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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1107. bluenosedave
12:51 AM GMT on July 03, 2008
"i never thought i'd see the term "tidy bowl" used to describe the cyclonic turning of an atmospheric feature! ROTFLMAO!"

93L ought to be flushed with pride. :-)
Member Since: August 26, 2006 Posts: 0 Comments: 361
1106. Tazmanian
5:55 PM PDT on July 02, 2008
1096. extreme236 5:53 PM PDT on July 02, 2008
EPAC dvorak numbers are out...92L and 93L numbers should be out soon.



they are???


not for me
Member Since: May 21, 2006 Posts: 5091 Comments: 114765
1105. cchsweatherman
12:50 AM GMT on July 03, 2008
In regards to Invest 92L, it seems like the convection has finally begun expanding and is far deeper than the past 24 hours. We may wake up tomorrow morning with Tropical Depression 2. From there, we will have to see if and how any weakness in the ridge may affect the track. For some reason, I don't see this moving NW like most models do.


Now, turning my attention towards Invest 93L, the circulation center has moved under the deepest convection. Looks rather well-organized.
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1104. hahaguy
8:56 PM EDT on July 02, 2008
When will the shear in the carribean and gomex relax?
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1103. GeoffreyWPB
8:54 PM EDT on July 02, 2008
LOL....that is not what i meant...but clever!
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1102. Baybuddy
12:47 AM GMT on July 03, 2008
Just got back from vacation in Clear Lake CA. No computers or tv for two weeks. AWESOME!
Got some before and after pics of the smoke from all of the wildfires in the area.
We had a great view of the mountains for the first week, then "poof" it vanished for the second week in a thick haze.
I would definately recommend Lake Co. California as a vacation spot though.
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1101. JRRP
12:49 AM GMT on Julio 03, 2008

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1100. reedzone
12:52 AM GMT on July 03, 2008
Off to the gym for a few hours, talk to you all later! pz
Member Since: July 1, 2008 Posts: 13 Comments: 7340
1099. Levi32
4:52 PM AKDT on July 02, 2008
1095. moonlightcowboy 4:52 PM AKDT on July 02, 2008 Hide this comment.
1073. Ike, I didn't say 92L would effect anyone. I just said it had the potential to become the first hurricane of the season. 93L will RIP, ****poooof****!


Genies still exist after going **poof** =)

Not saying 93L will amount to anything. My opinion is also that it will get ripped up. But if ANYTHING survives.....it will have to be watched as it moves into the MJO pulse. Anything and everything in the western Caribbean and GOM will have to be watched over the next 2 weeks.
Member Since: November 24, 2005 Posts: 635 Comments: 26562
1098. GeoffreyWPB
8:51 PM EDT on July 02, 2008
They finally have a floater on 93....gonna be really tough to develop further....
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1097. HurakanPR
8:34 PM AST on July 02, 2008
YEs GoeffreyWPB ,congratulations JFV, im pretty shure he is glad his wife ended a period with a baby..!!
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1096. extreme236
12:52 AM GMT on July 03, 2008
EPAC dvorak numbers are out...92L and 93L numbers should be out soon.
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1095. moonlightcowboy
7:50 PM CDT on July 02, 2008
1073. Ike, I didn't say 92L would effect anyone. I just said it had the potential to become the first hurricane of the season. 93L will RIP, ****poooof****!
Member Since: July 9, 2006 Posts: 184 Comments: 29594
1094. Levi32
4:51 PM AKDT on July 02, 2008
Really it all comes down to how strong 92L is while that weakness from the CATL ULL is there. That's basically all there is to it.
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1093. Tazmanian
5:51 PM PDT on July 02, 2008
for CA any way that i can re call
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1091. caribbeansurvivor1
12:46 AM GMT on July 03, 2008
Well JPR, we know that SA wind shear are "wanna b system killer"LOL
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1090. nash28
12:46 AM GMT on July 03, 2008
Yep Keeper... I still believe the GFS and others are overdoing the strength of the system in relation to the longwave. Splitting the High? Sure. That weakness though will not stay long.
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1089. pearlandaggie
12:46 AM GMT on July 03, 2008
1087. first time? that's like every day between April and November in Houston! LOL
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1088. IKE
7:45 PM CDT on July 02, 2008
1085. JFV 7:45 PM CDT on July 02, 2008
I'm back folks! Sorry about that IKE.


It's OK.....hope your lady is better.
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1087. Tazmanian
5:44 PM PDT on July 02, 2008
this is the 1st time i have evere seen this for sac ca


Ultraviolet
Ultraviolet Forecast
UV Index: 11
Exposure Risk: Extreme

i got that from kcra
Member Since: May 21, 2006 Posts: 5091 Comments: 114765
1086. KEEPEROFTHEGATE (Mod)
12:37 AM GMT on July 03, 2008
thats pretty much it mlc
also i beleive after the intial robust dev. 92l should weaken off some after that if it recurves out to sea
if it heads more west and curves later then all bets are off
i got a feelin 92l is not gonna play by the rules and gonna pull of many tricks in its long track
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1084. JLPR
12:40 AM GMT on July 03, 2008
1071. caribbeansurvivor1 12:38 AM GMT on July 03, 2008
jpr nice to see u comrade...what do u think about 93L?


