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Ozone pollution improving in the U.S.

By: Dr. Jeff Masters, 7:03 PM GMT on May 01, 2007

Air pollution season is here, and the good news is that ozone pollution in 2006 was considerably better than in previous years. Along with pollution due to small particles (particulate matter), ground-level ozone is the most serious pollutant in the U.S. Ozone levels in 2006 showed improvement in 23 out of 35 of the major cities in the U.S. (Figure 1) compared to 2005, and was at or below the 10-year average in all but five cities. Atlanta, Georgia, showed the greatest jump in the number of unhealthy days, from 17 in 2005 to 30 days in 2006; however, this number was still below the 10-year average. Many western cities reached levels at or above the 10-year average, including San Diego, Sacramento, Denver, and Las Vegas. This was in part due to much above average summertime temperatures in the western U.S. (Figure 2). Los Angeles had the worst ozone pollution in the U.S., with 46 unhealthy days. Los Angeles also was the most polluted city overall in 2006, according to the American Lung Association. However, Los Angeles' bad ozone days declined by 16% in 2006 compared to 2005.


Figure 1. The number of days in May through September of 2005 and 2006 in which ground-level ozone reached Unhealthy for Sensitive Groups--an Air Quality Index (AQI) above 100. Corresponding 10-year averages are also shown. Image credit: EPA.

Ozone pollution has improved
Is the improvement seen in ozone levels in 2006 merely due to a lack of meteorological conditions that favor air pollution? To check, I've plotted the difference in surface temperature (degrees C) from May-September 2006, compared to the 10-year average from 1995-2005 (Figure 2). The chemical reactions that form ozone are most efficient at high temperatures, so if the summer of 2006 was cooler than usual, we'd expect a drop in ozone levels. However, the summer of 2006 was the second warmest in U.S. history--but ozone levels still dropped. All of the cities where ozone increased significantly in 2006 over 2005 levels were areas where temperatures were above average. Los Angeles had summer temperatures more than 1 degree C above normal, yet still recorded a drop in ozone, suggesting that strategies to control ozone pollution there are paying dividends. In fact, new rules to limit nitrogen oxide emissions from power plants have been enacted nation-wide in the past few years, and the ozone pollution statistics from 2006 are evidence that these emissions rules are working. Ozone pollution since 1980 has dropped 21% (Figure 3), despite the fact that the average summer temperatures have generally been increasing.


Figure 2. The difference in surface temperature (degrees C) from May-September 2006, compared to the 10-year average from 1995-2005. Temperatures were above the 10-year average across most of the country, except for New Mexico, and portions of the Ohio Valley surrounding Kentucky. Image credit: NCAR/NCEP.


Figure 3. Trends in ozone air pollution in the U.S. (white line) and uncertainty (blue areas, marking the standard deviation). The federal standard of 0.08 ppm is indicated by the dashed line. Since 1980, maximum ozone levels have declined 21%. Since 1990, the decline has been 9%. Note that the lowest ozone levels were recorded in 2004, which was an exceptionally cool summer across most of the U.S. Image credit: U.S. EPA.

Next blog (Thursday): Pollution costs and deaths exceed the impact of a new Hurricane Katrina hitting the U.S. each year.

Jeff Masters

Air and Water Pollution

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

the dry air is definitely dissipating all over the Atlantic
...later kman...Good night, we'll catch up soon!
SJ...you are one of the best on here as far as knowledge! I respect that! Sure would like to know your thoughts!
lol thats cute
I'm out too. Got to get some sleep before that Wave gets here. heheheh
as for the melting ice american reseachers have confirmed that artic ice is melting three times faster then previously predicted
...yo, STORY!!! Any thoughts on the "smell?" lol
We need to start building an ark.
the smell? we listening to Lynyrd Skynyrd? what do you mean by "the smell"?
....no biggie Story. Good to see you on.

As far as MHO can tell, this one will be different from 06...some more serious.
ewww that smell, cant ya smell that smell
you cant say something that random and then not explain where it came from, whatd you mean? good to see you too.
...love the Freebird crew...but, I'm outta here tonight...keep the fire burning......this season will have much more into it thankfully....more participants...new tech..and all that....it'll be interesting.

Later on. Nite all.
Yep..at the present pyramidal rate of corporate expansion coupled with the demand created by exploding populations elsewhere on the planet, all north polar ice should be gone within ten years, and half or so in the south.
gonna leave me wondering are we? well I wont do you the pleasure, i no longer wonder
hey as long as I got food in my stomach and a roof over my head i could care less about polar ice caps, no sense in dwelling over something we can do absolutely nothing about. Only way to stop it is by eliminating half the world's population, until then I bid you all ado
im smelling 19 storms, 13 hurricanes, 7 majors and 7 landfalls this year, hows everybody else's sensory insticts holding up?
I have never hear the "smelling" issue - but I hear alot of "I am feeling something in the air." lol
just so you all know Ive come to the conclusion that there are 3 types of people on this blog:

Wishcasters - Those that want to see large storms.

