Most of the rules in this course were written after something went wrong. The timeline is the short version of why the warning system has its current shape, and why spotters are still in it.

In this lesson you will

  • Place key milestones in order: first tornado forecasts, the radar era, and storm-based warnings.
  • Explain how specific disasters changed warning practice.

The timeline

  • 1884: John P. Finley of the Army Signal Corps runs experimental tornado forecasts and publishes forecast rules, in the year of the 19 February Enigma outbreak.
  • 1885–1887: The word "tornado" is barred from official forecasts. The Weather Bureau keeps the ban after taking the service over in 1890, on the argument that naming the hazard would cause panic.
  • 1938: The word is permitted again, in warnings rather than in routine forecasts. Half a century of silence, and a public tornado forecast program still fourteen years away.
  • 25 Mar 1948: Fawbush and Miller at Tinker AFB issue the first successful tornado forecast, five days after a tornado struck the base.
  • 1952: The Weather Bureau stands up a severe weather unit in Washington in March, made permanent as the Severe Weather Unit on 21 May. Renamed SELS, the Severe Local Storms service, in June 1953, it is the direct ancestor of the National Severe Storms Forecast Center and then SPC.
  • 9 Apr 1953: The first documented tornadic hook echo, filmed by Don Staggs on the Illinois State Water Survey radar at Willard Airport, north of Champaign.
  • 11 Apr 1965: The Palm Sunday outbreak. The survey afterwards finds the public could not tell a "tornado forecast" from a warning, and that for many the message never arrived at all.
  • 1966: "Tornado forecast" becomes "tornado watch". Warning practice is tightened, and sirens and spotter networks expand.
  • late 1960s–70s: SKYWARN takes shape. Its impetus and its name come out of Palm Sunday, and the national program is in place by the early 1970s; organized spotting itself is older, going back to wartime and to local networks in the 1950s.
  • 3–4 Apr 1974: The Super Outbreak.
  • 1991–1997: NEXRAD deployment. Roughly 160 WSR-88D radars, counting the contiguous states, Alaska, Hawaii, the territories and Defense Department sites.
  • 1 Oct 2007: Storm-based polygon warnings replace county-based warnings, for tornado, severe thunderstorm, flash flood and marine products.
  • 22 May 2011: Joplin. The NWS Central Region Service Assessment, published that July, documents how people actually responded to the warnings they received.
  • 31 May 2013: El Reno. The first documented storm-chaser fatalities: Tim Samaras, Paul Samaras and Carl Young, and Richard Henderson. It is the reason spotter safety gets its own module later in this course.
  • 2013: The dual-polarization upgrade, rolling across the network since 2010, completes. It makes the Tornado Debris Signature an operational confirmation tool.

What the sequence shows

Two patterns run down that list. The first is that capability and permission moved separately. Finley was publishing tornado forecast rules in 1884; the word was barred from forecasts the following year and stayed out of them for half a century. The objection was that naming the hazard would cause panic, not that the forecasts were wrong. That argument still appears whenever a warning is held back over how people might react.

The second is that each technology narrowed the question rather than answering it. Radar told forecasters where to look. Polygon warnings shrank the warned area from a county to a shape. Dual-pol added debris aloft. None of them closed the gap this course is about: whether something is happening at the ground, right now, where people live. Each improvement made the remaining human observation more specific, not less necessary.

Teaching point
Joplin appears here as a disaster and as a document. The Service Assessment is why Lesson 6 covers what people do when a warning arrives, not just how it was delivered.

Check yourself

Which change moved warnings off county boundaries and onto a drawn shape?

  1. The NEXRAD WSR-88D deployment in the 1990s
  2. Storm-based polygon warnings, 1 October 2007
  3. The dual-polarization upgrade around 2013
  4. The formalization of SKYWARN after Palm Sunday 1965
Hint

Two of these are radar upgrades, one is a network, and one is a change to the product itself.

Answer

Storm-based polygon warnings, 1 October 2007

Storm-based warnings, from 1 October 2007. Radar upgrades changed what forecasters could see. The polygon changed what they issued, and with it the question a spotter answers, from "is my county affected" to "is this shape drawn in the right place".

Sources

  1. Doswell, Moller & Brooks 1999, Wea. Forecasting 14, 544–557: "Storm spotting and public awareness since the first tornado forecasts of 1948"
  2. Galway 1985, Bull. Amer. Meteor. Soc. 66(11), 1389–1395: "J. P. Finley: the first severe storms forecaster"
  3. NWS Joplin Service Assessment (2011)
  4. SPC history page