Blog Fiasco

April 20, 2014

Ten years since Jamestown

Filed under: Funnel Fiasco,Musings,Weather — Tags: , , — bcotton @ 8:47 pm

Ten years ago, I was sitting in my apartment on a rainy Tuesday afternoon. My last class of the day ended around 1:30 and I was settled in to get some work done on the forecast game that I ran for the University. WFO Lincoln had issued a few tornado warnings and there were reports of cold air funnels, so my friend Mike Kruze and I decided to spend the afternoon driving around getting rained on. Instead, we saw one of the most photogenic tornadoes ever recorded in Indiana. And then another one. And then a third (though this one is unofficial, since we could not see the ground from our position and no damage was observed in the empty field).

This was only two days after Mike and I had returned from a marathon drive to northern Iowa, where the most we saw was vivid lightning and large hail after sunset. By this point, I had been chasing for a year and a half. Chase attempts evolved from some undergrad doofuses piling in the car and driving around to a fairly mature venture with thoughtful forecasts, data stops, and real efforts to be in position. Of course, as luck would have it, April 20 ended up being somewhat of a doofus day. Mike had a data plan on his Sprint PCS phone, and it was just enough for us to pull up the occasional radar image. Without that, we’d never have found ourselves standing in rural Boone County with a tornado directly to our west.

At the time of the Jamestown tornado, FunnelFiasco.com wasn’t even a gleam in my eye. I was planning on making a career in the National Weather Service. I figured chasing would be a thing I did with regularity. Ten years on, I’ve earned my meteorology degree, but I’ve never worked as a professional in the field. I have one chase day in the last five years, and I’m less than a year from a decade-long tornado drought. I’ve still only chased west of the Mississippi twice. With a toddler and home and another baby due early summer, I’m not likely to get out this year. But I still feel the gentle tug of the storm, pulling me to go out and seek it. I know I will at some point. I just don’t know when.

March 10, 2014

Thoughts on the Weather Forecasting Improvement Act

Filed under: Weather — Tags: , , , , — bcotton @ 9:24 am

Insurance Journal reported last week on a bill sponsored by Representative Jim Bridenstine (R-Oklahoma). In a fit of poor reporting, the author says the bill makes the “protection of people and property a priority.” Unfortunately, the National Weather Service mission statement has included “protection of life and property” for years. The bill itself contains no such insulting verbiage. On the surface, it’s actually a welcome relief: a Congressman looking to direct over half a billion dollars of new funding to scientific research and operations. In reality, it strikes me as more of a pipe dream.

The average tornado warning lead time is currently around 13 minutes. The goal of Bridenstine’s bill is a lead time of 60 minutes or more. Stretch goals are good, but a 4x increase is not, perhaps, the most appropriate for legislation. Even so, there’s a question of how valuable such an increase would really be. Increased protection of property is probably not going to be that dramatic with hour-long lead times. It’s not like people can move their houses and businesses out of the way. Some damage could be prevented by securing loose objects and boarding windows, but it’s not likely to be significant.

Protecting life is the more important aspect, but would a one-hour lead time help? I’ve argued for years that there’s definitely an upper bound to lead times after which the returns diminish. My suspicion is that as the lead time grows beyond that point, people become more and more complacent. This argument has been based on hunches and unsubstantiated reasoning. It turns out, there’s evidence that increased lead time has no impact on injuries from tornadoes.

Even if the benefits are minimal, the amount of learning that would have to take place to get lead times up to an hour would aid our understanding of severe weather. The improvements to observation networks and modeling would benefit all areas of weather forecasting. Even  if tornado warning lead times remain unchanged, the scientific impact of this bill would be dramatic. I just worry that it’s setting the National Weather Service up for “failure”.

