Moore Tornado: More Lives Saved by Forecast

Risk Was Seen Days Ahead

According to the National Weather Service office in Norman, Okla., an estimated 13,500 people lived in the path of the Newcastle/Moore tornado.

The quality of both medium-range forecasts and short-term watches and warnings, coupled with the use of news choppers showing live video of the tornado as it happened, along with dedicated emergency managers and other personnel on the ground, likely saved many lives.  

In the following pages, we step through the forecast timeline of this event, providing some tips you can use to raise your awareness of these particularly dangerous severe weather events both several days out, and hours ahead of the development of these tornadic supercells.  

While not every severe thunderstorm event is the same, and some still remain difficult forecast challenges, there are subtle cues in the forecast that you can pay attention to that will separate a May 19-20 event from more common "60 mph winds, one-inch hail" severe events.  

The potential for severe thunderstorms, including possible tornadoes, became apparent as early as the middle of the previous week.  

Both the National Weather Service (NWS) in Norman, Okla. and severe weather expert Dr. Greg Forbes (Facebook | Twitter) highlighted central Oklahoma in an enhanced risk four days prior to the event.

How you can tell the threat is elevated:

• Use of the word "outbreak" in Dr. Forbes TOR:CON forecasts.  This word is reserved for those events that may be large enough in areal coverage or in which the meteorological ingredients look to be particularly volatile.
• An elevated TOR:CON forecast for any particular area.  Typically most severe thunderstorm days will feature TOR:CON forecasts of "2 or less", indicating hail or high winds are the main threats. Central Oklahoma's TOR:CON was elevated to a "5" four days out.  

By the weekend, the threat continued to rise.

T-Minus One Day:  Threat Rising

Sunday morning, most of the attention was focused on that day's potential for tornadic supercells, as was later borne out in a close call in Wichita, Kan. and a pair of destructive tornadoes from Edmond to Carney, Okla. and from east of Norman to Shawnee, Okla.  

However, both NWS-Norman and Dr. Greg Forbes were still quite concerned about the following day.

Forecast cues you can use:

• Dr. Forbes still used the word "outbreak" and, in fact, raised his TOR:CON forecast for central Okla. to a "6".
• NWS-Norman stenciled in an area labeled "most likely locations for tornadoes" over central Okla. including Moore.

In truth, communicating a multi-day tornado threat remains a challenge, given most attention is focused on the current day.

Next, the forecast the morning of May 20, 2013.

The Morning of May 20, 2013

Monday morning, less than 12 hours before the Moore, Okla. tornado, residents were still picking up the pieces from Sunday evening's EF4 tornado near Shawnee, Okla. and EF3 tornado affecting Luther and Carney, Okla.  

(RECAP:  May 19 tornadoes)

What you see in the map above is a tornado risk map from NOAA's Storm Prediction Center (SPC).  The SPC issues so-called "convective outlooks" covering the current day (day 1), as well as the following two days (days 2 and 3), and a general outlook for the extended period (days 4-8).  

The SPC day 1 outlook also breaks down individual severe weather threats, including the tornado threat, contoured by the threat of a tornado within 25 miles of a point.  A tornado threat of over 10% is an elevated one.  Also, note the black hatched area says not only a 10% chance of a tornado, but a tornado capable of EF2 or stronger damage.  

Then there was this sadly prescient tweet sent out from NWS-Norman that morning:

Forecast tips for you:

• Follow your local National Weather Service office on Facebook and Twitter.
• Follow The Weather Channel on Facebook, Twitter, and Google+.
• Using these social media channels, you may gain additional insight on the day's severe risk. 

Next, the tornado watch is issued.

Tornado Watch issued:  1:10 p.m.

NOAA's Storm Prediction Center (SPC), in coordination with local NWS offices, first issued a tornado watch including Newcastle and Moore, Okla. at 1:10 p.m.

In the SPC watch issuance were the following snippets:

• "Rapid, intense storm development is expected during the next few hours."
• "One or two strong tornadoes may not be out of the question."

Forecast tips for you:

• Tornado watches issued on days of particularly elevated tornado risk deserve special attention.  You may only have a few hours before tornadic supercells develop and threaten your area.
• The tornado watch was issued 1 hour and 35 minutes before initial tornado touchdown west of Newcastle, Okla.

Next, the first warning is not a tornado warning.

Severe Thunderstorm Warning:  2:12 p.m.

