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Jun 152015
 

20150612_094530 20150612_105620

 

On Friday, I had the pleasure of talking to students at Pleasant Hope Elementary School and it was wonderful!

I think in everyone’s career there are defining moments which help you to remember why you do what do.  My experience with these kids did just that.

As I was showing the kids video from one my more successful storm chases, I took a few seconds to pause my narration of the events to just “take in the room”.  The buzz was so exciting to see!  The younger kids were very chatty and excited (the kind of behavior which would be shut down in a hurry in a normal classroom setting but hey, I brought tornadoes!). The older kids were of course too cool for this open expression of excitement but knew I had reached some of them by the questions they asked after the video ended.

 

 Posted by at 7:19 am
Feb 282012
 

Tornado Probabilities This Evening/Overnight

There is a threat for severe storms late this evening over much of the Ozarks.

Generally, the tornado risk has been reduced especially in northern Arkansas and extreme southern Missouri.

The overall situation has stayed about the same today. At issue will be the amount of unstable air present during the evening hours.  Higher humidity values will be drawn rapidly northward today and by evening will possibily lead to unstable air worth noting just to our west in portions of Oklahoma and Kansas.  Any storms which fire in the this area say after 6 pm could initially be severe and might just hang on to that character as they cross into Missouri and Arkansas, then weaken rapidly.  This is the lesser threat.

As time ticks away closer to the late evening/midnight, better instability will begin to build into northwest Arkansas and then begin shifting eastward into northern Arkansas and extreme southern Missouri.  Any thunderstorm cells in this area during this time will likely be severe.

Finally, a squall line will form along and front overnight and drop northwest to southeast over the Ozarks.  Portions of this line could be severe as it drops through between midnight (west central Missouri)  and 6 am ( north central Arkansas).

10 am Dew Points and Surface Wind

Jan 242012
 

I announced the start of a new science series on KOZL Live at 4 a few weeks back.  We did a great show on January 10th about the Bernoulli principle. Here’s an update regarding this show which will be be seen on Tuesdays.

The installment scheduled for 1/17 didn’t air because I was home with a stomach flu.  Also, I’ll be off for the next two Tuesdays.

Despite the slow start, the show will be back in February!  The next air date will be February 7th.

 

Jan 232012
 

Strong Circulation Shown by Red Area West of DeWitt, AR Sunday Night

A huge outbreak of severe weather took shape Sunday evening over Arkansas and spread east and northeast into the wee hours of the morning.

The Storm Prediction Center Storm Reports page lists 20 tornado reports (not actual tornadoes) for the 24 hour period ending at 6 am Monday the 23rd.

Possible Arkansas Tornadoes - Vaild Monday Morning

The first wave of storms began to take shape as several well-defined supercell thunderstorms over southeastern Arkansas between 6:30 and 10 pm.

Damage was reported near Fordyce, AR in Dallas county.  Homes were torn apart but there have been no reports of serious injuries. [UPDATE]The National Weather Service has surveyed this storm and rated it an EF2 late this morning.

A detailed map of the storm reports in Arkansas can be found at Weather in Arkansas.

The storms produced lots of hail and wind damage overnight as the SPC map shows.

A second round of tornadoes then started to take shape overnight from Mississippi into Alabama.  The hardest hit area was just north of Birmingham, AL where fatalities have been reported. Many images of the damage can be seen on the Google+ profile for Meteorologist James Spann in Birmingham.

Severe Reports 24hr Ending 6 am Monday

Jan 222012
 

Dust Plume Over Oklahoma

Only a small portion of the Ozarks need concern itself with severe thunderstorms late this afternoon and evening.

A huge surge of jet stream-induced strong surface winds is making its way across Oklahoma.  Winds have gusted over 60 mph in a few spots this afternoon and wind gusts over 40 were common.  A huge plume of dust can be seen on visible satellite images from this afternoon over Texas and Oklahoma.  The air with this surge is warm and dry and thus grass fires are a big concern over much of this area.

Out ahead of this feature, a pool of cooler air has persisted over much of the Ozarks through the day. This air is very stable and will be hard to overcome. Where temperatures and humidity values will rise to marginal levels will be east and southeast of Springfield proper.  A large area of warmer and more humid air is building over eastern and central Arkansas and some of this will move northward during the next several hours.

The upshot is that areas of the Ozarks east of a line from let’s say Salem, MO to Mt. Home, AR might have a few severe storms through about 8pm.

Change in Dew Point, 1-4 pm Sunday

 

Jan 212012
 

Matt Rhodes, Pea Ridge, AR. 10/24/2011

[UPDATE]

SpaceWeather.com has reported that the CME due to strike the earth is overdue. It could still happen.  Some Northern Lights have been reported tonight at high latitudes.

—————————————-

Despite some clouds still hanging around this morning, clearing skies are expected later today and early this evening, making it possible to view the expected Aurora Borealis.