Noncasters - Those that base all of their decisions from the NHC and don't make predictions. (Playing it safe)

Hatecasters - Those that don't think any storm will ever form or hit land, ever.
yeah moonlight just came up with that one, not real sure what he means by it but i guess we'll have to wait and see
The surface low associated with the Texas storm system is just starting to approach the Gulf at the Texas Mexico border.

Area
Personal Weather stations

You forgot one type of people SOTC lol. Forecasters. There are some of us who actually try to do the job right.
Hatecasters - Those that don't think any storm will ever form or hit land, ever.

Well - I am not sure that you would call them hatecasters - just wishing for the best. lol
525. Inyo
Posted By: StoryOfTheCane at 3:18 AM GMT on May 03, 2007.
hey as long as I got food in my stomach and a roof over my head i could care less about polar ice caps, no sense in dwelling over something we can do absolutely nothing about. Only way to stop it is by eliminating half the world's population, until then I bid you all ado


Don't you live in Florida? If the ice caps melted, the OCEAN would be over your head, to say nothing of the roof.
nope, because once you do one of the listed above you are then labeled in one of the categories, no such thing as forecasters
lol nope I moved out of Florida in March.
lol but those wishing for the best (hatecasters) are usually the ones getting outraged at the wishcasters
i wasn't here for Katrina but I guarantee you it was "wishcaster this" "wishcaster that" 24/7 during that time
LOL, sounds like there's no room for the right stuff. What if someone doesn't do anything listed above? I mean cmon lol.
lol actually the forecaster would have to only be the NHC, which is the same as the "noncaster" because they simply relay the NHC's information
if you dont do any of the above you are just here for the beer (lurker)
Lol....interesting.
so anyone who tries to take an early approach at predicting a storm's formation before the NHC does is automatically considered a "wishcaster", we're just going to have to deal with it
if its like a storm in 75 degree water, 60 knots of shear and high SAL and you are "wishcasting" you are then put into a 4th category, "crazycaster"
nope, because once you do one of the listed above you are then labeled in one of the categories, no such thing as forecasters


Hmm - does that mean that everyone on the blog is listed in the three categories or only the ones which actually attempt to forecast?
i wasn't here for Katrina but I guarantee you it was "wishcaster this" "wishcaster that" 24/7 during that time

Everything makes sense now.
so what would you call someone who predicts major big storms that never hit land while using only nhc info as the bases of their prediction?
ok, here is a revised list of types of people on the blog:

Wishcaster - Takes an early approach at predicting formation.

Hatecaster - Never thinks a storm will develop.

Noncaster - Never predicts formation. Relays NHC information.

Crazycaster - Predicts formation when conditions are unfavorable.
Posted By: Bamatracker at 3:44 AM GMT on May 03, 2007.
so what would you call someone who predicts major big storms that never hit land while using only nhc info as the bases of their prediction?


Noncaster - they are only basing it off of NHC predictions. They arent making their own predictions.
ok...they make this decision when conditions arent favoriable.
but they fit the critera of the other categories
What about the caster that listen to the information, digests the information and chooses not the make a forecast but warns all his friends?
i think it just applies to what you say on this blog
i think it just applies to what you say on this blog

Hmmm - applies to what
what you are classified under. the funny thing about it is that only the "Noncasters" tend to label anyone a "Wishcaster", when they should be only labelling "Crazycasters"
now im just confused
youll see it when the season starts, people are so sensitive in here if you even mention the word "eye" they all freak out
i think ill just laugh at the fights between the different caster groups
hey hey.......no need to use the e-word
yeah its pretty entertaining lol
alright..im out for the evening. Somebody give me a call if anything develops!!! LOL
what you are classified under

That was not a question - because I don't care
we need to for sure begin the implementation of "Crazycaster" into the blog dictionary.
a lot of us are "wishcasters", a select few of us like StormTop are "crazycasters", Story out
Posted By: hornfan at 3:53 AM GMT on May 03, 2007.
i think it just applies to what you say on this blog

Hmmm - applies to what

Posted By: StoryOfTheCane at 3:56 AM GMT on May 03, 2007.
what you are classified under.



