African disturbance 92L chugs west; California fires generating significant pollution

By: Dr. Jeff Masters , 1:40 PM GMT on July 02, 2008

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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

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557. moonlightcowboy
1:58 PM CDT on July 02, 2008
534. Nice updates, Pearland.

543. K'man, whew, you are sooooo right about that TUTT there. That lil beast is still fighting though!
Member Since: July 9, 2006 Posts: 184 Comments: 29594
556. reedzone
7:00 PM GMT on July 02, 2008
549.
Yes it does!
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555. Drakoen
7:00 PM GMT on July 02, 2008
Some spiral banding starting to occur:
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554. melwerle
6:57 PM GMT on July 02, 2008
I lived out in San Diego for 20 years - moved east after the huge San Diego fire about 4 years ago...the fire dept does do controlled burns in a lot of areas, folks try to keep up with their yards and canyons however, the lack of rain as well as the fact that there are a zillion eucalyptis trees...the fires just take off especially during Santa Ana winds...and the trees just explode. It was very frightening - we were asked to evacuate, didn't lose our home but lots of folks that we knew did. Terrible situation. I like the goat idea myself...I think I'll send my sister a goat as a birthday present... :)
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553. IKE
1:56 PM CDT on July 02, 2008
543. kmanislander 1:54 PM CDT on July 02, 2008
Boy are we lucky there is a TUTT in the Central Caribbean !


I've been keeping an eye or 2 on that.
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552. marlinsfan1
2:58 PM EDT on July 02, 2008
Yea adrian, in that radar image you put up, I live in Pinecrest. We got hammered, but just started slowing down
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551. pearlandaggie
6:56 PM GMT on July 02, 2008
543. that exposed circulation almost looks like the remnants of Chris a couple years ago when it got whacked by wind shear overnight! very cool image :)
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550. Drakoen
6:55 PM GMT on July 02, 2008
Earlier microwave image pretty decent:
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549. HurakanPR
2:48 PM AST on July 02, 2008
reedzone??? Diurnal max increases convection, right?
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547. pearlandaggie
6:55 PM GMT on July 02, 2008
latest solar magnetogram....barely a crackle! not good......
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546. HadesGodWyvern (Mod)
6:48 PM GMT on July 02, 2008


Typhoon watch for the South China Sea
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545. 69Viking
1:40 PM CDT on July 02, 2008
521. smmcdavid

Very good point! Here in the Florida Panhandle we have a large nature preserve that is part of the Eglin AFB. They do controlled burns on a regular basis and we've never had major fires like in CA. Now keep in mind this is a much smaller area than the wilderness area of CA.
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544. pearlandaggie
6:52 PM GMT on July 02, 2008
there are some low shear areas directly west of 92L...
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543. kmanislander
6:52 PM GMT on July 02, 2008
Boy are we lucky there is a TUTT in the Central Caribbean !

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542. Levi32
10:52 AM AKDT on July 02, 2008
SSD has 92L with 1.0 Dvorak classification but they labeled it was 02L this time.....not sure why.
Member Since: November 24, 2005 Posts: 635 Comments: 26556
541. pearlandaggie
6:51 PM GMT on July 02, 2008
so are we still saying that the CAtl breakdown in the SAL is not a sign of a weakening ridge?
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540. Drakoen
6:51 PM GMT on July 02, 2008
02/1745 UTC 12.1N 20.7W T1.0/1.0 02L -- Atlantic Ocean
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539. CajunSubbie
6:52 PM GMT on July 02, 2008
Global Warming as Mass Neurosis
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538. smmcdavid
1:49 PM CDT on July 02, 2008
534... love the wildfire article. I feel so smart! LOL
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537. CybrTeddy
6:50 PM GMT on July 02, 2008
WeatherFreak, he ment it in that it will Explode Tonight.
Member Since: July 8, 2005 Posts: 259 Comments: 23606
536. reedzone
6:49 PM GMT on July 02, 2008
533.
That's what I meant ;)
Likes to blow up convection after a messing disorganized convection. It's what I've seen in lots of storms. Sorry if I worded it wrong.
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535. HurakanPR
2:43 PM AST on July 02, 2008
mmmm the UKMET brings this system pretty close to the northern leewards and Puerto Rico (55w 19 n), need to keep and I on.
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533. FLWeatherFreak91
2:46 PM EDT on July 02, 2008
Usually when this happens, Durinal Max takes a huge toll on it overnight so lets see what

