Oklahoma Supercell – August 17, 2009

081709bA great August chase day!  I usually spend the summer months just hoping for storms that will produce good lightning ops… but on Monday (17th), we got lucky with not only nice lightning – but good supercell structure to go along with it.  The atmosphere was extremely unstable with surface based CAPE in excess of 5000 j/kg over parts of northwest Oklahoma.  Mid level flow wasn’t the greatest….but was about 25 knots.  The two combined to produce several severe storms – some of which produced significant severe weather just northwest of Okarche.  The first storm we took a look at was just northwest of Watonga.  This storm had some decent structure for a bit and had a rotating wall cloud that opened eyes.  When this storm was undercut by outflow which spread to the southeast…. another storm formed just southeast of Watonga.  This storm quickly became severe and exhibited supercell characteristics right from the start.  It didn’t move very quickly… lazy would be the best way to put it… as it headed southeast around 5 mph.  Before it made it into Kingfisher or Canadian Counties… it started getting strong development on it’s southwest flank… which caused it to drift southwestward toward Geary.  The end result was us watching a severe storm about 10 miles from where we first started our chase.  The storm itself was incredible!  The supercell structure that it displayed was some of the best you could ever expect to see anytime of the year.  And the lightning that it produced was extremely impressive and fairly easy to photograph.   Below is a radar image of the storm when it looked it’s best visually.  Also… an image from about the same time.  This supercell stayed just west of Okarche and we only received 0.17 inches of rain from it.  Later that night (18th) and into the morning hours… another 1.89 inches of rain fell which set a record for the date.  Yes, things continue interesting around here – and as I type… a line of severe storms is moving east through the western part of the state.
Other images from the chase can be found at http://www.pbase.com/okweatherwatch/081709
It doesn’t appear that this month will make it to the wettest month on record… but it won’t take much to reach the number two spot…
The most rainfall for the month of August in Okarche:
1996 – 11.08 inches
2008 – 7.33
1989 – 7.20
2007 – 6.84
2005 – 6.25
2009 – 6.02
radar

Oklahoma Storms – August 16/17

Strong to severe thunderstorms formed over northwest Oklahoma during the early evening hours of August 16th and continued into the early morning hours of the 17th.  Hail to the size of half dollars and wind damage occurred in parts of Alfalfa, Grant, Garfield and Kay Counties.  The most impressive aspects of the storms may have been the flooding rainfall and lightning.  With regard to rainfall… radar estimates reached an astounding 12.57 inches between Carrier, Kremlin and North Enid.  The National Weather Service feels that this estimated amount may be more than double what actually fell… but there is no doubt that a good deal of rainfall occurred.

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Then there was the lightning!  For several hours… this display of lightning was intense enough for me to consider it one of my top 5 displays!  This includes everything I’ve seen in 28 years of storm chasing.  The poor people in Garfield County have to feel like they were under attack this evening….

Lightning west of Waukomis, OK

Wake up! It’s starting to get interesting…

We went from very little to talk about – to quite a bit to talk about in just a couple of days.  First off, the sun.  I’m happy to see it going away.  Sunrise this morning in Okarche was 6:50 a.m…. sunset was at 8:22 p.m.  In just one week, sunrise will be at 6:56 a.m. and sunset will be at 8:14 p.m.  14 minutes in one week.  Doesn’t seem like much at only two minutes a day… but we shell off a half hour in just two weeks.  I’ve never been a fan of mornings… afternoons as far as that goes.  Truth be known… sunset is the only time I enjoy being able to see the sun.  If it wasn’t needed to get storms…. It wouldn’t bother me if it never came up.  I notice the difference every year at this time because it was the first time since summer began that I was able to drive to work without having it blast me in the face on the way in.  Yes, the countdown to the start of Fall can begin soon…

Next up is the overall weather pattern.  We have been getting lucky so far this August with temperatures reaching 100 degrees only a couple of times and several days with highs around 90 lately.  Model data suggests that the general theme of a broad trough in the central and north central U.S. will continue for the next week which will bring near or below normal temperatures and chances of thunderstorms.  If this holds true…. we will be getting within a three week period remaining until the magic date of September 8 where extreme heat usually ends in central Oklahoma.  In Okarche… several days in the first week of September have reached 110 degrees in the past.  However… the record high for September 8 is only 98 degrees and temps typically trend downward from there.

Then there’s the tropics.  What has been a fairly quiet season so far in the Atlantic basin may be getting ready to change.  There are several disturbances that are roaming westward along the ITCZ.  More than one set of data suggests a major hurricane will be approaching the southeast part of the U.S. by the 23rd.  Time will tell on this…. but something to watch out for…

2009 Perseids

144 meteors.  My total observations since the Perseid Meteor Shower started ramping up in early August.  The full/near full moon made for some tough viewing conditions… and there were several days where high clouds from thunderstorms out west spread across the sky.  Otherwise, conditions couldn’t have been better with mostly light winds and mild temperatures.  Several of the meteors were impressive – but strange in that there wasn’t one that I would consider in my top 10.  A couple were caught on camera… but again, that dang moon made photography hard!  Other showers are just around the corner – and viewing conditions should be better.

Perseid from the early morning of August 12th.

