…SEVERE THUNDERSTORMS/TORNADOES EXPECTED THIS AFTERNOON (MAY 31)…

…DANGEROUS STORMS POSSIBLE TODAY IN CENTRAL AND EASTERN OKLAHOMA…

An upper level low pressure area is found over the Northern Plains this morning.  A strong jet segment curves cyclonically from the Colorado/New Mexico border to Kansas to Wisconsin.  Oklahoma is found near the southern edge of these stronger winds, and in a position favorable for thunderstorm formation relative to an embedded short wave trough which will move across the Southern and Central Plains this afternoon.

The surface weather map currently shows a low pressure area near the southwest corner of the state.  This low is forecast to deepen significantly during the afternoon.  A front will extend from the low northeastward into NC Oklahoma and a dryline will push eastward through the southwest section of the state.  These features will be the focus for thunderstorm development later today.

The atmosphere east of the dryline and south of the front is very moist and will become extremely unstable this afternoon.  Forecast wind profiles show strong deep layer shear across the state, and increasing low level shear by late afternoon and evening.

Thunderstorms are expected to develop from NC Oklahoma to west of the Oklahoma City area to north of Lawton by 4 pm.  All indications are, these storms will rapidly become severe and supercell in nature.  Very large hail to the size of baseballs or larger, damaging winds, and tornadoes will occur today.  Given the forecast shear profiles and instability, some strong or violent tornadoes are possible if storm mode evolves as expected.  The Oklahoma City and Tulsa metro areas are in the region of enhanced risk.  All people living in Central and Eastern Oklahoma should pay close attention to the weather and heed warnings this afternoon.

Severe storms possible again today (Thursday, May 30)

The morning surface analysis shows an area of low pressure just south of Alva.  A cold front/dryline extends south southwestward to just west of Altus, and an outflow boundary extends eastward from the low to near Miami, Oklahoma.  The atmosphere over the warm sector is very moist and highly unstable this morning.  Meanwhile, strong deep layer shear is spreading eastward over the state.  Conditions are rapidly becoming favorable for the development of severe thunderstorms.  While large hail and damaging winds will be the main threat, forecast soundings support the idea of a few supercell storms forming this afternoon with the potential for isolated tornadoes.  Oklahoma City, Tulsa, Lawton, Enid, Ponca City, Stillwater, Ardmore, and McAlester all reside in this region of enhanced threat.  People in these areas should pay attention for rapidly changing weather conditions and be prepared for move to safety if warnings are issued.

Severe thunderstorms will be possible once again on Friday the 31st.

Outlook (Thursday-Sunday)

Upper: A low pressure area near the northeast corner of Wyoming will move/redevelop slowly eastward through the middle of the weekend, and be located near Minneapolis Saturday afternoon.  A seasonably strong mid-level jet segment with embedded short wave troughs will extend cyclonically from Utah to Kansas to Wisconsin.  The mid-level flow will begin to weaken by the end of the weekend with a weak ridge building over the Southern Rockies and W Texas.

Surface: A front located just northwest of the main body of Oklahoma this evening will edge southeastward through Saturday morning, before pushing out of the state early on Sunday.  A dryline feature is expected to make daily moves eastward through SW Oklahoma Thursday and Friday.

Impacts: A warm, moist air mass will remain over Oklahoma – south of the front and east of the dryline.  Rounds of showers and thunderstorms are expected each day with the greatest chances of precipitation over E Oklahoma on Thursday / C and E Oklahoma on Friday / and S Oklahoma on Saturday.  Moderately strong deep layer shear will allow for many of the storms to become severe, producing damaging winds and large hail.  There will also continue to be a risk for tornadoes with sustained supercell storms.

Okarche Weather:

Thursday morning: 59

Thursday: 88 / Showers and thunderstorms

Friday morning: 66

Friday: 91 / Showers and thunderstorms

Saturday morning: 68 / Showers and thunderstorms

Saturday: 78

Sunday morning: 55

Sunday: 76

Severe Thunderstorm/Tornado Risk Today (May 29, 2013)

 

 

 

 

 

 

 

 

 

 

A strong short wave trough will be moving northeastward out of the Southern Rockies across the Southern and Central Plains this afternoon.  In response, deep surface low pressure will organize over SE Colorado and SW Kansas.  A dryline which is currently in far W Texas will begin to advance eastward during the afternoon.  This feature will be the primary focus for afternoon and evening thunderstorm development.

The basic setup is classic for a Plains severe weather episode.  The atmosphere east of the dryline is moist and will become quite unstable as heating begins this afternoon.  Forecast soundings show strong deep layer shear in place to allow for storms to rapidly organize into supercells.  The lowest levels show sufficient turning for tornado production with any sustained supercell storm.

