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SFSU's California Regional Weather Server:

Changes and Newest Features

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• 2/15/19: Fixed a bug in animation of Eastern Pacific/Western North America composite geopotential height/infrared satellite image/radiosond observation maps at 500 mb and 300 mb, and North American composite maps at 500 mb and 300 mb, in which animations that should include the most recent 12Z map failed to do so when the current UTC time is between 00Z and 03Z, inclusive (soon after which the 00Z GFS model analysis arrives and a new 00Z map becomes available, thereby becoming the last map in the animation).
• 6/19/10: Added a JavaScript animation of West Coast overview composite maps (sea-level pressure fields with visible satellite images and surface wind observations). It is accessible from the West Coast Overview Composite Weather Maps menu.
• 6/8/10: Added a JavaScript animation of West Coast overview composite maps (sea-level pressure fields with infrared satellite images and surface wind observations). It is accessible from the West Coast Overview Composite Weather Maps menu.
• 6/4/10: Added JavaScript animations of composite weather maps (pressure fields, infrared satellite images, and weather observations) for sea level, 500 mb, and 300 mb, for both the North America and Eastern Pacific/Western North America views.

  Also added JavaScript animations of archived composite weather maps for sea level, 500 mb, and 300 mb, for both the North America views and Eastern Pacific/Western North America views.

• 7/27/09: To increase the frequency with which West Coast overview composite maps are updated, started generating West Coast overview composite maps at 15Z and 21Z (for visible and infrared images) and 03Z and 09Z (infrared images only), using the Rapid Update Cycle (RUC) model as the source sea-level pressure analysis. The meso-NAM model, with it's somewhat greater coverage of the eastern Pacific Ocean, continues to be the source of the sea-level pressure analysis at 00Z, 06Z, 12Z, and 18Z.

• 5/28/08: At user request, added links to older, "noninteractive" (concatenated GIF image) animated jet stream forecast loops to the new jet stream forecast menu page, in addition to links to the "interactive" (JavaScript) animated loops and to inidividual forecast maps.
• 5/16/08: By popular demand, created a Jet Stream Forecasts Menu page with links to (a) the latest available, individual jet stream forecasts from NCEP's GFS forecast model, at 12 hour intervals out to 5 days; (b) the GFS model analysis (the starting conditions on which the forecasts are based); (c) the recently added JavaScript animations of the same maps (see item dated 4/13/08 below); and (d) a caveat about computer weather forecast models and references to the idea of ensemble forecasts as a way of dealing with the uncertainty inherent in such forecasts. There are links to the Jet Stream Forecasts page at the bottom of the regular Jet Stream Analyses Menu page. The links to individual forecast maps have been segregated in a separate Web page to reduce the clutter on the regular Jet Stream Analysis Menu page.
• 4/13/08: Added JavaScript animations of "big" (763x630, 50Kb) and "small" (512x412, 25Kb) jet stream forecast maps for the Eastern Pacific/Western North America, North America, and North Atlantic regions. The GFS model forecasts go out to 5 days; NAM model forecasts, which arrive several hours earlier, only go out to 2.5 days.

  Added links to these JavaScript animations to the jet stream menu page, and removed links to the concatenated GIF animation loops that the JavaScript animations are designed to replace. To conserve space, also removed links to individual forecast maps from the which can be examined via the JavaScript animation by pausing the loop and stepping through it foreward or backward.

• 5/3/04: Added jet stream analysis and forecast maps, and jet stream analysis maps overlying infrared satellite images, for the North Atlantic region. Also added a JavaScript animation of smaller versions of both types of jetstream maps. [These maps are basically the same as the Eastern Pacific/Western North American jet stream maps and the North America jet stream maps, simply extended westward and a bit northward.] An archive of the North Atlantic maps also established, along with an JavaScript animation of archived images.
• 7/01/03: Added Java Script animations of current, regular-sized ("big") satellite images (640x512 pixels). These are accessible through the satellite image menu and join the already existing animations of smaller satellite images (360x288 pixels). [Animations of the "big" images is not recommended for computers with 56Kbs and slower modem internet connections--all but the shortest animations would probably take quite a while.]
• 6/29/03: Added regular-sized ("big") satellite images (640x512 pixels) to the satellite image archive (images saved as far back as June 6, 2003 or two years, whichever comes first). These join the already archived smaller images (360x288 pixels). In addition, JavaScript animations of the archived regular-sized ("big") satillite images are now available as well.
• 9/28/02: Added global temperature maps at 700 mb (where the altitude is typically around 10,000 ft above sea level). These are color-fill contour maps on a global Mollweide projection. The latest available map, updated every six hours, can be found at http://virga.sfsu.edu/gif/temp700mw_latest.gif. A JavaScript animation script of the latest images is available at http://virga.sfsu.edu/scripts/temp_700_mw.html.