At the time, rotation in the cell was not sufficiently strong, tight, and deep enough to warrant issuance of a tornado warning.  Therefore, a severe thunderstorm warning alerting downstream residents to the threat of "half dollar size hail" and "damaging winds in excess of 60 mph" was issued by NWS-Norman.

However, this was a discrete supercell, developing on a day with an enhanced tornado risk.  Meteorologists were all watching this storm very closely:

Forecast tip:

• On a day with enhanced tornado risk, watch closely any discrete supercell even before a tornado warning is issued on it.
• A severe thunderstorm warning for such a rapidly developing thunderstorm on a heightened tornado risk day can serve as an advance alert to potential tornado development soon.  Note the additional lead time below.
• 33 minutes:  Lead time between issuance of severe thunderstorm warning and initial tornado touchdown near Newcastle.

Next, the initial tornado warning.

Tornado Warning:  2:40 p.m.

As feared, just about 25 minutes later, this supercell was morphing into a tornadic supercell quickly.

This prompted the first tornado warning from NWS-Norman, issued at 2:40 p.m.  

According to the official storm survey, the Newcastle-Moore tornado first touched down about 4 miles west of Newcastle at 2:45 p.m., or five minutes after this initial tornado warning was issued.  

The first report of a confirmed tornado was received by NWS-Norman around 2:55 p.m.

Forecast tips for you:

• Don't wait for confirmation of a tornado to act on a tornado warning, particularly on a day of heightened tornado risk.  Seek shelter immediately upon receiving the warning.
• 44 minutes:  Approximate lead time between issuance of this tornado warning and the tornado's arrival at the Warren Theater and Moore Medical Center.

Next, a tornado "emergency" is issued.

Tornado Emergency:  3:01 p.m.

Since being first used by the NWS-Norman in the May 3, 1999 tornado outbreak, the "tornado emergency" has been used in rare situations to highlight a severe threat to human life and catastrophic damage from a confirmed tornado.  

In this case, there was now a large, confirmed tornado near Newcastle moving toward the southern Oklahoma City metro area.  This tornado was being shown live on local media outlets, including KFOR-TV, which The Weather Channel was showing live on-air that afternoon.

Forecast tips for you:

• If you hear "tornado emergency" for your area, you need to seek shelter immediately below ground or in an interior room of a concrete building.  This is as dire a tornado alert as the NWS issues.
• 23 minutes:  Approximate lead time between issuance of the tornado emergency and the tornado's arrival at the Warren Theater and Moore Medical Center.

Finally...impact of the tornado in Moore.

Tornado Churns Through Moore:  3:14 p.m.

About 3:14 p.m., the tornado then entered the city of Moore, Okla., inflicting heavy damage and claiming two dozen lives.

It was estimated approximately 1,200 homes in Oklahoma City and Moore were affected by the tornado.  Preliminary estimates suggest this single tornado may have inflicted over $2 billion in total damage.

(MORE:  Costliest tornado? | Interactive damage map | Long tornado history)

Again, the death toll could have been much higher.  Almost two years prior to the day, an EF5 tornado tore a swath through Joplin, Mo., claiming 158 lives in the deadliest single U.S. tornado since 1947.

While meteorology clearly cannot pinpoint a massive, violent tornado will affect any given city or town before it's either spotted or there are indications on radar, let's recap the lead times presented here:

• One to four days prior:  Word "outbreak" mentioned; elevated tornado threat forecast
• Morning of the event: Peak tornado threat area, timing highlighted
• 95 minutes before tornado first touched down:  First tornado watch issued
• 33 minutes before tornado first touched down:  First severe t-storm warning issued
• 5 minutes before tornado first touched down:  First tornado warning issued
• 23 minutes before tornado hits Warren Theater, Moore Med. Center:  Tornado emergency issued.

The low death toll for such a violent tornado is a testament to the excellent work of the NWS office in Norman, Okla. (Rick Smith is the Warning Coordination Meteorologist, there), media partners and the emergency management community.  

As overwhelmingly proven with recent disasters such as the April 2011 Superoutbreak and Superstorm Sandy, an investment in the National Weather Service saves lives.  

By staying informed, you can buy yourself additional time to take action when dangerous weather approaches.  Download The Weather Channel app for your smartphone or tablet.  Follow The Weather Channel on Facebook, Twitter, and Google+.  

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MORE ON WEATHER.COM:  Photos from May 19-20 Tornadoes