Thats what I was answering. I now see I didn't do it very well. If you warn your friends that there is going to be something coming before the NHC does you are a "wishcaster", you are basing it off of what NHC says you are a "noncaster"
nie little bubble just leaving west africa lets see if it will pop
yeah, this is more impressive than most of the waves we saw in September of last year. Once SSTs rise and Shear falls we'll be seeing Verde storms like hotcakes

i personally don't even like the labels but I might as well clarify them since they are getting thrown around so much lately, I have been victimized myself many times
I agree with you Story so far this season looks to shape up to be a busy one, Anyone know when it would be a good time to start investigating the Bermuda High and its location since right now may be to early
the high is definitely holding its own, east coast troughs dont seem to be phasing it at all like they were last year, they are weaker and further north
its anybody's guess but if I had to bet I would bet $100 bucks its going to be a rough year for the U.S. coastline, I hope Im wrong



i truly hope your wrong because we here in south florida truly don't need anymore
: StoryOfTheCane i am going with you on that bet of $100 bucks
FL is going to take a hard hit this year i can this tell
well time for me to say good night lol
yea Taz as hard as it is for me to say your right
well has of now i think are Bermuda High is seting up shop and it looks like it is not moveing any time soon bad news for FL
Crisis57 well good night we sould get some sleep now at this point its now looking good
I am late to the party but one reason LA has such bad air is that its one of the few citys from about May-October its not that unlikely to have no rain and little wind.
good night TAZ take it easy
Crisis57 ok will talk more on thusday ok come by my blog some times ok
So for those of you still up - we have a low approaching the coast of Texas BUT the pressure at the buoys just SHOT up drastically. I wonder why. There must be a front leading this system and the ridge is passing over first??

But its strange for it to be so close.


Station PTAT2 - Port Aransas, TX


Atmospheric Pressure (PRES): 29.88 in Pressure Tendency (PTDY): +0.11 in ( Rising Rapidly )
Morning all

lmao SOTC.
Someone who predicts every blob will develop and hit there home town is a wishcaster. Someone who always goes against the models is a wishcaster. Someone who insists that they can tell you where a storm is going 2 weeks out is arrogant.

Personally I don't think there are any forecasters here, only data interpreters.

Forecasting is like weather, you need to be very fluid, and sometimes people just get too rigid when trying to forecast, or geusscast.


Someome who noncasts as you call it is smart.

Anywho, off to work y'all.

good morning

anyone know how often the GFS is run ?
It is still showing that low N of Panama but now only 8 days out instead of 384 hrs.
Morning kman

It is run 4 times per day if I am not mistaken. 00z, 06z, 12z, and 18z. It usually is a several hours later that we get the output. Ex the 06z run should be available a little before the 12z starts running.

Sorry to all you Floridians, but it looks like we're going to get all your rain over here in Louisiana:

Statement as of 5:26 AM CDT on May 03, 2007


...FLOOD WATCH NOW IN EFFECT FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON...

THE FLOOD WATCH IS NOW IN EFFECT FOR

* PORTIONS OF SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI... INCLUDING THE FOLLOWING AREAS...IN SOUTHEAST LOUISIANA... ASCENSION... ASSUMPTION...EAST BATON ROUGE...EAST FELICIANA... IBERVILLE... LIVINGSTON...LOWER JEFFERSON...LOWER LAFOURCHE... LOWER PLAQUEMINES... LOWER ST. BERNARD...LOWER TERREBONNE... ORLEANS...POINTE COUPEE...ST. CHARLES...ST. HELENA... ST. JAMES...ST. JOHN THE BAPTIST... ST. TAMMANY...TANGIPAHOA... UPPER JEFFERSON...UPPER LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD... UPPER TERREBONNE...WASHINGTON...WEST BATON ROUGE AND WEST FELICIANA. IN SOUTHERN MISSISSIPPI...AMITE... HANCOCK...HARRISON...JACKSON...PEARL RIVER...PIKE...WALTHALL AND WILKINSON.

* FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON

* A STRONG UPPER LEVEL DISTURBANCE MOVING ACROSS TEXAS TODAY WILL MOVE SLOWLY ACROSS THE LOWER MISSISSIPPI VALLEY TONIGHT AND FRIDAY. A MOISTURE RICH ATMOSPHERE WILL BE IN PLACE AS SOUTHERLY FLOW PERSISTS AND INCREASES IN STRENGTH TONIGHT AND FRIDAY OVER THE AREA. RAINFALL RATES OF ONE TO TWO INCHES PER HOUR WILL BE POSSIBLE AT TIMES WITH THUNDERSTORMS LATE TONIGHT AND FRIDAY RESULTING IN THE THREAT OF FLOODING. SOME NUMERICAL FORECAST MODELS ARE INDICATING COPIOUS RAINFALL AMOUNTS THAT MAY MATERIALIZE... INCLUDING ACCUMULATIONS BETWEEN 3 AND 6 INCHES WITHIN SIX HOUR PERIODS. IF THIS OCCURS...THEN FLOODING CAN ENSUE AND POSSIBLY BECOME EXTENSIVE.

