MJO Waves and USA Tornadoes

5.24.16_Dodge_City_KS_Tornadoes_small

Large tornado 24 May 2016 south of Dodge City, KS by Juston Drake & Simon Brewer

The Madden-Julian Oscillation (MJO) has been accepted by many meteorologists and long-range forecasters as an atmospheric teleconnection with a significant impact on global atmospheric patterns.  A relatively strong and progressive MJO wave can temporarily change a large-scale seasonal atmospheric pattern over a region the size of a continent.  Sometimes a regional blocking pattern can be broken into a progressive pattern by an MJO wave.

I first took notice of the importance of MJO waves during the Summer and Fall of 2005. The very active 2005 Atlantic Hurricane Season was significantly affected by strong progressive MJO waves.  Since then I’ve kept an eye on MJO Indices during the Hurricane Season.  A few years later, I also began to see the importance of how MJO waves affect winter and severe weather patterns over the United States.

A rapidly dying strong El Nino mostly dominated the pattern over western North America this Spring.  My good friend, a professional long-range forecaster and meteorologist Jim Bishop, felt this pattern was conducive for a large ridge over the Western U.S. and troughing over the Northeast throughout the Spring.  He suggested the biggest reason for temporary breaks in this pattern was possibly caused by MJO waves. After pretty much hanging up my gear for the Spring-early Summer severe weather season I took a look at the data to see if there were any correlations between the MJO and patterns conducive for USA tornadoes.

My research was simple:  I looked at the reported USA tornado graph from the Storm Prediction Center (SPC).  I located dramatic increases in the 2016 tornado count I refer to as “tornado surges”. I, also, located MJO Waves during the year 2016 on the 15-day Mean MJO Index from the Climate Prediction Center (CPC).  I created rough plots of the tornado surges on the MJO Index chart with MJO waves circled (SEE ATTACHED IMAGE BELOW).

2016 MJO Index via CPC & USA Tornado Chart via SPC

2016 MJO Index via CPC & USA Tornado Chart via SPC

What I found was very interesting. I expected to see a moderate correlation in the data, but instead, found a relatively strong one.  I subjectively determined there to be 6 tornado surges from January to mid-July of 2016.  I determined there to be 5 progressive MJO waves during that period, excluding a strong MJO wave in late December into early January.  It appears the 5 MJO waves matchup with 5 of the 6 tornado surges during the Spring and Summer of 2016.  This suggests there was a reasonably strong correlation between MJO Waves and the atmospheric pattern conducive for surges in the number of USA tornadoes during the Spring and Summer of 2016.

It’s important to note I only looked at the time period between January and mid-July of 2016.  I haven’t looked at any other years where other teleconnections may play a much different role in the large-scale atmospheric pattern over the USA. Also, this doesn’t suggest in any way that MJO waves create or cause patterns favorable for USA tornadoes. There are several big and many small atmospheric signals that affect global atmospheric patterns.

Tornado Target: Moore, OK

Map showing 8 tornado damage paths passing over Moore, OK from 1998 to 2015 (25 March 2015 path is preliminary)

Map showing 8 tornado damage paths passing over Moore, OK from 1998 to 2015 (25 March 2015 path is preliminary)

Yesterday evening, 25 March 2015, one or more tornadoes caused damage in Moore, OK as a large supercell thunderstorm passed over the city.  If only one tornado hit Moore last evening then 23 have been reported in the City of Moore since 1893.  Of those tornadoes 8 have occurred since 4 October 1998 including 4 violent tornadoes (EF5, F5, EF4, and F4).  The National Weather Service Office in Norman, OK is still conducting damage surveys, so all information regarding 25 March 2015 is preliminary.

***UPDATE:  1 April 2015 (not an April Fools joke) NWFO in Norman, OK has rated some of the damage as EF2 from the 25 March 2015 Moore tornado.  Intermittent damage was found along the tornado path, which can be common with a weak multivortex tornado.  I’ve posted a new tornado NWS damage path map image near the end of this article.

The City of Moore, OK has an area of 22.2 square miles.  At least 8 tornadoes have passed over that flat piece of land in a period of less than 17 years. Several tornadoes have narrowly missed Moore in the last 17 years, so it’s not like the city is a tornado magnet.  But still, 8 tornadoes over such a short length of time including 4 violent tornadoes is significant.  Two of those tornadoes, 3 May 1999 and 20 May 2013, are considered by several meteorologist to be among the most intense recorded!  If the preliminary tornado path from last evening is accurate it would cross 6 of the previous damage paths.

