A lot of the deaths appear to boil down to a few factors, but even those seem skewed. People who took the proper action died, and people that took no action lived. Therefore, there is no real finger pointer that wins here. The hope is that by better structuring the tornado warning process, people will be more likely to respond. However, one such speaker at AMS really captured my attention. Kim Klockow, a PhD at the University of Oklahoma really hit hard with what she said. (When the link comes from the AMS talk, I’ll be sure to post it). Klockow said that the first thing we need to do is to stop trying to control the people under a tornado warning. We cannot force them to act a certain way, no matter how hard we try, because it’s their right to act on their own free will, tornado or no tornado. This conclusion came about in her study of interviewing tornado victims and asking about their experience in the warning process. Almost all of the people Klockow interviewed took action, but the interesting thing was the train of verification it took for them to take action (again, the slides will make this easier to see when they come out). Several people only took action after verifying the tornado warning with 3 or more sources; some took an indirect action towards the tornado warning. For example, if the warning was issued and the person heard sirens, they would go inside, turn on the TV to the news station, and get their shelter area prepared and then wait for their warning to be verified on the TV. Klockow argues that this decision process of incremental action is natural, and the people that did this survived.

Therefore, my point to this post is to emphasize what Kim Klockow said in her presentation; it is not right of meteorologists to try to control a person’s actions to achieve a desired outcome. This sounds sinister, but it isn’t. Most meteorologists have very good intentions – they want to save lives in the warning process. However, if we acknowledge that people are smart enough to make their own decisions, then it changes our job from “how do we get people to respond?” to “how do we give people the most accurate and timely information so that they can make critical decisions?” THAT, right there, should be the core focus of the coming discussions about tornado warning effectiveness. In its current state, tornado warnings are good, but not effective enough. We’ve come a long way, but now it is time to go further yet. Hopefully you found this post intriguing, and I hope to get the slides up soon.

As far as my explanation, I am at the American Meteorological Society conference in New Orleans, LA. The image above (this morning’s sounding by LIX) is the fruit of this conference; Patrick Marsh released his new sounding analysis program called SHARPPy. I’ve been here since last Friday, attending talks, meetings, presentations, and the whole lot. I got to meet Reed Timmer, the now retiring Director of the National Hurricane Center, and Dr. Josh Wurman of the Doppler on Wheels (DOW). In other words, I’m in weather nerd heaven and having a great time. I return home Saturday and will be able to resume normal life, if life permits.

No severe weather is expected for the Middle Tennessee area over the next few days.

(LEFT: Surface Theta-E from a cold front on December 5th at 18z)

The decoder:

• New approach going from list indexing to loading data into dictionaries. This brings about an incredible speed boost in sifting through thousands and thousands of lines of METAR data.
• Several decoder bugs worked out while sifting through data
• NEW DATA SOURCE: Now reading data from http://metfs1.agron.iastate.edu/data/text/sao/ - This also speeds up the decoder because international stations like Iraq are not in these files, speeding up the sifting process.

GRIDMAKER:

• This new module handles ALL grid making processes, simplifying the plotting process and making the syntax more uniform.
• NEW GRID TYPES: 3 hour tendency (change over time) grids for all scalar outputs, new special grids (divergence, vorticity)
• NEW SCALAR GRIDS: Theta, Theta-E, Mixing Ratio, Relative Humidity, LCL Height in meters, SLP (Sea Level Pressure), wind speed scalar, wind chill, dewpoint depression, 3 hour tendencies of all of the above, and two new special grids: divergence and vorticity, including their 3 hour tendencies.

New Output Grid:

• Changed from a uniform 0.5 degree grid to the RUC 40km grid, the same grid used by the SPC’s mesoanalysis pages (Thanks again Patrick Marsh!)

