After about 17 inches of snow yesterday, Flagstaff went under a blizzard warning last night. Apparently the first one in about ten years. It blew pretty hard for much of the night, and I could hear things falling over in the carport. Between 11 pm and midnight, power flashes lit up our windows, followed by a darkening of the sky until power was re-routed. That happened three times with the last outage being the longest. We wondered how cold it would get in the house if it lasted all night. We've got four bodies and lots of blankets, so it wouldn't be unmanageable--just uncomfortable.

By morning, the snow was done, and the wind had died down. All snow covered surfaces were encrusted in an inch-thick layer of snow-ice. Shoveling the walk and driveway required chopping it into squares like a frosted dessert. My back, shoulders and arms have been complaining all day and will probably be a real mess tonight.

The morning after a big snow is always beautiful. As I worked on the mortared snow, I was treated to an amazing sunrise. All the remaining snow crystals drifting through the air allowed a sun pillar to form.

Some of the roads along the way to work were still suffering from blowing snow obscuring things.

The interstate was a dream to drive. I only saw 2 other cars on the way to work. It sounds like ADOT had closed access to I-40 from Kingman to Holbrook, so the only traffic was local, and that's me!

It's lunchtime!

Stormtrack.org is a website that serves severe weather enthusiasts. It has a particular focus on forecasting tornadic supercells and chasing them. During the off-season, some of the experienced members post "Chase Cases" where they pull up meteorological data from previous severe weather outbreaks without providing dates, and then gradually posting the information to give everyone a chance to forecast and do a virtual chase. I'm too inexperienced to post anything useful in the discussion, so I thought I'd post my own thoughts and results here as the chase goes on, to see how I do.

Earlier this week, they posted Chase Case #1 that involved a low pressure system moving out of the rockies into the Dakotas. In an effort to be realistic, I try to assume that I'll either start my chase from Flagstaff or from Elk City, Oklahoma. Being even more realistic, I figured there was no way I would chase as far north as the Dakotas unless I was really sure I knew what was going on. I saw a dryline positioned in western Kansas and thought I'd go for that as moisture moved up from the south. But I didn't think about how strong the CAP was in the area, and all I got to see were some small popcorn cumulus in the late afternoon. South Dakota went nuts with severe weather and tornadoes on that day, which turned out to be June 7, 2005.

And now on to the current chase case.

Chase Case #2

0Z Update:

A cold front is drooping down into the northern plains while a pronounced dryline is positioned southward from the Texas/Oklahoma panhandles. Rich moisture pooled in south Texas with surface winds pushing west-northwest. Directional shear looks really good across Texas and Oklahoma. Soundings don't look good to me in my limited experience, anywhere except the Del Rio sounding on the Texas/Mexico border where afternoon thunderstorms are blooming in all the moisture.

I'm not at all familiar with how a dryline and incoming moisture behave when the cold front is not pushing in from the west. I don't know if the drooping cold front will help with forcing in Kansas and Oklahoma. So I'm going to start my virtual chase from Elk City and will drive southwest to Lubbock, Texas, to get closer to the incoming moisture, high dewpoints, and to get in the vicinity of the dryline. I'm getting up at 2 AM to make the 4 hour drive and with stops and naps, would probably arrive at 7 am. I'll find a starbucks and check the 12Z data on my iPod. Then I can decide whether or not to head further south.

I just noticed a couple comments at the site about a possible "Caprock" event. I believe this refers to a geographic feature in west Texas that provides some orographic forcing. So I think if you can get additional help from the dryline, you can get a focal point for storms. We shall see.

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06Z Update

A 6Z weather service text update is posted.

If I were to check this before leaving at 2AM, it would probably influence my decision to leave Elk City at all. The weather service text in this update notes potential for severe thunderstorms east of a line from Amarillo to Hill City, KS and on into Nebraska. So, this all seems to set up much further north than I anticipated. The WS update shows that the moisture in the Rio Grande valley will be drawn northward by a 30-50KT low level jet. That's something I need to pay attention to in the future--is there a low level jet, and if so, is it positioned to maneuver available moisture.

