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Wednesday, July 16, 2014

Disaster Prep Wednesday: Weather Terms

The last couple of days I have been plugging away at some Red Cross volunteer weather work (yes, that's why blogging has been scarce around here), and it occurred to me that it might be a good idea to explain the sort of gradient that the National Weather Service (NWS) uses to differentiate weather threat levels from "weak" to "strong."

We are going, in part, to look to the NWS Glossary for some common terms you might here on the TV or radio weather news.

Take a look at the map below and see how the terms discussed below can help you decipher what the map is telling us about the weather in the U.S.:

Source: NWS

In the case of clear weather with no threats, the NWS, shockingly, has no term for that.

The first term of interest is "Outlook" for which the NWS has two definitions:
Outlook
An outlook is used to indicate that a hazardous weather or hydrologic event may develop. It is intended to provide information to those who need considerable lead time to prepare for the event.
Outlook
A broad discussion of the weather pattern expected across any given area, generally confined to forecast periods beyond 48 hours.

The second term to be familiar with is a "Watch," which the NWS defines as:
A watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still uncertain. It is intended to provide enough lead time so that those who need to set their plans in motion can do so.
The NWS also issues "Special Weather Statements":
A special weather statement may be issued by the NWS for hazards that have not yet reached warning or advisory status or that do not have a specific code of their own, such as widespread funnel clouds. They are also occasionally used to clear counties from severe weather watches. A common form of special weather statement is a significant weather alert. Occasionally special weather statements appear as heat advisories.
This can then be followed by an "Advisory," defined as:
Highlights special weather conditions that are less serious than a warning. They are for events that may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property.
Then there is a "Warning":
A warning is issued when a hazardous weather or hydrologic event is occurring, is imminent, or has a very high probability of occurring. A warning is used for conditions posing a threat to life or property.
A NWS guide to "Severe Weather Terms" can be found here:

Of course, there are other weather terms for snow and really cold weather (winter weather), really hot weather, hurricanes and typhoons

Generally, though, the "watch, advisory and warning" system applies throughout the weather spectrum.

Knowing what the weather terms mean can be helpful in choosing courses of action.

By the way, if you go to weather.gov,  you can find the current and interactive version of that map.

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