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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That SAL is bringing 42 deg C temps to me in Tenerife. Comes on the South Wind and we call it the "Calima".
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Russian heatwave is just an isolated event

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ECMWF shows Cape Verde development now as well.
Member Since: November 24, 2005 Posts: 635 Comments: 26547
Hmmm.... Came across this in the comments section under Dr. Klotzbach's article from the other day....

JKrob says:
August 12, 2010 at 8:36 am
PolishG asked…
“…Then suddenly there is the same temperature difference, and hurricanes! I ask — why? The message I gathered from the PT article is because heat input has increased due to high wind speeds — and high wind speeds are due to high heat input — but, my apologies, this is exactly what Baron Münchhausen did when getting out of a swamp by pulling his own hair…”

If I may, the thing that separates a mass of showers/thunderstorms from an organized tropical cyclone is the Upper-Level High (ULH) at the top of the storm. The ULH is what is driving the cyclone and causing the pressure drop at the surface. It is fed by the latent heat released from the moisture drawn up from below.

The airflow in the lower levels into an organized storm is a fairly long path, round in circles, compaired to the slightly curved path out & away from the storm at the top. The ULH is pushing the exhaust air out away from the storm faster than is being supplied from below. Since it cannot draw air from above the tropopause, it must draw (lift) air from below. This lowers the pressure at the surface since the entire column of air across a relatively broad area is being lifted.

The ability of the ULH to do this is governed by the temperature contrast from the center to the outer edges. The warmer the center of the ULH is, the greater it’s ‘pumping’ action is and since this heat is brought up from the surface, the warmer the water is, the stronger the ULH can be which translates to a stronger tropical cyclone.

The upper levels if the tropical cyclones have always been neglected from monitoring mainly due to the difficulty of reaching it but I believe *that* is where the ‘engine’ of the tropical cyclone resides and everyplace else below that we look, we are just seeing the effects of the storm (low pressure, high winds, eye wall, etc.) but not the cause and that is why I think this new NASA project to discover the cyclone genesis may miss the mark because they are looking in the wrong area. I notice the NASA ER-2 (U-2) is not involved with the project.

I have more details to this genesis theory if you are interested.

Jeff

Member Since: October 25, 2005 Posts: 19 Comments: 21484
Quoting IKE:


ECMWF hasn't shown much, beyond Alex, this entire season. It's shown other invests spinning up on a single run and then backed off.




Translate um...please.


The 850mb vorticity on the Euro from Raleighwx does, though.
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Quoting RitaEvac:
Pat is your house haunted? 110 yrs old should have a lot of history

It's been haunted for the last 4 years!
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The PRE-Depression Investigation of Cloud-systems in the Tropics (PREDICT - http://www.eol.ucar.edu/predict) field experiment will deploy the NSF/NCAR Gulfstream V aircraft in the Atlantic basin in the heart of hurricane season, August 15-September 30, 2010 to explore multi-scale interactions in tropical wave-like disturbances that promote or hinder the development of a tropical depression vortex.


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477. IKE
Quoting Cotillion:


Sees it coming off on Tuesday, same as the GFS and CMC, but doesn't do anything with it.


ECMWF hasn't shown much, beyond Alex, this entire season. It's shown other invests spinning up on a single run and then backed off.


Quoting mcluvincane:


Um.. ??????


Translate um...please.
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Been my sperience that those who root for calamity,,first have never sperienced it,,and secondly they usually the first Victims as well.

Jambalaya fer thought.
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Quoting 69Viking:


Not sure how my screen name computes to Summer Break in your head but I've been around here for a few years with the same name. Anyone that wishes for a Cat 5 is either a child or not of sound mind, I chose the child route because that's typically less insulting but should get the point across.


i WISH...i WISH... i WISH...
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Hi all
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Quoting IKE:
12Z ECMWF...


Eastern ATL view isn't picking up much in the next 10 days...Link


Um.. ??????
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Quoting pottery:

Agreed.
I know the Haitian history quite well.
Overpopulation is an issue, but there are plenty other Island Nations with 'as dense' populations as Haiti.
Anyway, as you say, a complex problem, but I think a solveable one, if the "civilised" world had the right approaches.
By and large, the "civilized world" has been taking either the wrong approach, or not bringing enough resources. They've either been treating the symptoms, and not the disease, or been trying to put out a forest fire with a garden hose.
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Seems Sen. Inhofe has "acquired" a wunderground Handle?
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Quoting IKE:
12Z ECMWF...


Eastern ATL view isn't picking up much in the next 10 days...Link


Sees it coming off on Tuesday, same as the GFS and CMC, but doesn't do anything with it.
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Quoting Neapolitan:
A huge blob o' dry and dusty SAL bulging into the eastern Atlantic today.





Also visible on the RGB loop



Its actually lessened since yesterday. It will stay well north.
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Quoting CycloneUK:


What about the Arctic?



below average all summer

These are the fastest warming places on earth! ha!

Land surface temperature anomalies:



seems like more blue to me. Russian heatwave blah blah blah...




^^
Member Since: November 24, 2005 Posts: 635 Comments: 26547
Quoting CybrTeddy:


Dean and Felix weren't enough? Those guys where only a little under 3 years ago.