Below is a map overlaid with damage paths from the past 8 Moore tornadoes (2015 path is preliminary):

1998-2015 Tornado Damage Paths over Moore, OK (25 March 2015 Damage Path is Preliminary)

1998-2015 Tornado Damage Paths over Moore, OK (25 March 2015 Damage Path is Preliminary)

The recent Moore tornado streak began after dark on October 4, 1998.  A large Fall Oklahoma tornado outbreak produced a relatively weak tornado over Moore.  It was not the strongest tornado of the outbreak, but it received a large amount of attention after hitting a heavily populated area.  The following year a devastating long track F5 tornado tracked 38 miles and passed through the heart of Moore.  4 years later an F4 tornado passed over a few of the same neighborhoods as the previous F5.  A 7 year period of calm followed before a large supercell produced 3 tornadoes over the city in one day; an EF4 and two EF1 tornadoes.  Only 3 years had passed when an EF5 wedge tornado caused horrific damage across the core of Moore.  This tornado caused the most widespread damage of all the tornadoes to hit the city.  The tornado, or tornadoes, last evening were much weaker and probably comparable to the 1998 October tornado.

4 October 1998 Radar Image showing hook echo over Moore OK as F2 Tornado is occurring

4 October 1998 Radar Image showing hook echo over Moore OK as F2 Tornado was ongoing

October 4, 1998: F2
Path:  3 miles, 550 yards width, 7 minutes
Deaths/Injuries: none
Storm Development:
Supercell developed in Southwest Oklahoma off the dryline.
Outbreak: 26 tornadoes in Oklahoma

3 May 1999 Radar Images while F5 tornado was impacting Moore, OK

3 May 1999 Radar Images while F5 tornado was impacting Moore, OK

May 3, 1999: F5
Path:  38 miles, 1760 yards max width, 1hr 25 mins
Deaths/Injuries:  36 killed, 295 injured
Storm Development:
Supercell developed over Southwest Oklahoma off a pre-dryline convergence boundary in the warm sector: possibly a horizontal convective roll or gravity wave.
This tornado is considered to be one of the most intense tornadoes in U.S. History. Tornado reached peak intensity near Bridge Creek, OK.
Mobile Doppler Radar measurement of approximately 301 mph winds
Outbreak: 63 tornadoes in Oklahoma (Largest Outbreak in Oklahoma History), 74 total tornadoes including Kansas

8 May 2003 Radar Image showing debris ball after F4 tornado exited Moore, OK

8 May 2003 Radar Image showing debris ball after F4 tornado exited Moore, OK

May 8, 2003: F4
Path Length: 17 miles, 700 yards max width, 28 minutes
Deaths/Injuries: 0 killed, 45 injuries
Storm Development:
Supercell developed off dryline boundary west of I-35 Southwest of Moore, OK
Outbreak:  5 tornadoes in Oklahoma (43 total tornadoes documented)
This was the southern most tornado in the outbreak. This tornado reached peak intensity over Eastern Oklahoma City as it passed over the GM Plant.

8 May 2003 Violent Tornado leaving Moore, OK

8 May 2003 Violent Tornado leaving Moore, OK

10 May 2010 Radar Image with debris ball in white circle where EF4 tornado has just left Moore, OK

10 May 2010 Radar Image with debris ball in white circle where EF4 tornado has just left Moore, OK

May 10, 2010: 3 tornadoes (EF4, EF1, and EF1)
Path Length:
EF4: 24 miles, max width of 2000 yards, 31 minutes
EF1: 4 miles, max width 250 yards, 5 minutes
EF1: 0.5 miles, max width 50 yards, 1 minute
Deaths/Injuries: killed 2, Injured 49 all from EF4 tornado
Storm Development:
Storm developed off dryline boundary West of I-35 West of Moore.
3 tornadoes moved over parts of the Moore City Limits.
Outbreak:  2nd Largest Oklahoma Tornado Outbreak (56 tornadoes in Oklahoma) behind May 3, 1999

20 May 2013 Radar Image shows large debris ball as EF5 Tornado is passing over Moore, OK

20 May 2013 Radar Image shows large debris ball as EF5 Tornado is impacting Moore, OK

May 20, 2013:  EF5
Path:  14 miles, 1900 yards max width, 39 minutes
Deaths/Injuries:  24 killed, 212 injured
Storm Development:
Supercell developed near Chickasha, OK off dryline boundary and appeared to have interacted with an outflow boundary near Moore.
Outbreak:  15 Tornadoes in Oklahoma (40 total tornadoes documented from event)
This tornado reached peak intensity near Briarwood Elementary School on 149th St and S. Hudson Ave.  This tornado is considered one of the most intense tornadoes in U.S. History.

