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APRIL 24: Mexico and Kansas
by Tim Vasquez
(4/24/07) -- A devastating multiple-vortex tornado hit the border towns of Piedras Negras, Mexico and Eagle Pass, Texas
Tuesday evening, killing 9 and injuring 40. Three of the deaths were on the Mexican side of the border.
More than 200 emergency responders, including National Guard units attached to the Border Patrol,
were conducting search and rescue efforts in the Eagle Pass area.
In other chase news, dozens of storm chasers reported tornado touchdowns northwest of the Hutchinson KS area.
These developed in a "last gasp" zone ahead of the cold front that had not been wiped out by the MCS activity
that plagued Oklahoma and parts of north Texas during the day.
The discussion forums (linked below) contain complete information on the tornadoes.
Earlier on Tuesday, an exceptionally powerful windstorm with torrential rain, driven by an intense cold core low,
lashed the town of Pueblo, Colorado. The airport recorded nearly continuous winds of 45 mph gusting up to 67 mph
for several hours, with visibilities as low as a mile in heavy rain accompanied by upper 30s temperatures.
The Pueblo Chieftain reported nearly 2000 homes without power, as well as over a foot of snow in the
mountains driven by intense upslope flow and orographic lift.
* Radar loop of Hutchinson supercell
* Radar loop of Mexican supercell
* Chase Reports
Photo: Tornado in Rice County, Kansas April 24. Courtesy Charles Edwards.
Top right: Piedras Negras - Eagle Pass storm, April 24.
Bottom right: Nickerson Kansas storm, April 24.
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APRIL 13: Tornadoes for Texas
by Tim Vasquez
(4/13/07) -- Two tornadoes ravaged parts of northwest and north central Texas Friday. Hardest hit was the area near
Seymour, about 120 miles northwest of Fort Worth, and the Fort Worth suburbs of Haltom City and Bedford.
The storms formed ahead of a powerful Pacific front that emerged from the Rocky Mountains Friday morning,
prompting SPC to put Texas in a rare high risk area.
The first isolated storm developed north of Abilene and moved across Seymour around 3 p.m. CDT before weakening in cooler air.
During its hour-long romp it brought baseball-sized hail and torrential rain to the U.S. 277 corridor, causing widespread
damage to vehicles in Seymour and destroying skylights at the hospital.
Further west, a squall line quickly formed and moved east to Fort Worth.
No major severe weather was reported until about 6 p.m. when a cell embedded in the squall line rapidly strengthened in Tarrant County.
This cell produced a tornado near Haltom City along with hail and high winds as it moved along US 183 through the mid cities,
across the Mockingbird area of Dallas, and into southern Garland where it strengthened again.
Other supercells developed elsewhere in Texas. A large supercell with a tornadic circulation
threatened parts of southwest San Antonio around 9 p.m.
The weather system was blamed for two deaths, both in the Dallas-Fort Worth area.
In Haltom City northeast of Fort Worth, a man was killed at a lumber yard after a pile of wood fell on top of him.
An Irving police officer died after his patrol car slid off a rain-slick highway and hit a light pole.
Five injuries were reported at a Fort Worth store whose windows blew out.
* Chase Reports
* Surface mesoanalysis - 18Z
Photo: Wedge tornado south of Seymour TX, around 3 pm 4/13/07. Courtesy Tony Laubach.
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Gas is expensive this spring
by Tim Vasquez
(4/8/07) -- Gasoline prices are up 25 cents a gallon in the Great Plains compared to a month ago, adding to the
worries of storm chasers.
Experts attributed the jump to a million-barrel per day cut in OPEC production, as well as problems at refineries which have cut production.
For example, Valero's refinery in McKee, Texas was forced to shut down after a fire on February 16.
Gas across the Plains this week averaged $2.64 per gallon in OKC,
$2.68 in Wichita, $2.69 in Dallas, $2.75 in Topeka, and $2.76 in Amarillo.
Nebraska's $2.78 statewide average surpassed that of all other Plains states.
The press reported that gas station operators have been seeing a decline in the sale of snacks and drinks due to the rising fuel prices.
