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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1538. xcool
ecmwf cmc GFS TD5XXX model support
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SW Carib AOI has vort at 850 but weak there is a upper level anticyclone coming over it good divergence and convergence should be slow or stationary to move yep something to watch
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Quoting FLPandhandleJG:

ya I kinda figure that.. but T'storms are pretty impressive though..


They are impressive. They appear to be caused by the interaction of the southern end of a tropical wave and the semipermanent Colombian heat low. No development here. It will come. Trust me.
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Quoting KoritheMan:
Not much at the surface or the mid-levels with the Caribbean feature.

ya I kinda figure that.. but T'storms are pretty impressive though..
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Not much at the surface or the mid-levels with the Caribbean feature.
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1533. xcool
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1532. xcool
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Some nice storms in the southern Caribbean.. What y'all think?
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Anyone else looking at the thing over Central America (SW of this image. Definitely deserves at least a yellow near 0% circle IMO! More like 30% if you ask me.

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Quoting sflawavedude:


And I would be one to really question the predicted activeness of this season if the system doesn't form or do much.


That's your prerogative. But I don't think many realize how quickly things can change. And they will. One needs only to look at the historical record to see that.
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Quoting KoritheMan:


If it doesn't, expect to hear the bustcasters.


And I would be one to really question the predicted activeness of this season if the system doesn't form or do much.
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1527. xcool
FLPandhandleJG ha
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Quoting sflawavedude:
Maybe the cape verde system will actually take place as progged. Can't beat the consistency! :)


If it doesn't, expect to hear the bustcasters.
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Maybe the cape verde system will actually take place as progged. Can't beat the consistency! :)
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xcool.. Its just us for now.. haha
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1522. xcool
game on now
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GFS


CMC


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ot.... but I just saw my first meteor of the night!!!
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Quoting JRRP:
NOGAPS
00z
Link


NOGAPS joining the GFS in the development of a Cape Verde storm in seven days. GFS has been foreseeing this for about two days or so now. It will be interesting indeed, to see if this continues.
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1514. JRRP
NOGAPS
00z
Link
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Quoting CosmicEvents:
Just for the record, in 2005, ST predicted every cyclone that was within 10 degrees to hit NOLA as a cat6. Katrina was roughly the 5th or 6th one that year that he forecast to hit NOLA.
.
There's nothing supernatural about it. Whoever he was he had a thing for forecasting cyclones to hit NOLA..
.
Then, when his dream turned into a real life tragedy....he stopped those forecasts.
.
I realize many think it's silly, but if anyone should get "credit" for forecasting Katrina's NOLA landfall, it's LaDobeLady and the ants that she reported...just for that one storm. And the ants were right.


yeah i remember him.......every storm was heading to New Orleans. I started reading the blog when Hurricane Emily was in the carribean. He was hell bent on Emily making landfall in New Orleans.
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1509. xcool
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Quoting CosmicEvents:
Just for the record, in 2005, ST predicted every cyclone that was within 10 degrees to hit NOLA as a cat6. Katrina was roughly the 5th or 6th one that year that he forecast to hit NOLA.
.
There's nothing supernatural about it. Whoever he was he had a thing for forecasting cyclones to hit NOLA..
.
Then, when his dream turned into a real life tragedy....he stopped those forecasts.
.
I realize many think it's silly, but if anyone should get "credit" for forecasting Katrina's NOLA landfall, it's LaDobeLady and the ants that she reported...just for that one storm. And the ants were right.