20 May 2013 EF5 wedge tornado hidden under ominous mesocyclone, debris, and rain in Moore, OK

20 May 2013 EF5 wedge tornado hidden under ominous mesocyclone, debris, & rain in Moore, OK

20 May 2013 Violent EF5 Moore, OK Tornado shrouded in debris

20 May 2013 Violent EF5 Moore, OK Tornado shrouded in debris

22 May 2013 pile of debris in area of EF5 damage path in Moore, OK

22 May 2013 pile of debris in area of EF5 damage path in Moore, OK

6:42 PM CDT 25 March 2015 Radar Image when one or more tornadoes were impacting Moore, OK (white circle around hook echo)

6:42 PM CDT 25 March 2015 Radar Image: one or more tornadoes were impacting Moore, OK at this time
(white circle around hook echo)

25 March 2015 Moore, OK EF2 Tornado Damage Path Map from NWS Norman, OK

25 March 2015 Moore, OK EF2 Tornado Damage Path Map from NWS Norman, OK

March 25, 2015:
Rating: Preliminary EF1 (might be more than one tornado) ***UPDATE: NWS Norman, OK Rated a single intermittent damage path with EF2 damage found
Path:  estimated 6 miles, but might be more than one tornado ***UPDATE: single 8-12 mile intermittent damage path with Max width of 0.6 miles
Outbreak: ???
Deaths/Injuries:  ???
Storm Development:
supercell developed West of Oklahoma City off cold front boundary.

22 Years ago: Remembering the March Superstorm of ’93

“The Superstorm of ’93”, also referred to as “The Storm of the Century”, is regarded as one of the most powerful mid-latitude cyclones in recorded history to affect the East Coast of North America.  On March 12-14, 1993 a high amplitude trough caused extreme bombogenesis to occur along the Gulf Coast. The deepening surface low pressure center intensified on a northeastward path up the U.S. East Coast causing damaging high winds, heavy snow, storm surge, and tornadoes.  NCDC attributed 208 deaths to this storm in the United States.

13 March 1993 18z Infrared Satellite Image

13 March 1993 18z Infrared Satellite Image

In Tallahassee, FL a 976.5 mb pressure was recorded as the surface low passed. An intense squall line caused several tornadoes and 80-100+ MPH wind gusts over the Gulf Coast and Florida.  The high winds from the deepening cyclone and squall line caused a 12 foot storm surge near Pine Island, FL.  A 109 MPH wind gust was reported in Dry Tortugas, FL.  NCDC reports 44 deaths are attributed to this storm just in the state of Florida.

12 March 1993 Storm Surge Map for Florida

12 March 1993 Storm Surge Map for Florida

6 inches of snow fell in parts of the Florida Panhandle.  17 inches of snow was reported in Birmingham, AL with 6 foot snow drifts!  56 inches of snow was reported on Mt. LeConte, TN and 43 inches in Syracuse, NY.  The NWS Office in Ashville, NC reported a 4.2 to 1 snow/water ratio and  NCDC reported 5.3 to 1 snow/water ratios nearby (normal snow/water ratio is 10 to 1).  This was very heavy wet snow, which caused many roof collapses across the region.

12-14 March 1993 Snowfall Totals

12-14 March 1993 Snowfall Totals

High winds slammed the length of the East Coast and Appalachians.  A 71 MPH wind gust was reported at LaGuardia Airport in NYC, and a 81 MPH wind gust was reported in Boston. Wind gusts of over 100 MPH were reported on many of the higher Appalachian summits.  A record low pressure of 960mb was recorded in White Plains, NY.  Surface pressure records were broken at many locations along the East Coast.

I still remember my Grandparents calling several days after the Superstorm had passed to tell us about their experience in Dandridge, TN.  They were without power for days and had to trudge roughly 100 yards through hip-deep snow, high winds, and white-out conditions to my uncle’s house next door to stay warm and have food and fresh water.  This was a very dangerous task for an elderly couple in a rural part of town in blizzard conditions.  Nearly 3 feet of snow had fallen over their area with much higher drifts.  30 inches of snow was reported only 30 miles away in Gatlinburg, TN.  They all huddled around a kerosene heater in my uncle’s living room as they waited out the storm.  Only 300 miles north in Moraine, OH my house received only a few inches form this historic event.