It could be worse, though. Premium gas in San Francisco is currently as high as $4.19.
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Law enforcement trouble in West Texas
by Tim Vasquez
SILVERTON, TEXAS (4/3/07) -- Chasers have been discussing
a March 28 incident in Texas
involving unprofessional conduct by a law enforcement official in Briscoe County, or possibly Hall County.
At least seven witnesses reported that a sheriff east of Silverton near the State Highway 256/70 junction
was detaining multiple vehicles and verbally abusing and intimidating the drivers.
The incident was reported on Stormtrack this week by Texas chasers Jason Boggs of Amarillo, David Drummond of Lubbock,
University of Oklahoma chasers Zac Flamig and Gerard Jebaily, Wesley Luginbyhl and David Wagener of Norman, Oklahoma,
and longtime chase veteran Gene Moore from San Antonio.
Wagener said the officer also requested to see a "storm chaser license".
No arrests or citations were reported.
Great Plains law enforcement has a long tradition of acting with great professionalism and courtesy.
Naturally it's in the best interests of the chase community to see this continue, and to a great extent it's up to us to make this happen.
Stormtrack would like to encourage chasers, when possible and appropriate, to use their available gear to document
encounters with law enforcement.
This can (and should) be as simple as turning the camera on and setting it aside out of sight so that it can pick up ambient audio.
If any unprofessional conduct is encountered, videotaping the markings on the officer's vehicle as it drives off will
assure a binding record of the incident.
In serious instances, the video can be circulated on venues such as YouTube and acquired by local media, and in other
circumstances it can by the key to resolving an unfair charge and getting a citation dropped, potentially
saving hundreds of dollars.
On the same token we would like to restate the importance of driving and behaving safely out in the field.
There's little doubt that local yahoos and irresponsible media crews are an ongoing problem, and
Charles Doswell has stated that
even University of Oklahoma's chase crews have a history of unsafe conduct.
Chaser Gene Moore speculates that this kind of questionable behavior was occurring on March 28 and may have been a catalyst for
the incident.
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Top ten radar holes on the Great Plains
by Tim Vasquez
(3/28/07) -- Hopefully when you're close to the storm, you're going visual. But for those who prefer
the high-tech tools or for those chasing vicariously, radar holes can be a problem.
Where are the ten worst places to be for radar coverage? According to maps from
a 2001 study by Jian Zhang
of NSSL, as well as from my own
radar plots, let's take a look at the ten worst radar holes for Great Plains chasers:
10. Eastern Ozarks. I'm not sure what I'd think if I heard about a radar-indicated tornado warning
in Carter County, Missouri. On second thought, I'd probably take cover, if it's something so
significant that it's being picked
up within two-mile wide beam widths up at 20,000 ft.
9. Big Bend of Texas. You can't get further away from a WSR-88D in the U.S. than the Big Bend.
And they do get some big storms, especially in March.
I used to handle warning services for B-1Bs, some of which flew routes in Presidio County, and there
we had nothing to go on except satellite and the NLDN lightning detection network.
8. Far western Oklahoma. What's the storm in Roger Mills county doing? Well, fortunately it's Oklahoma,
so you can bet there's 90 people around the storm finding out.
7. Southeast Montana. This is a big hole even by Montana standards, and it's created headaches on
days like 6/23/01, 5/20/05, and 6/6/05. I'm not going to rank it as a bad
hole, though, since the population density of Fallon County (the epicenter of the hole) is barely 2 people per square mile.
6. Paris, Texas. It's ironic that Paris Texas, which was devastated by the 1982 tornado,
is at the exact epicenter of the northeast Texas radar hole, 110 nm from any radar.
5. Western Minnesota. I'm guessing that Scott Woelm, Peggy Willenberg, and Melanie Metz are all familiar
with Minnesota's radar hole in the Alexandria-Wadena area.
4. Palestine-Crockett, Texas. This is a gap I'm personally familiar with. I did a
review of the tornadoes that hit here in December
and I found the radar signatures to be really poor.
