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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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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Quoting calder:


no-one's ever said that to me before taz, thanks...

I'm reporting both of you! LOL! J/K
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1036. robj144
Quoting Patrap:
TD ..Reggie Bushhhhhhhhhhhh


You guys finally scored... :)
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1035. SLU
Quoting JLPR2:


I'm thinking this season might last till December unless those SSTs cool suddenly, lots of hot water that if present at December could start something.


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.
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Quoting DestinJeff:


Rural reality.

LMAO!!
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1030. robj144
Quoting Tazmanian:



it will be too long


There you go... that's how you use "too". :)
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Quoting DestinJeff:


size doesn't matter.

Urban myth.
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Quoting Tazmanian:



it will be too long

That's what the ULL said...
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1027. aquak9
Quoting spathy:
Hi all
Getting ready to head out this evening to enjoy the best the non oiled GOM has to offer with the added icing on the cake of the meteor shower.
But are there any thoughts on the pent up Atlantic/ GOM SSTs?
IE an October storm like Wilma.
If we dont at least get many more fish storms .....
I fear a bad late season of storms.
Because this time of year The prevailing winds generally protect SW Florida.
When the late season starts adding fronts heading further South.
THINGS can take nasty turns towards me.
Yes selfish on my part but any thoughts on latent SST late season storm potential?


at this point I don't see SST's dropping any for a very long time. Might make for a goo winter gardening season, tho...
Member Since: August 13, 2005 Posts: 178 Comments: 26675
1026. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15684
Quoting IKE:


You Supply the Night, I'll Supply the Love.



Awesome!
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Quoting calder:
if I ever get banned from this blog i know what my new handle will be:

reallycoolguywhogetsallthechicks



it will be too long
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1022. Patrap
Quoting FEEDERBAND:
Thanks Pat. been lurking mostly now for 6 years. Guess its time to figure it out.


It took me a while so dont feel bad.
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1021. aquak9
it mighta been lentil soup, ripplin...didn't last very long.

swamplily- ya know poor old Recoon will get me banned. BUT, he's good at knocking out the storms!
Member Since: August 13, 2005 Posts: 178 Comments: 26675
1019. IKE
6-10 day precip for the contiguous 48........




6-10 day temp....the heat is on... in the SE USA.....




Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting aquak9:
destinjeff- maybe you could, oh, I don't know...

turn it sideways? make it move around a little? add some glitter?



It needs a "recoon" pointer :))
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I wonder since this La Nina is Mokiki if that has anything to do with the quiet Northern Hemisphere tropical season?
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Quoting aquak9:
sorry about that, ripplin. Something in a can, was callin' my name...I think it was alpo...

evening ya'll.
My water pup does the same thing...
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1012. Vero1
COMING next Tuesday:



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Thanks Pat. been lurking mostly now for 6 years. Guess its time to figure it out.
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Quoting Patrap:

Here in Ascension parish we have had ZERO rain from the storm. Just some virga, the rain seems to be dancing around us.
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Quoting LoneStarWeather:
So a TD, an open wave and a ULL walk into a bar and the ULL says...
you better drink up quick because you won't last long here....
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1007. Patrap
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Quoting robj144:


Good song... Weezer. :)

lol
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1005. xcool


wow
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1004. Patrap
On posting images..look to the right under recommended Links

How to start your own blog, and add blog images and links
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1003. Vero1
Quoting FEEDERBAND:
thanks Pat. Don't know how to post images. But the center is still over water at this time.Just refuses to come ashore.



GULF OF MEXICO...
DOPPLER RADAR IMAGERY INDICATES THAT THE REMNANT CIRCULATION OF
TROPICAL DEPRESSION FIVE IS LOCATED OVER CAT ISLAND...OFF THE
COAST OF MISSISSIPPI...NEAR 30N89W...ANALYZED AS A 1008 MB LOW
CENTER AT 2200 UTC. AT THIS POINT...MOST OF THE CONVECTION
PRODUCED BY THIS SYSTEM HAS MOVED INLAND. YET...SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION REMAINS OVER THE NORTHERN
GULF COAST NORTH OF 27N BETWEEN 82W AND 90W.
TOTAL PRECIPITABLE
WATER IMAGERY SHOWS THE CONVECTION IS FUELED BY PLENTY OF
LOW-MID LEVEL MOISTURE EMBEDDED IN THE SYSTEM ADVECTING ACROSS
THE SOUTHERN STATES WEST OF 94W. WATER VAPOR IMAGERY INDICATES
MODERATELY DRY AIR ACROSS THE SE GULF KEEPING WEATHER CONDITIONS
FAIR WITH CLEAR SKIES
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Quoting Cotillion:
If it hit Bermuda, it ain't a fish, folks.


How many points does it get for hitting Bermuda?
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1001. aquak9
destinjeff- maybe you could, oh, I don't know...

turn it sideways? make it move around a little? add some glitter?
Member Since: August 13, 2005 Posts: 178 Comments: 26675
1000. Patrap
Quoting FEEDERBAND:
thanks Pat. Don't know how to post images. But the center is still over water at this time.Just refuses to come ashore.


Itsa tough un..and thats always something to watch.

Nuther round here please..tyvm Barkeep
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Quoting StormGoddess:

Say it ain't so.


Good song... Weezer. :)
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thanks Pat. Don't know how to post images. But the center is still over water at this time.Just refuses to come ashore.
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sorry about that, ripplin. Something in a can, was callin' my name...I think it was alpo...

evening ya'll.
Member Since: August 13, 2005 Posts: 178 Comments: 26675
Quoting JLPR2:


I'm thinking this season might last till December unless those SSTs cool suddenly, lots of hot water that if present at December could start something.

Say it ain't so.
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Quoting DestinJeff:


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



Unnecessary 'tude.
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994. IKE
Quoting LoneStarWeather:
So a TD, an open wave and a ULL walk into a bar and the ULL says...


You Supply the Night, I'll Supply the Love.


Member Since: June 9, 2005 Posts: 23 Comments: 37860
992. JLPR2
Quoting SLU:
Goodnight all

I've been very busy today so I haven't been up to date with the lasted happenings. Apparently I haven't missed anything.

Just so add to what Dr. Masters said in his blog earlier. The Northern Hemisphere is off to a record slow start and going back to my post last night, I indicated that we could be in line for a season that conforms to climatology as far as when the main activity occurs. Now when you look at the SSTs profile of the whole world, the warmest anomalies in the tropics exist in the Atlantic. Based on that fact, there's no need to guess where the party will take place in 2010.

Now since the majority of the activity this year could take place in the Atlantic Basin, the main reason why the Northern Hemisphere's storm count is the lowest in recorded history could be because the Atlantic hasn't reached it's climatological peak as yet. When it does shortly, we could easily catch up.



I'm thinking this season might last till December unless those SSTs cool suddenly, lots of hot water that if present at December could start something.
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jasoncoolman - I hope you're prediction on whether Tom Brady would play tonight is not like your prediction of tropical weather. :)
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Quoting calder:


..."looks like i'm taking you both home for a spanking..."

Nice!
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Quoting LoneStarWeather:
So a TD, an open wave and a ULL walk into a bar and the ULL says...


..."looks like i'm taking you both home for a spanking..."
Member Since: Posts: Comments:

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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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