More Data Observations:

• Canadian METAR sites
• Mexican METAR sites
• Caribbean METAR sites
• Cuban METAR sites

UI Improvements:

• Constructed a command-line UI – GEMPAK veterans need not worry; the command line syntax is based off of the GEMPAK model. I didn’t want to fix what wasn’t broken. This familiar syntax will help seasoned meteorologists and new users alike to be able to easily navigate the program without too much hassle.
• Plans for an improved GUI

And that’s just what has already been done – I haven’t even touched on what I have planned! Things like frontogenesis, advection of scalar quantities, and upper air maps are in the process of being planned out. I also have not forgotten about the meteogram plots; even though no new development has taken place on this program, a lot of the improvements in the mapping program will apply to the meteogram program. How interesting would it be to have meteogram plots of conserved quantities like mixing ratio and theta-e? Or meteograms of values like the lcl height? Could be very interesting!

All of this post is to say, some exciting progress has been made. I figured it would be good to post and update since the last post drew so much of a positive response. However, one VERY important part of the program remains unfinished – THE NAME! I was thinking that in honor of AWIPS/GEMPAK, I would name it PyWIPS: Python Weather Interactive Processing System. It sounds cool, but I don’t think the name makes that much sense. Perhaps I should turn to the interwebs for help! What do you think the program should be named? (RIGHT: Surface Vorticity from December 5th at 18z. Values are multiplied * 10 to the 5th)

So what is Python? Well, I won’t go into too much detail, as any Google search could probably enlighten you better than I. Regardless, Python could be summarized as just another programming language. However, that would not be the truth. The truth is that Python is a very powerful programming language. Confused? Google. They use Python!

So what am I doing with Python, and how is it weather related? Well, I’m doing a lot, actually, and it could be very useful data if the community so desires it. At first I decided to write a program to simply decode METAR (weather station) data from the internet, but then I realized I could do more with that data. So, I am attempting to write a full fledged surface data analysis suite that will include meteograms, contoured plots, station plots – you name it! How is this useful? Well, as far as I am aware, there is no program that shows the raw (contoured) station data on a map (station plots are a different story) – most data you see is from a model analysis, save for some programs that will show the METAR station data, but won’t visualize that data beyond an ordinary plot. The second reason that this is useful is because there is only one program that can come close to doing this kind of stuff, called GEMPAK, which I use often. However, it is a pain in the butt to build, is extremely complex, cumbersome, and quite “buggy”. Where it does succeed is in its high level of customization and its diversity in showing a large array of products. What I am hoping to do with this program is provide a lightweight, fast, and functioning alternative to GEMPAK while keeping that customization intact. Python just happened to fit the bill!

Obviously I am not starting ENTIRELY from scratch here. The only “from scratch” part is the program that gathers and interprets the data. The rest of it is made possible with MATPLOTLIB via ENTHOUGHT. Matplotlib is what I am using to visualize the data and does a lot of heavy lifting.

So what do I have so far? The two major ones are meteograms and surface contours (with wind barbs). An example of the meteogram can be found above: It’s bare bones right now, only taking in temperature, dewpoint, and wind data. In the future, however, it will also support pressure data and possibly precip. Meteograms are great for viewing data over time for a particular station. The one above is quite interesting, for station KOUN (Norman, Oklahoma), and if you look closely, denotes the passage of a cold front. The other plot I have completed is contouring the surface data on a map. This proved to be quite a challenge. Thankfully I had a bit of help from Patrick Marsh, so a big thanks to him! I won’t get too detailed, but the data is interpolated onto a lon (x) lat (y) grid (like a graph) and then plotted on a map via Basemap, a part of MATPLOTLIB. This is an example image output to your right (the program supports all major image outputs – PNG, GIF, JPG, PS, PDF, etc.). Quite visible in the map is a surface cyclone with a trailing cold front. Again, this is ALL RAW METAR DATA. No model analysis. Pretty cool, huh? The best part is, the program supports interactive viewing, with pan and zoom functions available. However, the user interface is primitive, at best.

So what now? Well, it may look like a lot is done, but this is only the bare guts. The next step (which I am in the process of doing) is to optimize the code and make it faster. After that, the user interface will need to be built, followed by plenty more code revisions. Another huge step is to make it more interactive with the user, taking in options that the user can specify. As you can see, there is a ways to go! But, because the foundation has been lain, I figured it was time to make this public. If you are all intrigued and would like to know more, you are more than welcome to email me or message me on facebook/twitter/google+. I’m going to refrain from posting any code online, but if you’d like to ask questions or even make suggestions (help is always appreciated), give me a holler.

