6/13/2013 Woodrow, CO Convection

Walker and I left DeKalb around 5 AM central with an initial target near Sterling, CO.  We weren't expecting supercells given the lack of vertical speed shear, but we thought storms may showcase an interesting view around sunset in eastern Colorado.  After dropping south out of Brush, CO, commencing a heckuva long drive on I-80 W, we soaked in a pretty view of developing convection near Woodrow, CO.  These storms provided a spectacular high-plains view for the next hour, before we slid east to stay ahead of the surging outflow winds.  These winds kicked up plenty of dust, including a few gustnadoes (see below).  We spent the night in Ogallala, NE, reminiscing about the spectacular scenery.

Mammatus on the high plains...ahh...

More mammatus

CG lightning strike

Bracketed exposure; probably one of my favorites so far this year

One of several gustnadoes observed

Timelapse of the day's convection

6/12/13 Mount Carroll, IL Tornado

Wednesday featured the first High Risk for severe storms across northern IL in nearly a decade.  It was nice to not be in a morning rush to get to a target area, as this was clearly going to be a "backyard" chase day.  I trekked over to DeKalb, IL around noon to pick up Walker Ashley (NIU; prof), Stephen Strader (NIU; Ph.D. student), and Matt Piechota (CoD; met student).  After glancing over some data, we jogged west toward Shannon, IL as a focus for an initial target.  Convection was beginning to form in all quadrants, and we wanted to make sure to "pick" the right storm.  We spent a few minutes time-lapsing a multicell storm southwest of Rockford, before heading toward the Rockford metro to latch on to a cell with a little better appearance on RADAR.  This new cell was quickly swallowed by a left-split produced by a supercell in southern DeKalb county (an impressive storm in its own right!).  We finally pit-stopped in Stockton, IL to grab a quick sandwich and monitor the RADAR.  While we were about to cut our losses and head back home, a new cell moving out of extreme eastern IA exhibited an interesting appearance and was drifting toward Jo Davies county in Illinois.  This area is less than ideal terrain for viewing storms, but it was really the only storm worth viewing at this point.  We latched on to this storm on Elizabeth road, roughly 8 miles northwest of Mount Carrol.  After finding a ridge to view from, it was clear that this storm exhibited numerous supercellular characteristics. We watched as a tornado formed (or perhaps was already in progress) roughly 7 miles to our northwest (still on Elizabeth road at this time).  We watched this tornado for ~10-15 min. before loosing sight of it due to poor terrain.  The next visual we had on the storm confirmed that our day was probably over.  Cool outflow was present at the surface, and it was clear that the storm was choking itself off. 

Oh, we still made it home to watch the Blackhawks play! 

Wide-angle view of the tornadic supercell northwest of Mount Carroll, IL (courtesy of Walker Ashley)

Initial view of the tornado (rain was making it difficult to see)

Look close and you can see debris in the sky...We later found out this was producing EF2 damage

Walker's Time-lapse

Matt's Video

5/26/13 LP Supercell east of Broken Bow, NE

Geesh!  Another day, another great structure show.  After sitting most of the day waiting for convective initiation in Arthur, NE, a few towers began to form to our east.  We scrambled after a dominant tower south of Broken Bow, NE, and we were treated with a great westerly view of the little precipitation supercell.  After getting east of the storm (and enduring 1.25" hail), we were treated with a beautiful view that allowed for a few chances at time lapse.  We watched this storm for a couple hours before heading to Kearney, NE for the evening to get some sleep (the next couple of days appear to be very active!)

Time lapse can be found here.

5/25/13 Supercell north of Box Elder, SD

Wow!  What a structure fest.  Saturday featured some fantastic supercell structure in a slow moving environment that allowed for easy chasing.  We sat most of the day in Chadron, NE, before blasting north to a storm that was persistent north of Rapid City, SD.  This storm was HP, Classic, and LP, during it's lifetime and treated us to many beautiful views northeast of Rapid City.  Enjoy the pictures (and especially the time lapse) from Saturday!  These types of chase days are the best...

Dad taking in the great view...

Timelapse can be found here.

