earlier:

Quoting BahaHurican:
Since things are relatively slow, what about a "Legends of the Wunderblog" runoff? Nominate the three or five top tropical events that typify Wunderblog history or lore. The main requirement would be that the event has to have happened since the blog happened, and it has to have entered the "history" or collective memory of the blog as a notable event. Nominations close at 7 a.m. tomorrow.

Nominated so far:
Legends of the Wunderground


1. Katrina 2005 "StormTop said it would hit NOLA"
2. Rita 2005 "I tried to evacuate"
3. Wilma 2005 "the definitive pinhole eye"
4. Chris 2006 "Sheared again… Naturally"
5. Ernesto 2006 "yes it is; no it's not"
6. Dean 2007 "is that cat 5 landfall????"
7. Felix 2007 "graupel in the guts"
8. Humberto 2007? "Talk about explosive cyclogenesis"
9. Karen 2007 "never say die"
10. Dolly 2008 "no closed low"
11. Fay 2008 "Florida vacation"
12. Gustav 2008 "I can fake u out"
13. Ike 2008 aka "Ike Jr."
14. Portlight 2008 formation "We are the Blog"
15. Marco 2008 "World's Smallest 'cane or Largest Tornado"


Anybody else has suggestions?


16. IKE will hit SE Palm Beach County. Board up!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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