Little change to 90L; new African tropical wave is worth watching
Invest 90L is a tropical wave in the eastern Atlantic near 10N 33W with a very limited amount of heavy thunderstorm activity but a decent amount of spin. It does not have a well-defined surface circulation, and has shown little change in organization today. CIMMS wind-shear analyses show a low amount of wind shear (5 - 10 knots) over 90L, and sea surface temperatures are a record warm 29°C. The wave currently is in a moist environment and is not being affected by the dry Saharan Air Layer (SAL) to its northwest. The disturbance has moved far enough away from the Equator to leverage the Earth's spin to help it develop. The Saharan Air Layer with its dust and dry air lurks just to the north of 90L, but the SHIPS model predicts 90L will remain far enough from the dry air over the next five days so that it will not interfere with development.
Figure 1. Afternoon visible satellite image from 2pm EDT 7/30/10 of the relatively tiny 90L, and the large new tropical wave that moved off the coast of Africa yesterday.
Forecast for 90L
One factor inhibiting development of 90L this week will be the Madden-Julian Oscillation (MJO.) The MJO currently favors downward motion over the tropical Atlantic, which will act to decrease the chances of tropical storm formation. The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased.
Perhaps the main factor interfering with 90L's development will be the presence of the large tropical wave to the east of 90L that moved off the coast of Africa yesterday. This new wave is large enough and close enough to 90L that it will probably begin to dominate regional weather patterns this weekend, stealing away 90L's inflow of low-level moist air. The new wave may also act to bring sinking air over 90L that will tend to suppress 90L's thunderstorm activity. It may turn out that the new wave will also steal some of 90L's spin, and end up being a threat to develop itself later on this weekend.
The latest 8am EDT (12Z) model runs for 90L show very little in the way of development of the storm. The predominant track forecast takes 90L into or just north of the northern Lesser Antilles Islands about 6 - 8 days from now. Looking at climatology based on research done by Dr. Bob Hart at Florida State University,, 90L has a 19% chance of developing into a tropical cyclone by 2pm Sunday. NHC is putting these odds at 20%. Dr. Hart also has an experimental product showing that historically, about 30% of all tropical cyclones that develop at 90L's current position eventually hit land as a hurricane. Of course, 90L is not yet a tropical cyclone, and I think that the large tropical wave off the coast of Africa will kill 90L this weekend.
Tropical wave in the eastern Caribbean
A tropical wave in the eastern Caribbean, south of the Dominican Republic, is moving west at 15 - 20 mph with no signs of development. The wave is under a high 20 knots of wind shear, due to strong upper-level westerly winds from an upper level low centered north of Puerto Rico. This shear is expected to remain remain high through Saturday. By Sunday, when the wave will be approaching Nicaragua, the wave will be far enough away from the upper level low that shear should fall to the moderate range, 10 - 20 knots. Some development is possible on Sunday, but the wave will have only about a 1-day window to develop before its westerly motion brings it inland over Nicaragua on Monday. NHC is giving this wave a 10% chance of developing into a tropical depression by 2pm Sunday.
Extreme cold records for 2010
In my post yesterday, I reported that fourteen countries had set their all-time hottest temperature record this year. I neglected to mention that one country has also set its coldest temperature in recorded history mark in 2010. Guinea had its coldest temperature in its history on January 9, 2010, when the mercury hit 1.4°C (34.5°F) at Mali-ville in the Labe region. Of the 229 countries with extreme coldest temperature records, 14 of these records have occurred in the past ten years (6% of all countries). There have been five times as many (74) extreme hottest temperature records in the past ten years (33% of all countries.) My source for extreme weather records is Chris Burt, author of Extreme Weather.
New study finds huge drop in the plants that form the base of the oceanic food chain
A study published this week in the journal Nature documents that microscopic marine phytoplankton, which form the basis of the marine food chain, have declined by 40% globally since 1950. Joe Romm at climateprogress.org discusses the implications, using this headline:
Scientists may have found the most devastating impact yet of human-caused global warming — a 40% decline in phytoplankton since 1950 linked to the rise in ocean sea surface temperatures. If confirmed, it may represent the single most important finding of the year in climate science.
I plan to discuss this paper next week.
Next update
I'll have an update this weekend, probably by 8pm EDT Saturday.
Jeff Masters
Reader Comments
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2010 Northern Hemisphere Tropical Cyclones
Maximum Wind Speed & ACE per storm (ATCF operational intensity estimates)
North Atlantic
Alex (85 ACE = 7.3725)
TD02 (30 ACE = 0.0)
Bonnie (whirl) (35 ACE = 0.49)
Western North Pacific
01W (30 ACE = 0.0)
Omais (50 ACE = 2.0075)
Conson (75 ACE = 8.3225)
Chanthu (75 ACE = 3.5775)
Northern Indian Ocean & Arabian Sea
Laila (65 ACE = 4.46)
Bandu (55 ACE = 2.39)
Phet (125 ACE = 14.16)
Eastern Pacific
Agatha (40 ACE = 0.2825)
Blas (55 ACE = 2.715)
Celia (140 ACE = 25.4875 )
Darby (105 ACE = 10.3925)
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As much as I agree, there are hidden aspects to fish storms.
