This nowCOAST time-enabled map service provides maps depicting the forecasts of the sensible weather and marine weather elements for 12-hr precipitation probability, 6-hr precipitation amount, and snowfall forecasts. Generated by the weather forecasters at regional NWS Weather Forecast Offices (WFOs) and the National Centers for Environmental Prediction (NCEP). The NDFD is a seamless composite or mosaic of gridded forecasts from individual NWS Weather Forecast Offices (WFOs) from around the U.S. as well as the NCEP Ocean Prediction Center and National Hurricane Center/TAFB. The time resolution of forecast projections varies by variable (element) based on user needs, forecast skill, and forecaster workload. Each WFO prepares gridded NDFD forecasts for their specific geographic area of responsibility. When these locally generated forecasts are merged into a national mosaic, occasionally areas of discontinuity will be evident. Staff at NWS forecast offices attempt to resolve discontinuities along the boundaries of the forecasts by coordinating with forecasters at surrounding WFOs and using workstation forecast tools that identify and resolve some of these differences. The NWS is making progress in this area, and recognizes that this is a significant issue in which improvements are still needed. The NDFD was developed by NWS Meteorological Development Laboratory. The spatial resolution is about 2.5 km (1.6 mi) for CONUS, HI, and Guam, 1.25 km (0.8) for PR and 3km (1.9 mi) for Alaska. The probability of precipitation forecasts are available or each 12-hour period out to +72 hours (3 days) from 0000 UTC on Day 1 (current day). Precipitation forecasts are available for each 6-hour period out to +72 hours (3 days) from 0000 UTC on Day 1 (current day). Snowfall forecasts are available for each 6-hour period out to +48 hours (2 days) from 0000 UTC on Day 1 (current day). Day 1-3 forecasts are updated hourly from 00Z to 23Z and for 12-hr precipitation probability Day 4-7 forecasts are updated at 00, 06, 12, 18, and 22Z.