Hopefully this post wasn’t too terribly boring, but I wanted to share the project with the interwebs. You’ll be seeing more posts and photos about this in the future as things continue to progress. It’s really coming together quite nicely.

On a side note, this experiment was part of the NOAA CAS Weather Camp at Jackson State University. We were observing the rotation and rising motion within the tornado. Other campers involved in this experiment were Rachel, Steven, Kevin, Kiya (probably spelled it wrong, my apologies) and Max.

Severe weather forecasts will resume once I return home, if anything of interest appears.

-Kelton Halbert

So, what makes this risk of particular interest? Well the days of May 9th-11th are showing potential with a low pressure system over the plains. It is still a little too far out to rely solely on the GFS, but it is suggesting temperatures over 90 degrees, dewpoints of 80 degrees, CAPE values over 4,000, and some moderate wind shear. Minor details such as timing are still unclear, and the values above are subject to change, but the SPC says it best.

ALTHOUGH THERE ARE DIFFERENCES IN THE GUIDANCE…THEY DO AGREE THAT BEGINNING ON SUN/D6…A LARGER SCALE TROUGH WILL DEVELOP ACROSS THE WRN STATES…WITH RIDGING DEVELOPING AHEAD OF THIS TROUGH OVER THE PLAINS STATES. THIS WOULD PORTEND A GREATER SEVERE THREAT…WITH THE POSSIBILITY OF 3-4 CONSECUTIVE DAYS OF SIGNIFICANT SEVERE DEVELOPING FROM THE PLAINS STATES INTO THE MIDWEST BEGINNING ON MON/D7 INTO TUE/D8 AND LIKELY EXTENDING INTO D9. IF TREND IN MODEL GUIDANCE PERSISTS…SEVERE RISK AREAS WILL LIKELY BE FORTHCOMING IN SUBSEQUENT D4-8 OUTLOOKS.

So, I will continue to keep an eye on the situation for Oklahoma. I will also update the website before I head out, and be sure to keep everyone not only up to date with how the trip goes, but with any significant weather that occurs here in Middle Tennessee. Enjoy the quiet weather while it lasts!

The Importance of SKYWARN Storm Spotters

Today’s topic of Severe Weather Awareness Week is the importance of SKYWARN storm spotters. SKYWARN is the national program used by the National Weather Service to train up local storm spotters. These spotters are the eyes and ears on the ground for the forecasters, because Doppler Radar cannot see the what is happening on the ground below the storm. Storm spotters report damage, hail, tornadoes, flooding, and damaging winds. Again, even with the advanced technology of Doppler radar, it can only detect what is going on above ground, so spotters remove the guesswork involved.

Spotters are important, because spotters help provide early warning of any severe weather criteria. They can tell you when, where, how fast, how large, and in which direction in a matter of a phone call, which provides excellent details that help forecasters make warnings. This was the case on April 10th, 2009, when a storm spotter reported a large tornado heading for Murfreesboro. Murfreesboro got the warning, reducing the possible loss of life. If you are interested in becoming a SKYWARN spotter in Middle Tennessee, visit this link for the schedule of classes: http://www.srh.noaa.gov/ohx/?n=ohxspotterclasses

So, this Thursday, the use of spotters in several states will likely be needed, as a severe weather pattern has been shaping up over the last few days. There is still a lot of disagreement in the models, so the shape, size, and severity of the area could diminish by the time of the event. The two main models, the GFS and the ECMWF, disagree, making it hard for forecasters to make a call. If the GFS model is right, then Middle Tennessee will likely miss the brunt of this severe weather event. However, if the ECMWF is right, the Storm Prediction Center believed that this area could be facing a very severe risk for supercells and tornadoes. They even put it in the days 4-8 outlook, which is rare for severe weather events to be called out so soon with certainty. Here is what the SPC has to say.

BY THU MORNING… A SURFACE LOW IS FORECAST TO BE SOMEWHERE ACROSS NWRN TX OR CNTRL OK WITH BOUNDARY LAYER DEWPOINTS AS HIGH AS 60F UP TO THE LOW CENTER….AND UP TO A WARM FRONT THAT WILL EXTEND EWD ACROSS NRN OK/AR OR PERHAPS SRN MO. A SURFACE LOW AND POTENT UPPER LEVEL JET STREAK WILL THEN CONTINUE EWD ACROSS THE LOWER MS AND INTO THE TN/OH VALLEYS BY 00Z.