5/24/2013 Holyoke, CO - Grant, NE Convection

A strengthening lee-side surface low was the play on Friday, with strong (20kt+) ESE winds into ne CO.  We watched towering cumulus from a park in Holyoke, CO, where I had the pleasure of meeting up the chase crew (Josh, Grady, et al.) from Western Kentucky University.  We watched the Holyoke cell most of the day and finally let it go near Grant, NE.  We also ran into CoD Trip 3!

I'm glad we let the storms shift to our east, as we were treated with some spectacular skies as sunlit mammatus and numerous cloud-to-cloud lightning strikes were plentiful.  A timelapse of our day can be found here.

Initial LP storm near Holyoke, CO

Beautiful sky near Grant, NE (looking east)

The REAL Mammatus!

Click for animated timelapse of convection.

5/19/2013 Edmond / Carney, OK Tornadoes

A moderate risk was in place for severe thunderstorms on the morning of 5-19 along a N-S oriented dryline in the Central Plains.  We had been eying Sunday's setup most of the week, and our plan was to play isolated storms along the dryline in central OK, as models had been hinting at robust thunderstorm development in that area for multiple runs.  Shear vector orientation (an important factor for storm morphology) was favorable in this area for isolated storms, and given the magnitude of the vertical wind shear (50+ kts.), isolated supercell thunderstorms appeared likely. 

We awoke in Wichita and immediately noticed an outflow boundary oriented E-W in central OK from our "Coldwater Cold Pool" the previous evening.

Morning Target "Tweet" (@gensiniwx)

We slowly drifted S along I-35 before stopping in South Haven, KS at a nice park for a softball game (1-0 good guys!).  After examining visible satellite for a couple hours and watching the 1800 UTC OUN sounding come in, we were excited that our morning forecast target may play out as planned.  Towering cumulus began forming near Oklahoma City, and we quickly loaded up to head south toward Edmond, OK.  The storm rapidly became a supercell before producing a tornado that hit Edmond (we watched a few power flashes as it moved through Edmond).

Tornado moving through Edmond, OK

What happened next was rather bizarre.  While navigating east out of the bears cage, we stopped at a house with a very long gravel driveway to turn around and face the storm for a view.  When it became apparent that the tornado was quickly moving toward this location, we dropped about 1/4 mi. south of this house and watched as it was struck!  Thankfully, the damage did not appear to be too bad, and to my knowledge, the residents were unscathed. 

After the rope out stage of the Edmond tornado, a new (much stronger) mesocyclone formed to the northeast of Edmond.  This storm had a much "meaner" appearance, and it was pretty evident that it was going to produce a large tornado...and it did.  The motions in this tornado were *violent*, in fact, more-so than in the video that I have seen of the Moore, OK tornadoes on May 20th.  This tornado had at least one large horizontal roll vortex, and appeared at one point to be two large tornadoes rotating around each other.

Wedge tornado near Carney, OK

 We stuck with this storm a little to long before dropping south to the storm that produced the Shawnee, OK tornado.  By the time we got there, that storm had become outflow dominant, but still treated us to many beautiful crepuscular rays at sunset. We ended the evening in Tulsa, OK, celebrating our great chase day and Morgan's (trip participant) 21st birthday.

5/18/2013 Coldwater Cold Pool

5-18 featured a dual dryline structure across portions of S central KS.  After sitting in Greensburg, KS for nearly an hour, we got suckered south to an area of clumpy towering cumulus that were forming in steeper lapse-rate air coming out of the TX/OK panhandle area.  Once this convection crossed the boundary into substantially greater surface theta-e values, we were interested to see what would happen.  Turned out that a large cold pool was already established before moving into this area and all we were able to view was an outflow dominant cluster of sub-severe storms.  We made a decision to head south for the better environment, yet a storm formed north of Greensburg that produced a nice tornado.  Storm morphology really killed us this day.

Moore, OK Tornado Warning: Upon further review...