Another issue is that the severe forecast did not extend much further down toward the Rio Grande. One participant in the Chase thread commented that mid level air temps were rather warm in southwestern Texas, and this would stabilize the air. One thing I need to understand is how to determine conducive temperatures at different levels in the atmosphere. Right now, I'm completely lost in this area.

The report does note current convection over Northwest/North-central Texas that could lead to an outflow boundary in Western Oklahoma/East-Texas Panhandle that would greatly enhance severe potential.

Anyway, I committed to Lubbock already, and rather than change the destination, I'll punish myself by wasting virtual fuel when I'll likely need to backtrack. I should still well set to easily reposition for action on the southern side of things in the panhandle. I love looking for outflow boundaries on morning satellite. It'll be interesting to see what shows up at 12Z.

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12Z Update

Looking at the 12Z Update satellite imagery, I think I see two outflow boundaries. One crossing the Red River in SW Oklahoma and another in the eastern Texas panhandle. The Temp/Dew Point data in the surface plot seems to show very moist air all over the plains. The dry line drapes from SW Kansas, through the western panhandles, and cuts to the southwest through eastern New Mexico. The 850 Mb chart shows winds pushing the moisture northward across the panhandles. Directional shear looks awesome all the way up, and the 300 Mb chart shows a 70-90Kt jet over the panhandles, Oklahoma and Kansas. CAPE over Amarillo is at a gorgeous 2805.

I'd like to be near the outflow I think I see in the eastern TX panhandle and further north to get closer to better upper level winds. So I'll make the 2.5 hour drive up to Memphis, TX, arriving there about 10:30 AM where I can check the 15Z update.

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15Z Update

OK. I've been schooling myself on chart analysis at this excellent site: Weather Prediction Education. There's a whole lotta work to be done, but I'll try and dig a little deeper each time.

If things go well on this virtual chase, it won't be because I got to the right spot for all the right reasons. I didn't look for Vort Max indicators at 500 mb, check for large tdd at 500/700 mb, look for short waves at 700 mb, look for low level convergence/confluence, or look for upper level divergence/diffluence over unstable air, look for jet streaks at 300 mb...and a million other things. Anyway, at this point, it will be about watching satellite, radar, surface plots, and text updates. So the better map mojo will have to wait for the next chase.

The 15Z Update shows a storm complex over south-central Oklahoma with hail potential, but not worthy of a warning. This may help push more outflow for things to work on later in the day. The dryline is still hanging way back at the New Mexico border and SE Colorado. Convergence isn't strong along the dryline, but it's only 9 AM, and the moist surface air hasn't had a chance to mix out or the winds to pick up. So I'm going to stay where I'm at and grab some virtual nap time in Memphis, TX.

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18Z Update

It's noon, and skies aren't clearing over the eastern panhandle. Will that kill surface heating enough to deaden the area? Then there's the dryline. It's not advancing. I wasn't sure what it was going to do without a cold front pressing it from the west. Now it looks like there is a surface low spinning over western Colorado, and I don't know if it will move eastward in time to push the dryline along. In fact, I don't know if there will be enough convergence along the dryline to make it a good source of strong convection. Winds behind are from the south-southwest, and winds ahead are from the south-southeast.

I think that would bother me enough to start heading northwest where I can get at least closer to clearing skies and the upper stretches of the dryline. I'm driving up to Claude, TX...the name sends a shiver down my spine...

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19Z Update

Whew! Didn't have to stop long in Claude! The 19Z shows that dryline just sitting there, but cumulus are starting to pop along it's boundary. So onward through Amarillo and up to Dumas, Texas. I should get there by 3 PM and anticipate I'll want to shoot on west then NW toward Dalhart, Texas where I think I see a dryline bulge. That will depend on development noticed along them way. I'll have satellite and radar bookmarks ready to go on the iPod so I can check quickly at the nearest Starbucks or hotel parking lot and adjust path in Amarillo, Dumas or elswhere along the way. Now, watch something unanticipated kick off convection where I was at...

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20Z Update

Stopping in Amarillo, I check the 20Z update to find that convection is strengthening along the dryline, and it appears to be pushing eastward a bit now. I'll push on toward Dumas and see how things look from there. I should arrive there about about 3:20 PM (2120).

