National Weather Service – Madison Forecast. Reliable, briefly-worded “spot” forecast.
Hourly Forecast Graph or Hourly Numerical Data. A much “higher-resolution” view of the predicted weather to come. These give the NWS forecaster’s best prediction for future hourly readings of parameters like temperature, sky cover, wind speed and direction, precipitation potential, etc. They do not, however, indicate the confidence level (probability that the forecast will be accurate) for any given data point. For that, you should refer to the Forecast Discussion, issued daily around 3 AM and 3 PM, which will provide a much more nuanced view of the forecast being made, including reasoning and justification. While it usually contains some jargon and abbreviations, most technical terms are hyperlinked to definitions.
Milwaukee/Sullivan radar image, via Weather Underground. Updated every 5 minutes, with storm tracking (bearing, speed) and cell characteristics.
Water Vapor Image – 6KM, 24 Hr. This water-vapor image of North America from College of DuPage is one of the best we can find. A number of settings for adjusting the image appear near the top. Above the settings, at the top right, the “Sector Map” and “Product Menu” allow you to view different sub-regions of the U.S. and access additional graphics, including infra-red and visual satellite and radar composites. For additional images, both wider and narrower in scope, see “C.O.D. Satellite & Radar Page” below.
WV Image – 8KM, Northern Hemisphere. A wider-frame view of North America, showing roughly 4,000 miles of adjacent ocean on each side. The larger-scale structure of the upper-air pattern affecting the continent can be discerned here, allowing better comprehension of blocking patterns or the approach of a pattern change.
C.O.D. Satellite & Radar Page. The five menu banners on the L-hand side of this page allow you to view imagery at a number of scales. The “Hemispheric Products” include views of Canada, the North Pole, adjacent oceans and the entirety of the North/Western Hemisphere. High resolution visual images of regions as small as a few hundred miles square can be found under “1km Products.” In either case, first click on the type of image you want from the drop-down menu under the banner, then click into the map that appears to select a region. Once a static image has appeared, lengths of loop can be chosen from the “product menu” above the map.
7-Day Satellite Review. A useful and informative visual for comprehending larger scale atmospheric patterns over North America at a glance, courtesy of the Space Science and Engineering Center at the UW-Madison.
Wind Map. This popular (and beautiful) live graphic is actually a quite useful tool for seeing how surface-winds are blowing across the country.
Earth Wind Map. A similar graphic, but on a rotatable, tiltable earth and with views of many height levels, including stratosphere. (To change the view, click the word “Earth” in the lower left.)
SWODY1, SWODY2, & SWODY3 give the Storm Prediction Center’s severe weather outlooks for future days 1 (today) thru 3. Text and graphics assess risk-level, risk-type and etiology of the day’s threats. These are the go-to products for virtually everyone interested in severe weather, including spotters and chasers. Mesoscale Discussions (MDs) – which include a small weather map with near real-time analysis – are an excellent resource for assessing particular, more localized threats when severe weather is occurring.
Additional Graphics & other resources:
CPC Seasonal Outlook. This Climate Prediction Center page not only includes forecast maps out to 13 months, but also long-lead discussions for the upcoming 30 and 90 day periods which are updated around the 1st and 20th of each month.
Climate Prediction Center. The CPC’s homepage has assessments of drought and other hazards, as well as links to information on longer-term patterns like El Nino / La Nina, the Madden Julian Oscillation and the Arctic Oscillation.
Snow Cover. This NOAA site provides a wealth of data including snow depth, temperature, density, water-equivalence and much more (but remember to hit the “redraw map” button each time). Zoom in on the map for better detail.
72-Hour Observation Trace – Madison. This chart shows hourly conditions for the past three days at the Truax Field / KMSN recording station. The numbers in the “Sky Cond.” field refer to ceiling heights, and represent the first three digits of the cloud deck in feet above ground level (ie., 003 would be read as “300 feet;” 150 would be read as “15,000 feet.”
Weather Spark. This site provides a graphical representation of historical weather – including hourly readings of parameters such as percent of cloud cover, height of ceiling, dewpoint, wind speed and direction – going back to 1948 (an astonishing accomplishment in itself). Additional functionalities are available through the banner at the top.