Not terribly much to update on actually. Doing school at the moment and still working the geography job. I’ve been walking more…perhaps since this is a geography blog, I’ll take random pictures of my travels at some point this week. It’s been awhile since I’ve done an activity space posting
My fiancé Cassie (who’s on WordPress and could use some encouragement to get herself writing more) started a new job today. Hopefully she’ll write about it on her blog, but it’s a soil fertility agricultural job working under a professor and his graduate student, just like I’m doing with geography. She’s very happy and excited to have a job related to her bachelor’s degree program. I hope it continues to work out for her.
Meanwhile, besides working, I’m doing some practice forecasting. But instead of the usual public forecast writing practice, I’m practicing severe weather forecasting. The practice entails forecasting an exact location in the Continental US for large hail, damaging winds or a tornado. I still write up a technical discussion for my own benefit. The goal is of course to get as correct of a forecast as possible…this means picking a location where I think the highest concentration of the severe weather type I choose will be. I use computer models and the Storm Prediction Center for guidance along with my own scientific intuition. I’ve done the practice for 4 days now (including today). Here are my results (Location, Severe Weather Type, Verification Location and Description, Distance of Verification):
Friday: Sioux Falls, SD - Hail, 1.5 inch diameter one mile west-northwest of Hartley, IA, 66 miles
Saturday: Fort Morgan, CO – Hail, 2 inch diameter five miles west of Akron, CO, 26 miles
Sunday: Hays, KS – Wind, 72mph gust in Russell, KS, 26 miles
Monday: Burlington, CO – Hail, 1 inch diameter 22 miles south of Burlington, CO (forecast period ongoing as of this post…but thinking this will likely be the closest hail report)
The verification goes out to 100 miles for the nearest storm report. This severe weather challenge is based on a real challenge done for a course for employees at the NWS dealing with severe weather and warning operations. I learned about it from a friend of mine who works for the NWS and I decided to give it a try. I’m trying to stick to the rules as much as possible including the scoring system as well as completing forecasts by 16 UTC for the 19 UTC-11:59 UTC valid forecast period. I’m on week two and will do it for another 6 weeks and then see how things turned out ultimately in terms of best and worst days and forecast precision on differing severe weather types.
The only other thing I have is that I shared my preliminary full thesis with Dr. Sherman-Morris of Mississippi State University…the professor who runs the Applied Meteorology Program. She’s the first person to read it in full. She said she liked it and found it interesting, especially the interdisciplinarity of it. She also said she would give it a closer read the next time she does a tornado-related paper I can apply to Mississippi State starting August 1st. I’m definitely looking forward to it.
All else is good in Brookings, SD. The weather is nice, although muggy. Glad to have summer finally here, even though I’m still having to do school. Once I’ve defended my thesis late next month, I’ll just be sailing my way towards graduation day in December.
This thunderstorm complex began as some severe storms in northern IL and is now moving offshore the coast of New Jersey. An incredible display of the power of Mother Nature as it delivered a swath of damaging winds (58mph+) across portions of IL, IN, OH, PA, WV, MD, DE and NJ. Anyone in WordPress world experience this thunderstorm complex today?
Click for the full-size animation:
Cool story from Smithsonian Blog on possible links between geography, altitude and the evolution of languages:
You likely don’t give a ton of thought to the sounds and patterns that make up the language you speak everyday. But the human voice is capable making of a tremendous variety of noises, and no language includes all of them.
About 20 percent of the world’s languages, for example, make use of a type of sound called an ejective consonant, in which an intense burst of air is released suddenly. (Listen to all the ejectives here.) English, however—along with most European languages—does not include this noise.
Linguists have long assumed that the incorporation of different sounds into various languages is an entirely random process—that the fact that English includes no ejectives, for instance, is an accident of history, simply a result of the sounds arbitrarily incorporated into the language that would evolve into German, English and most other European languages. But recently, Caleb Everett, a linguist at the University of Miami, made a surprising discovery that suggests the assortment of sounds in human languages is not so random after all.
So yesterday here in South Dakota, the southern sections of the state were expected to see the development and propagation of a significant thunderstorm complex which could produce a concentrated swath of high winds from Rapid City to Sioux Falls and possibly impacting me in Brookings. Well, while there were some scattered high wind reports, the event largely did not happen as expected. Now it wasn’t a completely busted forecast…while it was talked about by the Storm Prediction Center in Norman, OK during the morning and afternoon, the forecast was changed by mid-evening to reflect changes in thinking…the most recent forecast turned out pretty much correct compared to the earlier forecasts. But the earlier ones were definitely a bust. Let’s see why…
First, I’ll define some terms I’ll use in this brief case study.
Mesoscale Convective System or MCS- A large, organized complex of thunderstorms which can last several hours and produce strong winds and dump heavy rain and hail along its path
Convective Available Potential Energy or CAPE- The amount of potential energy for upward vertical motion (convection) which is stored in the atmosphere
Convective Inhibition or CIN- The amount of potential energy which is countering upward vertical motion (convection). It is essentially anti-CAPE.