He was bound to eventually get it right...
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1506. xcool
TD5 COME BACK..
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1505. xcool



fun week head
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Just for the record, in 2005, ST predicted every cyclone that was within 10 degrees to hit NOLA as a cat6. Katrina was roughly the 5th or 6th one that year that he forecast to hit NOLA.
.
There's nothing supernatural about it. Whoever he was he had a thing for forecasting cyclones to hit NOLA..
.
Then, when his dream turned into a real life tragedy....he stopped those forecasts.
.
I realize many think it's silly, but if anyone should get "credit" for forecasting Katrina's NOLA landfall, it's LaDobeLady and the ants that she reported...just for that one storm. And the ants were right.
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1503. xcool
lol
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1501. centex
Steering

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1500. centex
Quoting help4u:
All bow to the NHC!!!
All be anti NHC, I guess your in that camp. The experts on this sight follow them and like NHC center prdict the future but don't explain why wrong and expect you to follow future predictions. They are the same at best.
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1499. centex
850 Vorticity
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1498. help4u
All bow to the NHC!!!
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1497. xcool
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1496. xcool
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1131 PM CDT THU AUG 12 2010

.UPDATE...

THE REMNANT LOW THAT WAS TROPICAL DEPRESSION FIVE IS SLOWLY MOVING
INTO COASTAL MISSISSIPPI TONIGHT. SCATTERED CONVECTION NEAR THE
CENTER OF LOW WILL CONTINUE TO BRING A CHANCE OF SHOWERS TO KGPT.
AS A RESULT...HAVE VCSH INCLUDED TO SHOW THIS RISK. AT ALL OF THE
OTHER TERMINALS...LITTLE PRECIP IS EXPECTED OVERNIGHT...AS A
SOMEWHAT MORE STABLE ATMOSPHERE HAS SETTLED IN. THIS PERIOD OF
STABILITY SHOULD COME TO AN END AROUND 10Z...WITH SCATTERED
CONVECTION REFIRING OVER INLAND AREAS BY 14Z...AND THEN PERSISTING
THROUGH THE DAY. GIVEN THE UNCERTAIN TIMING OF EXACTLY WHEN
CONVECTION MAY IMPACT A TERMINAL...HAVE SIMPLY INCLUDED VCTS IN
THE TAF FOR EACH STATION BEGINNING AT 12-14Z AND LASTING THROUGH
AROUND 00Z. OUTSIDE OF THE CONVECTION...VFR CONDITIONS ARE
EXPECTED WITH A BROKEN DECK AT AROUND 5-8000 FEET AND ANOTHER
BROKEN TO OVERCAST DECK AT AROUND 15000 FEET. HEADING INTO
TOMORROW NIGHT...SOME DRIER AIR IS EXPECTED TO FEED INTO THE
REGION...ALLOWING FOR A DIMINISHING RAINFALL THREAT. THUS HAVE
REMOVED ANY VCSH OR VCTS WORDING. 32

&&

.PREV DISCUSSION... /ISSUED 341 PM CDT THU AUG 12 2010/

SHORT TERM...
DISORGANIZED REMNANTS OF TD 5 ARE CONTINUING TO IMPACT PORTIONS OF
SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI. RADAR/SATELLITE
LOOPS INDICATE THAT THE EARLIER LOW PRESSURE CIRCULATION IS
LARGELY UNAPPARENT...ALTHOUGH IT APPEARS THAT SOME SORT OF
WEAK CIRCULATION HAS REFORMED SLIGHTLY TO THE EAST DIRECTLY SOUTH
OF COASTAL MISSISSIPPI. CONVECTION IS LARGELY CONFINED TO WEST
SIDE OF THE LOW...WHICH IS KEEPING PORTIONS OF FAR SOUTHEAST
LOUISIANA...INCLUDING THE NEW ORLEANS METRO AREA...IN THE
IMMEDIATE HEAVY RAIN THREAT. ACROSS THE REMAINDER OF THE
AREA...CONVECTION HAS BEEN SLOW TO DEVELOP AROUND THE BATON ROUGE
AND MCCOMB AREAS...BUT SCATTERED DIURNAL CONVECTION IS BEGINNING
TO SHOW ITSELF IN THESE AREAS.

