Information Shown on Composite Weather Maps:
West Coast Overview

Composite weather maps showing an overview of the West Coast of North America are generated three times daily (for 00Z and 12Z, the latter replaced later by 18Z, overlaying visible satellite images) or four times daily (for 00Z, 06Z, 12Z, and 18Z overlaying infrared satellite images). They display the following information:
(1) Contours of sea-level pressure (at intervals of 4 millibars).
The analyses come from the eta-model initialization (00Z and 12Z maps) or the meso-eta-model initialization (6Z and 18Z maps), each performed twice daily by the National Centers for Environmental Prediction (NCEP--formerly the National Meteorological Center, NMC);

(2) Either a visible or a color-enhanced infrared satellite image from the GOES-West satellite, usually recorded at the same time as the analyses in (1) above (except for the visible image for the 12Z map, which is too early--instead, a 14Z or 15Z image is used with the 12Z analysis, which is later replaced by an 18Z image and analysis when they become available); and

(3) Plots of surface winds and cloud cover recorded at the same time as the satellite image in (2) above. The wind information includes:

The time and date appearing on these maps is in Universal Time Coordinates (UTC), formerly known as Greenwich Mean Time (GMT). (See comments about time labels for more information.)


For information about reading some of the meteorological information on these maps, refer to the key to weather-station plots and general description of visible and infrared satellite images.

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