Search results
Results From The WOW.Com Content Network
The international definition of fog is a visibility of less than 1 km (3,300 ft); mist is a visibility of between 1 km (0.62 mi) and 2 km (1.2 mi) and haze from 2 km (1.2 mi) to 5 km (3.1 mi). Fog and mist are generally assumed to be composed principally of water droplets, haze and smoke can be of smaller particle size.
Globe at Night is an international scientific research program that crowdsources measurements of light pollution in the night sky. At set time periods within each year, the project asks people to count the number of stars that they can see from their location and report it to the project's website.
A prognostic chart is a map displaying the likely weather forecast for a future time. Such charts generated by atmospheric models as output from numerical weather prediction and contain a variety of information such as temperature , wind , precipitation and weather fronts .
NOAA distributed this Northern Lights visibility prediction map. But viewers much further south are reporting seeing auroras in their areas. See the full map and description on the NOAA site .
SYNOP (surface synoptic observations) is a numerical code (called FM-12 by WMO) used for reporting weather observations made by staffed and automated weather stations. SYNOP reports are typically sent every six hours by Deutscher Wetterdienst on shortwave and low frequency using RTTY.
Prevailing visibility in aviation is a measurement of the greatest distance visible throughout at least half of the horizon, not necessarily continuously. To take the prevailing visibility, controllers reference a number of visual reference points: usually buildings , hills , or other geographic features.
Such maps have been in use since the mid-19th century and are used for research and weather forecasting purposes. Maps using isotherms show temperature gradients, [2] which can help locate weather fronts. Isotach maps, analyzing lines of equal wind speed, [3] on a constant pressure surface of 300 or 250 hPa show where the jet stream is located.
The forecast begins by listing areas with gale warnings, followed by a general synopsis of pressure areas, then a forecast for each individual sea area covering wind speed and direction, precipitation, and visibility. Extended forecasts at 00:48 and 05:20 include information from coastal weather stations and an inshore waters forecast.