* POTENTIAL IMPACTS OF FLOODING INCLUDE EXTENSIVE PONDING AND FLOODING OF STREETS AND URBAN AREAS WHERE TORRENTIAL RAINS MAY BRIEFLY OVERWHELM DRAINAGE SYSTEM CAPACITY. EXCESSIVE RAINFALL RUNOFF TYPICALLY CAUSES RIVES AND STREAMS TO RISE RAPIDLY. MOST AREA STEAMS ARE AT LOW FLOWS AND SHOULD BE ABLE TO ACCOMMODATE LOW TO MODERATE RAIN RATES AND ACCUMULATIONS. IF RAIN RATES BECOME TORRENTIAL...TYPICALLY EXCEEDING TWO INCHES PER HOUR...THEN RIVER AND STREAM FLOODING MAY RESULT. THE LOWER MISSISSIPPI RIVER FORECAST CENTER WILL BE EVALUATING THE RIVER FLOWS THROUGHOUT THE DAY AND MAY ISSUE A HYDROLOGIC OUTLOOK HIGHLIGHTING ANY POTENTIAL RIVER FLOOD CONCERNS.


241
fxus64 klix 030948
afdlix


Area forecast discussion
National Weather Service New Orleans la
448 am CDT Thursday may 3 2007


Discussion...
main forecast concerns for the period will focus primarily on the
convection expected over the next 36 hours and the possibility of
heavy rain and severe weather. Difficult forecast through Friday
with very different model solutions with regards to convective
development and the associated heavy rain threat across the forecast
area. Middle/upper trough currently over west/central Texas early this
morning is forecast to be kicked out across the lower Mississippi
Valley tonight and Friday as an upper trough digs into the western
Continental U.S.. as this takes place...the ejected upper trough is prodg to
take on a negative tilt as it moves across the lower Mississippi
Valley. The GFS is very aggressive with convective development
across the area later tonight and Friday and forecasts several
inches of rain across sections of the forecast area. While the GFS
is most definitely an outlier with respect to quantitative precipitation forecast totals and
convective feedback is a possible cause...it is noteworthy that it
has been quite consistent for several model runs in forecasting
heavy rainfall over the forecast area. The NAM...UKMET and
Canadian all agree in moving significant convection across the
area tonight and Friday...most likely in the form of an mesoscale convective system or
two...but they are much less generous with the quantitative precipitation forecast amounts. It
should be noted that the models have performed somewhat poorly
tonight in forecasting the rainfall over Texas. It is also
interesting to note that despite the GFS forecasting such heavy
rain over western sections of the forecast area tonight...GFS mav
guidance probability of precipitation are no higher than 40 percent during the period.


Although the forecast upper level jet pattern tonight and Friday
is not all that impressive...significant large scale ascent and dfln
aloft will prevail over lower Mississippi Valley late tonight into
Friday as the increasingly negatively tilted upper trough swings
across the lower Mississippi Valley. In addition...a very moist
and unstable atmosphere will be in place for this system to work
with high precipitable water values...precipitable waters of nearly 2 inches
forecast by the GFS and around 1.6 inches by the NAM...as a
forecasted low level jet of 30 to 35 knots brings moisture north
from the Gulf as it develops and translates eastward across the
lower Mississippi Valley. Both GFS and to some degree the NAM forecast
a low level boundary or convergence zone across the forecast area
late tonight and Friday that may well serve as a focus for
convective development and heavy rain. As far as the GFS is
concerned...it is not clear if this forecast boundary is
associated with any possible convective feedback. With all this
said...the inherited Flood Watch will be maintained but the
starting time will be pushed back until midnight tonight since any
heavy rain threat will not be until late tonight or early Friday
morning. Rainfall amounts of 3 to 6 inches with locally higher
values are certainly possible. Plan to also mention the severe
threat late tonight with damaging winds and large hail being the
primary threats.
Posted By: Crisis57 at 12:36 AM EDT on May 03, 2007.

I agree with you Story so far this season looks to shape up to be a busy one, Anyone know when it would be a good time to start investigating the Bermuda High and its location since right now may be to early


The Bermuda High usually anchors into place in July! Consistent High Pressure over the east coast will make the CONUS lows travel further North and West, thus having less of an impact on the movement of the high. High pressure has been lingering on the east coast and the long range forcast is for this to continue. That being said, if the forcast holds, I don't think we will see much movement in the BH before it anchors into place in July! Keep in mind that these are long range forcast and are subject to large errors.
Nevermind...
Its all about the passing of info,...best to be informed.Instead of 1st. The system has the potential to train T-storms over the same areas for extended periods tommorrow.
But we aint a-skeered,..LOL, Stay dry MissBennet!
I just realized yours is completely different from mine. =)
Thanks SJ. I had to step away for a bit
you too Pat! Me, I'll probably forget my umbrella like always. =(
The GFSx shows the trouble here tommorrow..then slides it toward Fla and weakens it,..sadly. Link
Yea patrap the dry weather across most of florida is expected to continue.Dont see any significant rain chances anytime soon.A couple of more weeks till the rainy season gets going for us.Lets hope.

