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

By: Dr. Jeff Masters , 01:40 PM GMT em 02 de Julho de 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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1607. ticka1
8:25 AM GMT on July 03, 2008
Maybe this time its for real - but waiting on the NHC announcement but the NRL(Navy) site has 92L as NONAME today July 3rd.
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1606. CybrTeddy
8:11 AM GMT on July 03, 2008
Things looking interesting with 92L.
Member Since: Julho 8, 2005 Posts: 259 Comments: 24476
1605. jscs
7:54 AM GMT on July 03, 2008
Temps in GOM and Atlantic higher than normal. Two waves. Not good. Not at all good.
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1604. KrazyKaneLove
7:17 AM GMT on July 03, 2008
shoot Levi left ... going to go to bed, I will probably be seeing more of you late-niters later though..g'nite
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1603. KrazyKaneLove
7:00 AM GMT on July 03, 2008
thanks Levi, I just asked weather because he had just posted, I don't care who answers as long as they are knowledgeable( as you seem to be)..but I am a little ignorant and alot confused..does the ULL cause a fish storm or lead it west? Or is it brief and later waves will go west after its gone... just not sure what you meant..oh and with the current position of the bedrmuda high are we looking at another 2004 season or further up the eastern seaboard?
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1602. TampaSpin
3:13 AM EDT on July 03, 2008
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1601. Fshhead
7:09 AM GMT on July 03, 2008
Take it Easy Levi!!!!
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1600. Fshhead
7:07 AM GMT on July 03, 2008
LOL LETS DO THE TIME WARP AGAIN!!!
Blog is actin weird. It will probably crash tomm. when the word gets out about it gaining TD status.......
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1599. Levi32
11:06 PM AKDT on July 02, 2008
Yeah if you're seeing anything it's just the main feeder band forming and starting to wrap around the COC.......nothing like an eye yet.

I'm gonna head out for the night. See you guys tomorrow.
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1598. Fshhead
7:02 AM GMT on July 03, 2008
Thunder what you are seeing is the center of circulation......
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1597. Levi32
11:03 PM AKDT on July 02, 2008
1595.

Lol....well I don't care what anyone says, it's a TS. Should be upgraded to at least TD #2 at 5am.
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1596. Levi32
10:57 PM AKDT on July 02, 2008
NOGAPS 0z on board with a weak open wave moving westward throughout the forecast period.
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1595. Thundercloud01221991
6:56 AM GMT on July 03, 2008
1593. Levi32 6:55 AM GMT on July 03, 2008 Hide this comment.
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
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1594. Fshhead
6:56 AM GMT on July 03, 2008
One thing for sure the positioning of the Bermuda high is everything.....
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1593. Levi32
10:55 PM AKDT on July 02, 2008
03/0545 UTC 12.6N 22.8W T1.5/1.5 92L

Dvorak classification up to 1.5
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1592. Levi32
10:50 PM AKDT on July 02, 2008
1590. KrazyKaneLove 10:48 PM AKDT on July 02, 2008

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.
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1591. 7544
6:51 AM GMT on July 03, 2008
hmm 92l taking a little dip to sw at this hour
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1590. KrazyKaneLove
6:42 AM GMT on July 03, 2008
weather456, if this storm does the classic 'fish' storm, is it because of the bermuda high or the time of season(i.e do you think it will foretell if later cape verde storms will follow suit?)Thanks in advance..
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1589. KrazyKaneLove
6:40 AM GMT on July 03, 2008
thanks guys, figures that things just start heating up when my hardest classes start up... kinda hopin a nice TS will grant me a week off..lol
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1588. Weather456
2:39 AM AST on July 03, 2008
High chance of development

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1587. Fshhead
6:38 AM GMT on July 03, 2008
KrazyKane 93L heading into wind shear. If it does head here it will probably be just rain.
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1586. Levi32
10:36 PM AKDT on July 02, 2008
1582. 7544 10:34 PM AKDT on July 02, 2008

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.