Okarche Severe Thunderstorm (August 3, 2009)

I woke up a little before 2 a.m. and thought I would give it a go at another meteor watch session.  I was more than a little surprised to see that my target had shifted from meteors to thunderstorms.  A severe thunderstorm was moving straight for Okarche.  Cloud to ground lightning strikes were hard to see… but still, a wall of intense lightning was quickly moving our direction from central Kingfisher County.

The radar image below shows the storm about the time it was producing wind over 60 mph in Okarche.

Ref/Vel image @ 2:11 a.m.

 

My weather station plot below also shows some interesting things.  There was a rapid pressure rise (29.89 to 29.98 inches) when the storm hit….followed quickly by a wind gust to 61 mph at 2:13 a.m.   After the storm had moved to the southeast… there was a rapid pressure fall (30.03 to 29.88 inches) which resulted in another burst of strong winds with a peak of 54 mph.  Rain for the event was also impressive… reaching 3.43 inches which set a record for the day.  The rapid increase of rain in the plot was from manually changing the total after reading the standard guage.

Okarche Plot

Look up, Look around….

You say you saw something streak across the sky while you were out last night?  I did too… in fact, 13 times during one hour of observing.  We’ve made it to August and are now ramping up toward the peak of the Perseid Meteor Shower which should occur during the early morning hours of August 12th.  It’s one of the top three each year with regard to the frequency and brightness of the meteors.  I also like the Perseids because they occur during Summer – making it nice to sit out and observe – and, they stretch over a long period of time (17 July – 24 August).  You may not see many, but you can see a couple – or several – almost any night for a few weeks.

Of course, what you see may not be a Perseid.  In fact, there are no less than eight showers listed as occurring today:  Sigma Capricornids, Piscis Austrinids, Southern Delta Aquariids, Alpha Capricornids, Southern lota Aquariids, Northern Delta Aquariids, Perseids and Kappa Cygnids.  A lot of these minor showers may only produce a couple of meteors an hour… but it is definitely possible that you will see meteors that are not associated with the Perseids.

The Perseids are associated with the comet Swift-Tuttle… and they are called Perseids because they appear to come from the constellation Perseus.  The best time to see them is during the first few hours before sunrise – 3 a.m.’ish  is good.  If you catch yourself not sleeping over the next few weeks, take the time to go outside and look around – it might be well worth your time!

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The peak can produce up to 90 visible meteors per hour in areas with the darkest skies.

End of July Rain

A five day stretch of rain totaling over two inches is pretty good anytime of the year… but especially nice at the end of July.  2.13 inches of rain fell in Okarche from July 26-30 which was middle of the pack as far as the state was concerned.  Four to six inches of rain fell in the OKC metro area and in southern Grady/Caddo Counties.  Parts of west central and southeast Oklahoma also received a good soaking.

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Severe Storms – July 28, 2009

Numerous severe storms moved southward through northern and central Oklahoma during the late afternoon and evening.  Typical for July, wind damage was the primary threat with these storms.  However, some large hail also occurred.  One storm that passed just northeast of Blanchard likely produced hail to near tennis ball size and displayed a classic large hail signiture on radar as it did.

Known as a three body scatter spike (TBSS), the long stretch of weak echo extending off the backside of the storm in this radar image can often indicate hail to golfball size or larger.

From Wikipedia:

Also known as hail spikes, these are the result of energy from the radar hitting hail and being deflected to the ground, where they deflect back to the hail and then to the radar. Because of the energy hitting the ground at least once and the hail multiple times, it has a weaker return echo than the energy that went from the radar to the hail and back to the radar. The spike occurs where the energy took more time to go from the hail to the ground and back as opposed to the energy that went direct from the hail to the radar. This results in the radar picking up the energy at a later time which puts the echo further away from the radar than the actual location of the hail on the same radial path.

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Rain and Records

It has been strange to have a July start out so hot and dry and end it up with what we are having now.  Northwest flow aloft will continue to keep temperatures on the mild side with several chances of rain and storms over the next several days.

On July 27th, heavy rain parked over Okarche for a time in the late afternoon and the total precipitation on the date was a record setting 0.91 inches.  The previous record was 0.90 inches set in 1981.  Also… the clouds and rain led to a record low, high temperature.  We only made it to 75 degrees – well short of the 84 degree record set back in 1994.

The cooler and wetter than normal weather pattern should continue into August.  It’s still probably a tad too early to say…. but as I watch things continue to rapidly green up outside…. we may have a hard time reaching the 100 degree mark again this summer.  Keep the rain coming!

July 25, 2009 – Oklahoma Heat

It appeared for several hours that Okarche might have had the highest temperature in the state this day.  But, before it was over – several other locations tied or exceeded the 105 degree temperature:

1 – Tipton, OK – 105.6 degrees @ 5:05 p.m.

2 – Okarche, OK – 105.4 degrees @ 2:34 p.m.

3 – Hooker, OK – 105.3 degrees @ 4:25 p.m.

4 – Kingfisher, OK – 104.5 degrees @ 2:20 p.m.

For Okarche… the high temperature wasn’t record setting.  The record – 108 degrees set during the brutal summer of 1998.

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Okarche, Oklahoma