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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1507. StormJunkie
5:15 AM GMT on July 03, 2008
Evening Sc07

Watch the loop. You see the way that ball of convection has been circling for the past several hours. Also notice the improved banding to the N. Looks pretty good to me, for what and where it is.
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1506. Levi32
9:13 PM AKDT on July 02, 2008
1501.

It's TS Bertha.....NHC or no NHC.....it should be. They should upgrade it at 5am.
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1505. StormJunkie
5:11 AM GMT on July 03, 2008
Evening all

Levi, I concur. There is no question it is a TD, and very likely a TS right now. It continues to take advantage of the Dmax.
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1504. moonlightcowboy
12:13 AM CDT on July 03, 2008
Yeah, have a good sleep, JFV. (Um, keep a damp towel close by!) ;)
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1503. Levi32
9:12 PM AKDT on July 02, 2008
Have a good night JFV
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1502. TheWeatherMan504
5:12 AM GMT on July 03, 2008
.

Member Since: Maio 18, 2008 Posts: 2 Comments: 1042
1501. Stormchaser2007
5:12 AM GMT on July 03, 2008
Dunt look to good to me

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1499. HurakanPR
12:59 AM AST on July 03, 2008
93 getting a punch but still holding, the TUTT, is lifting north,not sure if it will exit fast enough for not destroying our little fighter.
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1498. moonlightcowboy
12:07 AM CDT on July 03, 2008
Yeah, three games on the Sox. Good to see them doing so well!
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1497. vabeachurricanes222
5:09 AM GMT on July 03, 2008
i hope the rays go far this year
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1496. TheWeatherMan504
5:05 AM GMT on July 03, 2008
LOL! TS
Member Since: Maio 18, 2008 Posts: 2 Comments: 1042
1495. TampaSpin
1:04 AM EDT on July 03, 2008
MLC how about my RAYS sweep baby.....lol
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1494. TheWeatherMan504
4:59 AM GMT on July 03, 2008
yes he is a good guy mlc and you are too.TS is gonna make my parents in nola nervous. lol
Member Since: Maio 18, 2008 Posts: 2 Comments: 1042
1493. TampaSpin
1:00 AM EDT on July 03, 2008
92L intensity forcast
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1492. Levi32
8:56 PM AKDT on July 02, 2008
I really think the NHC should upgrade this straight to TS Bertha at 5am.
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1491. moonlightcowboy
11:55 PM CDT on July 02, 2008
1482. No worries, TS! But, I'm glad to know I was doing better anyways! Yeah, Flood has had a rough time for sure and I hope he gets back to some normalcy soon. Wait! Did I just say "Flood" and "normal" in the same sentence? Whew! I must be slipping! j/k, Flood's a good guy! :)
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1490. TampaSpin
12:56 AM EDT on July 03, 2008
93L intensity forcast.....interesting forcast to get stronger it appears.
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1489. reedzone
4:56 AM GMT on July 03, 2008
Hello everyone, just got back from the gym.. I see 92L has blown up a bit more.. We might have a TD first thing in the morning.
Member Since: Julho 1, 2008 Posts: 13 Comments: 7340
1488. rareaire
4:49 AM GMT on July 03, 2008
Thanks Levi and Tampa thought i was hollering down an empty well. I have been up in Iowa working the floods and I just returned home last night. Ive been gone for 4 months working claims here and there and I really do not want to have to head to Florida any time soon.. I ned to relax and enjoy some down time

Thanks for answering my question. I appreciate it !
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1487. moonlightcowboy
11:43 PM CDT on July 02, 2008
Rairaire, sometimes "patience" is needed here with questions. Usually, the qualified folks (not saying me) are either answering other questions or are making observations, watching a loop load or something. So, hang out, watch - someone will eventually get around to answering your question. And, I say that to you, because a couple of years ago, I felt much the same way. Your anxious, eager to see what a system will do and where it will go.

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! :)
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1486. weatherblog
4:51 AM GMT on July 03, 2008
There, now he had three people answer his question.
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1485. weatherblog
4:44 AM GMT on July 03, 2008
1460. rareaire 4:17 AM GMT on July 03, 2008
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.
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1484. TampaSpin
12:47 AM EDT on July 03, 2008
1460. rareaire 12:17 AM EDT on July 03, 2008
do you guys think there is any chance of a conus land fall on 92?


93L has probably higher threat than 92L
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1483. TheWeatherMan504
4:47 AM GMT on July 03, 2008
then some people might have to worry about something ts.yhis might not be good
Member Since: Maio 18, 2008 Posts: 2 Comments: 1042
1482. TampaSpin
12:46 AM EDT on July 03, 2008
MLC my bad it is Floodman that was under the weather..sorry for putting you in a ditch....lol
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1481. Levi32
8:43 PM AKDT on July 02, 2008
1479.

