JLWSS

JONAH LARSEN WINTER STORM SCALE

First and foremost, to be classified as a winter system at all, be rated on this scale, and receive a number or name, a system must be sufficiently organized, as determined by a DCWS forecaster, that a single weathermap symbol overlayed on radar would be sufficient to denote it without confusion about which radar signatures constitute part of the storm. It also must occur at non-muntainous elevations. a "Winter Storm Warning for the Colorado rockies above 2000 feet" does not a winter storm make.

The JLWSS is a new way of indicating the intensity of winter storms. It works by rating a system on a scale of 0-5 and assigning it a storm type. This complements the DCWS's recently introduced system of naming winter storms. The system is shown below.

As you can see, an organized winter system is classified under one of the following terms, listed in order of ascending severity:

  • Freezing Drizzle Disturbance
  • Sleet Disturbance
  • Freezing Rain Disturbance
  • Winter Disturbance
  • Severe Freezing Rain Disturbance
  • Sleet Storm
  • Winter Storm
  • Ice Storm
  • Major Sleet Storm
  • Major Winter Storm
  • Major Ice Storm
  • Blizzard
  • Major Blizzard

After being preliminarily classified according to the JLWSS by a DCWS forecaster, a system will be paired with a name or number. It will be named if it is a Winter Storm or higher. It will be numbered if it is a Severe Freezing Rain Disturbance or less. The classification of a storm can change at any time, but a storm which has ever been named will retain its name until dissipation. A storm named with the name CARLI, for example, could be Winter Storm CARLI, Ice Storm CARLI, or Blizzard CARLI. but if Winter Storm CARLI were later reclassified as a Winter Disturbance, it would become Winter Disturbance CARLI.

The other important part of the system, of course, is the Lv. number. Lv.0 storms are utterly a nuisance and nothing more, but Lv.5 storm can paralyze a region for days.

Level Description Example
Lv.0 Nuisance. Roads may be slightly slick. So minor that no notable examples.
Lv.1 Minor storm. May cause school delay. Some road hazard. No example yet
Lv.2 Storm. May be enough to close school if early in morning. Increased road hazard. No example yet
Lv.3 Major storm. May close school, possibly for 2 or more days if ongoing. Significant road hazard. Power outages possible. 2011 Central Ohio Ice Storm; 2011 Dublin, OH surprise blizzard.
Lv.4 Crippling storm. Most likely schools and/or roads are closed. If continuing for multiple days, can paralyze regions for a couple of days. Power outages possible. 2011 Central Indiana Ice Storm
Lv.5 Extreme storm. Schools and/or roads closed and inaccessible. Regions paralyzed for days. Power outages likely. 2011 Chicago Blizzard; 2010 Snowmageddon storm

The difference between this system and others that have been used before it is that others are biased towards the creators' areas. This scale is based purely on meteorological data (wind speed, snowfall total, ice accretion) and can be used anywhere. Now, obviously a Lv.3 storm is going to be more crippling in Atlanta than in Chicago, but the same is true of other blanket scales like the Saffir-Simpson Hurricane Scale (SSHS). A Category 3 hurricane obviously does more damage in New York City, where hurricanes rarely hit, than in well-prepared Florida! This scale assumes a well-prepared location for impact descriptions, like Central Ohio, New York, Chicago, or another frequent-snow city. Nevertheless, in the same way as the SSHS, we can still use the scale for areas which are less well prepared because the scale is understood to represent snowy locations and specifically quantifies the exact amounts required to attain the level which a storm receives.