Adrian's Weather
storyofthecane. Just wondering if you could post a pic of the SAL. I believe you posted earlier that it was weaking or at least the dry air across the atlantic was weaking.

Is there a pic you could put up? thanks in advance
hey pat, we ain't picky and certainly not greedy right now! we will take WHATEVER gfsx wants to give us, jo
Here is a pic of current SAL across the atlantic basin.More here




Adrian's Weather
There is still plenty dry air, North of 10 deg. North. But the dry air is lifting North and the ITCZ is begining to lift north as well. ITCZ is still a long way south, less than 5 deg.
Good Morning everyone. Listen if you'll would please stop bye my blog and read it. It's important.
Sheri
Morning all.

23, I am just going to start calling you stretch...lol☺

No problem kman, hey where are you and pottery?
Morning All,
Patrap, what is that blob thing coming up towards Cuba at the end of the GFS x run you posted?
thanks
SJ

If you mean where we live the answer is that I am on Grand Cayman in the Cayman Islands and Pottery is in Trinidad
Me stretch you gotta be kidding with guys here posting all kind large images lol!Anyway i was trying to post an image someone requested.Useing thumbnails is the correct way to post images during busy times but things are all quite and will likely stay that way for a couple of weeks.
WOW!! Finally, a rain shower here on 7-mile beach on Grand Cayman.Hope it will last a while.
Patrap you just had to say the words weaken it. i was hoping that it would be more along the line of staying strong and giving us some much needed rain.
This was sent to me by a friend yesterday afternoon threw email and it included Larry Cosgrove's thoughts on this summer and the tropics in 2007.For those how dont know Larry he is a broadcast/private meteorologist always gives a very detailed forcast.

Here is part of his thoughts on the tropics...

The Tropics
After a long period of westerly flow dominating the equatorial regions, GOES
EAST and METEOSAT 2 images show a slow regrouping of deep mean easterlies
over north central Brazil and central Africa. Perhaps most importantly
(favoring future tropical cyclone formation and growth), mesoscale convective
clusters are appearing while monsoonal-type synoptic-scale groupings are
disappearing from the Amazon and Congo Basins.

Thoughts on ridge...

) When all three heat ridges (Sonoran, Bermudan, Azores) interconnect, deep
mean easterlies will increase the threat of tropical cyclone landfalls in
the Florida Peninsula and along the Gulf Coast (most likely strike: Texas) in
late summer and early autumn.

A look at the overall synoptic pattern for atmospheric features and the SST
anomalies present around and over North America would seem to favor an
abundance of hot weather and increased potential for tropical cyclone landfalls.
The presence of abundant warm water through the lower reaches of the Atlantic
Basin, an upcoming (probably moderate intensity) La Nina episode and increased
ridging from the southeast to the middle part of the U.S. favors
disturbances striking the Florida Peninsula and western Gulf Coast. Some of the systems
may recurve seaward or toward Newfoundland, depending on the position and
strength of the Azores heat ridge."

If you want his complete forcast just email me and i'll sent it to you.Adrian
That is what I meant kman. Thanks!

I know 23, just giving you a hard time!

Great article you posted there. Nice sighting of source and all. I would love to read the rest of it.

Thanks!
StormjJunkie & H23- Thanks for stopping by. SJ I agree if everyone would get on board especially all the good folks here In the WUBA Family and passed the word on it might help, I mean well never know unless EVERYONE does it. Cause I know there's alot of people here, Just the word of mouth does wonders. Me and u both know this.
Thanks,
Sheri
I figured ya'lled be hyping the potental blob in here..


gfs. The NWS has been talking about the surface low forming for 24hrs now. Should move off to the NE but hoping it will erode the ridge before it leaves, giving FL a chance at a backdoor front come sunday...
I have a slightly unrelated question for yall, hopefully someone with some forecasting experience can shed some light on this for me.

When my local weather man forecasts that there is a 30% chance of rain, what does he mean?

1. There is a 30% chance that it will rain in the next 24 hours at a particular location?
2. 30% of the channel's viewing area will receive rain in the next 24 hours?
3. A certain location will receive rain for 30% of the day?
4. 30% of the people watching the news will see rain 30% of the time?

Do these numbers have any actual defined meaning, or are they just a heuristic measure?
No problem Sheri anytime....

SJ sent you the complete article threw email.