February 13, 2014

The Sperry–Piltz Ice Accumulation (SPIA) Index

Filed under: Weather — Tags: , , — bcotton @ 10:31 pm

Earlier this winter, Weather.com posted an article about a new index to rate ice storms. Setting aside the illiteracy of the author (the article talks about how the index was used experimentally in 2009), it’s a good introduction to a new-to-me index that can help meteorologists communicate impacts to the public. The Sperry–Piltz Ice Accumulation (SPIA) Index uses ice accumulation, wind speeds, and temperatures to predict the impact of winter storms on public utilities (particularly power lines). The algorithm appears to be protected by copyright, which is disappointing, since it limits the ability of the scientific community to evaluate the methodology.

Communicating impact is one of the major challenges in forecasting. Even when the forecast is technically precise, the general public often doesn’t know what to do with the information. Widespread use of the SPIA Index can help people and utility crews prepare. Unfortunately, the closed nature of the index may limit its adoption.

January 19, 2014

2013 severe weather watches

Filed under: Weather — Tags: , , , , , — bcotton @ 11:41 am

Greg Carbin, Warning Coordination Meteorologist at the Storm Prediction Center, recently updated his website to include maps of 2013 severe thunderstorm and tornado watches. I always like looking at these, because they highlight areas of increased and diminished severe weather threat. It’s important to not read too much into them though. As with hurricanes, it’s not always the frequency of events that makes a year memorable. 2013 was a below- or near-normal year for watches in the areas of Illinois and Indiana that were hit by a major tornado outbreak on November 17.

Tornado (left) and severe thunderstorm (right) watch count (top) and difference from 20 year average (bottom) by county. Maps are by the NOAA Storm Prediction Center and in the public domain.

Speaking of hurricanes, the quietness of the 2013 Atlantic hurricane season is evident in the below-average tornado watch count along the entire Gulf coast. Landfalling hurricanes are a major source of tornado watches for coastal states, so an anomaly in watches is often reflective of an anomaly in tropical activity. Preliminary tornado counts for 2013 are the lowest (detrended) on record. It’s not surprising, then, that the combined severe thunderstorm and tornado watch counts are generally below normal.

Severe weather watches (left) and departure from normal (right) by county. Maps are by the NOAA Storm Prediction Center and are in the public domain.

As you’d expect, Oklahoma and Kansas had the largest number of watches. What’s really interesting about the above map is the anomalously large number of watches in western South Dakota, western Montana, and Maine. Indeed, western South Dakota counties are comparable to Kansas in terms of raw watch count. Of course, that doesn’t mean the watches verified, but it’s an interesting note. Looking back through past years, the last 4 years have been anomalously high in western South Dakota. Is this an indication of a population increase, forecaster bias, or a change in severe weather climatology?

January 5, 2014

Never believe year-long forecasts

Filed under: Weather — Tags: , — bcotton @ 10:22 pm

On my to-do list, this post is titled “Chad Evans, you son of a bitch.” Though the specifics are about the failings of a specific local TV meteorologist, the broader lesson is that weather forecasts longer than about a week aren’t worth the time it takes to make or read them. AccuWeather’s 45-day forecasts have caught some flack for being awful, as everyone expected they would be. Less attention has been paid to verifying the long-range forecasts from WLFI meteorologist Chad Evans.

I decided to take a look at the September 2011 forecast to see how it fared (there’s probably a forecast from September 2012, but I’m too lazy to search for it). As the graphs below show, it’s hard to beat climatology for long-range forecasts. Interestingly, there’s not a noticeable drop in skill over time with temperatures. The precipitation forecast does seem to get worse over the life of the forecast, with the exception of a lucky break in the summer.

Forecast and climatology monthly average temperatures.

Forecast and climatology monthly average temperature errors.

 

Forecast and climatology precipitation total errors.

Forecast and climatology precipitation total errors.

Mr. Evans was smart enough not to include day-by-day specifics, except for Christmas. This year, he claimed  claimed to be 4-0 on his white Christmas forecasts. The forecast called for 1″ or more of snow on Christmas morning. Unfortunately, there was none. Several inches fell the week before, but warm and rainy weather the weekend prior took care of that. Speaking of snowfall, 10″ was forecast for January 2014. In six days, we’ve already passed that, and the snow continues to fall as I write.

