African disturbance 92L chugs west; California fires generating significant pollution
A strong tropical wave (Invest 92L) is a few hundred miles off the coast of Africa, south of the Cape Verde Islands. This low has the potential to develop into a tropical depression later this week as it moves westwards at 15-20 mph. The low is under about 5-10 knots of wind shear, which is favorable for development. Sea Surface Temperatures are about 28°C, which is about 2-3°C above average for this date, and well above the 26°C threshold for tropical storm formation. There is not much African dust or dry air near the storm, but the low appears much as it did yesterday, with little heavy thunderstorm activity. The low has plenty of spin, as seen on this morning's QuikSCAT pass (Figure 1). One 35 mph (30 knot) wind vector was noted to the southwest of the storm's center in the QuikSCAT data, so 92L is kicking up some strong winds. There aren't really any negatives for development, except for climatology--there has never been a tropical depression that has formed east of 34° longitude in the first half of July (see the first image I posted in my July Atlantic hurricane outlook). NHC is giving a medium (20-50% chance) that 92L will develop into a tropical depression by Friday afternoon. All the models are developing this system into a tropical depression by Saturday. Wind shear is forecast by the SHIPS model to remain below 10 knots for the next four days, and the waters will stay warm (above 26°C) for the next 2-3 days of 92L's life. None of the computer models foresee that 92L will become a threat to land, and it currently appears that the storm will recurve in the middle of the Atlantic Ocean, east of Bermuda.
Figure 1. QuikSCAT image of 92L from 3:12am EDT Wed July 2, 2008. Image credit: Paul Chang, NOAA/NESDIS/ORA.
California fires cause significant air pollution
It was a destructive April, May, and June for fires in California, with 889,000 acres burned (71% of this acreage since June 20!) This is over five times the acreage burned during the same months in 2007. Satellite-detected fires from April through June this year totaled over 13,000, compared to only 1,200 during the same time period in 2007. These fires have caused many cities in the state to exceed the EPA's daily standard of 35 µg/m3 for particulate air pollution (Figure 2).
Figure 2. Location of all satellite-detected fires from last year (left panel) and this year (right panel) for the months of April through June, along with the number of days when surface particle pollution exceeded EPA's daily standard in several major cities in California. Image credit: Environmental Protection Agency (EPA), National Aeronautics and Space Administration (NASA).
Air quality is improving this week in California due to the onset of west-southwesterly winds aloft that have enhanced mixing and dispersion in the atmosphere. The moist flow of air off the ocean has brought fog and raised humidity levels, aiding firefighting efforts. However, with fire season's peak still months away, expect many more fires and significant pollution episodes later this summer.
Jeff Masters
Reader Comments
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1449. TampaSpin 7:59 PM AKDT on July 02, 2008
Again....surface.....lol
huh
We have a different surge problem. No continental shelf but a very low island ( Grand Cayman) that has an average height above sea level of something like 8 feet or so. The highest point is 60 feet above sea level.
Ivan carried a surge of about 13 feet coupled with wave action above that anywhere close to 30 feet in places. The ocean ran inland about 2 miles in most places.
With the island being only 8 miles across at the max quite a problem. In some places the island is only a mile or two across.
I see a ridge weakness in this generalized 700-850 mb steering flow. Probably more pronounced below 850mb
Guerra Family in their Own Words,Aug 29th 2005,St.Bernard. Se La.
93L is being sheared out but will probably fight back overnight.
92L is consolidationg a CDO. Probably making its run to TD status
Will be back tomorrow
1450. Levi32 12:00 AM EDT on July 03, 2008
1449. TampaSpin 7:59 PM AKDT on July 02, 2008
Again....surface.....lol
huh
Sorry lol......couple people have posted that map today.....I told them all the same thing. It looks that way at the surface but it's the upper-atmosphere that controls what goes on at the surface. The ULL in the central Atlantic is creating a weakness in the high that will beckon 92L to come north. The strength of 92L will determine how much it's affected by it.
Just like I have repetitively mentioned, shear is decreasing rapidly for Invest 93L and will become marginally favorable by tomorrow. The TUTT has been rising at such a fast clip from the Eastern Caribbean. Just watch Invest 93L. I feel we're in for a surprise.
Levi i think you are correct if the storm would deepen into at least a storm...that has not happened so, do you think it will still go north as a weak system ......i don't see that in my opinion. As long as it is a weak system it should go W it think....i don't work at NHC tho....lol
If 92L stays at minimal TS status over the next several days I just don't see it recurving that early. A stronger system...say 65mph....will get pulled more but I'm still not quite buying into the models at this point. It's still a waiting watching and seeing game.
Just like I have repetitively mentioned, shear is decreasing rapidly for Invest 93L
CCHS i'm not sure what you have looked at all day....but i do not think shear is decreasing rapidly....can you show me this.....i looked at shear this morning and it appears to me not much has changed but just a very small amount...
Yep that is exactly what i too have been stating......my exact thoughts.
Have a good sleep, friend.
Gulf of Mexico 4 FT Wave Probability Link
93L has less convection
Navy Meteorological and Oceanography Command Link
More Links from FNMOC Link
Anytime, with any storm, where there is dry air and SAL, conditions are not exactly prime for development. In 92L's case, conditions are quite favorable, but somewhat less than prime given noteable, evidenced dry air and almost tangent SAL in close proximity to the system.
Alright alright lol. How about "hindering" factor then? =)
I thank that confusion is interesting....I'll bet it will start tracking further West in the next runs.
It's an interesting process. I like to learn all I can about them.
Hey, and I just want you to know, too, that I appreciate your thoughts on the tropics. I think you've got a good handle/eye on the processes. Good work.
As do you MLC :)
I love the learning experience. I especially like Cape Verde storms as they are always a special challenge. I hope we get better with them each time.
I'm sorry I honestly didn't see your question. Even if you're leaving I'm going to answer it anyway.
CONUS landfall is way too far out to guess on, and if this was the middle of the day I'd get thrown out for westcasting for what I'm about to say. There is a chance that 92L will follow in the previous Bertha's footsteps, and slip under the high, thereby threatening the eastern seaboard. At this point everything is speculation and we have to watch, wait, and see what happens.
do you guys think there is any chance of a conus land fall on 92?
93L has probably higher threat than 92L
do you guys think there is any chance of a conus land fall on 92?
A chance? Yes
A good chance? Nope
I think it will go on a W or WNW track until it nears the northern islands, and there it will slowly go out to sea. Also, it could possibly become a hurricane but not until I know for sure the shear will relax in its future path.
As far as 92L goes, imo, (and I like to say this if anyone hasn't noticed) there's lots of "liquid real estate" in front of this system. And, it's probably between 3 and 4 thousand miles from effecting any land (guessing). That's several days away even if it were a possibility.
The models seem to indicate curvature at some point back out into the nATL. But, some are keeping the system weaker and moving a bit further west. With that much time and that much distance, conditions can change and intensity and track may also change. So, that's why we diligently watch, wait and then we see.
Rest assured, some of these very knowledgeable folks like Levi and a host of others, will gladly answer your questions and also let folks know what they think it's doing and where it might go!
Patience is virtue! Great question though! And, questions are always good! Never bad questions, just bad answers! I've asked and do still ask plenty and I appreciate all the helpful folks who answer them! :)
Thanks for answering my question. I appreciate it !
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