Its quite interesting as he seems to think the ridge will hold strong and force systems on a westward path towards the states.
23, I'd like to read all of it, too. Sounds very interesting. Is it too long to post?
Dont think there much chance of any kind of development there you can see the clouds being blown of to the NE.As far as the rain chances for south florida they look very low about 30 percent at best threw the weekend.The only bright side is temps are set to cool of a bit this weekend but should ramp back up into the mid to upper 80's by early next week with dry conditions persisting.Adrian


Adrian's Weather
Very interesting post you put up H23 do you mind emailing it to me so i can read the rest of it. I just hope that everyone in the gulf and Florida is ready for this season and didn't let there guard down after 2006.
Per NOAA~

Chance of Wetting Rain (CWR)

Is the likelihood, expressed as a percent, of a wetting rainfall (1/100th of an inch) at a grid point during the indicated valid period.


The low isn't really expected to develop, gfs & other models play it up more then what is expected with all that shear. It's not suppose to bring us the rain 23~ but if it fails to errode the ridge then you can kiss your 30% chance on sunday goodbye, cause there won't be a backdoor front...
crisis57 just sent that out to you.
Whats up Skye....

No rain just bright blue skys out there.Iam cool with that for now but we definately need the rain.
Thanks alot H23 his points of views and the article itself is very interesting if that high stays in place like he says wouldn't that be a repeat of what we saw in 2005?
I remember an old blog by one of the members saying the first storm would be May 15th. I've been marking my calendar. And we all have noticed the GFS forecasting that system 284 hours from now. Lands right around May 15th.
I guess I'm the lucky one. We had great downpour last night..
pat's down.....pat's down
dos any one no what day it is today????


The May 3, 1999, Oklahoma Tornado Outbreak was the first stage of a severe weather event that lasted from May 3 to May 6 and brought violent storms to Oklahoma, Kansas, Arkansas, and Tennessee. This article concentrates on the events in Oklahoma. On May 3, 66 tornadoes broke out in Oklahoma and Kansas. The most significant tornado first touched down southwest of Chickasha, Oklahoma, and became an F5 before dissipating over Midwest City, Oklahoma. The tornado tore through Bridge Creek, Oklahoma, leveling the town. Forty-eight people perished during the outbreak. This tornadic event ranks in severity with the Palm Sunday tornado outbreak of 1965. With a total of 66 tornadoes, it was the most prolific tornado outbreak in Oklahoma history, although not the deadliest.

Contents [hide]
1 Outbreak description
2 The Moore F5
2.1 Path
2.2 Casualties
2.3 Impact
2.3.1 The risk of using overpasses as storm shelters
2.3.2 Fujita scale
3 Other significant tornadoes
4 Damage estimates
5 See also
6 External links and references



[edit] Outbreak description
The day started sunny, warm, and humid. The Storm Prediction Center in Norman, Oklahoma initially issued a "slight risk" for severe weather for most of the state of Oklahoma early that morning. By late morning the latest observations and forecasts began to indicate an increasing likelihood of widespread severe weather, and the SPC upgraded sections of the southern plains to "moderate risk." By 3 pm, it had become evident that a widespread severe weather event was imminent. Parts of Oklahoma and Kansas were then further upgraded to "high risk." When a "high risk" is issued, this usually indicates a significant threat for severe thunderstorms and tornadoes including damaging tornadoes. The SPC issued a tornado watch by mid-afternoon as conditions gathered together for what would be a historic tornado outbreak. The CAPE values reached nearly 6,000 J/kg during the day.

The beautiful May morning gave way to raging dark skies in the afternoon. Large supercell thunderstorms developed and in the late afternoon through the mid-evening hours of that Monday, tornadoes began to break out across the state.

Confirmed
Total Confirmed
F0 Confirmed
F1 Confirmed
F2 Confirmed
F3 Confirmed
F4 Confirmed
F5
66 33 12 10 7 3 1

(based on NOAA Storm Data)


[edit] The Moore F5

[edit] Path

A home torn apart by the Moore, Oklahoma F5 tornadoThe most significant touched down just southwest of the community of Amber, Oklahoma, and headed northeast, parallel to Interstate 44, just after another tornado had passed over the airport in Chickasha, OK. (Note: it may be argued that the storms touching down in Chickasha and Amber were the same storm; however, for weather tracking purposes, each touchdown is counted as a separate tornado which is most probable.) The storm continued moving northeast, destroying the community of Bridge Creek and crossing I-44 just north of Newcastle.

The tornado then crossed the Canadian River, passing into far southern Oklahoma City. As it passed over Bridge Creek, Oklahoma, around 6:54 pm, a Doppler On Wheels (DOW: Wurman et al. 1997, Wurman 2001) mobile Doppler radar detected winds of 301 +/- 20 mph [1] inside the tornado at a height of 32 m AGL (Wurman et al. 2007). (The old record was a 257-268 mph wind measurement from a Doppler radar near Red Rock, Oklahoma, as reported in a formal publication by Bluesetein et al. (1993)). These winds, however, occurred above the ground, and winds at the surface may not have been quite this intense. The tornado continued on into Moore and then passed over the intersection of Shields Boulevard and Interstate 35 and back into Oklahoma City, crossing Interstate 240 near Bryant Avenue. The storm then turned more northerly, striking parts of Del City and Tinker Air Force Base near Sooner Road as an F4 before diminishing over Midwest City and finally lifting near the intersection of Reno Avenue and Woodcrest Drive.