2015 Lake Effect Snow

6 Jan 2015 heavy lake effect snow with traffic in Watertown, NY

6 Jan 2015 heavy lake effect snow with traffic in Watertown, NY

Happy New Year!  It’s now 2015, hard to believe I’m starting my 16th year of chasing storms and extreme weather events (began chasing in Fall of 1999). I’ve spent most of the new year driving between Cleveland, OH and Watertown, NY documenting lake effect snow events. Only once have I chased a synoptic scale storm this winter and even that chase ended with lake effect snow in western New York.  So far I’ll remember this winter for its lake effect.  All of my late 2014 lake effect snow chases were from Lake Erie snow bands, including and event near Erie, PA and Cherry Creek, NY just before the New Year on December 30th. As of now, all of my 2015 chases have been focused on Lake Ontario snow bands.

7 Jan 2015 2:49 am KTYX base reflectivity showing intense lake effect snow band over Adams Center, NY

7 Jan 2015 2:49 am KTYX base reflectivity showing intense lake effect snow band over Adams Center, NY

January 5-9th one of the most significant lake effect events of the winter, 2nd only to the Nov 17-19 Buffalo Event, hit the east shore of Lake Ontario in Upstate New York dropping over 4 feet of snow in some areas.  I documented this storm in towns like Fulton, Adams Center, Watertown, and Parish, NY.  At times this lake effect band was of equal intensity as the infamous November Buffalo band with 40-50 dBz reflectivity detected on radar.  White out conditions and 3-5 inch per hour snowfall rates were common in this Lake Ontario snow band! January 5th 3 feet of snow accumulated in less than 24 hours in Fulton, NY, and over 4 feet of snow fell on Adams Center on January 6th thru 9th.

Update 9am 26 Jan 2015: I’ll be documenting a Nor’easter in New England from the 26-28 Jan 2015, so I’ll be adding another non-lake effect event to my list of Winter 2014-15 Chases. 

Below are a few images from January 5-7, 2015 in region between Fulton to Watertown:

6 Jan 2015 Watertown, NY Lake Effect Snow

6 Jan 2015 Watertown, NY Lake Effect Snow

6 Jan 2015 snow-covered cars in Fulton, NY

6 Jan 2015 snow-covered cars in Fulton, NY

5 Jan 2015 truck buried in 3ft of snow near Fulton, NY

5 Jan 2015 truck buried in 3ft of snow near Fulton, NY

5 Jan 2015 car stranded in 2+ feet of snow near Fulton, NY

5 Jan 2015 car stranded in 2+ feet of snow near Fulton, NY

6 Jan 2015 snow-covered van in Fulton, NY

6 Jan 2015 snow-covered van in Fulton, NY

6 Jan 2015 man clears drive with snow blower in Fulton, NY where 3 feet of snow fell in less than 24 hours

6 Jan 2015 man clears drive with snow blower in Fulton, NY where 3 feet of snow fell in less than 24 hours

5 Jan 2015 snow collected on top of fire hydrant in Fulton, NY

5 Jan 2015 snow collected on top of fire hydrant in Fulton, NY

5 Jan 2015 police assisting stranded motorist near Parish, NY in heavy lake effect snow band

5 Jan 2015 police assisting stranded motorist near Parish, NY in heavy lake effect snow band

5 Jan 2015 sun shines through edge of intnse lake effect snow bane south of Fulton, NY where 3ft of snow fell in less than 24 hours

5 Jan 2015 sun shines through edge of intnse lake effect snow bane south of Fulton, NY where 3ft of snow fell in less than 24 hours

Violent Coleridge Nebraska Tornado

Violent Wedge Tornado & Mesocyclone near Coleridge, NE June 17, 2014

Violent Wedge Tornado & Mesocyclone near Coleridge, NE June 17, 2014

Violent Wedge Tornado & Wall Cloud near Coleridge, NE June 16, 2014

Violent Wedge Tornado & Wall Cloud near Coleridge, NE June 16, 2014

It’s a cliché statement on websites and blogs, but it’s been way too long since my last post.  Above are 2 photographs taken on June 17, 2014 showing one of the most powerful tornadoes Juston Drake and I have ever witnessed near the town of Coleridge, NE.  Juston and I performed a damage survey 3 days later and discovered a large region of severe ground scouring from this tornado north of Coleridge.  This was one of many tornadoes from the most productive 3 days of storm chasing during the Spring of 2014. This Spring was slow to say the least for chasing storms.  It’s inactivity was probably only eclipsed by the slow Spring of 2013.  Several powerful tornadoes did occur despite the low numbers.   Most severe setups during the Springs of 2013 and 2014 were weakened by a strong Capping inversion and/or dry air mixing into the boundary layer.  It’s difficult for significant tornadoes to develop in the absence of deep boundary layer moisture.  The presence of a strong CAP may have aided the few very intense tornadoes the past 2 years.  Incredible instability developed aided by a strong CAP when deep moisture was present (i.e. 15-31 May 2013, 27 & 28 April 2014, and 16-18 June 2014). I’ll make an effort to write “2014 Spring Recap” and “Hurricane Arthur” posts soon.

