Clear Sky Clocks
National Weather Service Forecasts
NWS Model Output Statistical (MOS) graphics (Learn more)
NWS mid-range model for probability of clear skies. (goes out 4 days)
NWS mid-range model for probability of sky cover. (goes out 4 days)
(goes out 8 days)
NWS Digital Forecasts
NWS Experimental Cloud Cover Graphical Forecasts (Northeast Metro Area)
Forecasts from local NWS forecast offices
NWS Sterling Weather Office (Virginia/Maryland
NWS Charleston Weather Office (West Virginia)
Dulles Upper Air Sounding Plot (Java applet)
Upper air soundings plot temperature and dew point of the atmosphere as collected by a weather balloon. A tutorial for reading these is available. For astronomers, these can provide clues as to the stablity of the air – how good will the seeing be? These are normally updated every 12 hours.
Real-time Observation Monitor and Analysis Network (ROMAN). Locate weather stations near a location and see the most recent data. A map of the region showing available stations is available.
Quick links to stations in:
NWS Experimental Smoke and Ozone Forecasts – Might be usable to guage impact forest fires will have on transparency.
If you are LOST in all this data, perhaps the best single source is the NWS forecast discussion. Here, the duty forecaster at the NWS office in Sterling puts down their thinking process behind the current forecast. Find it here. A glossary is available here.
Astronomy Weather Sites
– Has stargazing section showing sky conditions throughout the day and night
– Shows sun and moon rise/set times and has an interactive star chart