In the first two months of the most recent annual forecast, the temperature errors aren’t awful, but the precip forecasts miss the mark pretty hard (though the direction of the error was right in both cases). As the year progresses, you’d expect to see the skill diminish.

Nov Dec
Tmax 9 1
Tmin 5 8
Tavg 3.9 2.1
Precip .73″ (25%) .95″ (38%)
Forecast absolute error

And that’s really the point here: seasonal (or longer) outlooks are really bad at giving specific information. You can sometimes make use of them for trends, but even then they’re not very reliable. I can’t fault a forecaster for busting a forecast, I’ve had plenty of busts. But presenting skill-less forecasts to the public is a disservice to the public and to the reputation of the meteorology profession.

December 24, 2013

New entry in the Forecast Discussion Hall of Fame

Filed under: Weather — Tags: , — bcotton @ 8:33 pm

As a Christmas gift to you, my dear reader, I have added two new entries to the Forecast Discussion Hall of Fame. Forecasters from WFO Lubbock put their area forecast discussion to the tune of “‘Twas the Night Before Christmas”. It’s pretty fantastic. Texas is apparently very Christmasty this year, as WFO Brownsville has included Santa in their discussion as well.

Because I’m in a giving mood, here’s a picture that WFO Miami posted earlier tonight. It looks like Santa will get his cookies at cruising altitude.

A sounding balloon with cookies attached launched by the National Weather Service Office in Miami.

A sounding balloon with cookies attached launched by the National Weather Service Office in Miami.

December 23, 2013

Why I hate winter

Filed under: Weather — Tags: , , — bcotton @ 10:31 pm

Whenever snow appears in the forecast, I’m filled with dread. There are two reasons: 1) I hate shoveling the driveway and 2) people ask me “how much snow are we going to get?” I consider myself a pretty decent severe weather forecaster. It’s my particular area of interest, and I’ve given myself some practice at it. Winter weather forecasting is a whole ‘nother beast.

It’s not just that I don’t like it, or that I haven’t practiced (both are true), but winter weather forecasting is really more challenging. There are a variety of reasons — some scientific, some psychological. The most obvious scientific reason is that temperature matters. A three degree difference doesn’t mean much when the temperature is 80 degrees; the rain will still be rain. When the temperature is in the lower 30s, a three degree difference can be the difference between rain, snow, or some awful mix. Surface temperatures aren’t the only ones that matter; small differences in the low-level air temperatures can have an impact on the precipitation type.

Even when you nail the precipitation type, how much snow do you get? A common rule of thumb is that one inch of rain is equal to 10 inches of snow, but that’s a really awful rule. The snow-to-liquid ratio can vary widely. I’ve measured from 2.7:1 to 30:1 at my house, with the average somewhere around 14:1. With half an inch of liquid, the difference between the rule of thumb and my observed average is 2″ of snow.

Then there’s the psychological aspect. For the most part, people don’t care how much rain falls in a given event. Sure, ridiculous torrents like southern Indiana saw last weekend are noticeable, but how many people can look outside and tell the difference between .25″ and .5″of rain? I bet they can tell the difference between 3″ and 7″ of snow, though. Snow also requires more preparation than rain does. You generally don’t see grocery store bread and milk shelves scoured clean before a rain storm. The highway department doesn’t put in overtime to salt the streets before it rains. Schools very rarely delay or cancel classes because of rain.

Snow draws attention to itself. It’s the biggest prima donna of the non-destructive weather phenomena. The natural result is that people become very sensitive to how well a forecast verifies. Unfortunately, it verifies “not good” all too often. I suppose this is my way of saying “is it spring yet?”

November 23, 2013

Reflecting on my tornado response

Filed under: Weather — Tags: , — bcotton @ 9:06 pm

A week ago, a large tornado outbreak struck the Midwest. In Indiana alone, 28 tornadoes caused considerable damage. Fortunately, the outbreak was well-forecast, and the human toll was much lower than for other similar events. I’m not going to review the synoptic conditions here, because this isn’t about the weather, per se, but how I handled it.