Forecasting the exact arrival time and intensity of these blasts of particles from the sun called Coronal Mass Ejections (CME’s) has gotten better but is still not precise.  Space Weather is still calling for arrival at earth around 4:30 local time with a several hour margin of error.  But since we’re only concerned about anything after sunset, our hope would be that the forecast is exact or perhaps early by several hours.

We had a decent CME back on October 24th with reports of the Northern Lights as far south as Arkansas and the Carolina’s.  They were observed in the Ozarks as well.  I did a report on Auroras at this time:

At this latitude, the Northern Lights are not likely to be noticed casually.  You’ll have to make an effort to optimize viewing.  This includes getting as far away from lights as possible and having an unobstructed view of the northern horizon, i.e. n0 trees or hills.

Also, many photographs showing an Aurora feature long time exposures which make for a more vivid image than what might be visible to the naked eye.  Something to keep in mind when viewing.

So, anytime after dark tonight.  We’ll see what shows up!

Jan 202012
 

Beer from the Fermenter to the Barrel!

Hi all!  You might want to read my first post on this very cool project to catch you up on what the group is doing.

Since that last posting, a lot has happened.  In order to fill the bourbon barrel, everyone in the group contributed either 5 or 10 gallons of home brew.  Many gathered before Christmas to start their batches:

I was away and made mine at home.

All totaled, there are nine individuals contributing ten different batches of beer.  This past Saturday, we all met to fill up the barrel.  But before that could happen, each batch was taste-tested by the group.  You know what they say about one bad apple!  Nobody wanted to be the one who inadvertently made a bad batch of beer which would of course affect the entire barrel.  Even the most careful brewer can brew a batch of beer that is off in some way.

Sample Glasses Lined Up!

Now these guys are all good and I don’t think anybody really expected a completely fowl batch.  What it really came down to was subtlety.  It was amazing to me how different variations can come out of what was essentially the same ingredients.  The ways a beer can turn out slightly different are vast and include whether you went all-grain or used an extract, the exact timing and quantity of ingredients, type of water used, health of the yeast, temperature and conditions during fermentation and the amount of time a beer sits before being transferred into secondary (to get it away from a lot of the dead yeast cells).

Bret McGowne has been organizing all of us from the start and summed up the tasting on Saturday quite nicely:

“A big thank you to Steve and Travis McDonald for bringing some of their homebrew and helping with the blind taste tests.  They were a HUGE help!

We took hydrometer readings and sampled each batch.  The hydrometer readings ranged from the low 20s (1.20 or so) up to the low 30s (1.30 or so).  The sampling revealed a variety of flavors from “on the money” to a few that had a bit of a green apple flavor and one that was described as smelling like burned hair.  In the end, it was decided that the green apple beers just needed some more time with the yeast and they were added to the barrel.

The burned hair beer may or may not be suffering from autolysis which is a function of leaving the beer on dead yeast too long.  We racked that beer to two carboys so we could let it age and see if the problem with it could be solved by a little more conditioning time.  Depending on how that aging goes, we can decide if we want to use that batch as our “top off” beer or not.  If not, we may be looking at brewing another 5 or 10 gallons so we can hit our volume and account for evaporation losses.

We also added 5 gallons of boiled and cooled water to try and correct our short volume.  The barrel right now is still probably 5 – 10 gallons short on volume.

On Monday of this week (2 days after we racked to the barrel), Stan took a hydrometer reading and tasted the blended
beer.   He got a reading of 1.021 and said it tasted just fine.  He didn’t detect the green apple flavor and said he drank the whole hydrometer
sample since it was so good!  There was just a hint of bourbon flavor in it and no sign of the oak yet.”

In listening to the group and their discussions about beers and breweries and processes, it was clear to me how much more I need to learn.

 

 

 

 

Jan 202012
 

Surface Map Forecast for Saturday AM

As we shiver through this Friday with its low cloud cover, it will actually get a little colder by this evening as north winds kick in.

There is just an outside shot at some freezing drizzle out east of Springfield during the evening hours.  It doesn’t look like a huge threat at this time.

A seasonal chill is instore for Saturday under the influence of high pressure.  The sun will come back which will help matters greatly!

Aurora Viewing?

It’s possible!  A rather large solar flare left the sun yesterday and the latest NASA forecast has it arriving at earth shortly before 5 pm Saturday.  So, anything after dark Saturday would work.  NASA does put a large error (+/- 7 hours) on the forecast.  It would be best if the CME got here according to forecast or perhaps a little late to maximize darkness.

As always at our latitude, the Aurora Borealis is hard to see in all but the best shows and conditions.  If you want to try, you must have a clear and very dark view of the northern horizon.  It does look like we will have clear skies.  Monitor Space Weather for updates.

Cool to Mild Weekend

A temporary return of south winds on Sunday will drive our temperatures back up.  The extent of the warmth will depend on cloud cover and on the exact timing 0f another colder wind shift later on this day.  I’m thinking we should be able to climb into the sixties.