Takes a huge toll? I thought it increased convection
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532. smmcdavid
1:43 PM CDT on July 02, 2008
Hmm, goats... that could work!

And yes, the drought is definitely a factor.
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531. Skyepony (Mod)
6:42 PM GMT on July 02, 2008
Oh good, they finally made the angry blob in the EPAC an invest..97E.
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530. hurricane23
2:45 PM EDT on July 02, 2008
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529. reedzone
6:45 PM GMT on July 02, 2008
Stay safe Adrian, we had 77 mph gusts with the storms here in Flagler County 2 days ago!

Here's the latest image of 92L and you noticed convection is there but not strong. Usually when this happens, Durinal Max takes a huge toll on it overnight so lets see what happens.
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528. MonkeeInDaTrunk
11:40 AM PDT on July 02, 2008
521. smmcdavid 11:31 AM PDT on July 02, 2008
Here is my two cents about the California wild fires:

Wild fires occur naturally, however, we have been putting them out instead of letting them burn (for obvious reasons). But, this keeps more underbrush/plants/trees alive and more growing every year. Then when another fire happens, it's worse because there is more "stuff" to burn.

What's the solution? Maybe some controlled clearing of underbrush? I think a lot of people might be against that


the solution? goats...and lots of them..

and, the fires are worse due to the drought...no rain...no rain...no rain....
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527. hurricane23
2:27 PM EDT on July 02, 2008
42mph wind gust here at the house...Getting nailed.
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526. CajunSubbie
6:33 PM GMT on July 02, 2008
smmc

haha you hit it on the nail! congrats you are more intelligent than a liberal!

moonlight,

yeah its actually a scary site, honestly i'd rather global warming than global cooling.
if we don't see sc24 ramp up by december, it could get ugly.
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525. blueranch1
6:37 PM GMT on July 02, 2008
Nice stormW.
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523. nrtiwlnvragn
2:37 PM EDT on July 02, 2008
The state is giving Florida International University $10 million -- and the school plans to throw the money into the wind.


The university's International Hurricane Research Center will use the grant to develop its Wall of Wind, a massive wind tunnel that can simulate Category 4 hurricanes.
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522. hurricane23
2:31 PM EDT on July 02, 2008
JP heres the loop for the 12z UKMET which takes a weaker storm to the west/wnw.

Comes to about 52-55west but very weak possibly due to the TUTT in the vicinity createing hostile conditions.
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521. smmcdavid
1:28 PM CDT on July 02, 2008
Here is my two cents about the California wild fires:

Wild fires occur naturally, however, we have been putting them out instead of letting them burn (for obvious reasons). But, this keeps more underbrush/plants/trees alive and more growing every year. Then when another fire happens, it's worse because there is more "stuff" to burn.

What's the solution? Maybe some controlled clearing of underbrush? I think a lot of people might be against that.
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520. NEwxguy
6:29 PM GMT on July 02, 2008
now that pic should stretch a few displays
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519. moonlightcowboy
1:24 PM CDT on July 02, 2008



...SSC24, still cool and smooth as a baby's butt.
Member Since: July 9, 2006 Posts: 184 Comments: 29594
518. presslord
2:27 PM EDT on July 02, 2008
you're on the list ...
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516. smmcdavid
1:23 PM CDT on July 02, 2008
press... I better be invited this year, especially if there is plenty of alcohol floating around!
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515. Levi32
10:11 AM AKDT on July 02, 2008
Good morning all.

