The lower this measure is the better, so being below the target is exceeded and above the target is not met. Visibility and cloud ceiling forecasts are critical for aircraft safety and efficient operations. When visibility or cloud ceilings are low, pilots rely on instruments to navigate instead of visual reconnaissance. The Federal Aviation Administration establishes Instrument Flight Rule (IFR) thresholds—visibility less than three statute miles and/or cloud ceilings at, or below, 1000 feet—for safety. NWS assesses the quality of IFR threshold forecasts in response to these requirements. Fundamental statistical metrics, specifically Probability of Detection (POD) and False Alarm Ratio (FAR), are used to track IFR forecast performance. Probability of Detection (POD), also known as Accuracy, is a ratio that describes the number of times IFR is correctly forecasted compared to the total number of IFR occurrences. FAR is a ratio that describes the number of IFR forecasts when IFR was not observed compared to the total number of forecast attempts. These two metrics must always be used in conjunction, as one can be improved at the expense of the other. Greater accuracy and a minimized FAR result in safer flights and fewer flight delays; conversely, poorer accuracy and an increased FAR result in a greater incidence of unnecessary flight delays.

*Please also note that a FAR is the number of false alarms per the total number of warnings. So if a FAR actual is higher than the target, then the target has not been met. If the actual is the same number or less, then it has been met or exceeded.

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.

The annual number of peer reviewed publications is an indicator of productivity and relevance and is tracked using online resources. Peer review is one of the important procedures used to ensure that the quality of published information meets the standards of the scientific and technical community.
* FY 2019 is the first year that we are reporting on both NOAA-authored publications (previously the only type of publication measured) and NOAA-funded publications.

Visibility and cloud ceiling forecasts are critical for aircraft safety and efficient operations. When visibility or cloud ceilings are low, pilots rely on instruments to navigate instead of visual reconnaissance. The Federal Aviation Administration establishes Instrument Flight Rule (IFR) thresholds—visibility less than three statute miles and/or cloud ceilings at, or below, 1000 feet—for safety.

NWS assesses the quality of IFR threshold forecasts in response to these requirements. Fundamental statistical metrics, specifically Probability of Detection (POD) and False Alarm Ratio (FAR), are used to track IFR forecast performance. Probability of Detection (POD), also known as Accuracy, is a ratio that describes the number of times IFR is correctly forecasted compared to the total number of IFR occurrences. FAR is a ratio that describes the number of IFR forecasts when IFR was not observed compared to the total number of forecast attempts. These two metrics must always be used in conjunction, as one can be improved at the expense of the other. Greater accuracy and a minimized FAR result in safer flights and fewer flight delays; conversely, poorer accuracy and an increased FAR result in a greater incidence of unnecessary flight delays.

A winter storm warning provides NOAA customers and partners advanced notice of a hazardous winter weather event that endangers life or property, or provides an impediment to commerce. Winter storm warnings are issued for winter weather phenomena like blizzards, ice storms, heavy sleet, and heavy snow. This performance indicator measures the advance warning lead time in hours of winter storm events.

Improving the accuracy and advance warnings of winter storms enables the public to take the necessary steps to prepare for disruptive winter weather conditions.

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.

For each reported flash flood event, the flash flood warning lead-time is the difference in minutes between the issuance of a flash flood warning and the onset of a geographically corresponding flash flood event. The lead times for all flash flood events, within the United States and territories served by the National Weather Service, are averaged to calculate the national average flash flood warning lead-time metric for a given fiscal year. This average includes all warned events with zero lead times and all unwarned events.

Historically, flash flood warnings were issued and verified on a countywide basis. Starting in FY 2010, the storm-based warnings were implemented with verification based solely for the areas impacted by the warning and event.

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.