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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AN AREA OF LOW PRESSURE...ASSOCIATED WITH A STRONG TROPICAL
WAVE...IS CENTERED A COUPLE HUNDRED NM SOUTH OF THE CAPE VERDE
ISLANDS NEAR 12N22W...ANALYZED 1009 MB. THIS LOW HAS BEEN
TRACKING W ABOUT 10 KT OVER THE PAST COUPLE OF DAYS. THE
CIRCULATION IS WELL DEFINED AND CONVECTION (SCATTERED TO
NUMEROUS MODERATE IN NATURE) HAS INCREASED SLIGHTLY WITHIN
90-120 NM OF THE CENTER. ENVIRONMENTAL CONDITIONS APPEAR
CONDUCIVE FOR SOME ADDITIONAL DEVELOPMENT AND THERE IS THE
POTENTIAL FOR IT TO BECOME A TROPICAL DEPRESSION AT ANY TIME
TODAY.
Still west.....and slower.....both helpful to get this thing under the high. I'm very surprised they didn't just go ahead and upgrade.....must be waiting for the stupid visible imagery....lol
That's it SJ! The NHC is holding a grudge....there's something new....lol
It was pretty funny Levi!
No harm meant to the folks at the NHC. Big fan as a matter of fact, but this time they are hedging their bets, and being how far away it is I don't really have a problem with that. Not very scientific though...
Have a good sleep, Levi and WB.
GFDL and HWRF 0z runs are out.....still going with the flow.....all because they have GFS data put into them....
I was saying goodnight to WB...I ain't leaving..it's only 10 here in Alaska lol.
Hmmmm looks like we got something huh?
Swim little fishy, Swim!!!
gnight all
Exepct a TD at 5AM
Lol....goodnight.....yup TD at 5am for sure
A VERY HAPPY 4TH OF JULY BACK AT YA!!!!
Nah, them a bunch of losers to think that lol.
I am getting myself to bed real soon. May catch one or two more images from the Eumetsat.
Link
SJ that mic looks like 93L is looking better also.
It looks like the precip. going north is probably where its gonna follow??
Yea for sure!!!!! & correct me if I am wrong.
It looks like the precip. going north is probably where its gonna follow??
The moisture is getting pulled by the ULL in the central Atlantic, and notice how the ULL is moving west faster than 92L. However that is evidence of the weakness the models are talking about.
Within the hour.
1584. KrazyKaneLove 10:35 PM AKDT on July 02, 2008
93L is running into southerly shear and is slightly more disorganized tonight. The TUTT is in the process of lifting out of the Caribbean and if 93L survives for the next 48 hours I think it will be something to watch very closely as the models have it moving in the general direction of the GOM and as the MJO pulse comes across anything will have to be watched, even if it's a remnant low.
I don't like answering questions directed at other people but I think 456 just pops in really late and then leaves right away for bed.....so just in case....
Time of season is mainly for development. As Dr. Masters said no TD has ever developed east of 34w in the first half of July, and Cape Verde systems are rare until August. The westerlies are usually far enough north by now to allow some systems to make it across, although they will continue to retreat throughout the summer. With the high setup this year I think we are going to see an active Cape Verde season with several systems coming across to threaten the US east coast. Right now the situation is quite unique with an ULL in the central Atlantic, and this has never happened before in recorded history. I do think it is indicative of the active Cape Verde season we have been saying will happen this year, and the high will continue to be in a position to steer long-track storms westward throughout the season I believe.
Dvorak classification up to 1.5
03/0545 UTC 12.6N 22.8W T1.5/1.5 92L
Dvorak classification up to 1.5
Action: | Ignore User
I was thinking more like a 2.5 this thing really looks good it almost looks like(I know I am wrong) but a wrap around eye is forming
Lol....well I don't care what anyone says, it's a TS. Should be upgraded to at least TD #2 at 5am.
I'm gonna head out for the night. See you guys tomorrow.
Blog is actin weird. It will probably crash tomm. when the word gets out about it gaining TD status.......
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