3. Central South Dakota / North Central Nebraska. What would happen if a tornadic storm was bearing down on
the capital city of Pierre? Would radar be of any use? Good question. I like that North Platte's
radar
is smack dab in the remote Sand Hills region, but further east as you pick up the corn belt it does get sketchy.
2. Raton Mesa complex, New Mexico. This is often a hot convective area when a cold air mass is stagnating on the Plains.
Ah, the familiar "AMA or PUX" radar dilemma, and if either of those go offline, it's back to satellite imagery
or 248 km radar.
1. Northern Missouri. I've got to hand it to Missouri -- this is poor coverage for such a well-populated area.
Woe to Kirksville as the calendar turns to June. I'm rating this a #1 radar hole.
Granted, I don't want to complain about our fine radar network, and money is certainly a finite resource,
but my hope is that we'll see these holes filled in one day to give better tornado detection coverage.
Also it must be mentioned that some media outlets do operate within NEXRAD holes... for example
KETK TV's radar covers the east Texas gap.
It's not Weathertap, but it is data.
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High Instability comes to your Internet Radio dial
by Tim Vasquez
(3/7/07) -- The third episode of the High Instability radio show aired last night
(Wednesday March 7) at 7 pm Central, and featured Roger Edwards.
The show, which runs about 90 minutes, is hosted by Gene Rhoden and
produced by R.J. Evans, and is broadcast live from Norman, Oklahoma.
Next week's guest is slated to be Jim Ladue of the National Weather Service Warning Decision Training Branch.
The guest lineup so far is as follows:
Show 1 - Charles Doswell - February 21
Show 2 - Kevin Kloesel - February 28
Show 3 - Roger Edwards - March 7
Show 4 - Jim Ladue - March 14
High Instability posts recordings of the program on Sunday.
You can listen to previous shows here.
NOTE: The show is equivalent to a PG rating for language and minor suggestive content.
* High Instability webpage
* Link to broadcast (LoudCity.com)
* Link to broadcast (WRBN.net)
* Winamp is strongly recommended.
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Storms hit Alabama
by Tim Vasquez
(3/1/07) -- CNN was reporting 15 deaths Thursday evening in
Enterprise, Alabama due to a tornado that crossed through the town
this afternoon. It was reported that students did take cover and
that the school had 28 minutes of warning, but
structural failures were responsible for the deaths and injuries.
Other tornadoes hit parts of Alabama, and in Missouri last night.
Ironically Enterprise is home to Enterprise Electronics Corporation,
whose website was down as of this evening. Enterprise Radar was a bidder
on the NEXRAD project and has sold radar systems to weather agencies
in Asia and other parts of the globe.
>> Radar animation of Enterprise tornado (school is
represented by square block)
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When you can't get radar, buy one!
by Tim Vasquez
(2/25/07) -- While digging through my photos this weekend I found some pictures
of a unique item of interest known to a lot of Dallas area chasers during the 1980s.
Back in those days, radar data was hard to get. Some cable companies (back when
public service was actually part of their charter) were starting to tie in to
NWS radars and show a basic presentation. However, even if you did get this information
you were limited to select zoom levels, plus whatever overlay they chose to use.
Enter Randy Byrd, a weather enthusiast in Rockwall just east of Dallas. Sometime
in the mid-1980s he purchased a WSR-57 unit from Georgia Power & Light, got the
appropriate licensing, and began doing his own storm analysis. That's how I hooked
up with him. Randy had the technology, and I had the knowledge. So I taught him a
bit of radar meteorology, and he allowed me time on his radar system to learn more
about storms that were going through north Texas in 1988 and 1989. It was great
to be able to take the controls and actually see the BWER and vault regions that
Les Lemon, Chuck Doswell, and others talked about in their articles. You certainly
couldn't see these things with regular TV radar.
The unit was not a cheap marine radar. This was a standard WSR-57 (the backbone
of the NWS network from the 1960s through the 1990s). It was equipped with a DVIP (digital video
integrating processor). It was probably state-of-the-art in the early 1980s.
The dish was mounted on a 40-foot tower atop a ridge
overlooking much of Rockwall County. In a little hut at the base of the tower,
a waveguide fed into a magnetron cabinet. The signals came from here into an
upstairs bedroom in his house, where a radar console and display showed
all the activity.