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1585. Levi32
10:33 PM AKDT on July 02, 2008
92L is the first wave this year firmly embedded in deep-layer moisture. It's extremely impressive for early July. I don't expect any problems with dry air as it comes across the eastern Atlantic. The biggest issue over the next 3 days will be how strong 92L gets after gaining Bertha status. If it stays at minimal TS status I believe it will follow the CMC and UKMET projections. If it bombs out......and it can't go very far...maybe Cat 1...we'll have to watch how things evolve very carefully and see if it recurves as the GFS thinks.
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1584. KrazyKaneLove
6:31 AM GMT on July 03, 2008
good evening all, wats up with 93? I haven't been able to watch as much as I just started some online classes..is it looking favorable for development? towards florida?
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1583. Fshhead
6:33 AM GMT on July 03, 2008
Hey Storm Junkie I was just going through my links & came across yours from last year & tried to go to it. It said page not found? Do you have an updated link? Please?
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1582. 7544
6:33 AM GMT on July 03, 2008
93l is looking better but is it now drifting to nw . when are new runs for 93l thanx
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1581. Fshhead
6:32 AM GMT on July 03, 2008
Thats what I thought. THANX!!
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1580. Levi32
10:27 PM AKDT on July 02, 2008
1579. Fshhead 10:26 PM AKDT on July 02, 2008 Hide this comment.
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.
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1579. Fshhead
6:25 AM GMT on July 03, 2008
Yea for sure!!!!! & correct me if I am wrong.
It looks like the precip. going north is probably where its gonna follow??
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1578. TampaSpin
2:23 AM EDT on July 03, 2008
1574. StormJunkie 2:22 AM EDT on July 03, 2008

SJ that mic looks like 93L is looking better also.
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1577. StormJunkie
6:23 AM GMT on July 03, 2008
Good call Fsh, love the Mimic :~)
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1576. Fshhead
6:23 AM GMT on July 03, 2008
LOL Yup Junkie that one shows it even better...
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1575. Fshhead
6:22 AM GMT on July 03, 2008
I say TD for sure. This clearly shows the rotation ...
Link
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1574. StormJunkie
6:19 AM GMT on July 03, 2008
Nice view...
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1573. CybrTeddy
6:18 AM GMT on July 03, 2008
What are the Ts? Not at 1.0 anymore I dont think.
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1572. StormJunkie
6:15 AM GMT on July 03, 2008
Evening Fh, good to see ya

I am getting myself to bed real soon. May catch one or two more images from the Eumetsat.

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1571. Levi32
10:14 PM AKDT on July 02, 2008
1568. Fshhead 10:14 PM AKDT on July 02, 2008

Nah, them a bunch of losers to think that lol.
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1570. TampaSpin
2:13 AM EDT on July 03, 2008
i think dmax is working
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1569. Fshhead
6:16 AM GMT on July 03, 2008
Yea MLC, I saw that. THANX for postin' it &
A VERY HAPPY 4TH OF JULY BACK AT YA!!!!
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1568. Fshhead
6:12 AM GMT on July 03, 2008
Mmmmm Levi, if your including me as one of those great minds? Word of caution cause I am sure many on here think I am nutz lol
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1567. moonlightcowboy
1:12 AM CDT on July 03, 2008
Hey, Fish! Rough day today on the fuel, friend! UGH!
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1566. Levi32
10:13 PM AKDT on July 02, 2008
1565.

Lol....goodnight.....yup TD at 5am for sure
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1565. weathersp
6:09 AM GMT on July 03, 2008
If I am too tired to post a link then I am either.. 99 cant find percent button and too lazy to do it. or had too msny sodas.

gnight all

Exepct a TD at 5AM
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1564. moonlightcowboy
1:11 AM CDT on July 03, 2008
1561. LOL, I knew that sounded a bit early for you!
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1563. Levi32
10:11 PM AKDT on July 02, 2008
Hey fshhead! Welcome to the late-night club. I like it this time of night with just a few great minds going at it together instead of the big bustle in the middle of the day lol.
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1562. Fshhead
6:09 AM GMT on July 03, 2008
Evening All!!
Hmmmm looks like we got something huh?
Swim little fishy, Swim!!!
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1561. Levi32
10:09 PM AKDT on July 02, 2008
1559.

I was saying goodnight to WB...I ain't leaving..it's only 10 here in Alaska lol.
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1560. Levi32
10:07 PM AKDT on July 02, 2008


GFDL and HWRF 0z runs are out.....still going with the flow.....all because they have GFS data put into them....
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1559. moonlightcowboy
1:07 AM CDT on July 03, 2008
Good stuff, Levi - all interesting and fun to watch.

Have a good sleep, Levi and WB.
Member Since: Julho 9, 2006 Posts: 184 Comments: 29610
1558. weathersp
6:02 AM GMT on July 03, 2008
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1557. Levi32
10:05 PM AKDT on July 02, 2008
Goodnight
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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.

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