  Archived 700 mb global temperature maps can be found at http://virga.sfsu.edu/crws/archive/temp700mw_arch.html. A JavaScript animation script of archived maps, available at http://virga.sfsu.edu/scripts/temp_700_mw_archloop.html, allows easy browsing of the archive.

• 6/10/02: Added global Mollweide composite infrared satellite images to the satellite image archive. The most current image, updated every six hours, is available at http://virga.sfsu.edu/gif/mwir_latest.gif. A JavaScript animation script allows easy browsing of the archived images.
• 6/10/02: Fixed a bug in all JavaScript animation scripts for archived jet stream images. When the user specified an animation with images at intervals of 6 hours, the scripts loaded them in the wrong order.
• 3/7/02: Added a 300 mb jet stream analysis map for the Southern Hemisphere. Like the Northern Hemisphere jet stream maps, the Southern Hemisphere version displays wind vectors and contours of wind speed (isotachs) to show the wind patterns in the upper troposphere, revealing where air in the polar jet stream (and sometimes the subtropical jet stream) races eastward. An archive of these maps dating back to September 23, 2001, has been established, and JavaScript animations for both current maps and archived maps are available.
• 3/6/02: Created JavaScript animations of archived visible satellite images. This makes it possible to access sequences of archived visible satellite images of your choice (within limits), in addition to individual images, from the satellite image archive.
• 2/27/02: Created JavaScript animations of archived infrared satellite images. This makes it possible to access sequences of archived infrared satellite images of your choice (within limits), in addition to individual images, from the satellite image archive.
• 2/26/02: Created JavaScript animations of archived jet stream maps. This makes it possible to access sequences of archived jet stream maps of your choice (within limits), in addition to individual maps, from the jet stream map archive.
• 2/26/02: Created friendlier interfaces for most map and image archives. The archives include:
  • Jet stream analysis map archive
  • Composite pressure/satellite-image/weather-observation map archive
  • Satellite image archive
  • U.S. weather-radar map archive (interface not improved)

  (There are links to the California Regional Weather Server archives from individucal menu pages, including the jet stream map menu, the composite pressure/satellite image/weather observations map menu, the U.S. West Coast composite map menu, the satellite image menu, and the U.S. weather radar map menu.)

