A record quiet start to the 2010 Northern Hemisphere tropical cyclone season
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
Reader Comments
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Ah. The Doc has put the finger on something we may not have been thinking about. I also like the sophisticated way he has incorporated all the posts about the Russian heat wave - which many dismissed as pandering to GW supporters - into his discussion of the 2010 ATL tropical season.... puts a lot of people in their places... and thereby made a very strong point about how an understanding of the macro-weather patterns is vital to understanding of micro patterns.
Someone was talking yesterday about how the Doc's lowered the standard of the blog by his posts.
???????
Good stuff, Doc. Appreciate it.
Just watched it, many thanks! Was just curious if you had any feelings of likelyhood. Seems some of the other models are picking up on some pressure drops in GOM around that time frame(100hrs). Wasn't sure if this might be them starting to hint at that potential, of if they were looking at a different system.
Note 1: From Dr. Jeff Masters: "When using the TCHP map, TCHP is not really a good measurement in water that is shallow (less than 50 meters or so). Because TCHP is a function of volume and depth of warm water, TCHP will never appear to be high around coastlines/ocean shelves that are shallow. Remember Charley of 2004 strengthened significantly just offshore of SW FL. [That is,] in a region of low TCHP."
Note 2: most of the Gulf generally sees its maximum SSTs in August, while the northern half of the Caribbean tops out in September. The southern Caribbean and parts of the eastern Atlantic max out in October. (Link)
I do understand that the oceans are positively huge, but with oil being a hydrophobic molecule, I thought it possible that it could spread in a thin layer on the surface. A single drop of oil can coat the top of a kitchen sink.
There was even some silly talk (research papers?) a few years back about reducing evaporation in the MDR by spreading a sheen of oil over the surface. Dr. Masters dismissed that in particular (rightly I think), and geoengineering in general, as irresponsible given that we don't know the long term impacts of that.
The exchange of heat energy between land/ocean and the atmosphere via evaporation and condensation is a very critical component of earth's habitability due to the temperature regulation the interaction provides.
Anyway, I guess even though many things are lining up this season, it doesn't mean we're guaranteed a storm. Just because each dice has an extra 6 on it doesn't mean you're gonna roll boxcars every time!
Didn't the GFS sniff out Gustav or Ike a long way out too? (or was that the ECMWF?)
Does make sense at least i think so any.
Thanks
That is likely.
Can you elaborate?
Not sure.
Sugarcane farmers shot a video of an oil well blowout in Assumption Parish that happened about 4:00am this morning. Apparently the well is blowing oil and natural gas. People have reported oil raining down as far away as 1-mile from the well blowout.
Link
I was watching the convection Locally
The ever Illusive yet dreaded 200mph Hurricane.
Bill
Thanks, Storm...
Ya there are some hints on the other models. With a potential trough-split occurring the area should definitely be monitored for homegrown mischief.
Emerges off the coast late Tuesday, looks to be a pretty good looking invest at that point.
High's usually bring stability to the atmosphere so it is a good possibility it contributed greatly to it.
It will stay elusive until we develop a 225mph anemometer
New Orleans, Storm Total Surface Rainfall Accumulation Range 124 NMI
you two give me more insight in 20 min. I could find all day. Thank you guys for all that you do. Storm i bought those 20 units on google shopping a few months ago.
LOL Floodman... I definitely understand your point. It was soooo creepy to watch the long term radar loop out of Slidell Louisiana as the infamous 'K' came in. I presume the entire radar facility was destroyed as the last radar image from that site for a month was of the eyewall hitting it.
Surfers Perspective SWFL
Thx Gulfster
photo gulfster
TD #5 here today gone tomorrow! Leftover crumbs this morning in the thigh high range with a light to moderate onshore wind. The tide is starting to fill in and may help improve overall shape, but what little swell is left is starting to drop off. Get it while its there it could be even smaller this afternoon on the low tide. Models have this area of low pressure dropping back into the Gulf and getting caught in a sagging cold front that stalls in the NE. Onshore flow will be with us for a few days so grom/longboard size waves could be the result.
Gulf Temp 89°
Thank you very much for this blog.
I was wondering what the possible reasoning for the 'slow' season could be.
Lots to ponder here.......
Particularly interesting to me (someone raised this earlier as well) is the co-relation between the extarordinary heat in some regions and the Atl. Hurricane season.
Again, thanks for the insights.
Being a Mechanical Engineer, I could design a 225 mph anemometer.... but it would have to be a hand-held model. If you were very brave, you could record wind speeds up to 200 mph. ;>)
GRIP Mission trailer
Two have had readings of 190mph Camille and Allen. It is reasonable that 200mph could be seen if the situation arises. Then again, why would it be needed.
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