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21Z Update and 2130Z Update

Something worked here! I approach Dumas as a storm with a great radar signature is blooming over the town. (I doubt I would stop to check radar and would just hop on this storm to see what it's doing.) Storm motion appears to be a bit north of east at 30 mph. I'll try following this cell eastward on Rt. 152 through Stinnett (reaching Stinnett at 4:00 PM (2200)) and then up Rt 207 toward Spearman if it seems productive and conditions allow.

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22Z Update and 2130Z Update

At 22Z along Rt. 152, the storm is growing, and it looks like I'm able to keep pace with it as it tears things up 5 miles to the north. The radar signature still looks great.

At 2230Z, I've broken off Rt 207 and taken Rt 136 straight north toward Morse, to get closer to this monster as it stradles the Hutchinson/Hansford County line. A beautiful inflow band is coursing in from the east. Wow! Just noticed, there is report of a wedge tornado near Pringle at 2235, moving ENE. That's on Rt 136, right in front of me!

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23Z Update

At 2300Z, Anvils from upstream storms have merged into the cell I've been following. My eastward road options are falling apart as I approach the east end of Hutchinson County. I need to decide if this storm is worth following from the west, or if I should head back down Hwy 207 toward Borger to check radar and see if the upstream storms are looking good. I think I had a good ride with this storm, and I'll head down to Borger and see if anything looks good along the way, or else check radar when I get there (which should be about 2345 if I don't divert along the way).

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Final Reports

The day was May 5, 2002

Looks like I may have been able to view another strong cell on the way down to Borger, but all remaining tornado reports in this direction happened south of Amarillo in Happy, TX. The storm I was following earlier appeared to put down a couple more tornadoes at the Oklahoma border, and further into Oklahoma. As dusk darkened the sky, I'm not sure what my escape plan would have been with more storms flashing to the southeast. I guess I'd hang out somewhere with wireless and see how they were moving and developing on radar and then time a good path home or to dinner.

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Summary

This virtual chase worked perfectly. I caught the Pringle tornado, and it looks like I got to witness some beautiful storm structure along the way. And it was not because I forecasted well. I need to work on a lot on chart analysis. But I also need to understand how boundaries respond to different starting conditions. The dryline fired further west than I thought it would. But then, it wasn't being pushed along by a trailing cold front. From the first hints of cumulus along the dryline (1800Z) to serious convection (2000Z) to the first supercell (2100) was under 3 hours. So I need to have that ballpark time frame in mind when I see the first signs of cumulus building on the dryline and try to decide what I have time to drive to. It was also helpful to note that the cell I followed formed along the southeast quadrant of the dryline bulge noticed earlier in the day.

Eric Nguyen's analysis of this day can be found here: 2002 May 5.

Silver Lining Tours report on the chase and how the Pringle storm evolved as it traveled into Oklahoma: Tour 1, Day 10.

Animated GIF showing my virtual chase route and basic rationale can be found here (1.5 Mb): Chase 2 Animation.

My first attempt at photographing fluorescent minerals was pretty rough. Although the rocks looked great visually, the camera was less than pleased with the situation. I'm currently using a simple black light to do this, and I quickly realized that the huge amount of visible light produced by these lamps tends to swamp the camera's CCD/CMOS. It really overwhelmed the actual fluorescing colors in my first batch, and I had to do a lot of heavy overall correction in Camera RAW and LAB color space.

After doing some more research, I realized that this is just what professional grade UV lights are made to overcome. They are filtered to emit very little visible light, so that everything you do see and photograph is the result of genuine fluorescence. Because I'm not ready to invest in that kind of set up, I decided to piece together a more affordable system and see how I like it. I purchased a Long Wave UV Filter from UV Systems and paired it with a Phillips black light bulb from Home Depot. By positioning the filter above the rock, then resting the black light over the filter, I got an immediate improvement. Visually the difference was apparent, although not really spectacular. However, the photographs benefited immensely. Notice the comparison below.

The first image is from my original set of photographs using a GE black light bulb and no filter. The second image is from my latest set of photos using the Phillips black light bulb and the Long Wave UV Fillter. These are original, unprocessed images, opened using the default Camera RAW settings, with only scaling, cropping and labeling applied.