• 2/23/02: Fixed bug in JavaScript animations. It is now possible to update animations after they have already been running simply by pressing the "Build Animation" button again, which has not heretofore been true. Any newly arrived images will be loaded and the oldest image in the loop will be dropped. The fix applies to animations of GOES-West IR satellite images, GOES-West visible satellite images, GOES-East IR satellite images, GOES-East visible satellite images, U.S. weather-radar maps, small-sized Eastern Pacific/Western North America jet stream maps, large-sized Eastern Pacific/Western North America jet stream maps, small-sized North America/North Atlantic Ocean jet stream maps, large-sized North America/North Atlantic Ocean jet stream maps, Eastern Pacific/Western North America jet stream maps with IR satellite images, North America/North Atlantic Ocean jet stream maps with IR satellite images, and Northern Hemisphere jet stream maps. In addition, the jet stream animations now permit selection of either 6 hour or 12 hour intervals between images in the loops, and the U.S. weather-radar map animation now permits selection of 1 hr, 2 hr, 3 hr, and 4 hr intervals between images and animation lengths of 12 hours, 1 day, 2 days, and 3 days. Finally, the user interface and the instructions for all animations have been improved.
• 2/11/02: Modified satellite image animations.
The animations of GOES-West visible images and GOES-East visible images have been modified to allow animations covering all of the current day; all of the current day plus the previous day; all of the current day plus the two previous days; and all of the current day plus the three previous days.
The animations of GOES-West infrared images and GOES-East infrared images have been modified to allow animations covering the previous 12 hours, 1 day, 2 days, or 3 days.
In addition, to allow users to reduce the number of images that have to be downloaded for an animation covering a given period, users can specify the interval between images as 1 hour, 2 hours, or 3 hours on the visible image animations, and 1 hour, 2 hours, 3 hours, or 4 hours on the infrared image animations. A longer interval between images reduces the total number images in the loop and increases the change that occurs between subsequent images, giving the impression of a faster animation.
• 11/20/01: Modified animations (loops) of composite maps of jet stream analysis/infrared satellite image. These animations (loops), accessible from the jet stream analysis and forecast menu, now show maps every 6 hours (4 per day), rather than every 12 hours (2 per day). This additional temporal resolution reduces the jerkiness in the evolution of the both the jet stream pattern and, especially, the cloud patterns, displayed by these composite-map animations. Animations of 1, 2, 3, 4, and 5 days' worth of analyses are now available.
• 11/11/01: More frequent sea-level/surface composite weather maps (sea-level pressure, surface weather observations, and infrared satellite image). These maps--including maps for the eastern Pacific/western N. America and for North America--were previously updated for only the 00Z and 12Z computer forecast model runs. Analysis maps at 06Z and 18Z have now been added, so analyses are now available every 6 hours instead of every 12 hours. In addition, links to the four most recently available maps (usually 6 hours apart), instead of just the two most recently available maps (12 hours apart), have been established. (The 500 mb and 300 mb composite analysis maps remain unchanged because radiosonde observations are available only twice daily.)
• 11/11/01: More frequent jet stream analysis maps. These maps--including maps for the eastern Pacific/western N. America; for North America; for versions of the previous two maps superimposed on an infrared satellite image; and for the Northern Hemisphere--were previously updated for only the 00Z and 12Z computer forecast model runs. Analysis maps at 06Z and 18Z have now been added, so analyses are now available every 6 hours instead of every 12 hours. In addition, links to the four most recently available maps (usually 6 hours apart), instead of just the two most recently available maps (12 hours apart), have been established.
• 3/8/01: More frequent West Coast composite maps of infrared satellite images, sea-level pressure contours, and surface observations added. Previously these maps were available only for 00Z and 12Z. To these, 06Z and 18Z have been added, so maps are now available every 6 hours instead of every 12 hours. In addition, a West Coast composite map of visible satellite image, sea-level pressure contours, and surface observations at 18Z will replace the 12Z map by 20Z each day. (The reason for this that there is not enough visible light for a 12Z visible satellite image on the West Coast, so the 12Z map comprises a 12Z eta-model sea-level pressure analysis superimposed on a 14Z, 15Z, or 16Z satellite image and surface observations. The lag between the different types of data is not very desirable. The 18Z map uses the sea-level pressure analysis of the meso-eta model, together with a visible image and surface observations recorded at the same time, a more desirable combination that is only a couple of hours later than the nominally 12Z map's visible image and surface observations.
• 1/4/01: Jet stream forecast loops added. Simple loops (concatenated GIF images) of jet stream AVN model forecast maps, starting from the initial jet stream analysis and followed by 12, 24, 36, 48, 60, and 72 hour jet stream forecasts.
• 1/2/01: More jet stream forecasts added. Jet stream forecast maps for 12, 36, 60, and 72 hours from the initial analysis time have been added to the previously available 24 and 48 hour forecast maps. (The 72 hour forecast is available for the aviation [AVN] model only, not the eta model.)
• 1/13-1/16/00: Improved animations.
The animations of GOES-West visible images and GOES-East visible images have been modified to automatically skip blank nighttime images. This reduces the number of images that must be downloaded and eliminates sequences of up to nine or ten blank nighttime images.
The two animations above now load the latest available image 30 and 15 minutes earlier, respectively, than they used to, making the animations a little more timely.
The animations of GOES-West infrared satellite images, GOES-East infrared satellite images, and U.S. weather-radar images have similarly improved timeliness of the latest-available image.
The maximum possible number of images appearing in the animation of Northern Hemisphere jet stream maps has been increased from 12 to 20, thereby allowing loops covering periods up to ten days.
All of scripts above (and several others) automatically skip each missing image rather than load a distracting blank image. However, this makes it harder to tell when images are missing--users must watch for sudden, large jumps in weather patterns and keep an eye on the time labels on the images/maps. To help compensate, the number of missing images (if any), and the date/times for the last two of them, are provided.
A bug that afflicted the "Prev" and "Next" loop control buttons has been fixed in all of the scripts above (and several others).

(These animations are adapted from JavaScript demonstrations created by Dave Miller of Stanford University in cooperation with the California Regional Weather Server. All of the loops are optimized for Netscape, version 3.0 or later.)