I need to catch up on sleep and process some pictures from 5-19 (it has been a long ten days on the road with Trip 2), but I wanted to clear the air of some erroneous claims and facts that I have been hearing about yesterday's (5-20-2013) tornadoes in OK.  I've heard everything from "no warnings were issued" to "lead time was 45 min."

First, let me preface by saying I was not chasing on this particular day.  Sunday was the last day of our trip and we *had* to come home Monday afternoon.  However, the drive back to Chicago allowed me to watch the events in Moore, OK unfold with a keen eye.  Luckily, I archived a lot of data and am just now starting to sift through some of it.

The media reporting of the warning aspect of this storm is particularly troubling to me (in addition to many other rediculous claims certain local Oklahoma City stations were blurting out).  That discussion is for another post.

Let's take a further look into the timeline of the Moore, OK tornado warning:

5-20-2013 19:40 UTC   WFO OUN issues tornado warning (red polygon) including the city of Moore. 

I have included the 19:40 UTC tornado warning polygon and the 19:38 radar suite (BREF image shown) that likely prompted the tornado warning.

19:38 UTC BREF & Tornado Warning Polygon

At 20:01 UTC, WFO OUN issues a tornado emergency for the town of Moore.

At 20:16 UTC, the tornadic circulation was just southwest of Moore (probably just entering town around this time). 

20:16 UTC BREF and initial tornado warning polygon

20:16 UTC SRV (258 @ 23kts) and initial tornado warning polygon

Via radar, it appears the tornadic radar signature was in Moore around 20:20 UTC. 

20:21 UTC SRV and initial tornado warning

So, taking this approach (which I will agree is not the "T"ruth), this puts the tornado lead time for the folks in Moore at roughly 40 minutes! Not this bull#$%* I am hearing about 10-15 min! Even the tornado emergency had nearly a 20 minute lead time for Moore.  This was a great tornado warning by the same great forecaster who issued a tornado warning back on 3 May 1999 for an eerily similar situation.

Obviously, not all locations in the warning receive the same lead time.  It is a function of how far you are away from the tornado when the initial warning is issued.  This can make the lead time for a particular warning tricky.  If you score this on a city-by-city basis, then Moore has an amazing 40 minute lead time for this event. Hats of to the Norman, OK National Weather Service Office for a job well done!

It disgusts me how inaccurate journalists are becoming (see recent Boston Marathon bombing timeline).  Everyone races to the answer without doing the important detective work.  Ratings baby!

While I have your attention...consider donating to the central Oklahoma chapter of the Red Cross.  I had a pit in my stomach most of the day yesterday after hearing about the situation with the elementary school children.  The photos speak for themselves.

This is why I'm a severe storms scientist.

Now back to regularly scheduled blogging.

5/17/2013 Ellsworth, NE Convection Timelapse

COD's Trip 2 watched a nearly stationary storm for an hour in northwest NE on Friday afternoon.  This area is always a tough place to chase storms, because of the hilly terrain of the Nebraska Sandhills.  However, the area we stopped to watch this storm provided a unique opportunity to time lapse passing trains and convection spreading eastward toward our location.  At one point (during the end of the timelapse), this storm began to develop supercell characteristics, but then was quickly undercut by its own outflow due to a lack of vertical speed shear. Enjoy the timelapse!

Tomorrow should be a pretty interesting day across southern KS as the eastern fringe of the jetstream begins to overspread the central Plains.  Our current target is Pratt, KS for some significant storms around sunset.  Check back soon for updates.

5/17/2013 Ellsworth, NE Convection Timelapse

5/16/2013 Storm Intercept in Northwest KS

We intercepted a severe thunderstorm warned storm in northwest KS on Thursday afternoon.  We didn't stay to watch long, as we headed north to set-up for Friday's chasing opportunities in South Dakota. Make sure to watch the YouTube video in High Definition!

High-based pretty convection

http://www.youtube.com/watch?v=IsQf6pRNv0g

5/15/2013 Weatherford, TX Tornadic Supercell

Wednesday featured a unique setup in northwesterly flow behind a closed upper-level low pressure system migrating eastward over Oklahoma.  In short, we documented three tornadoes.  I hope to have better video after the season concludes and I can process it.  Until then, enjoy videos from our group:

http://www.youtube.com/watch?v=aSxauC_CIf0

http://www.youtube.com/watch?v=HaM2f17aK88

Rapidly Rotating Rugged Wall Cloud

Tornado!

