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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Says the Navy, again. This time Its not a joke or an Error.
000
WTNT32 KNHC 030858
TCPAT2
BULLETIN
TROPICAL DEPRESSION TWO ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008
500 AM EDT THU JUL 03 2008
...TROPICAL DEPRESSION FORMS OVER THE FAR EASTERN ATLANTIC OCEAN...
AT 500 AM EDT...0900Z...THE CENTER OF TROPICAL DEPRESSION TWO WAS
LOCATED NEAR LATITUDE 12.6 NORTH...LONGITUDE 22.7 WEST OR ABOUT 250
MILES...405 KM...SOUTH-SOUTHEAST OF THE CAPE VERDE ISLANDS.
THE DEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH AND
THIS GENERAL MOTION WITH SOME INCREASE IN FORWARD SPEED IS EXPECTED
FOR THE NEXT COUPLE OF DAYS.
MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH...55 KM/HR...WITH HIGHER
GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS AND
THE DEPRESSION COULD BECOME A TROPICAL STORM LATER TODAY.
THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB...29.77 INCHES.
REPEATING THE 500 AM EDT POSITION...12.6 N...22.7 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 9 MPH. MAXIMUM SUSTAINED WINDS...35
MPH. MINIMUM CENTRAL PRESSURE...1008 MB.
THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 AM EDT.
Wow, 92L finally made it to TD status. I missed the 5 AM advisory while reading the 800+ comments which has been added to the blog since yesterday around 22 GMT when I went to bed. I'm somewhere stuck in the 1300s *lol* and then I just thought I ought to check again the NHC because it looked more and more like a TD and there it was... cool.
I'm going back to read the rest of the night's. Damn the time difference... 6 hours ahead of EDT.
Greetings currently from Germany
Now I'm trying to remember who it was who said we'd have a named storm by 5th July . . .
Geez! and the blog has taken off . . . over 1600 posts since 9:30 a. m. yesterday . . .
1615. taistelutipu 5:29 AM EDT on July 03, 2008
Good to see u! I usually open two windows to refresh separately; one is the current page, so I can keep an ey on the current blog activity, while the other is the older page I'm reading to catch up . . .
And there are more than 300 comments here since I went to bed around 0400 UTC . . .
"It should be noted that most global models...especially the
GFS...suggested the possibility of genesis in this area over a week
ago...a remarkable achievement."
Crow gets thrown outside for the cats.
500 AM EDT THU JUL 03 2008
THE STRONG TROPICAL WAVE AND SURFACE LOW OVER THE EASTERN ATLANTIC
OCEAN HAS ACQUIRED ENOUGH ORGANIZED CONVECTION TO NOW BE CONSIDERED
A TROPICAL DEPRESSION. SATELLITE IMAGES INDICATE THAT A STRONG
BURST OF CONVECTION HAS PERSISTED FOR OVER 12 HOURS NEAR OR JUST
WEST OF THE APPARENT CENTER OF THE SYSTEM. BANDING FEATURES ARE
ALSO BECOMING MORE PRONOUNCED IN THE NORTHWESTERN PART OF THE
CIRCULATION. THE INITIAL INTENSITY OF 30 KT IS BASED ON A QUIKSCAT
PASS FROM LATE YESTERDAY THAT SHOWED SOME RELIABLE 25-30 KT WINDS.
IT SHOULD BE NOTED THAT MOST GLOBAL MODELS...ESPECIALLY THE
GFS...SUGGESTED THE POSSIBILITY OF GENESIS IN THIS AREA OVER A WEEK
AGO...A REMARKABLE ACHIEVEMENT.
This is proof of two things - first, that NHC is in fact watching and eager to see stuff develop, just like we are. They did notice the models, same as we did. Second, it's obvious that at least ONE somebody at NHC is reading this blog . . .LOL
Morning Ike. That jumped out at me too when I read it. It IS unusual
Good morning......
VERTICAL WIND SHEAR IS FORECAST TO REMAIN LIGHT FOR THE NEXT FEW
DAYS NEAR THIS SYSTEM...SO THE BIGGEST LIMITING FACTOR ON THE
FUTURE STRENGTH OF THE DEPRESSION IS THE COOLER WATERS AND MORE
STABLE AIR IN ITS PATH. AFTER ABOUT 24 HR ON THE NHC TRACK...SSTS
DROP BELOW 26C AND STAY BELOW THAT THRESHOLD FOR A COUPLE DAYS.
THEREAFTER SSTS WARM SLIGHTLY AND MOST GLOBAL MODELS FORECAST AN
ENVIRONMENT THAT WOULD FAVOR SOME INTENSIFICATION. THE OFFICIAL
INTENSITY FORECAST REFLECTS THIS SCENARIO...SHOWING STRENGTHENING
AT THE START AND END OF THE FORECAST PERIOD AND NO SIGNIFICANT
CHANGE IN BETWEEN WHILE THE SYSTEM IS OVER THE COOLEST SSTS. THE
SHIPS/GFDL MODELS ARE A LITTLE MORE BULLISH WITH THIS
SYSTEM...MAKING IT A HURRICANE WITHIN 5 DAYS.
I'm knocking on wood. Now that they mentioned how well the models did, they won't be worth the crap for the rest of the season...lol.
GFS does a good job...not always right...but, it does good.
'Cept when it 'hiccups' and splats precip all over the place. LOL
Yup...it does do that.
Hmmm. . . I miss the old EUMETSAT sector viewers, which showed the MDR in almost its entirety and allowed excellent CV storm watching . . . however, here's the latest:
CIMSS Shear Map
Later!
Viewing: 1601 - 1651
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