Original photo using GE UV bulb and no filter
 

Latest photo using Phillips UV bulb and Long Wave UV filter

I've replaced the images in that original post with the new photos, including a new angle of the rock to show a striking sliver of white running across one side.

I had basically given up on a piece of fluorescent chalcedony from that original photo session that glowed with a soft orange. The purple overwhelmed it and I couldn't get rid of it without eliminating the fluorescent orange too. Using the new bulb and filter I got excellent results with it last week. So I'll eventually get that one posted here too.

Comstock Mine Dumps
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Amanda picks through the rocks at the base of the mine dump.
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On the last day of a camping and rockhounding trip through Northern Arizona and Southern Utah, we visited a mine dump west of Cedar City, Utah. The rock piles were immense and forbidding. But there was much to be found. The material contained a great deal of magnetite as we later discovered its effect on a compass needle. I still haven't identified a number of the clear, cream, yellow and orange crystals that adorned the stones we brought back. Several specimens turned out to be fluorescent, glowing orange, yellow and white under long wave UV. This is definitely an area I would like to pick through again.

Collection of rocks I collected at the site.
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Collection Site	Comstock Mine Dumps, Iron County, Utah, USA 37:36.874 N 113:23.576 W
Date	June 21, 2009
Minerals Collected	Calcite, Dendrites, Magnetite, ++

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This stone is only mildly magnetic, giving just the slightest tug on a compass needle. Rust colored and clear crystal runs through it. The outer structure of the orange mineral is best seen in the enlarged image. A very small, turquoise colored fleck can be seen in the center of the wide image. I'm not sure if this is contamination from another stone in the rock dump or if it is native to this specimen, but we collected no other material of that color. It is yet another piece in need of testing to try and narrow down the species.

One possibility I'll look into is whether the orange/brown material is Limonite after Pyrite. The external brown form has emerging crystal forms that appear to be cubic amid striated, botryoidal features.

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Mineral Type	Magnetite - Fe+2Fe+32O4 Unidentified Minerals
Size	7.5 x 4.5 x 3 cm
Collection ID	09062107J
Collection Location	Near Comstock Mine, Iron Springs County, Utah, USA 37:36.874 N 113:23.576 W
Collection Date	June 21, 2009

We've enjoyed some evening lightning lately--the best kind of fireworks.

This first shot was from Edmond, Oklahoma on August 5, 2009. While sitting outside, we watched as a line of anxious cumulus to the north finally pushed their way through the cap and sprouted a healthy storm. The frequent and constant lightning illuminated the crisp, sculpted edges of the cloud and occasionally revealed bright stitching as warped streamers fell from the sides.

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Subject	Cumulonimbus and Lightning
Location	Edmond, Oklahoma, USA
Date	AUG 05, 2009; 10:07 PM CDT
Equipment	Canon EOS 300D + Kit Lens
Settings	30 sec, f/9.0, 18.0 mm, ISO 800
Processing	Noise reduction, power line removal, contrast & color management in Photoshop CS3

This next shot was taken from home earlier this evening as a storm was pushed north by a line of convection along the Mogollon Rim. Flagstaff doesn't often see evening lightning displays since the storms fire up earlier in the day before racing off to the lower elevations leaving more stable air behind for the rest of the night. That wasn't the case tonight and we saw some brilliant webs of light igniting the sky to the south.

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Subject	Lightning
Location	Flagstaff, Arizona, USA
Date	AUG 12, 2009; 08:26 PM MST
Equipment	Canon EOS 300D + Kit Lens
Settings	30 sec, f/9.0, 18.0 mm, ISO 200
Processing	Noise reduction, contrast & color management in Photoshop CS3

Click image for larger version.

This delicately detailed pair of stones seemed a bit out of place among all the other material at the mine dump. I couldn't leave them there. A quick scan in a couple field guides suggests Dendritic Pyrolusite. However, it appears that the true mineral identity of the dendrites requires some meticulous laboratory examination...which means I'll leave this identified generically for now.