Stable Air – Air in which the temperature of the layer increases with height
Unstable Air- Air in which the temperature of the layer decreases with height
Elevated Convection- Upward vertical motion which is originating from a layer of air located well above the surface of the earth (the layer isn’t interacting directly with the surface).
First let’s take a look at the categorical and probabilistic forecasts along with the storm reports:
The scenario was supposed to play out like this: Thunderstorms would develop over northeastern WY into western SD, they would eventually congeal into a mesoscale convective system (MCS), tap into the near-surface convective available potential energy (CAPE) and produce a swath of damaging winds mostly over 58mph, but potentially isolated gusts over 74mph across southern South Dakota over the course of the night. Well, the scenario did start off as expected. Thunderstorms did fire off over northeastern WY into western SD and did merge into what became an MCS. In fact, here is the evolution of the MCS starting at 10mph CDT last night to 7am CDT this morning as the system was weakening.
One thing of notice? The MCS completely remains underdeveloped or simply nonexistent across much of the moderate risk area. Why? Because of convective inhibition (CIN) over the region.
The surface air over southern South Dakota simply remained too stable with too high of CIN for the MCS to tap into the CAPE needed to develop farther south and produce widespread strong winds. There was ample CAPE for strong vertical motions (and what goes up, must come down and would’ve done so as intense wind), but simply too much CIN countering it. The internal dynamics of the storm complex just weren’t enough to overcome it. So very little happened basically along and south of Interstate 90 in South Dakota. And increasingly, with a northward component of motion, what isolated damaging winds did happen happened far off to the north and east. The MCS largely tapped into elevated CAPE with downdrafts (the cool wind you feel when you’re under a thunderstorm) only occasionally penetrating stable air below and reaching the surface (if you’re confused about the whole elevated convection thing…imagine a cup with oil and water…oil is the dense, cool stable surface air and the water above it is the unstable, buoyant elevated layer riding atop of the oil). Hence, those spotty high wind reports you see in (and just beyond) the slight risk area north of the moderate risk. A couple of those reports were significantly severe winds.
The CIN can be seen graphically via a thermodynamic diagram. I’ll keep it simple…the line on the right is the vertical air temperature profile…the line on the left is the vertical dew point temperature profile (dew point is the measure of the amount of moisture in the atmosphere). This profile was from a sounding of the atmosphere over Rapid City, SD around 6-7pm CDT last night.
The best thing to take away from this if you’re a novice to meteorology is the rapid increase in temperature (the rightward turn) and the rapid drop in dew point temperature (the leftward turn) with height at a certain altitude…around 3000 meters. This layer of warm, dry air is the stable layer strongly preventing convection across southern South Dakota and this is what prompted the moderate risk to be dropped by the Storm Prediction Center at the 8pm CDT forecast update. There was plenty of CAPE…but the MCS never had a chance to tap into any of it as all that potential energy was basically locked up by the CIN. Meanwhile it stayed developed to the north and progressed east-northeast for several hours.
As it moved far north, it managed (as mentioned earlier) to produce some destructive winds. Why? The surface air was stable, but fairly dry near the surface. As rain fell into the dry air, it evaporated, rapidly cooling the surounding air, allowing for strong downdrafts to penetrate to the surface. You can see the dry layer in this sounding profile from Aberdeen, SD around 6-7pm last night.
The very southern edge of the MCS did impact Brookings around 5-6am this morning. I woke up for its arrival after sleeping through the night not sure how intense it would be.
Not exactly sure how fast the winds got in Brookings, but Huron (you can see on the radar map to the west) had a peak gust of 56mph from the storms. I’m guessing the winds at least got to 45mph from what I managed to see before the storms passed.
Overall, this event just goes to show the difficulties in forecasting severe weather. It also shows how appropriate probabilities are when it comes to describing weather. Forecasts come with uncertainty and some forecasts are far more uncertain than others. At least people were warned of the potential for severe weather…for many it didn’t come to fruition…but for some, it did.
Southeastern Colorado wheat crop a disaster from drought, freezes
Ongoing drought and late-spring freezes are conspiring to produce one of southeastern Colorado’s poorest wheat crops in memory.
“It’s the worst I’ve ever seen,” said Kiowa County farmer Chris Tallman. “We are at zero. We will have absolutely no wheat crop. The entire county is full of dead wheat fields.”
Drought has been a constant conundrum for much of the past decade. But wheat growers suffered an additional blow in April when a series of freezes damaged the already weakened wheat crop.
“The freeze was just the death knell,” said farmer Burl Scherler, who grows wheat near the Kansas border. “I’ve never in my 40 years here had a wheat stand just die like this.”
With little or no wheat growth, parched fields are losing their topsoil and causing dust storms reminiscent of the 1930s Dust Bowl.