UPPER LEVEL COOLING AND A PLUME OF STEEP DEEP LAYER LAPSE RATES WILL OVERSPREAD THE WARM SECTOR…CREATING A VERY UNSTABLE SITUATION. ALTHOUGH THE EXACT GEOMETRY OF THE TROUGH MAY NOT BE WELL HANDLED THIS FAR IN ADVANCE…THE CURRENT MODEL DEPICTION WOULD INDICATE THE POTENTIAL FOR NUMEROUS SUPERCELLS ALONG THE DRYLINE/COLD FRONT…RATHER THAN A MORE LINEAR STORM MODE. IN THIS SCENARIO…A SUBSTANTIAL TORNADO THREAT COULD MATERIALIZE BY AFTERNOON AND EVENING.

So, each day up until this event will be a topic of Severe Weather Awareness Week, followed by a forecast of the coming severe weather. Please keep checking back for more information!

“Tennessee declares emergency in advance of snow arrival

The Tennessee Emergency Management Agency has increased its activation level and called in additional staff to monitor the winter storm anticipated across much of Tennessee.

Update 6:30 p.m.: TEMA’s activation level was moved to level 3 and the state is under a declared state of emergency.

On Sunday at 6 p.m., James Bassham, Director of TEMA, raised the State Emergency Operation Center’s readiness to Level 4. In addition to staff being placed on duty at TEMA’s facilities in Jackson and Knoxville, a number of TEMA staff and emergency service coordinators from the Departments of Safety (Highway Patrol) and Transportation have reported to TEMA’s headquarters in Nashville.

TEMA’s Media Line will be available from 6 p.m. – 11 p.m. Sunday and again at 6 a.m. Monday morning.

Media can call 615-741-0482 to speak with a TEMA representative.”

Stay safe, as the snow will arrive in Nashville around Midnight tonight. The snow will continue until roughly Tuesday evening. It is safest to stay off of the road, as they will be slick with compact snow and possibly even ice. A Winter Storm Warning remains in effect until 6 PM Monday.

…WINTER STORM WARNING FOR ALL OF MIDDLE TENNESSEE FROM MIDNIGHT TONIGHT THROUGH MONDAY…

.A SURFACE LOW PRESSURE SYSTEM WAS CENTERED JUST SOUTH OF LAKE CHARLES LOUISIANA AT MID-AFTERNOON. A BROAD AREA OF WINTRY PRECIPITATION WAS SPREADING INTO CENTRAL ARKANSAS…AND INTO NORTH CENTRAL MISSISSIPPI…WESTERN ALABAMA AND PARTS OF EASTERN OKLAHOMA. THE WINTRY PRECIPITATION AREA WILL CONTINUE TO ADVANCE NORTHEASTWARD DURING THE AFTERNOON AND INTO THE MID STATE TONIGHT.

SNOW IS EXPECTED TO COMMENCE OVER FAR SOUTHWEST MIDDLE TENNESSEE AFTER 7 PM THIS EVENING…AND SPREAD INTO THE NASHVILLE AREA AROUND MIDNIGHT…AND OVER NORTHEAST MIDDLE TENNESSEE AND PLATEAU AFTER MIDNIGHT.

POTENTIAL SNOWFALL ACCUMULATIONS…GENERALLY TWO TO FOUR INCHES ALONG AND NORTH INTERSTATE 40…AND FOUR TO SEVEN INCHES OVER SOUTHERN MIDDLE TENNESSEE…WITH LOCALLY HIGHER AMOUNTS ALONG THE PLATEAU.

IN ADDITION…MORE SNOW IS FORECAST MONDAY NIGHT AND TUESDAY WHICH WILL ADD MORE ACCUMULATION TO THE SNOW TOTALS BROUGHT BY THE WINTER STORM.

Remember, this is because clouds are composed of water vapor. Just as air has weight (hence air pressure), so does water vapor. Fascinating stuff. I hope this intrigued you.