92L hasn't made any progress in organizing overnight, which in essence is a bad thing, as the slower this thing develops, the further west it will get, as shown by the UKMET 12z run. Really this is all it's going to come down to is the strength of the system as it moves west, and how fast the Bermuda High builds back in after the ULL finally gets picked up. Even the models recurving the system (GFS, ECMWF) still build the ridge back fast enough after the ULL leaves to trap 92L under the ridge for a while until the next trough comes along. This shows how a weaker system could easily keep a westward track for a longer period of time. Right now it's just wait, watch, and see. Gradual development should be expected with 92L, and again the strength of the system over the next week will be critical. In 1996 Hurricane Bertha slipped under the high, and 92L can do the same if it remains weak enough, but we'll see how it all goes.
Member Since: November 24, 2005 Posts: 635 Comments: 26556
514. presslord
2:18 PM EDT on July 02, 2008
actually...stormjunkie and I discussed GW at my Christmas party...but he was pretty drunk...so maybe he doesn't remember....
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513. reedzone
6:16 PM GMT on July 02, 2008
509.

Notice it doesn't considerably strengthen or weaken the storm. This model is showing what I believe is going to pan out.. A strong B/A High! small weakness that might move it north but not recurve it BUT anything is possible and we have a few days to track it. Honestly, I see too much troughiness on the east coast for anything to get there. Bermuda might just be the only target.
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512. mrpuertorico
6:18 PM GMT on July 02, 2008
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1200 PM AST WED JUL 2 2008

.UPDATE...PARTLY CLOUDY SKIES PREVAILED THIS MORNING ACROSS PUERTO
RICO...THE U.S. VIRGIN ISLANDS AND THE SURROUNDING COASTAL WATERS.
THE DOPPLER WEATHER RADAR INDICATED ISOLATED TO SCATTERED SHOWERS
ACROSS THE COASTAL WATERS AND ACROSS THE NORTHERN COASTAL
MUNICIPALITIES OF PUERTO RICO. A 1030 MB SURFACE HIGH PRESSURE
ACROSS THE CENTRAL ATLANTIC THIS MORNING WITH A RIDGE EXTENDING
SOUTHWESTWARD ACROSS THE NORTHERN BAHAMAS AND FLORIDA. THIS SYSTEM
WILL SHIFT SLOWLY NORTH NORTHEAST MAINTAINING AN EAST SOUTHEAST
TRADE WIND FLOW ACROSS THE REGION UNTIL AT LEAST TOMORROW. A
TROPICAL WAVE ALONG 58 WEST LATE THIS MORNING WILL CONTINUE TO MOVE
TO THE WEST NORTHWEST APPROACHING TO THE LOCAL ISLANDS LATE THIS
EVENING AND TOMORROW WITH AN INCREASE IN SHOWERS AND THUNDERSTORMS
ACROSS THE FA. AN UPPER LOW (TUTT) NORTHEAST OF THE LOCAL ISLANDS
LATE THIS MORNING WILL CONTINUE TO PROMOTE A SOUTHWESTERLY WIND FLOW
ALOFT AND WILL ALLOW TO ENHANCE THE SHOWER ACTIVITY THIS AFTERNOON
AND TOMORROW AFTERNOON. LOOKING WELL AHEAD...A STRONG TROPICAL WAVE
NEAR THE CAPE VERDE ISLANDS...IS ACCOMPANIED BY A BROAD AREA OF
SHOWERS AND THUNDERSTORMS. ENVIRONMENTAL CONDITIONS COULD ALLOW FOR
SOME DEVELOPMENT OF THIS SYSTEM AND THE TROPICAL WAVE HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION OVER THE NEXT COUPLE OF
DAYS. LATEST MODEL GUIDANCE CONTINUE TO INDICATED THAT THIS SYSTEM
WILL PASS WELL NORTHEAST OF THE LOCAL ISLANDS
...REPRESENTING MAINLY
A CONCERN TO THE GENERAL MARINE COMMUNITY.