THE LOW ITSELF SHOULD BEGIN TO MOVE SLOWLY TO THE NORTHWEST
THROUGH THE NIGHT AND INTO FRIDAY...WITH PERIODS OF HEAVY RAIN
CONTINUING. GREATEST HEAVY RAIN IMPACT STILL LOOKS TO BE ACROSS
FAR SOUTHEAST LOUISIANA...PARISHES ALONG THE GULF COAST...AND
COASTAL MISSISSIPPI. HOWEVER...MORE ISOLATED BOUTS OF MODERATE TO
HEAVY RAIN COULD OCCUR ACROSS THE REMAINDER OF THE FORECAST AREA.
WILL LEAVE THE ORIENTATION AND DURATION OF THE FLASH FLOOD WATCH
AS IS FOR NOW...WITH ENOUGH UNCERTAINTY REMAINING AS TO HOW LONG
THE LOW WILL REMAIN IN THE AREA.
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1495. xcool
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1494. centex
Quoting hurricanejunky:


looking forward to hearing the analysis on this one...
Don't look forward to kids acting like better than NHC.
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Quoting Levi32:
GFS still starts trying to feedback TD 5 again before it's even back out over the water.

90 hours:



looking forward to hearing the analysis on this one...
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When I moved to SEFL from Finland in 2005, I didn't even know the difference between a tornado and a hurricane. My neighbors were blessing the April and May heavy rains saying that so much rain and cool temps mean there won't be many hurricanes that year. It was my first lesson in meteorology... lol
Then I found WU and the best info is here. But nobody can say for sure what a blob will do - except for the almost paranormal Katrina forecast by ST.

Here's a historical case from 2005:
The official forecasts from the National Hurricane Center predicted the cyclone Epsilon would weaken further in the highly sheared environment before becoming an extratropical system again.Unexpectedly, Epsilon strengthened again on December 2 and became a hurricane over cooler waters averaging 21–24 °C (70–75 °F) and continuing shear. The official forecasts continued to predict weakening and eventual dissipation but the storm defied them and remained at hurricane strength for several days. At one point on December 4 it was thought that Epsilon had briefly weakened into a tropical storm, but later re-analysis showed that it had remained a hurricane. Hurricane Epsilon then strengthened further to its peak intensity of 85 mph (135 km/h) just hours later
Hurricane Epsilon frustrated forecasters, and the lack of any weakening led NOAA hurricane forecaster Dr. Avila to say "There are no clear reasons...and I am not going to make one up...to explain the recent strengthening of Epsilon..."
The storm maintained its hurricane status for five days while most of the six-hourly forecasts during that period called for it to weaken below that intensity.

We can remain humble and share our thoughts and knowledge and get good info from the wise ones early enough to make our plans when the biggies start rolling in during the peak season.
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Just a thought. Could the ULL's be making up for heat redistribution? Do they tend to head poleward?
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1490. msphar
The wave at 35W is about 7.5 days away from 80W. So things could stay calm for a while. There are three waves working their way NW out of the East Caribbean.
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1489. JRRP
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1488. centex
Quoting alfabob:
I don't understand why anyone would question global climate change. Not to be a "doomcaster", as I consider real evidence key to any discussion; but our actions have in fact caused some deviation from the "norm". It is not possible to look into the past and make any real conclusions about the future, at least with current technology. What can be concluded is that the possibility for increased natural disaster damage is only going to rise in the future. So making decisions based on this assumption is key, because all factors currently point to it. Even more so with this seasons predictions and the current state of the Gulf.

As with predicting hurricane seasons, I don't understand how a prediction can already be under criticism. Those who are not professionals in the field need to understand that predictions are based upon defined principles. Regardless if something occurs or not, our current understanding of nature allows a prediction to be produced. If incorrect then another "prediction" is produced. Chances are, this is going to be an over average hurricane season. So go flip a coin 10 times, and if you get heads 8/10 times then it is just as likely that this season will be uneventful.
Many are stupid on this site but may know some about the tropics. Most don't understand the science behind GM and only react negatively. I would suggest asking all your questions directly to JM and not this blog. More than half of the stupid bloggers do not follow JM, go figure. Just shows how ignorant they are. They still think political issue which is a decades old dead argument.
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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.