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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1088. pottery
Quoting doorman79:


Pat, did u check the conditions there before or after u broke out ;)

LOL. I was wondering.........
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1087. Patrap
Quoting doorman79:


Pat, did u check the conditions there before or after u broke out ;)


Daphne ,Ala has a much better Jail..definitely,chow wise.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
1086. Patrap
NEXRAD Radar
New Orleans, Storm Relative Mean Radial Velocity 0.50 Degree Elevation Range 124 NMI


Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting Patrap:
Gulfport Jail, Mississippi

Current Conditions

East Lyman, Gulfport, Mississippi (PWS)
Updated: 10 min 3 sec ago
Clear
81.4 °F
Clear
Humidity: 90%
Dew Point: 78 °F
Wind: Calm
Wind Gust: 4.0 mph
Pressure: 29.70 in (Falling)
Heat Index: 90 °F
Visibility: 10.0 miles


Pat, did u check the conditions there before or after u broke out ;)
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WHO DAT NATION is gonna go to the locker room down by 10...
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1083. Patrap
Of note in Gulfport..

Pressure: 29.70 in (Falling)
Member Since: July 3, 2005 Posts: 426 Comments: 129093
1082. SLU
Quoting hydrus:
The CMC has the remnants of T.D.5 hanging around for a week. And there is a lil something out by the Cape Verde Islands...Link


Right on time for the climatological start.
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Quoting Patrap:
Now that the Sun has set..TD-5 has found the 90F water temps appreciable.





looks like EX TD 5 is likeing it off land
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1080. Patrap
Quoting AllyBama:
Pat, could you please send some of that rain back my way? lol


I'll put it in the request cue Allybama..
Member Since: July 3, 2005 Posts: 426 Comments: 129093
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1077. Patrap
Gulfport Jail, Mississippi

Current Conditions

East Lyman, Gulfport, Mississippi (PWS)
Updated: 10 min 3 sec ago
Clear
81.4 °F
Clear
Humidity: 90%
Dew Point: 78 °F
Wind: Calm
Wind Gust: 4.0 mph
Pressure: 29.70 in (Falling)
Heat Index: 90 °F
Visibility: 10.0 miles
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Pat, could you please send some of that rain back my way? lol
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1075. pottery
Quoting Patrap:


One could chuck a sonde up with a good quality Slingshot almost

heheheheh
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ive been lurking here for years. just never signed up untill a couple days ago
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1071. Patrap
Quoting FLPandhandleJG:

Hey the hurricane hunters dont have to travel that far if it tries reform..


One could chuck a sonde up with a good quality Slingshot almost
Member Since: July 3, 2005 Posts: 426 Comments: 129093
Quoting Patrap:


Cool ..dats not far from us here Uptown.


nope, my great grandfather owned a grocery somewhere there. my mom could tell ya. they moved north in 72 so i dont know a whole lot about it
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Quoting Patrap:
Why behind Uranus, of course.


Got a big chuckle out of me!
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Quoting Patrap:
Now that the Sun has set..TD-5 has found the 90F water temps appreciable.


Hey the hurricane hunters dont have to travel that far if it tries reform..
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1066. Patrap
Convection on the Up-tick South and East of the center.

Member Since: July 3, 2005 Posts: 426 Comments: 129093
1065. pottery
Lovely Sunset here in yellows and orane and pink and lilac.
Then the Moon with Venus, Saturn, Mars, (could not see Mercury) all in a cluster.
Its Virgo and Leo, man.
Gotta be Good...
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1063. robj144
Quoting hurricaneben:
To whoever lives now in South Florida: What winds did you experience during Fay? I got 25-30 MPH sustained winds with higher gusts but didn't lose electricity.


I don't remember, so it couldn't be much.
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1062. Patrap
Quoting doorman79:
Havent had a drop of rain all day from this all day on the north shore. now its pouring and the tv went out during the saints game. go figure bye the way pat, my mom grew up 2 houses from the corner of magazine and fuscher(not sure if thats how u spell it)in the 50s


Cool ..dats not far from us here Uptown.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
1061. Patrap
Now that the Sun has set..TD-5 has found the 90F water temps appreciable.

Member Since: July 3, 2005 Posts: 426 Comments: 129093
Havent had a drop of rain all day from this all day on the north shore. now its pouring and the tv went out during the saints game. go figure bye the way pat, my mom grew up 2 houses from the corner of magazine and fuscher(not sure if thats how u spell it)in the 50s
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To whoever lives now in South Florida: What winds did you experience during Fay? I got 25-30 MPH sustained winds with higher gusts but didn't lose electricity.
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1057. flsky
Quoting Patrap:


The other 2 Planets will show up as the western Sky darkens as they are a few magnitudes dimmer.

Binoculars should help now if ya have some.

Now, that's helpful. Thanks!
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1056. Patrap
Quoting flsky:

I guess I'm only seeing the moon and Venus. Nothing above. Is it too early?


The other 2 Planets will show up as the western Sky darkens as they are a few magnitudes dimmer.

Binoculars should help now if ya have some.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
1054. pottery
Quoting BahaHurican:
I know quite a few Scotts. A couple of them school down that way. Or was there on business?

The young man was a-courtin' a Trini Babe.
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1053. hydrus
Quoting SLU:


For the SSTs to cool suddenly, one of two things must happen.

1. A strong positive NAO outburst to drive well above average trades across the region. (UNLIKELY)

or

2. Upwelling caused by powerful hurricanes (MORE LIKELY)

When one adds to the mix the strenghtening La Nina, we can expect lower than normal windshear across the Atlantic towards the end of the season. Generally, the "real" hurricane season starts when the thermodynamics improve and ends when the wind shear increases. So a late ending season this year is certainly on the cards.
The CMC has the remnants of T.D.5 hanging around for a week. And there is a lil something out by the Cape Verde Islands...Link
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1052. Patrap
Its stuck in Neutral.

Member Since: July 3, 2005 Posts: 426 Comments: 129093
1051. flsky
Quoting spathy:



I guess I'm only seeing the moon and Venus. Nothing above. Is it too early?
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1048. geepy86
DJ you are killing tonight, lol
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1047. Patrap
Ty very little.

...itsa libations Im sure.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
1044. flsky
Quoting Patrap:
Why behind Uranus, of course.

Beyond corny! and quite predictable!
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Quoting DestinJeff:


My apologies. I'll try to mix it up a little more.



lmao made me spit my beer. back to lurking
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1042. Patrap
Why behind Uranus, of course.
Member Since: July 3, 2005 Posts: 426 Comments: 129093
1041. flsky
I can see the crescent moon and one planet above it - where are the other two planets??
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Aint's only down by 3 now...
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1038. SLU
After I compile all the data i'll post a report showing what pattern of storm formation we may see in 2010.
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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.