Metric calculated as the percent of Climate Prediction Center extended (outlooks out to 14 days) and long range (monthly and seasonal outlooks) temperature and precipitation outlooks exceeding Heidke Skill Score (HSS) of 10 (10% better than a climatological forecast). Due to the scarcity of long range outlooks (six per month), scores are smoothed over a three year period. To better track results, three individual metrics are tracked – 1) All forecasts combined, 2) Temperature only, and 3) Precipitation only.

Metric calculated as the percent of Climate Prediction Center extended range temperature and precipitation outlooks (outlooks out to 14 days) exceeding Heidke Skill Score (HSS) of 10 (10% better than a climatological forecast). To better track results, three individual metrics are tracked – 1) All forecasts combined, 2) Temperature only, and 3) Precipitation only.

Metric calculated as the percent of Climate Prediction Center extended range temperature and precipitation outlooks (outlooks out to 14 days) exceeding Heidke Skill Score (HSS) of 10 (10% better than a climatological forecast). To better track results, three individual metrics are tracked – 1) All forecasts combined, 2) Temperature only, and 3) Precipitation only.

Metric calculated as the percent of Climate Prediction Center long range temperature and precipitation outlooks (monthly and seasonal outlooks) exceeding Heidke Skill Score (HSS) of 10 (10% better than a climatological forecast). Due to the scarcity of long range outlooks (six per month), scores are smoothed over a three year period. To better track results, three individual metrics are tracked – 1) All forecasts combined, 2) Temperature only, and 3) Precipitation only.

Metric calculated as the percent of Climate Prediction Center extended (outlooks out to 14 days) and long range (monthly and seasonal outlooks) temperature and precipitation outlooks exceeding Heidke Skill Score (HSS) of 10 (10% better than a climatological forecast). Due to the scarcity of long range outlooks (six per month), scores are smoothed over a three year period. To better track results, three individual metrics are tracked – 1) All forecasts combined, 2) Temperature only, and 3) Precipitation only.

Metric calculated as the percent of Climate Prediction Center extended (outlooks out to 14 days) and long range (monthly and seasonal outlooks) temperature and precipitation outlooks exceeding Heidke Skill Score (HSS) of 10 (10% better than a climatological forecast). Due to the scarcity of long range outlooks (six per month), scores are smoothed over a three year period. To better track results, three individual metrics are tracked – 1) All forecasts combined, 2) Temperature only, and 3) Precipitation only.

Seasonal outlooks are reported as the probability of temperature being above normal, near normal, below normal or, where no definite seasonal guidance can be provided, equal chances. The seasonal outlooks are the cumulative skill calculated for regions where predictions are made. These forecasts are verified using a 48-month running mean of Heidke Skill score computed for seasonal outlooks for each 3-month seasonal mean (e.g., January-February-March mean; February-March-April mean; March-April-May mean; and so on). The previous dataset used to verify the CPC seasonal temperature outlook has developed a cold bias across a large portion of the western United States during the past 5-10 years. CPC has developed a new dataset which consists of Synoptic and Metar stations only, which is consistent throughout the historical and real time periods. This change will not impact the measure itself, nor how it is reported, but will remove biases identified in the old verification dataset, resulting in a more accurate performance indicator.

Americans live in the most severe weather-prone country on Earth. StormReady Communities support a Weather-Ready Nation by preparing for the occurrence of high impact environmental events. On an annual basis NWS targets 100 new StormReady Communities pending funding availability.

StormReady supports NWS’ disaster risk reduction strategy and is offered to provide guidance and incentive to officials who want to improve their hazardous weather and flood operations. A long-term goal for the program is to make every county or county-equivalent in the United States StormReady. The 2010 U.S. Census identifies 3,234 county or county-equivalents in the United States. We are 34 percent of the way there with 1,092 county or county-equivalents currently recognized as StormReady. A StormReady Community is defined as a local government* entity or facility** that has the authority and ability to adopt the StormReady recognition guidelines for the residents and visitors within its jurisdiction.

*The term “local government” means –
(A) A county, parish, borough, municipality, city, town, township, local public authority, school district, special district, intrastate district, council of governments (regardless of whether the council of governments is incorporated as a nonprofit corporation under State law), regional or interstate government entity, or agency or instrumentality of a local government;
(B) An Indian tribe or authorized tribal organization, or Alaska Native village or organization; and
a rural community, unincorporated town or village, or other public entity, which has the ability to achieve StormReady recognition.
**The term “facility” for a StormReady community exclusively means - universities, military installations, state/national parks, power plants/utilities, transportation centers (e.g., airports), theme parks/entertainment complex, and large event venues (e.g. stadiums).

The Arctic is a vast, remote region that is critical to the United States economy, weather and sea ice forecasting, our understanding of ecosystem health (including marine mammals and fisheries), and our understanding of climate change. Due to the presence of low temperatures, harsh sea conditions, limited telecommunications infrastructure, and sea ice, maintaining a network of sea ice buoys, Air-Launched Autonomous Micro-Observers, and Bering & Chukchi moorings is difficult, necessitating constant deployment of a combination of expendable technologies and retrieval and redeployment of a large network of moorings in the Bering and Chukchi Seas.

Tornado Warnings are issued to enable the public to get out of harm’s way and mitigate preventable loss. NWS forecasters issue approximately 2,900 Tornado Warnings per year, primarily between the Rockies and Appalachian Mountains. Tornado Warning statistics are based on a comparison of warnings issued and weather spotter observations of tornadoes and/or storm damage surveys from Weather Forecast Offices in the United States.

Lead Time (LT) for a Tornado Warning is the difference between the time the warning was issued and the time the tornado occurred (based on certified reports) in minutes, assuming the tornado tracked within the bounds of the warned area. Lead Times for all tornado occurrences within the U.S. are averaged to get this statistic for a given fiscal year. This average includes all warned events with zero lead times and all unwarned events.

Lead Time is calculated down to the minute for individual Tornado Warnings and tornadic events. Although the timing of the warning transmission is recorded to the nearest second, typically there is only an estimate to the nearest minute of when a tornado touches down. Additionally, even though we can compute the average tornado warning lead time to a precision of 30 second increments or less, the reporting of this value implies greater accuracy in the data based on scientific and logistical restrictions on tornado reporting and surveying. Most tornadoes cannot be visually tracked from beginning to end and post-storm damage surveying is the official method with which the NWS categorizes tornado characteristics (intensity, path length & width) but must rely on radar data to estimate the timing of the tornado track.