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.
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1480. TampaSpin
12:42 AM EDT on July 03, 2008
If Shear was to drop like CCHS suggests this could be an intersting weekend coming up, i don't see it but i have been wrong a couple of times......lol..
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1479. rareaire
4:42 AM GMT on July 03, 2008
well i guess no one can see my questions so i'll head to bed. night all!!
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1478. Levi32
8:40 PM AKDT on July 02, 2008
1476.

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.
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1477. moonlightcowboy
11:41 PM CDT on July 02, 2008
1473. TS, I didn't know I was feeling bad, friend? Um, do you know something I don't? LOL ;P - but, thanks for asking. I feel pretty good actually!
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1476. moonlightcowboy
11:36 PM CDT on July 02, 2008
1472. Yeah, that does sound better suited, Levi. While we observe and study this system (these systems), it's fun to break them down and see and interpret the cyclogenesis process. And, for me, that's much preferred as to most of the crowd on here that'd soon have it as a CAT 5 hitting NOLA in three days. LOL

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.
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1475. TampaSpin
12:37 AM EDT on July 03, 2008
1474. Levi32 12:37 AM EDT on July 03, 2008

I thank that confusion is interesting....I'll bet it will start tracking further West in the next runs.
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1474. Levi32
8:34 PM AKDT on July 02, 2008
GFS still splitting the energy and sending a piece to the northern islands....then trapping the other piece under the high when the ULL leaves. I think this model is majorly confused lol. The GFS has serious issues in this area.
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1473. TampaSpin
12:34 AM EDT on July 03, 2008
MLC how you feeling.....better i hope and feeling alittle pain also.
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1472. Levi32
8:32 PM AKDT on July 02, 2008
1471.

Alright alright lol. How about "hindering" factor then? =)
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1471. moonlightcowboy
11:26 PM CDT on July 02, 2008
1445. LOL, Levi. I didn't say SAL would be a limiting factor at all! I just noted there was less moist air at the mid-levels as evidenced by the sat pics. While NOT limited, it may be what has kept or helped the system remain somewhat weaker and slower to build. However, I've said all along that I think this system would strengthen and likely gain named status with 48 hrs possibly from last night.

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.

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1470. Patrap
11:28 PM CDT on July 02, 2008
Oceanographer of the Navy Link

Navy Meteorological and Oceanography Command Link

More Links from FNMOC Link
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1469. JRRP
4:22 AM GMT on Julio 03, 2008

93L has less convection
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1468. moonlightcowboy
11:26 PM CDT on July 02, 2008
Alright, cchs! Prolly more action tomorrow. Have a good one!
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1467. Patrap
11:22 PM CDT on July 02, 2008
FNMOC (UNCLASSIFIED)
Gulf of Mexico 4 FT Wave Probability Link
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1466. moonlightcowboy
11:21 PM CDT on July 02, 2008
1452. Yeah, K'man. I see your point, especially with no more sea level height than you have there. Even a strong TS would not be a very welcomed visitor I imagine!

Have a good sleep, friend.
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1465. cchsweatherman
4:23 AM GMT on July 03, 2008
Good night all! I will be back tomorrow AM.
Member Since: Abril 14, 2007 Posts: 8 Comments: 5163
1464. TampaSpin
12:21 AM EDT on July 03, 2008
1462. Levi32 12:20 AM EDT on July 03, 2008

Yep that is exactly what i too have been stating......my exact thoughts.
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1463. TampaSpin
12:18 AM EDT on July 03, 2008
1458. cchsweatherman 12:16 AM EDT on July 03, 2008
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...
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1462. Levi32
8:17 PM AKDT on July 02, 2008
1459. TampaSpin 8:17 PM AKDT on July 02, 2008

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.
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1461. Levi32
8:14 PM AKDT on July 02, 2008
0z GFS taking a different look so far...
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1460. rareaire
4:15 AM GMT on July 03, 2008
do you guys think there is any chance of a conus land fall on 92?
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1459. TampaSpin
12:13 AM EDT on July 03, 2008
1457. Levi32 12:12 AM EDT on July 03, 2008

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
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1458. cchsweatherman
4:12 AM GMT on July 03, 2008
Just like Kman stated, it appears that Invest 92L may be forming a CDO now.


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.
Member Since: Abril 14, 2007 Posts: 8 Comments: 5163
1457. Levi32
8:07 PM AKDT on July 02, 2008
1451. TampaSpin 8:03 PM AKDT on July 02, 2008 Hide this comment.
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.
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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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