[edit] Casualties

The frame of a pickup truck wrapped around a utility pole from the Moore, Oklahoma F5 tornado36 people were killed in this tornado. More than 10,500 buildings and 47 businesses were destroyed. This tornado caused $1.1 billion in damage, making it the fourth costliest single tornado in U.S. history. This was the deadliest tornado since the April 10, 1979 Wichita Falls, Texas Tornado which killed 42 people. However, early warning saved many lives. Warnings were issued well in advance of the tornado's arrival, and the Oklahoma City broadcast media interrupted programming to follow the storms on radar and even by helicopter. The death toll would have been much higher if people had not been warned so far in advance. Following the storm, three of the local television stations in Oklahoma City: KOCO-TV, KWTV and KFOR-TV continued coverage of the damaging and deadly tornadoes throughout the day on May 4.


[edit] Impact
Outbreak death toll State Total County County
total
Kansas 6 Sedgwick 6
Oklahoma 40 Cleveland 11
Grady 12
Kingfisher 1
Logan 1
McClain 1
Payne 1
Pottawatomie 1
Oklahoma 12
Tennessee 3 Perry 3
Texas 1 Titus 1
Totals 50
All deaths were tornado-related

[edit] The risk of using overpasses as storm shelters
Three of the deaths reported in the tornado were from people who took shelter underneath overpasses in the area of the path of the Moore-Bridge Creek F5 tornado. The deaths occurred at the 16th Street overpass over Interstate 44 in Newcastle (just east of Bridge Creek), at the Shields Boulevard overpass over Interstate 35 in Moore, and the overpass at mile marker 176.5 on Interstate 35 in rural northwestern Payne County (west of Stillwater).

The two overpass deaths associated with the Oklahoma City storm occurred when the tornado was at its most violent (i.e. F4 or F5) intensity. However, it is of note that the tornado that caused the fatality at Interstate 35 mile marker 176.5 in Payne County was of F2 intensity when it struck the overpass and was NOT in an urban area. This suggests, contrary to the Kansas Turnpike video (see the El Dorado Lake Tornado), that a tornado need not be a large, violent tornado with a considerable debris cloud to cause fatal injuries to people seeking shelter from storms under overpasses. In addition to the fatal injuries to three people, there were also many severe, potentially life-threatening and gruesome injuries inflicted upon people underneath the overpasses that in some cases has left these people with permanent disabilities.


[edit] Fujita scale
This tornado's remarkable wind speed, at the high extreme of the Fujita Scale's F5, led to much speculation that the scale would be modified to include an F6 category, due to the winds possibly exceeding 320 mph. This speculation ignored the fact that the Fujita scale measures damage rather than windspeed, since the scale was developed prior to the introduction of Doppler radar. Windspeed estimates associated with the different categories represent the speeds scientists believe are required to produce that damage rather than the windspeed in that particular storm. The damage caused by an F5-designated tornado leaves very little room for a higher category



thats right today is may 3dr 2007 wish is 5 year a go we had this
Posted By: Crisis57 at 12:33 EDT le 03 mai 2007.

Thanks alot H23 his points of views and the article itself is very interesting if that high stays in place like he says wouldn't that be a repeat of what we saw in 2005?

A repeat of 2005 is extremely unlikely as those type of seasons will only occur about once every fifty years.

One thing thats very important is not to put to much focus on numbers that are predicted as it only takes one to ruin lives.IF we have 25 systems form out in the middle of the atlantic it wont matter cause its the ones that actually make landfall that have the greatest impact.Use this time wisely and take advantage of tax free week on hurricane supplies coming a few weeks and have that hurricane plan in place.Adrian

Adrian's Weather
I here you i think i worded that wrong H23 i didn't mean a repeat of storms i meant a repeat of the placement of the B-high
Nice post about 'Today in Weather History' Taz...Interesting that so many people were injured under overpasses. Any idea why?
Here in east Central Florida today it's smoky, breezy and dry.
Posted By: Crisis57 at 13:09 EDT le 03 mai 2007.

I here you i think i worded that wrong H23 i didn't mean a repeat of storms i meant a repeat of the placement of the B-high.

We'll the high is hard to predict to weeks out but overall as the weeks progress we will begin to get a better idea how the steering pattern might be shaping up.
Chicklit well most people sould no not to hid under a overpasses
TSR has released their May forecast update.They dropped their TS numbers slightly with 16/9/4,compared to 17/9/4 last month.
Posted By: Chicklit at 5:16 PM GMT on May 03, 2007.