Some time after that I began forecasting in the Air Force and lost touch with him.
It would be interesting to know whether that relic of the golden age of meteorology
is still in working condition. I know at the time he was talking about adding
velocity (Doppler) circuitry onto the radar, but I'm betting that stalled as it
was only about 5 years before the Internet arrived and gave us all the gift of
high-resolution, multiple-product radar imagery, straight from the new WSR-88D units.
(All photos ©1989 Tim Vasquez; photographed April 28, 1989)
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Duststorm strikes northwest Texas
by Tim Vasquez
(2/24/07) -- A swath of dust blanketed a large portion of northwest Texas Saturday
as a deep surface low moved westward through the southern Plains.
Winds at the Guadalupe Pass observing site in west Texas peaked at 73 mph.
Official surface winds had reached as high as
64 mph at Lubbock,
63 mph at Childress, and 62 mph at both Snyder Texas and Frederick, Oklahoma,
Other gusts included 59 mph at Wichita Falls, 58 mph at Amarillo, 53 mph at Abilene.
Most media outlets in the southern Plains appeared to be asleep at the switch
in the midst of Saturday afternoon's events, however WFAA News
reported minor damage in the Dallas area and a business jet
blown off the runway at Dallas Love Field.
At DFW International Airport, 54 mph winds created a 45 mph crosswind on the primary runways,
forcing the closure of the airport. Over 400 flights were cancelled.
At one instant in time, Fort Worth Center was handling only 14 IFR flights in the north Texas region
Saturday afternoon, compared to a normal number of about 100.
Not surprisingly, the low raised a huge plume of dust from the Llano Estacado,
carrying it eastward across northwest Texas. Most of the dust was concentrated from
Interstate 20 to the Red River, and had reached Fort Worth by late afternoon.
Visibilities were as low as one mile across much of northwest Texas, and DFW webcams
showed scenery largely obscured by dust.
Conditions in the DFW Metroplex had dropped to solid IFR in dust conditions by 3 pm,
with DFW Airport reporting a 900 foot ceiling and Dallas Love Field reporting a 100 foot ceiling.
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So, you want historical satellite pictures?
by Tim Vasquez
(2/13/07) -- For us dyed-in-the-wool forecasting aficionados, it's always been near-impossible to get
historical satellite images of our favorite storms.
Some data is offered at the NCDC GOES browser
but it only covers 1996-2004 and is rather low resolution.
However a little known method exists for getting full-resolution satellite images back through the 1990s
and part of the 1980s. It's called CLASS (Comprehensive Large Array-data Stewardship System), a massive
database run by NOAA and another perk of your tax dollars.
The upside is that it's a fantastic warehouse of satellite images. The downside is it's very cumbersome
to use and not very user-friendly. However not to fear -- here's a guide to get you started.
CLASS RETRIEVAL TUTORIAL
1. Make sure your browser has Java enabled.
2. Go to: www.class.noaa.gov.
3. Click Register at the top right and make yourself an account. Because of poor design this system
does not make it obvious what your username is, however I think it uses the scheme "first.last" where
first is the first name you registered with, and last the last.
4. Before you go any further make sure you are logged in. There should be no "Login" at the top right of the page.
5. At the top dropdown search click on GOES Satellite Data - Imager (GVAR_IMG) for 1994 onward, or
GOES / VISSR for images up to 1995.
6. For Area of Interest or Coverage it's best to go with only the Continental United States choices and Other.
For Sub Mode (VISSR only) check only VISSR.
For Satellite leave them all selected.
For Temporal enter the UTC dates and time you want to look at (pick a small range; you can refine it later).
For Spatial pick your area in the map box; it is very important to set this up correctly because you
are actually sectorizing your image. I recommend a 9° high by 6° wide area for best results.
Rememember the U.S. has a negative longitude.
7. Now click Search.
8. A popup list of all possible satellite images comes up. Pick the satellite scan you want by checkmarking it
under the "Shopping Cart" column (try to pick just one). Generally you will
simply look at the times to get the closest match. You can View Details but the image thumbnails shown
are much cruder than what you'll get. When you're done, click Goto Cart.