We are in the leewards islands... felix and dean was not for us !

We just want to experience THE BIG ONE
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Quoting StSimonsIslandGAGuy:
Calder I've always like Calder mobiles. In a breeze they would be awesome!





!! never even heard of them, you learn something new every day...
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461. IKE
12Z ECMWF...


Eastern ATL view isn't picking up much in the next 10 days...Link
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anyway its called hurricane 10 in the arcives
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NHC updated

DISTURBANCE FIVE (AL052010) 20100812 1800 UTC


...INITIAL CONDITIONS...
LATCUR = 29.8N LONCUR = 89.1W DIRCUR = 0DEG SPDCUR = 0KT
LATM12 = 29.4N LONM12 = 88.7W DIRM12 = 317DEG SPDM12 = 8KT
LATM24 = 28.0N LONM24 = 87.3W
WNDCUR = 25KT RMAXWD = 90NM WNDM12 = 25KT
CENPRS = 1008MB OUTPRS = 1010MB OUTRAD = 100NM SDEPTH = S
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

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Quoting Neapolitan:


Yeah. It's called "winter at the South Pole". And it's oddly periodic, showing up on average once every twelve months... ;-)


What about the Arctic?



below average all summer

These are the fastest warming places on earth! ha!

Land surface temperature anomalies:



seems like more blue to me. Russian heatwave blah blah blah...


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Quoting ElConando:
387. There are a host of reasons why Haiti has been regressing as a country for the past half century. Too many to put on. One thing I believe is that there are far to many people living in Haiti for it to improve at its current state.

Agreed.
I know the Haitian history quite well.
Overpopulation is an issue, but there are plenty other Island Nations with 'as dense' populations as Haiti.
Anyway, as you say, a complex problem, but I think a solveable one, if the "civilised" world had the right approaches.
Member Since: October 24, 2005 Posts: 0 Comments: 24023
This will wash out da oil down there

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A huge blob o' dry and dusty SAL bulging into the eastern Atlantic today.





Also visible on the RGB loop

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i have a quick question to ask any of the experts here. all the talk about fastest wind speeds in the atlantic made me think of something. i know that the NHC uses a 1 minute average to get their top speed. but what about storms in the pacific or other basins? i know some areas use 10 minute averages.

the thing is, because of this, wouldnt a 150 mph storm in the pacific actually be stronger than a 150 mph storm here in the atlantic? is it just me or would a pacific storm being measured on a 10 minute average more likely to have higher speeds but they werent 'counted' as a 10 minute average is taken?
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Looking back at arcives came across this
with all the talk recently about storms getting
stronger at coast lines it has happened before just pray this dont happen agian cant imagine
this thanks
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Patrap I didn't know you were that good looking.I'm staying home now less I lose my girl friend.(ref.418)
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Quoting Enigma713:

LOL. Good comment.

BTW Pat, next time I'm in NOLA with any amount of time to spend, you and I need to get together. (I was up there last week, but aside from hitting up Daquiri's in Metarie to see the Top Cats, I was too busy seeing the other half's family)


Cool..just wu mail and we can do dat.
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LA Storm Total So Far, Impressive...15 inches in some spots.
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Video shot from our Porch as Gustav Approached in aug 08,,the Orange Home was Built by the Same builder in 1901.

This the First outer Band of Gustav's approach.

Everyone was gone save for a few folks Uptown in the hood. Was nice and Quiet.

But feeling the House "move" during the Storms height was a unique experience,,as well as when a Limb crashed thru the only Window Upstairs I didnt cover.



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Quoting Patrap:



Only when I drink..

LOL. Good comment.

BTW Pat, next time I'm in NOLA with any amount of time to spend, you and I need to get together. (I was up there last week, but aside from hitting up Daquiri's in Metarie to see the Top Cats, I was too busy seeing the other half's family) Send me a WUmail, and we can figure something out.

~Jeffs713
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folks if you look at visible this is the first undeclared tropical system that isn't a depression according to the NHC that has an eye on visible loops
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How do we get hurricanes? Chris Davis on the PREDICT project

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Quoting fuzzy3456:
quick question, have there been any significant winds recorded with the "landfall" of former TD5?

This station has been on the west side of the CoC all day.
Shell Beach
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Quoting CycloneUK:
Everyones always going on about GW but what about Antarctica!

Latest minimum temperature: -80.3°C

lololololol


Yeah. It's called "winter at the South Pole". And it's oddly periodic, showing up on average once every twelve months... ;-)
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Quoting Floodman:


LOL...and you used the King's English too!

How have you been, NEwx (just so you know, I pronounce that "nukes")?


Doing good,my friend,staying out of trouble,or at least haven't been caught.
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Quoting wdtcnewsonlinewx:
Have you guys noticed what the 12Z GFS is predicting 192 hours out?



Then look at it 288 hours out.



Its very far out, but very impressive. CMC and ECMWF also showing this wave, though not as strong.
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Quoting RitaEvac:
Pat is your house haunted? 110 yrs old should have a lot of history



Only when I drink..
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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.