1. They do cause swells that are felt on beaches thousands of miles away. I've heard of plenty of times where fish storms have taken lives due to rip currents and swells. However, if people don't abide by the warnings, it's their fault.
2. There are ships, mainly cargo, etc. that are out on the water where these storms are running by and easily enough a ship can capsize and take life.
I'm not downcasting, but fish storms, as well as the storms that impact land can both be dangerous in their own ways.
LOL I knew you were over there somewhere good morning !!!
Because a COC from which they initialize models dissipates does not mean they're "wrong."
At the earliest stages it is always speculation, a "What If" scenario.
It's the nature of the game.
Updated Jul 27 , 2010
BASIN CURRENT YEAR TO DATE
Northern Hemisphere 82
Western Pacific 14
Southern Hemisphere 196 [2009-2010]
BASIN NORMAL YEARLY ACE** NORMAL YEAR TO DATE
Northern Hemisphere 569 122
Western North Pacific 310 70
Southern Hemisphere 204 --
Agreed. However, many people put trust into these models way too early. Invests are areas that could develop. Everyone thinks that it will develop when models are in consensus, which is totally reasonable. However, it's just an area of interest.
Mostly do the very inactive WPAC typhoon season. Atlantic is about average where we are suppose to be coming into August with 2 named storms.
They say this about the eastern Atlantic in the 8 a.m. Discussion:
...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 16N19W 11N21W 6N22W MOVING WESTWARD 10 TO 15 KT. SCATTERED STRONG SHOWERS AND THUNDERSTORMS ARE FROM 5N TO 7N BETWEEN 22W AND 24W...AND FROM 9N TO 12N BETWEEN 22W AND 30W.
THE 1010 MB LOW PRESSURE CENTER THAT WAS NEAR 10N34W SIX HOURS AGO HAS DISSIPATED. A SURFACE TROUGH REMAINS ALONG 34W/35W FROM 7N TO 13N. ANY OF THE PRECIPITATION THAT JUST IS RELATED TO THIS TROPICAL WAVE UNDOUBTEDLY IS MIXED WITH THE ITCZ SCATTERED STRONG SHOWERS AND THUNDERSTORMS THAT ARE FROM 2N TO 10N BETWEEN
32W AND 43W.
Morning Chief, looking forward to your input.
Well then if August doesn't see a system, this season will probably be 7-8 storms. It would be only the 2nd season that I know of that the WPAC, Atlantic, and EPAC where all inactive.
Keeper, gambler, ike, Seenya-Cheef and everyone.
SaintHurrifan now that was funny. That was a good laugh. I needed that cause otherwise things was lookin' mighty scary!
Well if your telling me this yr. will have less storms than last yr. I think you and all the other forecasting agency are out of their mind and flawed because how can you go with a hyperactive season to a below normal one, it just doesn't make sense in this day in age?
3hrs ago
Wind Direction (WDIR): ENE ( 70 deg true )
Wind Speed (WSPD): 13.6 kts
Wind Gust (GST): 17.5 kts
Wave Height (WVHT): 5.2 ft
Dominant Wave Period (DPD): 7 sec
Average Period (APD): 4.7 sec
Atmospheric Pressure (PRES): 29.81 in
Pressure Tendency (PTDY): -0.02 in ( Falling )
Now
Wind Direction (WDIR): ESE ( 110 deg true )
Wind Speed (WSPD): 15.5 kts
Wind Gust (GST): 19.4 kts
Wave Height (WVHT): 5.6 ft
Dominant Wave Period (DPD): 7 sec
Average Period (APD): 5.1 sec
Atmospheric Pressure (PRES): 29.85 in
Pressure Tendency (PTDY): 0.03 in ( Rising )
Bouy
Winds were up to 25kts at a point when closer to the wave. Winds have shifted from ene to ese as the wave passed below.
Hi Storm Petrol, are you over your drought in the Caymans?
I didn't say that. I said if August (which is unlikely to say the least) has no storms that this season will be 7-8 named. I highly doubt that will happen, as 2009 with high shear, lower SSTs, lower TCHP pulled out 4. We should be able to pull out 4, we'd be a 6 going into September
It's gonna surprise a lot of us the heat is enormous I mean 100 degrees + in Florida I believe we may be tracking storms into Nov. and even a straggler or two in Dec.
This season has proven once they get going..
They get going.
Oh okay i was wondering if that was what u meant. I think SAL is giving us some problems what do you think?
If we knew all of the parameters, and how they interact with each other we would have seasonal forecasts that would demonstrate skill. We don't.
Morning
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