• 11/19/99: Reversed the change below. The change below (11/17/99) has been reversed due to user complaint about the need to resize the window containing the menus in order to see maps and images without first resizing THOSE windows.
• Changed 11/17/99: Hyperlinks to most of the weather maps and images available through the California Regional Weather Server now will open a new window separate from the main WWWeb browser window. This allows users to view several different maps side by side, or see both a map/image and the menu from which it was selected. (Users will have to close each new window opened this way--we'll see what the response from users about this is.)
• Changed 4/9/99: Weather-Radar Maps (U.S. overview), which now show RCM ("radar coded messages") weather-radar echoes rather than MDR ("manually digitized radar") across the U.S. The RCM radar data have a resolution about four times as great as MDR radar data (12 kilometers vs. 48 kilometers), yielding considerably more detailed maps. RCM radar data are now also shown on all California subregional weather maps and other western subregional weather maps.
• Added 10/16/98: Composite maps of the jet stream and infrared satellite images. These show a 300 mb jet stream analysis superimposed on a spliced GOES-East and GOES-West infrared satellite image, for the North America and the Eastern Pacific domains. Animated loops of these images have also been added. (The loops are adapted from JavaScript demonstrations created by Dave Miller of Stanford University in cooperation with the California Regional Weather Server. All of the loops are optimized for Netscape, version 3.0 or later.) The maps and the animated loops are all accessible through the Jet Stream Analyses and Forecasts map menu. (For more information, see "Information Shown on Jet Stream Maps: Northern Hemisphere, North America and Eastern Pacific Overviews".)
• Added 2/26/98: links to WWWeb sites offering information on El Niño/Southern Oscillation (ENSO), tropical meteorology and hurricanes, and a few more national and other meteorological organizations. Accessible through Weather Information link from the California Regional Weather Server Home Page.
• Modified 1/26/98: shaded contours shown on jet stream analyses and forecasts. The slowest wind speed highlighted using shaded contours is now 60 knots; it used to be 50 knots. The new threshhold is more in line with the convention that defines a jet stream at 300 millibars (namely, 30 meters per second or faster, or around 60 knots). This will reduce the total area shaded on the jetstream analyses and forecasts and more sharply define the location of the jet stream(s), particularly during the winter. Dashed-line wind speed contours that overlay the shaded contours at 20 knot intervals now start at 70 knots rather than 60 knots. (See the general description of jet stream analysis and forecast maps.)
• Added 9/30/97: an animated loop of Northern Hemisphere jet stream analyses. It is accessible through the jetstream analyses and forecasts menu. The loop is adapted from JavaScript demonstrations created by Dave Miller of Stanford University in cooperation with the California Regional Weather Server. All of the loops are optimized for Netscape, version 3.0 or later.
• Modified 9/20/97: all jetstream maps, to have a white rather than a black background. Although not quite as striking as maps with a black background, the white-background maps make better black and white hard copies and don't use as much toner in laser printers. (This modification is an experiment to see if the users approve.)
• Reintroduced 7/2/97: for the summer season, some regional weather maps showing weather observations overlaid upon visible satellite images (during daylight hours). These include all of the California subregional weather Maps and the Hawaii, Alaska, western Oregon, western Washington state, and central Colorado regional weather maps.
• Upgraded 6/18/97: the introductory, college-level meteorology lab exercise on weather-satellite image interpretation. The new version implements frames and JavaScript, so browsers with those capabilities can take full advantage of the exercises in its new form. (The older version, which does not use frames or JavaScript, is still available as well.)
• Modified 5/22/97: all California subregional weather maps, western regional weather maps, and U.S. weather-radar maps, so that they have white backgrounds (rather than black). This makes them much more printer friendly, requiring far less ink or toner to print.
• Added 5/07/97: the option to view smaller-sized visible and infrared satellite images, which are significantly faster to download than the original, larger images. (The larger original images remain available.) The original, larger visible images range in size typically from 155 to 250 Kb (depending on the time of day and how much of the earth in the image is illuminated by the sun), whereas the new, smaller visible images range typically from 30 to 55 Kb. The original, larger infrared images range from 143 to 153 Kb, whereas the new, smaller images range from 33 to 37 Kb. All are accessible through the Satelite Images menu.
• 3/24/97: Added analyses of the 300 mb jet stream pattern, over the entire Northern Hemisphere. Like the North American and Eastern Pacific jetstream maps, these full Northern Hemisphere maps display wind vectors and contours of wind speed (isotachs) to show the wind patterns in the upper troposphere, revealing where air in the polar jet stream and sometimes the subtropical jet stream races eastward.
