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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Now to convince SWMBO it is both of yours fault......
What do you mean? Literature that shows we are headed towards a cold PDO or something else?
I can not seem to get the Austin powers theme song out of my head... oh behave....
Net change is zero no matter how extreme the extremes are, according to the equal and opposite reaction thing you said. -1 and 1 average zero.....-1000000 and 1000000 average zero.
Yeah you said it all, I like to come in here and maybe learn a thing or to but as you said its nothing to get all worked up over. Take care and try to stay (kool)
GOES-E Satellite loop
Invest 90L floater shows convection slowly increasing again in the overall area.
Yes, seems to be hot everywhere. Glad to see ya on here.
Ninety-nine degrees in Dallas-Ft Worth, TX is actually "pleasant", as dew points drop from 72F in the AM to 60-62F by 5PM, usually with a hot, dry SW breeze at 10MPH. Tolerable..
Ninety-nine in FL is "torture", with heat indices making a run on 115-120F!!
RAINFALL.
XCOOL
I don't believe it's popular with Palin, either.
Nor was it popular with Bush, from another oily state, Texas.
It seems that "American Scientist" is the only publication still in existence that has not been politically co-opted.
Very sad.
On 90L, it appears certain that it will be driven from existence by its follower wave - which bears watching.
ISLANDS ALONG 21W S OF 18N MOVING W NEAR 10-15 KT. THIS WAVE IS
EMBEDDED WITHIN AN AREA OF A HIGH AMPLITUDE MOISTURE MAXIMUM. A
WELL DEFINED LOW TO MID LEVEL CYCLONIC FLOW SURROUNDS THE WAVE
AXIS EVIDENT ON INFRA RED SATELLITE DATA. SCATTERED MODERATE
CONVECTION IS WITHIN 35 NM ON EITHER SIDE OF THE WAVE AXIS NORTH
OF 12N. THE REST OF THE CONVECTION SOUTH OF 12N IS ASSOCIATED
WITH THE ITCZ.
THE ITCZ AXIS IS ANALYZED FROM THE WESTERN AFRICAN COAST OF
SENEGAL NEAR 14N17W...WESTWARD ALONG 10N25W 8N30W 9N40W 8N50W
12N60W...CONTINUING ACROSS NORTHERN SOUTH AMERICA. A 1010 MB
SURFACE LOW IS EMBEDDED IN THE ITCZ NEAR 9N33W. CLUSTERS OF
SCATTERED MODERATE TO STRONG CONVECTION ARE FROM 7N TO 13N
BETWEEN 20W AND 31W AND FROM 10N TO 16N BETWEEN 57 AND 61W
INCLUDING THE LESSER ANTILLES SOUTH OF 15N. SMALL CLUSTERS OF
SCATTERED MODERATE CONVECTION DOT THE AREA FROM 2N TO 10N
BETWEEN 35W AND 48W.
looks like it is still attached to that trof
Was unlike anything I've ever seen. Would love to experience it again. However I would not want to see all of those crops destroyed again.
Tropical Weather Analysis - July 30 2010 - Invest 90L and several other areas
That area NW of the Bahama's keeps flaring up.
No, dead sea plankton due to heat and dead trees and plants due to frost mean net minus zero.
This year and next year will be La Nina years, so yeah, thats pretty much not happening, although there is always a possibility..
Some 850 mb vorticity on disturbance of East Coast
Good Divergence
Not much convergence
Shear's 10 knots.
We've had more record low temperatures in Florida here this year than I can ever remember.
It's almost a daily thing now.
Then don't apply the laws of equal and opposite reaction to it. It was a flawed statement.
HMMMMMM or with Clinton... this information was available to him as well... You neglected to mention him... HMMMmm.. Wake up folks.. it is ALL OF THEM! Like it or not!! They are all on the take in DC period.. They love to divide and conquer.... So many brainy people in here but still think it is one party against another... So silly....
It is us against them period. United we stand!
Your right too, and surface pressures are high there too. Its a interesting feature none of the less.
p;z stop flooding up the blog with that thank you
Yes unlikely lol. We just went through one of the most historic winters we will all ever see for the eastern and southern United States.
I figured your were all frying on FL, after the brutal winter you've had!
She means record high lows lol.
Funny, I'm not taking your word for it.
Yeah... I hope next year goes Nino sometime before winter arrives though. Call me a snow-caster! And 2008 was a La Nina year, and we had snow the 2008-2009 summer as well. Although it was on March 1st 09 and La Nina was likely well over by then lol.
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