Nice post about 'Today in Weather History' Taz...Interesting that so many people were injured under overpasses. Any idea why?
Here in east Central Florida today it's smoky, breezy and dry.


The poeple get sucked out of the overpasses.

625. 882MB
Hey everybody, What has happened with the UKMET 12Z it look really weird! But the other models also showing a LOW PRESSURE IN THAT AREA MEANDERING!
Severe Weather starting to fire in Central and Southeast Florida. Very ripe outside right now!

Humidity: 60%
Dew Point: 72 F / 22 C
Wind: Calm
Wind Gust: 0.0 mph / 0.0 km/h
Pressure: 30.00 in / 1015.8 hPa (Falling)
Heat Index: 93 F / 34 C
Visibility: 10.0 miles / 16.1 kilometers
UV: 12 out of 16
Clouds: Scattered Clouds 2200 ft / 670 m

(Above Ground Level)
Afternoon all!

Interesting point 882. Granted that is around the 144hr time frame. THat being said, what I find interesting is the difference in the way the high plays out over the next week according to the Ukmet. Every other model has been putting a big break in the high and pushing the Western portion to the south....The Ukmet keeps it bridged and does not push it as far south. This seems unlikely since it is the outlier as of now.
Over the last few hours the low embedded in the surface front in the gulf is looking cool. No real convection - just a lot of the remnants of yesterdays storm. Still its getting into an area of warmer waters. Zoom in and Rock it on the controls. You can see the low at the center.

As it moves into an area of lower/decreasing shear and warmer waters - even though it wont do much, its like a test to show the potential of the area I guess.
Interesting that so many people were injured under overpasses. Any idea why?

One reason I saw on a show about tornadoes a few years ago is the wind is being funneled through a small space and can actually increase the velocity by 30% in that small space.
Gee, Airman...are you sure it isn't because they didn't live in Portugal?

;)
Could be. Thats an interesting theory. However I have never heard of a tornado in Portugal, although there was one in Spain a few years ago. Come on now NRAamy, Im being good tonight and not rubbing anything in.......yet.
Chiklit - about the underpass thing: generally overpasses are one of the most dangerous places to "take cover" in a tornado. However, there is a naughty little misnomer that its safe! So suddenly you have people caught on the roads during a tornado and they are all flocking to the most dangerous place (rather than a ditch, where they would be safer). I know for me, before I learned that it was unsafe - I spent many years thinking it was what people were supposed to do (what did I know about Tornadoes - I was from Utah!). I saw tornado videos that people made and it always showed them under the overpasses. I just thought that's what you did. Apparently there were other not so lucky people in my thought camp.
hello everyone i just saw this.

ATLANTIC...
THE ONLY AREA OF ACTIVE WEATHER IN THE ATLC DISCUSSION
AREA...OUTSIDE OF CONVECTION ASSOCIATED WITH THE ITCZ...IS
ASSOCIATED WITH A SLOW MOVING SFC TROUGH ANALYZED FROM THE NW
TIP OF HAITI TO 27N73W. LOW-LEVEL CONVERGENCE ALONG THIS
BOUNDARY ALONG WITH UPPER DIFFLUENCE/SWLY SHEAR TO THE E OF AN
UPPER TROUGH OFF THE SE CONUS IS GENERATING SCATTERED SHOWERS
AND TSTMS WITHIN 180 NM E OF THE SFC BOUNDARY AND FROM 28N-30N
BETWEEN 73W-75W. MOST OF THE MODEL GUIDANCE CONTINUES TO SHOW
DEVELOPMENT OF THIS SYSTEM INTO A CLOSED LOW WITHIN THE NEXT 24
HOUR OR SO AS IT GAINS UPPER SUPPORT BY THE TROUGH TO ITS W. AS
THIS HAPPENS...THE LOW WILL BE GIVEN A KICK BY THE UPPER
STEERING ACCELERATING IT TO THE NE. THE ONLY OTHER SFC FEATURE
IS A BACK-DOOR COLD FRONT THAT IS EXPECTED TO SAG INTO THE AREA
TOMORROW.

i think im no longer going to be completely trusting NHC forecasts, aren't they being limited to what they can tell the public now? Im sure that would entail not being able to let the public know of an active season ahead, they're probably going to now be more conservative than ever before. Does anybody know exactly what they are limited from informing?
interetsting draekon
880 mb need links. Heading south to Ft Lauderdale tomorrow Could be some storms for the ballgame. MI vs Cardinal Gibbons
not sure of the limitations on nhc but expect a differt approch remeber new cap at the helm so its a whole different ballgame and the first year for new cap is only just beginning