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The latest monthly briefing was posted today on the Intermountain West Climate Dashboard. The highlights, also provided below, cover current snowpack and drought conditions, forecasted spring-summer streamflows, recent precipitation, and ENSO and precipitation outlooks.
Snowpack conditions have improved substantially across the region since mid-January, with most basins gaining 10-20 percentage points relative to median SWE conditions. The February 1 seasonal runoff forecasts call for below-average (70-90%) or near-average (90-110%) spring-summer runoff for the vast majority of forecast points across the region, with the NOAA forecasts anticipating lower volumes than the NRCS forecasts. Right after we waved the ‘drought flag’ in the January briefing, a very active weather pattern emerged, with frequent storms affecting all three states over the past month. As of February 12, snowpack conditions are very near or above normal in every basin in Colorado, Utah, and Wyoming, with most basins reporting between 100-115% of normal SWE. Even southwestern Colorado, which had been lagging behind all season, is now reporting near-normal SWE. The SNOTEL basin average for the Upper Colorado River Basin is at 107% of normal, up from 90% one month ago. NRCS released their first (February 1) seasonal runoff forecasts of the season, and they call for near-average (90-110%) spring-summer runoff for most forecast points in Colorado and Utah, and below-average (70-89%) runoff for most points in Wyoming, as well as for southwestern Colorado. The February 1 forecasts from NOAA CBRFC and its neighboring RFCs are generally more pessimistic, as they explicitly factor in the low antecedent soil moisture, while the NRCS forecasts do not. For example, the NOAA CBRFC February 1 forecast for Lake Powell April-July inflows is for 74% of average (5.30 MAF), while the NRCS February 1 forecast is for 87% of average (6.23 MAF). Because above-normal precipitation has continued into February, the latest (February 12) CBRFC daily ESP forecast is higher than the official February 1 forecast, calling for 80% of average Lake Powell inflows (5.75 MAF). Due to the above-normal precipitation and snow since early January in most parts of the region, there has been widespread improvement in drought conditions over much of Utah and western Colorado. Most of the area of exceptional drought (D4) in the Four Corners region has improved to D3. There has also been some degradation or expansion of D0-D2 conditions in northeastern Colorado and southern and central Wyoming, where the recent storms did not have much impact. ‘El Niño-ish’ conditions continue in the tropical Pacific. It is still likely (~65%) that an El Niño event will emerge by the end of spring, but it will be weak and unlikely to persist. The CPC seasonal precipitation outlooks for the February-April and March-May periods show enhanced chances for above-normal precipitation for Colorado, with slightly enhanced chances for adjacent parts of the region.