well it started to look interesting yesterday but wind shear should tear it apart soon =P
93L options are:
stalling: then the shear would go down in front of it
surviving: pass through the shear and pray for some regeneration
dying: lol I don't have to explain this one =D

but if 93L had better conditions it could have become a TS or even a cane

but this little systems are good at strengthening fast but they tend to get ripped apart quickly by hostile conditions (there are exceptions)=P
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1083. pearlandaggie
12:43 AM GMT on July 03, 2008
1080. now THAT'S a great username :)
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1082. nash28
12:43 AM GMT on July 03, 2008
Well, I think the TUTT knows how long:-)

Us? No clue.
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1081. stormhank
12:38 AM GMT on July 03, 2008
evening all....does anyone know how much longer the shear in GOM n carribean is expected to persist?
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1080. Stoopid1
12:42 AM GMT on July 03, 2008
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1079. pearlandaggie
12:41 AM GMT on July 03, 2008
later, atmo. i'll be sending your wife a copy of your comments! LOL
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1078. nash28
12:40 AM GMT on July 03, 2008
92L, 93L....

I think the L should be reclassified to mean "LONG TIME TO DO ANYTHING!"

Jk:-)
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1077. extreme236
12:40 AM GMT on July 03, 2008
But its pointless arguing over whether or not it can survive the shear because we will know soon enough. In fact, its already being hit with some shear and you tell on the satellite imagery.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
1076. pearlandaggie
12:39 AM GMT on July 03, 2008
i never thought i'd see the term "tidy bowl" used to describe the cyclonic turning of an atmospheric feature! ROTFLMAO!
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1075. JLPR
12:38 AM GMT on July 03, 2008
1069. extreme236 12:38 AM GMT on July 03, 2008

that was mt thinking exactly =)
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1074. atmoaggie
12:38 AM GMT on July 03, 2008
dang, tired of waiting for 0Z products. Got things to do, later all.
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1073. IKE
7:37 PM CDT on July 02, 2008
1064. moonlightcowboy 7:37 PM CDT on July 02, 2008
93L is RIP! That is, unless, it keeps a small, tidy bowl swirl feature to it near the surface for regeneration after the diminishing winds pass through. And, that's a stretch even imo! Sure, it's fun to watch and speculate, but it's not likely to ever become much. 92L, on the other hand, has the potential to become the first hurricane of the season.


92L will affect no one but WU bloggers. 93L is more of a concern, but that 30 knots of shear........tough to beat.
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1072. moonlightcowboy
7:38 PM CDT on July 02, 2008
Evening, Keeper!
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1071. caribbeansurvivor1
12:36 AM GMT on July 03, 2008
jpr nice to see u comrade...what do u think about 93L?
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1070. TheWeatherMan504
12:35 AM GMT on July 03, 2008
1052. IKE 12:32 AM GMT on July 03, 2008
1043. TheWeatherMan504 7:30 PM CDT on July 02, 2008
Jp my magic 8 ball predicted 93l.

If I'm not mistaken, 93L is the CATL wave w/a circulation...it's survived up til now.


i know im jus saying my 8 ball predicted that invest to form.
Member Since: May 18, 2008 Posts: 2 Comments: 1042
1069. extreme236
12:37 AM GMT on July 03, 2008
1061.

Well the SHIPS can be good for intensity forecasts although it is all too often too bullish for invests.

1060.

JLPR that is a good point. Subtropical systems tend to do better with shear than tropical ones.
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1068. moonlightcowboy
7:37 PM CDT on July 02, 2008
1044. LMAO! ;)
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1067. GeoffreyWPB
8:36 PM EDT on July 02, 2008
LOL Pearland...I wish him and his family the very best
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1066. atmoaggie
12:35 AM GMT on July 03, 2008
JFV is going to be a daddy...Congrats dude. I am just finally happy that he ended a post with a period (.)

All sorts of rotten non-weather comments come to mind...nah. Restraint wins out...this time.
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1065. KEEPEROFTHEGATE (Mod)
12:32 AM GMT on July 03, 2008
g'evening all
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1064. moonlightcowboy
7:32 PM CDT on July 02, 2008
93L is RIP! That is, unless, it keeps a small, tidy bowl swirl feature to it near the surface for regeneration after the diminishing winds pass through. And, that's a stretch even imo! Sure, it's fun to watch and speculate, but it's not likely to ever become much. 92L, on the other hand, has the potential to become the first hurricane of the season.
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1063. IKE
7:35 PM CDT on July 02, 2008
1059. pearlandaggie 7:35 PM CDT on July 02, 2008
1051. LMFAO! NOW we know WHY they're engaged! ;]


With a child on the way~~~~~JFV marry that woman!
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1062. caribbeansurvivor1
12:35 AM GMT on July 03, 2008
guys this "minimal" stroms some times bring a lot of rain...think about it....
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1060. JLPR
12:35 AM GMT on July 03, 2008
umm but wasnt the pre-Gabby subtropical?
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1059. pearlandaggie
12:33 AM GMT on July 03, 2008
1051. LMFAO! NOW we know WHY they're engaged! ;]

Geoff, a friendly reminder...
During active periods of hurricane season, these rules will be strictly enforced. Violations will be met with a minimum 24 hour ban.
hehehe
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1058. caribbeansurvivor1
12:33 AM GMT on July 03, 2008
gents....have anyone may tell me what the actual translation of the 93L looks going wnw...
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1057. HurricaneTracker01
12:34 AM GMT on July 03, 2008
im vacationing near daytona this week.. until the 15th... will i be affected by one of these storms?
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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.