It doesn’t look at this point that storms are a threat as the brunt of the deeper humidity and hence unstable air won’t return in time or will be shunted to the east.  For folks living east of Springfield, there is a small chance of a storm or two Sunday afternoon.

It will be windy Sunday afternoon as well with gusts over 30 mph expected!

Mid Week System

Lots of speculation about how the middle of next week will play out.  It seems as if the bulk of the spring-like storms with this storm will stay south of our area.  But with this many days left and with some of the jumping around the computer models have displayed, I’ll reserve judgement for a bit longer.

There doesn’t appear to be enough cold air for meaningful snow.

The best possibility would be some decent rains and that is certainly on the table for Wednesday especially.

 

 

 

Jan 132012
 
6-10 Day Temperature Forecast

Welcome Winter!

Thursday was probably the most winter-like day we’ve had so far this winter.  Temperatures fell all day, wind chills were in the single digits and snow continued to fly well into the afternoon in many parts of the Ozarks.  Springfield’s official snow measurement was 0.6″.  January’s total is 0.7″.  This season, 1.1″  There were reports of a few 1″ plus totals peppered mostly across areas north and northeast of Springfield.

It looks like our low temperature this morning stopped at 13 degrees which is about as cold as the coldest we’ve had so far this season.

Trends

We’re heading back up in temperature this weekend. Expect a return of forties and fifties to last into Monday.

The cold air I referenced last week has been building in Canada.  While it will be making some inroads into the northern and northeastern U.S., we here in the Ozarks will have another “chunk” (cold front) of cold air coming in Monday night and perhaps a few weaker cool fronts after that in what will amount to a cooler but still mild pattern of weather for us and much of the southern U.S. next week.

North Atlantic Oscillation

There is an index which meteorologists follow (one of many) called the North Atlantic Oscillation (NAO).  It measures the difference in pressure between higher latitudes (closer to the north pole) and lower (closer to the equator).  When the index runs positive, it means that there an unusually large difference in pressure. Negative values indicate lower pressure differences.

If one analyzes the pressure over the northern Atlantic over a long period of time, it becomes clear that a so-called”semi permanent” low pressure area shows up near Iceland and it fact bears the name of that island nation “the Icelandic Low”.  But like so many long-term averages, there is often significant departure from year to year or season to season.

For the past two Decembers, the Icelandic low has taken a hiatus.  The NAO has been strongly negative meaning the low was weak or replaced by higher pressure.  This sent lots of cold air southward into the U.S. where it energised the storm track and provided enough cold air for snowstorms. Like this one in 2010 in the northeast and of course our major two snows last February on the 1st mostly affecting Missouri and on the 9th targeting northwest Arkansas and northeast Oklahoma. 

This December, the index has been strongly positive meaning a strong low which keeps the arctic air bottled up at higher latitudes.  It shows up to the north but doesn’t have a path directly into the central U.S.  As a result, the country has been mild in particular the northcentral U.S. which has been much above normal and setting temperature records.

There is every indication that this pattern will continue for much of January.  All patterns can and do break or shift, even temporarily, so we’ll keep watching for when that might happen.

Until then, mild and dry are the two weather words!

 

 

 

 

Jan 102012
 

Today’s Topic: Bernoulli Principle.

Before I start up with Bernoulli, what is the Venturi principle?  The idea is pretty simple and more intuitive than the Bernoulli’s.

Take a fluid (air qualifies under certain conditions), moving at a certain speed and force it through a narrower space.  The speed of the fluid will increase.  This principle is used in carburetors.

Daniel Bernoulli took it one step further in his paper “Hydrodynamica” published in 1738. He showed that the pressure exerted by the faster moving fluid decreases. It will increase again when the fluid slows.

The other thing you need to know is that a pressure force will always point toward lower pressure whenever a difference in pressure appears.

There are numerous demonstrations of the Bernoulli principle.  One oft used is a beach ball suspended in mid-air over a stream of air.  The air stream hitting the bottom of the ball is moving faster in the middle than on the sides therefore lower pressure exists right against the ball.  This inward-directed pressure force keeps the ball in the middle of the airstream.

Other examples include a table tennis ball in a funnel, round cheese balls (like Cheetos only round) and soda straws, air blown between two empty two liter bottles and air blown over paper. Toilet paper rolls and a leaf blower make a pretty dynamic demonstration too!

A wonderful interactive example of the Bernoulli principle is located at this web site.

What I found most surprising during my investigation of  the Bernoulli principle is the debate about how to best describe how an airfoil works or: what really gives a plane wing lift?  The other surprising item is that some text books are stating that air which separates above and below a wing must meet up exactly on the other side, forcing it to go faster on top of the wing and setting up the pressure difference required by Bernoulli’s principle.  Experiments have clearly shown that the air parcels never meet again after the wing splits them up.

Next Week’s Topic:

Fun Science Principles With 2 Liter Soda Bottles