Eric Graff has been providing a lot of helpful input on the specimens I've posted so far. He notes the following about this one:

Interesting rock! My first guess would be tenorite, CuO, (the only mineral listed from Iron Springs District that is noted for the formation of dendritic patterns).

From Mindat entry on tenorite: http://www.mindat.org/min-3912.html

Morphology:Paper-thin twinned aggregates and laths parallel {100} and elongated [011] (Vesuvius); striated [010] on {100}. Curved plates. Thin shining flexible scales. Stellate groups. Earthy, pulverulent.

Twinning:1. Common on {011}, producing dovetail reentrants and feather-like forms as senn on {100}; also stellate groups andcomplex dendritic patterns. 2. On {100} ?

My second guess would be iron oxide (hematite) as I've heard that can also form dendritic patterns. While manganese oxide does frequently form these types of structures, I don't see any manganese-bearing minerals from that district.

Eric

Thanks Eric!

I'm wondering about scraping some of it off and attempting a flame test on it...

Click image for larger version.

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Mineral Type	Dendritic Condensations
Size	21 x 7 x 8 cm, 8 x 7 x 3 cm
Collection ID	09062105J, 09062106J
Collection Location	Near Comstock Mine, Iron Springs County, Utah, USA 37:36.874 N 113:23.576 W
Collection Date	June 21, 2009

White Light View
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Long Wave UV View
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Amanda collected this little chunk of crystal-infused magnetite. It featured two different types of crystaline structures. The best part though was seeing it under a black light. The two different crystal types fluoresced with different colors: yellow and orange. Additionally, some less prominent material exhibited a white fluorescence. It should be interesting working on identifications for this one.

The LW Ultraviolet images can be seen below each of the white light views. Visible in the second set of images is a beautiful, thin vein of the white-fluorescing material along a less exposed edge of the stone. This was my second attempt at black light photography. It turns out to be pretty tricky. My first set of image exposed a huge amount of visible purple from the light that didn't seem as prominent visually. A lot of heavy color balance gymnastics in the camera RAW conversion process brought it back to something that was workable. Further work in the LAB color space while looking at the rock under black light was also required to take it the rest of the way.

After doing some more research, I picked up a Long Wave UV Filter from UV Systems. I also picked up an 18" black light bulb manufactured by Phillips since it apparently has a higher density of UV compared to visible emission. Placing the LW UV filter across the bulb produced a noticeable reduction in visible purple and the photographs turned out much better. I didn't need to horse around with color balance in RAW or LAB. The only issue was some of the crystal faces that reflected the light directly into the camera still possessed a purple appearance, and I needed to use the selective color filter to remove that. The images you see here are a result of that 2nd set of photographs.

White Light View
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Long Wave UV View
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Mineral Type	Magnetite - Fe+2Fe+32O4 Unidentified Crystal Unidentified Crystal Unidentified Crystal
Size	11 x 8 x 3 cm
Collection ID	09062104A
Collection Location	Near Comstock Mine, Iron Springs County, Utah, USA 37:36.874 N 113:23.576 W
Collection Date	June 21, 2009

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The larger crystals on this rock are about 1 cm in length.

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Mineral Type	Calcite - CaCO3 Magnetite (Matrix) - Fe+2Fe+32O4
Size	15 x 16 x 8 cm
Collection ID	09062103J
Collection Location	Near Comstock Mine, Iron Springs County, Utah, USA 37:36.874 N 113:23.576 W
Collection Date	June 21, 2009
Testing Results	Crystals: Acetic Acid: Positive Reaction Streak: Colorless Hardness: 3 Magnetite: Magnetism: Positive, weak Streak: Dark Gray Hardness: 3-6

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This piece of magnetite possessed the largest crystals of those we found on July 21st. Although, even at that, the longest edge on any of the crystals is no more than 6 mm.

Mineral Type	Magnetite - Fe+2Fe+32O4
Size	6.5 x 5.5 x 2.5 cm
Collection ID	09062101J
Collection Location	Near Comstock Mine, Iron Springs County, Utah, USA 37:36.874 N 113:23.576 W
Collection Date	June 21, 2009
Testing Results	Magnetism: Positive, weak Streak: Dark Gray Hardness: 3-6