Map of central Indiana tornado tracks. Produced by the National Weather Service in Indianapolis.

Map of central Indiana tornado tracks. Produced by the National Weather Service in Indianapolis.

My friends Kevin and Colleen were visiting. Kevin is also a storm chaser, so shortly after they arrived he and I were on the couch with our laptops, watching a line approach us from the west. The first indications that the forecast would verify were the startling images from Washington, Illinois. The early pictures of the damage left no doubt that the environment would support violent tornadoes.

By early afternoon, it was time for my daughter to take her nap. My wife took her upstairs and the adults sat downstairs and socialized. And watched radar. As the line approached, several areas of concern presented themselves. Kevin and I considered a trip north to Fowler, but decided that with the speed the line was moving, we’d have a hard time intercepting it. The linear nature of the storms made visibility and escape real concerns as well. Around that time, I noticed another area of rotation around Interstate 74 near the Illinois/Indiana line. I remarked that it was heading for us, so that was another good reason not to go after something else.

As the 3:00 hour approached, it was evident that the rotation really was heading toward us, and I suggested that we should put our shoes on in anticipation of seeking shelter in the basement. When the rotation crossed into Tippecanoe County, I determined that it would pass safely south of us, but I was concerned about our friends on the south side of Lafayette. I let them know to get to their basement immediately. Around that time, Kevin went to stand on the front porch.

The rain began, and the wind picked up. At approximately 2:52 PM, the wind speed picked up dramatically. I estimated the gusts to be 80 miles per hour. Kevin came running in from the porch and said we needed to get to the basement right away. My wife was already on her way upstairs to grab my still-sleeping daughter. A few seconds later, we were all downstairs. Kevin had seen a sudden shift in wind direction, and the blowing leaves lifting up made him wonder if we had just been tornadoed. I began to wonder if I had made an error in judgment.

After a couple of minutes, we went back upstairs. The power had gone out before we went to the basement and it remained off (it would be about 39 hours before power was restored to my house). I went outside to survey the damage and was pleasantly surprised to see none. Four and a half miles to the south, it was a different story. NWS damage surveys would show that an EF-3 tornado had carved a 29-mile path across three counties, causing major damage to two area manufacturing facilities.

After an event like this, it’s natural (and appropriate) to look back and see what went right and wrong. Before the storms arrived, we had packed a diaper bag and brought it downstairs. We constantly monitored the weather conditions. I correctly judged that we were not threatened by the tornado. What I did wrong was I focused solely on the tornado threat. With the line moving at 70 mph, the wind threat was considerable. Although it didn’t cause any damage at our house, an 80 mph wind gust is not something to take lightly. My timing was okay, but in retrospect, I’d rather have pulled the trigger a minute sooner to make our trip to the basement more controlled. Even though we were well-prepared, the execution was still uncomfortably rushed. The balance between minimal disruption and safety is sometimes hard to make.

 

KIND radial velocity image from 1952Z on November 17. The area of rotation (circled) is moving northeast. The X roughly approximates the location of my house.

KIND radial velocity image from 1952Z on November 17. The area of rotation (circled) is moving northeast. The X roughly approximates the location of my house.

September 26, 2013

Added weather songs

Filed under: Funnel Fiasco,Weather — Tags: — bcotton @ 10:18 pm

A while ago, I wrote some weather-themed song parodies. I’ve finally dug them up and posted them to the Funnel Fiasco weather page. Sadly, I can’t seem to find the song “Your Progs” that I co-wrote with my friend Joe. If I can ever find a copy of it somewhere, I’ll add that, too.

September 23, 2013

New discussions in the Hall of Fame

Filed under: Funnel Fiasco,Weather — Tags: , — bcotton @ 1:47 pm

This has been a good week for the National Weather Service. Two new discussions have been added to the Hall of Fame.

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