High pressure off the California coast kept much of California, Nevada, Arizona, and Utah precipitation-free this week, with above-normal temperatures in California. Instead, Pacific storm systems were deflected northward or southward, allowing the Pacific Northwest to receive welcome moisture after such a dry start to the Water Year (mainly October and November 2019). The precipitation, along with enough cold air, has steadily increased the SNOTEL basin average WYTD precipitation and SWC in the Washington Cascades to near- or above-normal values, thus easing drought in western and eastern sections of the state. These values decrease as one heads southward, with SWC between 77-91% of normal in the Oregon Cascades, and dropping to between 52-71% of normal in the Sierra Nevada. In southern Idaho, light to moderate precipitation in the southwest helped to improve the D1 to D0 as SWC rose to 92% of normal. However, the SWC of the Big Lost, Big Wood, and Little Wood basins have dropped to between 58-74% of normal, with WYTD precipitation ranging from 52-60% of normal. Thus, D1 was expanded southward to encompass these basins, and additional deterioration may be required soon if it stays dry. Since many changes were made last week, only minor modifications were made to the Far West this week. This included bridging the D0 gap in northern California as conditions were similar to the two D0 areas to the north and south; slightly expanding D1 into central Oregon while improving D1 to D0 and D0 to nothing in eastern Oregon; slightly retreating the D0 and D1 in the northern Oregon and Washington Cascades eastward as another round of decent precipitation fell there, increasing both the SNOTEL WYTD basin average precipitation and SWC; and slightly readjusting the D1 area in central Washington eastward to better reflect where the driest indices were. In the Southwest, a southern tracking storm system brought welcome precipitation to southern Arizona and most of New Mexico over the 2-week period, allowing for 1-category improvements (D0 to nothing) in southwestern and southeastern New Mexico, along with some slight D1 improvements in central and east-central sections. The balancing between the poor 2019 summer monsoon versus favorable 2019-2020 winter precipitation was taken into account. The northern areas (D2) were left unchanged this week since they was hit harder by the weak summer and fall monsoon, and because the WYTD basin average precipitation has been below-normal (73-94%), while southern areas were at or above-normal (95-144%). Elsewhere, no changes were made, although the boundary between the short-term (S) versus short and long-term (SL) impacts were differentiated in the Far West with impact lines.

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