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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1138. robj144
Quoting Patrap:
Who Dat..?

97 yard Kickoff return for TD.

U betcha.


Are you still down 10? :)
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Quoting pottery:

Never could understand Baseball..........

heheheh

You ain't right, Pot. :)
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1135. pottery
Quoting blsealevel:


Nice block and a 97 yard run back nice

Never could understand Baseball..........

heheheh
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1134. Drakoen
Surface observation in the northern quadrant of the LLC
Long Beach - 1-1/2 Miles Inland
Temperature: 82 °F
Dew Point: 75 °F
Humidity: 78%
Wind: NNE at 4mph
Pressure: 29.62in
Precipitation: 0.00in
Daily Precip.: 0.67in
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1132. pottery
Quoting jasoncoolman2010xx:

East of that, is plenty more moisture as well.
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Quoting StSimonsIslandGAGuy:


It's the Chandeleur crawler!


unfortunately the chandeleur islands arent really there anymore except for a few sandbars on low tide :(
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1128. pottery
Quoting Jedkins01:
Well at least we are getting plenty of rain in west central Florida despite the lack of unstable air all summer, August total has now surpassed 13 inches at my location in northern pinellas county!


It is interesting though, that DR. Masters mentioned the lack of unstable air in the tropical atlantic. Florida has had this same problem for about the last 5 months. Most of the time, we have had extremely moist air masses around. But Thr NWS always mentioning the unusually warm air aloft around here, creating weaker convection...

This lack of instability has meant less lightning and severe weather in Florida, and more just heavy showery activity...

Has any body else noticed the lack of strong storms here in Florida this wet season? I sure have... Even all the upper lows haven't been able to steepen lapse rates to near normal this time of year. Its so warm aloft, that even after a heavy down pour, its often between 82 and 85 still, Ive never seen such warm convective processes...

Those are interesting observations.
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Well at least we are getting plenty of rain in west central Florida despite the lack of unstable air all summer, August total has now surpassed 13 inches at my location in northern pinellas county!


It is interesting though, that DR. Masters mentioned the lack of unstable air in the tropical atlantic. Florida has had this same problem for about the last 5 months. Most of the time, we have had extremely moist air masses around. But Thr NWS always mentioning the unusually warm air aloft around here, creating weaker convection...

This lack of instability has meant less lightning and severe weather in Florida, and more just heavy showery activity...

Has any body else noticed the lack of strong storms here in Florida this wet season? I sure have... Even all the upper lows haven't been able to steepen lapse rates to near normal this time of year. Its so warm aloft, that even after a heavy down pour, its often between 82 and 85 still, Ive never seen such warm convective processes...
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1122. Patrap
Quoting Drakoen:
Surface observations support a 1006.5mb low pressure center east of southeastern Louisiana.
Full Image



Dont tell the NHC..they may Upgrade to something notable.

Pfffth
Member Since: July 3, 2005 Posts: 428 Comments: 129902
1121. fishcop
Quoting StormW:


This?



That one is even better, Storm. You did however post one a while back showing the African coast looking West to East but this one is great. Thanks
Member Since: September 16, 2008 Posts: 0 Comments: 71
1119. Drakoen
Surface observations support a 1006.5mb low pressure center east of southeastern Louisiana.
Full Image

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1118. pottery
Quoting doorman79:


makes for a good life.

True!
Lookijng at the WV images and loops for Africa...
Plenty Moist stuff accumulating over there, and the Trop. Atl is not as dry as it was 4 days ago

Gonna be lots of pinhole eyes soon ?
LOL
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If the High supposed to drop to south east.. will it push it back in the gulf or what would u think Drak or Pat?
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Quoting pottery:

Here too!
And really, that's the way it should be.


makes for a good life.
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1113. GetReal
It looks like the convection is on the increase for this evening... Nice banding heading into that center swirling south of Gulfport...

If that were to drift south tonight, things could get interesting for tomorrow.
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1112. pottery
Quoting doorman79:


Ha U forget we learn how to drive a boat before a car around here lol

Here too!
And really, that's the way it should be.
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1110. pottery
Quoting Patrap:


Doom is a way of Life here seems.

Canes,Oil..Politicians.

We survive and thrive though.




Only the Strong survive.
You OK.
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Quoting Patrap:


Doom is a way of Life here seems.

Canes,Oil..Politicians.

We survive and thrive though.





yea u right
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1108. Patrap
Coastal Flood Statement, Flash Flood Watch
Member Since: July 3, 2005 Posts: 428 Comments: 129902
Quoting pottery:

1008 !!!
Heh!! Yer Doomed, Pat.
You too, Doorman.
Been real nice knowing you guys.


Ha U forget we learn how to drive a boat before a car around here lol
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1104. pottery
Quoting Patrap:


Itsa liking the environment tonight Drak. Steering is null too.
And a lotta convection is coming around toward the S Shore off the lake seems as well.

Flash Flood Watch up till Friday evening now.





Oooops!
That does not sound so good.
Keep Dry.......
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1103. Patrap
Quoting pottery:

1008 !!!
Heh!! Yer Doomed, Pat.
You too, Doorman.
Been real nice knowing you guys.


Doom is a way of Life here seems.

Canes,Oil..Politicians.

We survive and thrive though.



Member Since: July 3, 2005 Posts: 428 Comments: 129902
Evening all. WHO DAT's, just fun'n, it's only football, good luck in the second half. Aqua, lay off the lentil's. PATRAP, good info on the jail's...
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1101. Drakoen
Quoting DestinJeff:


does that feature look to have an easterly component to it?


Stationary
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I thought I saw a lil eastward movement?
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1099. Patrap


Itsa liking the environment tonight Drak. Steering is null too.
And a lotta convection is coming around toward the S Shore off the lake seems as well.

Flash Flood Watch up till Friday evening now.




Member Since: July 3, 2005 Posts: 428 Comments: 129902
Quoting Drakoen:


If you go to the RGB satellite imagery animation and click on front it shows a 1008mb low pressure center east of you.


Im wondering if the high to the north may push it south. Just a dumb thought so please dont bash me for it :)
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Not much movement


AL 05 2010081206 BEST 0 294N 887W 25 1009 LO
AL 05 2010081212 BEST 0 298N 892W 25 1007 LO
AL 05 2010081218 BEST 0 298N 890W 25 1008 LO
AL 05 2010081300 BEST 0 301N 889W 25 1007 LO
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1096. pottery
Quoting Drakoen:


If you go to the RGB satellite imagery animation and click on front it shows a 1008mb low pressure center east of you.

1008 !!!
Heh!! Yer Doomed, Pat.
You too, Doorman.
Been real nice knowing you guys.
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1095. GetReal
Ref: 1086. Patrap



Interesting swirl south of Gulfport, along with that falling pressure....
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1094. robj144
Quoting Patrap:
NEXRAD Radar
New Orleans, Storm Relative Mean Radial Velocity 0.50 Degree Elevation Range 124 NMI




Is that the mean radial velocity with respect to the center of the storm, or to the radar station?
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1091. Drakoen
Quoting Patrap:
Of note in Gulfport..

Pressure: 29.70 in (Falling)


If you go to the RGB satellite imagery animation and click on front it shows a 1008mb low pressure center east of you.
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Quoting Patrap:


Daphne ,Ala has a much better Jail..definitely,chow wise.


I will have to remember that lol
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I'll put it in the request cue Allybama..

thanks Pat!..
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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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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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