• Added 2/14/97: animated loops of visible satellite images, joining previous loops of infrared satellite images, jet stream images, and weather-radar maps (see entry 1/27/97 below). The new visible satellite image loops are accessible through the satellite images menu. The loops are JavaScript demonstrations created by Dave Miller of Stanford University in cooperation with the California Regional Weather Server. All of the loops are optimized for Netscape version 3.0 or higher.
• Added 2/5/97: links to archives of two weeks' worth of many of our most popular images. Links can be found from the menus for jet stream maps, satellite images, weather-radar maps, and pressure-field/satellite composite maps.
• Added 1/27/97: animated loops of jet stream analyses, infrared satellite images, and weather-radar maps. These are accessible through the jetstream analyses and forecasts menu, the satellite images menu, and the weather-radar maps menu, respectively. The loops are JavaScript demonstrations created by Dave Miller of Stanford University in cooperation with the California Regional Weather Server. All of the loops are optimized for Netscape version 3.0 or higher.
• Removed 12/20/96: the regional weather maps for the West Coast that show both weather observations and visible satellite images (during daylight hours). The same regional weather maps without visible satellite images are still available. (Regional weather maps with visible satellite images overlaid are most useful in summer, when fog hugs the West Coast. In winter, there are fewer daylight hours and clouds associated with midlatitude cyclones tend to cover wide areas, interfering with the other weather data appearing on the maps and adding little information of value to the small regions covered by the maps.)
• Removed 9/96: NEXRAD Doppler radar images for the San Francisco Bay Area. The contract with our NEXRAD Doppler radar data provider, WSI, Inc., stipulates that we cannot make Doppler radar images available, except within the SFSU campus for educational or research purposes, until they are at least 48 hours old. We feel that the fast-changing Doppler radar images data are no longer of general interest to the public when they are that old and so we no longer make them available. Sorry about that--gotta obey the law!
• Reintroduced 6/16/96: for the summer season, some regional weather maps showing weather observations overlying visible satellite images (during daylight hours). These include all of the California subregional weather maps and the western Oregon and western Washington regional weather maps.
• Modified 6/15/96: The Home Page menus, putting them into table format. Moved the West Coast Overview (composite maps of sea-level pressure and satellite images) to the "Regional Weather Maps" menu from the "North Pacific and North American Overviews" menu.
• Added 3/15/96: Analyses and 24- and 48-hour forecasts of the 300 mb jet stream pattern, over North America and the North Pacific. These maps display wind vectors and contours of wind speed (isotachs) to show the wind patterns in the upper troposphere, revealing where air in the polar and subtropical jet streams races eastward.
• Added 2/9/96: NEXRAD doppler radar echoes from the San Francisco radar (situated on the summit of Mt. Umunhum in the Santa Cruz Mts. between San Jose and Santa Cruz, south of San Francisco Bay). Latest available image must, by contract with WSI (our supplier of the images), be no more recent than one hour old. Images approximately one to two hours old and two to three hours old are currently available through the California Regional Weather Server, via the Northern California, San Francisco Bay Area (and surrounding region), and San Francisco Bay subregional weather map menus, under the California Subregional Weather Maps menu. These images are updated every ten minutes. [Note: they don't show anything when it's not raining or snowing within the range of the radar; in the absence of precipitation, the radar only shows ground clutter near the radar site.]
• Changed 2/6/96: the California and other western subregional weather maps no longer include overlays of visible and IR satellite images. In most cases, these images were deemed distracting and the scale of the maps too small to extract useful information from the satellite images, at least at this time of year, when weather patterns tend to be dominated by synoptic-scale storm systems. Satellite images on larger scales are still available through the Satellite Images (North America/North Pacific) menu and the various Pressure Field/Satellite Image Composite Maps. However, to capture the position of summer-time coastal fog and stratus clouds along the west coast, visible satellite image overlays on west coast subregional weather maps may resume some time in May, 1996. Satellite image overlays may resume on other subregional weather maps as well, to capture spring and summer convective storms.
• Added 12/95: Weather-Radar Maps (U.S. overview), showing weather-radar echoes across the U.S. for each of the two hours for which data were most recently available.
• Added 12/95: western Oregon subregional weather map, showing surface weather observations and radar echoes for western Oregon for each of the two hours for which data were most recently available. Accessible via the Western Subregional Weather Maps menu.