9. In the Cart, go with the defaults shown, but remember to check JPG under Output Format. Click
Commit Changes. Then verify your email address at the top and click "Place Order".
10. You will see "Thank you for placing your order with the Comprehensive Large-Array data Stewardship System".
11. On the far left part of the CLASS web page you will see the choice "Order Query". Click this. Refresh
the page every few minutes. I prefer doing it this way instead of waiting for the email notification
as the emails are often slow or never show up.
12. When your order is finished, you're in business. Click on the little "www" link.
13. Now you will see various bands listed; 1 is visible and 2-6 are infrared. These are all JPEG files. Unfortunately CLASS
neglects to put a JPG file extension on these, rendering it unrecognizable by most browsers (sigh),
so you need to right-click on the image you
want to view and choose "Save As", choose a preferred directory, then enter a file name of "anynameuwant.jpg"
(you MUST use the quotation marks).
Personally I like to use "c:\temp.jpg" if I'm just browsing.
14. Now view that image by loading it in your favorite graphics program or pointing your browser at it.
The grayscale may need enhancement; decreasing the "Highlight" value in the Image Shadow/Highlight control of most
paint programs works well for this. You can also resize images with nonsymmetrical aspect ratios to remove
foreshortening.
Yeah, admittedly it's a lot of work, but to those of us who spend hours getting that unique picture of a
spectacular storm it's nothing new.
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The power of NOMADS
by Tim Vasquez
(2/11/07) -- Chasers are lucky to live in the United States. I think I could make a solid case that the
National Oceanic and Atmospheric Administration shares more weather data online than all other nations combined.
Lately I have been floored by the amount of data that NCEP and other weather agencies place on their servers.
To the right you see a plot for the morning of April 10, 1979, the day of the damaging Wichita Falls F5 tornado.
The risk and timing on this particular day was not well-understood until the final hours leading up to the event,
largely because the dynamics (shown in the illustration) went through a sparsely sampled area of northern Mexico.
The data density in that area remains poor to this very day.
How did I get this plot? Simple.
NOAA runs a rather sophisticated models distribution system called NOMADS.
I went to the
North American Regional Reanalysis page. I picked out the date and then asked for "Geopotential height analysis"
at 500 mb, then did another plot for Absolute Vorticity. I actually cheated a bit and merged 2 images in
PaintShop to get the examples you see here, as their built-in Heights and Vorticity tool didn't work and you
can't do more than 2 fields at the same time. However you can also get the data as GRIB files and use it
in a GRIB plotting program.
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Drowning in weather data
by Tim Vasquez
(2/8/07) -- I think finally we can say at last that chasers have reached data nirvana.
While it's still tough to get any useful information out in rural areas, the situation in
the 2000s is a phenomenal improvement over decades past. Nowadays anyone getting lunch in
a small town can find the latest surface plots, clear air radar loops, RUC runs, and more, in just minutes.
Let's step back and see how we got here.
The 1970s: The stone age
Imagine mulling over tomorrow's chase and having nothing but the 10 pm weathercast to go on.
Now you can see what pioneers David Hoadley and Roger Jensen were up against, who didn't have the
convenience of a weather school nearby like old guard NSSL/OU chasers did.
Back in the 1970s, your options were (a) track media weathercasts,
(b) visit a nearby NWS office or FAA flight service station, or (c) get NOAA Weather Wire.
The latter required a
teleprinter and dedicated phone line, but ironically these connections were cheap before deregulation
and I knew some people who had them at home.
The holy grail was a DIFAX connection, and though the connection was free this generally required a circuit to
NMC Washington through AT&T Long Line Services for $1200+ per month.
However some weather enthusiasts could get a hodgepodge of fax maps over shortwave radio, most of them for marine use.
In 1978, some PBS stations began opening the day with Aviation Weather, a highly detailed weather briefing show
that was a harbinger of things to come. It became A.M. Weather in 1985.
The 1980s: Computer technology makes inroads
Modems made inroads in the late 1970s and the concept reached mainstream America in the 1983 film War Games.