People across much of Central and Western Oklahoma should stay alert this afternoon and evening.  Thunderstorms will be capable of producing all facets of severe weather with some strong tornadoes expected.  While it appears that the risk late this evening will wane some as storms approach C Oklahoma, there will continue to be a tornado threat with any long-track supercell storm that may develop this afternoon.

Northwest Kansas supercell – May 24, 2013

A somewhat interesting day.  I got to witness what may have been the longest lived mediocre supercell I’ve ever seen.  The storm organized near Sheridan Lake, Colorado and tracked north northeastward over the next several hours to near the Nebraska border north of Goodland, Kansas.  There were times that the structure was interesting, and lightning popped just enough for a few photographs, but overall the storm never took that final jump to be something special.

Over three hours of video crammed into three minutes:

http://www.youtube.com/watch?v=9PPn8m2gIuE&feature=youtu.be

 

Almost bust, Texas Panhandle – May 23, 2013

Severe thunderstorms developed early in the afternoon over the SE Texas Panhandle and were moving toward my “no-chase-zone”.  We were playing an area around Amarillo where there were model signals of late afternoon storm development, and a moist easterly flow was in place.  Storms did end up forming just northwest of the city when we arrived.  A lot of dust was being blown around thanks to strong surface winds, and when combined with haze, storms were hard to see.  We did stop to look toward a storm that was severe warned just north of Amarillo, and became a bit surprised how fast the storm fell apart.  With little to keep our attention, we followed a left split for awhile that moved north northeast, but it was evident that sinking air under ridging aloft and behind the initial storms was not going to be overcome.  We settled in Dalhart and took the time to photograph some nighttime lightning as it approached from the southwest.

Outlook (Monday-Wednesday)

Upper: Models are having a tough time maintaining continuity as they reach out past mid-week, but reasonable agreement exists through the MON/TUE/WED time frame.  A weak ridge of high pressure over the Plains will flatten on Monday as strong jet segments/short wave troughs work into the Western U.S. trough.  A significant trough will be moving out of the Southern Rockies into the Plains on Wednesday.

Surface: In general, low pressure will be nearly stationary over W Kansas through Wednesday.  Warm and moist southerly flow will continue across Oklahoma east of a dryline feature that will reside over the Panhandle.

Impacts: A combination of moderate to strong instability and deep layer shear will produce an environment supportive of severe supercell storms through the period.  The most likely focus for thunderstorm development each day will be the dryline located either over the Texas/Oklahoma Panhandles or far W Oklahoma.  The flow steering the storms will keep the greatest risk of severe weather confined to the NW third of the state, but the threat in C Oklahoma cannot be considered zero.

There will be a slight chance of these storms on Monday, with a greater risk on Tuesday and even greater risk on Wednesday.  The storms will be capable of producing all facets of severe weather, and tornadoes / some strong / will be possible by Wednesday.

People living in all areas of Oklahoma should stay updated on the weather as severe storms and tornadoes will be possible each day Monday through Friday.  There are likely to be some high end risk days during that time which cannot be detailed at this time.  It currently looks like the threat of severe weather will wane by next weekend after a cold front clears the state.

Okarche Weather:

Monday morning: 67

Monday: 89

Tuesday morning: 67

Tuesday: 84

Wednesday morning: 67 / Showers and thunderstorms

Wednesday: 82 / Showers and thunderstorms

Outlook (Thursday-Sunday)

Upper: This evening, a deep area of low pressure is centered over SW Washington.  Another trough of low pressure extends from the Western Great Lakes to the Ozarks.  In between a weak ridge of high pressure is found over the High Plains.  The ridge is expected to shift slightly eastward on Thursday, and build into the Northern Plains on Friday.  Generally weak flow aloft will be found over the state through Saturday before the ridge starts to flatten and shift east on Sunday.  There are also indications that a couple of weak low pressure circulations may slide under the Northern Plains ridge from SW to NE Texas.

Surface: In general, low pressure is expected to become established over the High Plains through the weekend.  High Pressure will be sliding southeastward through the Great Lakes and Ohio Valley.  Low level moisture is expected to surge northward across the state tonight and Saturday.  As cool and dry air moves southward over the eastern part of the U.S., some of this may work into the eastern parts of the state on Saturday and Sunday.

Impacts: The returning low level moisture will result in a few showers and thunderstorms over W Oklahoma as early as Thursday morning.  By afternoon, conditions for severe thunderstorms are expected to come together over the Texas Panhandle as 35 knot mid-level flow overrides a moist southeast surface flow.  These storms will affect portions of SW Oklahoma late in the afternoon and evening with the potential for some large hail and damaging wind gusts.  A few showers and thunderstorms will linger over the state through the nighttime hours into Friday morning.  On Friday, showers and thunderstorms will likely be limited to the Panhandle and Red River Valley.  Widely scattered showers and thunderstorms are likely to continue across the state on Saturday and Sunday as well.  The greatest chance at a severe storm Friday through Sunday will be across the Panhandle.