2014 Mid-Spring Recap

It’s early May and 2014 has already rivaled 2013 in terms of below average number of tornadoes. Tornado outbreaks on April 27, 28, and 29 pushed the annual preliminary tornado count above 2013 up to the date of May 2nd. The large-scale pattern appears to be favorable for at least the next week or two for more severe weather events over the United States.  The forecast for a pattern conducive for severe weather becomes much more difficult as May progresses.  A significant ridge is likely to build and dominate the Western U.S. by late May and June.  Once in place this pattern will be difficult to change, but can be temporarily broken by MJO waves, similar to June of 2009.

Juston Drake and I have been roaming the Plains and Southeast documenting storms and tornadoes. Most of the events we’ve chased lacked deep low-level moisture making the storms high-based, outflow dominant and generally weak in nature.  The outbreaks of April 27 and 28 had deep Gulf of Mexico moisture available, which played a significant role in those deadly events.  Below are a few images we’ve captured so far this year:

Dramatic supercell west of Eldorado, OK Apr 20, 2014

Dramatic supercell west of Eldorado, OK Apr 20, 2014

Tornado-warned supercell over Memphis, TN Feb 20, 2014

Tornado-warned supercell over Memphis, TN Feb 20, 2014

Juston Drake photographs mesocyclone structure southwest of Columbus, MS Apr 28, 2014

Juston Drake photographs mesocyclone structure southwest of Columbus, MS Apr 28, 2014

Mammatus from MCS anvil near Hearne, TX Mar 28, 2014

Mammatus from MCS anvil near Hearne, TX Mar 28, 2014

RFD gust front structure near Eldorado, OK Apr 20, 2014

RFD gust front structure near Eldorado, OK Apr 20, 2014

Juston Drake films wall cloud before it produces Greenville, TX tornado Apr 3, 2014

Juston Drake films wall cloud before it produces Greenville, TX tornado Apr 3, 2014

Mesocyclone & wedge tornado approaching Louisville, MS Apr 28, 2014

Mesocyclone & wedge tornado approaching Louisville, MS Apr 28, 2014

Tornado-warned supercell near Holden, MO Mar 27, 2014

Tornado-warned supercell near Holden, MO Mar 27, 2014

Occluded mesocyclone & wedge tornado south of Columbus, MS Apr 28, 2014

Occluded mesocyclone & wedge tornado south of Columbus, MS Apr 28, 2014

Wedge-shaped tornado south of Columbus, MS Apr 28, 2014

Wedge-shaped tornado south of Columbus, MS Apr 28, 2014

Juston Drake photographs supercell west of Eldorado, OK Apr 20, 2014

Juston Drake photographs supercell west of Eldorado, OK Apr 20, 2014

Anvil Crawler lightning over Altus, OK Apr 26, 2014

Anvil Crawler lightning over Altus, OK Apr 26, 2014

MCS shelf cloud southeast of Pine Bluff, AR Apr 24, 2014

MCS shelf cloud southeast of Pine Bluff, AR Apr 24, 2014

High-based supercell thunderstorm north of Hollis, OK Apr 23, 2014

High-based supercell thunderstorm north of Hollis, OK Apr 23, 2014

Tornadic Supercell with wall cloud west of Eldorado, OK Apr 20, 2014

Tornadic Supercell with wall cloud west of Eldorado, OK Apr 20, 2014

Wall cloud near Princeton, TX Apr 3, 2014

Wall cloud near Princeton, TX Apr 3, 2014

Wall cloud shortly before producing wedge tornado southwest of Columbus, MS Apr 28, 2014

Wall cloud shortly before producing wedge tornado southwest of Columbus, MS Apr 28, 2014

High-based supercell at sunset west of Wichita Falls, TX Apr 23, 2014

High-based supercell at sunset west of Wichita Falls, TX Apr 23, 2014