As with the Core Supply, regional precipitation is presented using both the corrected NWS data feed and GG Weather values, offering a comprehensive perspective on how precipitation has been distributed across the region. The NWS stations reflect higher-elevation, basin-oriented conditions most relevant to water supply, while GG Weather values represent valley- and coastal-based observations and in situ recharge.

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Differences between the two reflect where precipitation has been most concentrated this season. In a year characterized by predominantly warm storms and coastal-focused storm tracks, lower-elevation locations have generally received a greater share of precipitation.

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ALICE model output indicates that Region 3 will receive 100-120% of normal precipitation. Region 3 shows the largest divergence between datasets, with observed totals ranging from 87.7% (NWS) to 104.0% (GG Weather) of average. This reflects the strong influence of coastal and valley precipitation this season, driven by a series of Northern California cutoff lows that did not propagate south as is more typical. Instead, these systems stalled near the North-Central coast before progressing inland, focusing precipitation across the Bay Area and Central Coast. As a result, lower-elevation locations in the coastal plain and adjacent valleys have received substantially more precipitation than inland and elevation-influenced stations. For coastal- and valley-based operations, the GG values may provide a more representative picture of current conditions.

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NWS data indicates that Region 3 saw 3.5 inches of accumulation during the month of April, adding ~13 percentage points to the accumulation.