Okarche Weather:

Thursday morning: 55 / Showers and thunderstorms

Thursday: 81 / Showers

Friday morning: 58

Friday: 79

Saturday morning: 64

Saturday: 80 / Showers and thunderstorms

Sunday morning: 63 / Showers

Sunday: 81 / Showers and thunderstorms

Disaster at Moore, Oklahoma – May 20, 2013

An unbelievable experience.  We anticipated the day to have large tornadoes and the threat basically extended from the Oklahoma City area southward to the Red River.  I told people in Oklahoma City to pay attention, but that in general, the biggest threat would be just south of the city.

I picked up Thom at his house near 19th and Eastern in Moore and we started driving south on I-35.  The plan was to get well ahead of the Highway 81 corridor where storms would first form – let them evolve a little – and jump on the one that looked to have the best long-term potential.  We stopped at the Wayne/Payne exit and observed several storms to our NW, W, and SW both visually and on radar.  When I saw the storm forming southwest of Moore, I mentioned to the others that it was forming in a dangerous spot.  Northeast would cut through Oklahoma City – east northeast would go through Moore – a hard right and it would hit Norman.  I also didn’t think established tornado producing storms would wait until they got by the population center.  Still, we really didn’t have a plan of targeting this storm because it can be extremely difficult to chase through a metro area.  We had just made the decision to go south toward the Duncan storm when I saw radar data that told me a tornado was imminent.  A tornado warning was issued and without much thought we were all of a sudden north bound on I-35 trying to figure out an easy intercept.  The first plan was to take Highway 9 and move around the east side of Norman/Moore and wait for it to come out, but the farther up I-35 we went there were little signs that the road was congested or blocked / either by State Troopers or people parking under overpasses.  With a good fix on the location of the tornado by radar and spotter reports, we drove to 19th street in Moore and took up a viewing position just east of the interstate.  The expectation was that the tornado would cross I-35 between 19th and 4th (or very close to our north) and if we needed to, we could flee east on 19th.

The tornado became visible to our west in a mass of debris that extended out north and south about the width of the tornado itself.  The entire “blob” was about two miles wide.  As the tornado approached, we watched for signs of a northward component to the movement.  There wasn’t much and I became concerned that we would not be a safe distance from the tornado when it passed.  When the tornado got to within two miles, the roar started and we began to have light debris falling on us.  Larger pieces of debris were not that far off and it became time to move.  The first thought was about Thom’s wife who was at his house about 1/2 mile from us.  I made contact with her and had her meet us out front for pick-up.  This worked well and after the two minute pick-up process we started heading south to a comfortable position.  Before we found that, we stared the tornado in the face about 24th and Eastern.  Motion was incredible, the sound was incredible and the amount of debris that was moving around the tornado was incredible.  I had a brief sick feeling for a bit that we may have waited too long to make a move to safety.  We did get south without incident and found a viewing area just east of Bryant on 34th where we watched the tornado until it dissipated just west of Draper Lake.

We made a quick stop to pick up Thom’s son at one of the local non-affected schools and dropped he and his wife off back at their house.  There was no damage to their house, but the neighborhood was littered with all kinds of small debris.  The damage survey shows that the tornado passed between 1/2 and one mile to their north northwest.  We made a somewhat half hearted attempt at playing storms farther south near Pauls Valley, but after the adrenaline had drained from us, we were pretty much done for the day.  Getting Thom back home and finding a way around the damage path was a bit of an adventure.  We left Thom about 1/4 mile short of his house and he had to walk back in.

Numerous things flash through your mind after an event like this.  Within a few hours we were hearing about the loss of life among children and it just made us sick.  I find myself asking the question, why?  How in the world does a city get hit by four violent (2 EF4′s, 2 EF5′s) tornadoes in 14 years?  My scientific thinking mind tells me that the odds of that happening are astronomical.  I have also had to remind myself that this event would have happened whether we were there or not.  And, we had nothing to do with it happening.  From a storm chaser/weather enthusiast point of view, the chance of seeing the dynamics of a storm like that up close was important.  I’m not sure how, but it just causes the chase, the forecast, everything involved to be viewed a little differently.

And finally, if you are caught in the path of a storm like this, don’t let the TV weather folks issue you a death sentence!  These storms ARE survivable!  Thousands of people lived by taking typical, suggested advice.  We saw an incredible amount of traffic that may have been enhanced by people on TV yelling that you either have to be underground or out of the way to survive.  I wonder if anyone was killed that left a house they could have survived in and were caught in their car?  Yes, underground is best – but if that is not available – go to the center part of the house / lowest level / smallest room.  Cover up with blankets and pillows / stay down and hang on!  It works most of the time!