Hello clear slot!

5/14/2013 Warmin' Up the Gear

Tuesday provided the first chaseable weather for College of Dupage's Storm Chasing Trip 2.  We awoke to some map analysis in Abilene, TX and decided it would be best to slowly drift southwestward toward Ozona, TX. We intercepted a sub-severe storm north of Rankin, TX, producing penny size hail and heavy rainfall.  We stayed ahead of the storms as they grew upscale and were treated with nice shelf features.  We were whitnessed a lengthy gustnado near Rankin (I'm trying to find students with decent pictures). 

4/28/13 Signs of Spring at Morton Arboretum

This spring (or should I say winter?) has offered few chances to get out and enjoy Ma' Nature.  Finally, this weekend offered back-to-back days of nice conditions with temps into the mid 60's amidst mostly sunny skies.  Jenna and I visited one of our favorite "nature" places (Morton Arboretum) this afternoon to take in the signs of spring as there have not been too many thus far.  With storm season in the offing, it was nice to get out and give all of the camera gear a test.  My first chasing trip departs on May 10th, so be sure to check back for soon for storm chronicles!

Bumble bee in action!

Very common site in IL this time of the year...

Drake Mallard

Whaddya' lookin' at?

Spatial Variations of Supercell Environments 1980-2011

Over the past couple of weeks, I've thrown together a spatial environment climatology of supercell environments based on 0000 UTC North American Regional Reanalysis data.  A "supercell" environment is defined here as MLCAPE >= 1,500 J/kg, 0-6km BWD >= 35 kts., 0-3km SRH >= 150 J/kg, all in the presence of MLCIN >= -25 J/kg (a small capping inversion).  This equates to an old 'fixed' Supercell Composite Parameter (SCP) calculation of around two.  Remember that a majority of right-moving supercells are associated with SCP values greater than a value of one (Thompson et al. 2003).  Basically, if a storm is present in this environment, it has a statistically significant chance of being a supercell. 

The spatial anomaly plots shown in the link below are all plotting the frequency of the particular threshold discussed above.  Keep in mind that environments favorable for supercells can (and often do) arise outside of +/- 3 hours around 0000 UTC.  Thus, this environment climatology is biased towards diurnally driven convective environments.  Black 'freckles' on the anomaly maps indicate a statistically significant (α=.05) difference between that particular year and the 1980-2011 climatology.  Before you ask, yes, I have made similar images for individual months, but I have not made an online repository for them yet.  Please send any questions to my e-mail, or comment below.

http://weather.cod.edu/~vgensini/NARR

Discover Python!

A few weeks ago, I visited Northern Illinois University (NIU; my Alma mater) for Geography's annual career day.  It is a day focused on networking for students and alumni that helps build and maintain a strong foundation for all who graduate from the program.

When the chance came to give advice to meteorology students (no, not the advice to ignore Gilbert!), I promptly responded with Geographic Information Systems (GIS) and Python.  There is an ArcPY module for Python, and many tools in ArcMap run via Python scripts.  In my opinion, Python is *the* answer for budding scientists.  Its ease of use, open source, and large support community nature make it an obvious choice.  However, don't ask just me!  The latest issue of the Bulletin of the American Meteorological Society (BAMS) highlights the utility of Python for use in atmospheric science.  Python can easily deal with netCDF arrays (numPy module) or GRIB data (Nio module), both of which are commonplace data formats in meteorology.

Patrick Marsh (OU SoM) does a lot of amazing things in Python, and it is easy to see how useful it can be for research purposes.

For example, a Python script of mine was able to deal with all 1980-2011 NARR data and produce this map in about 3 hours!

It's also great for plotting any sort of GRIB message:

Download Python today and get started!  Some of my most used add-on modules are:

NumPy
ArcPy (good BLOG here)
matlibplot
basemap
pygrib
netCDF4
pyNIO