Right at this time CompuServe had begun offering some of the FAA 604 circuit data for a total of about $16/hr.
This competed with AccuData and WSI, which charged $30/hr on top of the long distance call.
Then of course we can't forget The Weather Channel, which went on the air in 1982. Under the
stewardship of meteorologist-at-heart John Coleman, chasers were served up 24/7 weather briefings by
weather school alumni: no Storm Stories marathons and fluff back in those days.
In the late 1980s, the FAA developed some systems that were known to be used frequently by chasers.
One was the IVRS (Interim Voice Response System), which allowed you to call a "voice menu" system and
enter station identifiers with your touchtone phone to hear weather observations.
One could easily plot maps by hand in this way.
This was quickly followed with DUAT, which offered free observations across the board with a 1-800 number.
The 1990s: The Internet and cell phone revolution
In 1994, the first Internet Service providers sprung up, allowing access to data via WWW and Gopher.
By 1995 the data scene was completely revolutionized, and nearly all chasers rapidly focused on the Internet.
One of the biggest draws was not necessarily model charts or observations but the brand new NEXRAD network
that had come online. Ironically though, you largely got bad radar or old radar due to the 1990s-era
WSI-DTN-Unisys monopoly, and many of us had to deal with unpleasant sites like Intellicast for our radar appetites
until better alternatives arrived later in the decade.
Cell phones also became widespread, and though it was not possible to connect to the Internet, it was
possible to use dialup services from the comfort of a chase vehicle.
Also the advent of compact direct broadcast satellite in 1996 allowed chasers to take DSS boxes and
get The Weather Channel out in the field where no other data could reach.
The 2000s: Wireless Internet reaches almost everywhere
It wasn't until 2001 when the first WiFi access points began popping up around the Plains. They spread like
wildfire through 2002 and 2003, allowing anyone to roam around a town and use an "open" Internet connection
to get data.
And for the rest of the story and the latest technology, you can continue in our
Equipment Forum.
I think it's safe to say that we're living in a golden age of data.
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Stormtrack celebrates ten years online
by Tim Vasquez
(2/6/07) — It came as a surprise to me when I realized (after the fact) that Stormtrack has entered its tenth year online!
If any of you are veterans of the old days, you may remember some of the page layouts illustrated here.
Anyhow let's look back on ten years of Stormtrack, starting with our first appearance online.
November 1996 - Stormtrack appears on the Internet at www.telepath.com/www/storm, shortly
after peaking at 930 subscribers in the storm chase frenzy following the film Twister. The front
page starts up as a fairly dry events calendar, but the chase logs are loaded with photos.
July 1998 - Stormtrack gets its own domain name at www.storm-track.com. The site
becomes a regularly-updated chaser news page and hosts a popular chaser directory.
October 2000 - Stormtrack Magazine merges with the legendary NIU Storm Chaser Homepage and moves to
operations at www.stormtrack.org to eliminate the old hyphenated domain name.
Cyberchase guru Gilbert Sebenste helps out for a few months to keep the site going.
February 2001 - Stormtrack starts its first online message board using Ultraboard.
January 2002 - Stormtrack Magazine sends out its last paper issue after a 25 year run, and becomes an online community.
February 2002 - Stormtrack closes Ultraboard and hosts its forum on
Yahoo Groups.
The Ultraboard incarnation saw about 10 posts a day, accumulating over 2000 posts during its one-year run.
Take a trip back in time and view it
(note: posts are nonviewable; sorry, it's out of our control).
May 2003 - We develop our first community blog system, with hundreds of stories posted during 2003.
Take a trip back in time and view it!
December 2003 - Our first major forum is developed using phpBB. The board gets vandalized while I'm in
the hospital with our newborn son, so we quickly appoint a team of moderators who become our community's backbone.
July 2005 - Stormtrack experiments with a separate forum area for established, experienced chasers called "The Core".
It proves to be too controversial of an idea and is withdrawn.
October 2006 - The Stormtrack forum becomes a vbulletin system and is moved to its own dedicated server
in San Diego. David Drummond of Dryline Hosting becomes our forum technical administrator
a couple of months later.
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