&&

.AVIATION...ISOLATED SHOWER ACTIVITY WILL CONTINUE ACROSS TIST
AND TISX UNTIL 17Z...ALTHOUGH AIRPORT CONDITIONS ARE EXPECTED TO
REMAIN VFR ACROSS THESE SITES. FOR THIS AFTERNOON...ESE FLOW ALOFT
WILL HAVE THE POTENTIAL TO STEER A PASSING SHRA OR TSRA ACROSS
TJMZ...TJBQ AND TJSJ BETWEEN 17Z- 22Z...CREATING TEMPORARY MVFR
CONDITIONS...WITH VFR CONDITIONS EXPECTED TO PERSIST ELSEWHERE.
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511. hurricane23
2:15 PM EDT on July 02, 2008
NHC-2:05 Discussion

A STRONG TROPICAL WAVE IN THE FAR E ATLANTIC IS JUST EAST OF THE
CAPE VERDE ISLANDS ALONG 22W S OF 19N MOVING W 10-15 KT. VISIBLE
IMAGERY REVEALS AN IMPRESSIVE CLOUD STRUCTURE WITH WELL DEFINED
MID-LEVEL CYCLONIC CIRCULATION CENTER ALONG THE WAVE NEAR 12N.
THE SURFACE LOW PRESSURE CENTER ASSOCIATED WITH THE WAVE IS
ACTUALLY DISPLACED EAST OF THE WAVE NEAR 12N20W. ISOLATED
MODERATE CONVECTION IS WITHIN 240 NM ON BOTH SIDES OF THE WAVE
FROM 11N-14N. SIMILAR CONVECTION IS WITHIN 400NM E AND 100NM W
OF THE WAVE FROM 5N-10N. THIS SYSTEM IS BEING CLOSELY MONITORED
AND THERE IS THE POTENTIAL FOR IT TO BECOME A TROPICAL
DEPRESSION OVER THE NEXT COUPLE OF DAYS.
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510. CajunSubbie
6:16 PM GMT on July 02, 2008
presslord

haha no reason to be jumpy.
i was commenting on the article.


Compare 2007 to 2008 Arctic Ice Coverage

Interesting 2008 has more ice, but the media is pushing stories that the ice will be gone?

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509. HadesGodWyvern (Mod)
6:13 PM GMT on July 02, 2008
TROPICAL STORM DEVELOPED IN THE MODEL

ANALYSIS AT POSITION :
11.1N 20.9W

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 02.07.2008 11.1N 20.9W WEAK
00UTC 03.07.2008 11.1N 21.8W MODERATE INTENSIFYING SLIGHTLY
12UTC 03.07.2008 12.2N 24.5W WEAK WEAKENING RAPIDLY
00UTC 04.07.2008 12.1N 27.3W WEAK LITTLE CHANGE
12UTC 04.07.2008 12.6N 30.2W WEAK LITTLE CHANGE
00UTC 05.07.2008 14.8N 32.9W WEAK LITTLE CHANGE
12UTC 05.07.2008 15.4N 36.2W WEAK LITTLE CHANGE
00UTC 06.07.2008 16.1N 39.7W WEAK WEAKENING SLIGHTLY
12UTC 06.07.2008 17.1N 43.6W WEAK LITTLE CHANGE
00UTC 07.07.2008 17.5N 47.0W WEAK LITTLE CHANGE
12UTC 07.07.2008 17.9N 49.8W WEAK INTENSIFYING SLIGHTLY
00UTC 08.07.2008 19.3N 53.1W WEAK WEAKENING SLIGHTLY
12UTC 08.07.2008 19.7N 55.8W WEAK LITTLE CHANGE


MODERATE strength (strong tropical storm) again in the model from the UKMET.
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508. smmcdavid
1:10 PM CDT on July 02, 2008
presslord

too bad temps have gone down since 98.
global warming is so last decade.


I like how you make it sound like a fashion trend... LOL!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.