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Southwest Climate Outlook November 2014 | CLIMAS


Southwest Climate Outlook November 2014

Thursday, November 20, 2014

From the Nov 20, 2014 Southwest Climate Outlook

Precipitation: Little precipitation fell in Arizona from mid-October to mid-November following the official end of the monsoon on September 30. New Mexico recorded some precipitation of note, mainly in the southeastern corner and in scattered pockets of the central and north-central parts of the state. This is a marked change from monsoon precipitation and the substantial contributions made by the incursions of tropical storms, but this drop-off in rainfall is typical for this time of year; November joins April as one of the driest months for the region.

Temperature: Most of Arizona and New Mexico were warmer than average in the past 30 days, a pattern that was consistent across much of the Southwest. The cold front that brought winter weather to much of the U.S. in mid-November also stretched into the region, but with limited effect and primarily in portions of eastern and southeastern New Mexico. There was a shift towards colder temperatures across the region in the last few days (at time of publication), and while the air feels colder given the previously above average temperatures, the temperatures are close to historical averages. 

Snowpack: Sporadic early winter precipitation resulted in below to above-average snowpack levels across the region. It remains to be seen how much of this early season snowpack will remain, and an above-average snowpack is needed this winter to improve storage in the Upper Colorado and Rio Grande basins. Water Supply: In October, total reservoir storage was 46 percent (compared to 47 percent last year) in Arizona, while total reservoir storage was 22 percent (compared to 21 percent last year) in New Mexico.

Drought: Above-average monsoon precipitation and an active Pacific hurricane season provided some short-term drought relief in the Southwest. Long-term drought relief was limited by the inconsistency of precipitation coverage and the runoff and evaporation associated with high-intensity precipitation events. The likelihood of an El Niño event continues to offer hope for additional drought relief, as these events are typically associated with increased winter precipitation in the region.

ENSO: The latest ENSO projections indicate a 70-75 percent chance that an El Niño event will develop this winter. Some experts believe that conditions are already in place, and that it is only a matter of time before the El Niño event is officially declared. There is less confidence, however, that a moderate to strong event will form and uncertainty about whether a weak event will drive winter precipitation much above average.

Precipitation Forecasts: The NOAA-Climate Prediction Center is calling for elevated chances for above-average precipitation through the winter and into early spring. These predictions are thought to be picking up on both the possibility of an El Niño event this winter and the impact of the Pacific Decadal Oscillation. 

Temperature Forecasts: The NOAA-Climate Prediction Center temperature forecasts are split across the region, with elevated chances for above-average temperatures along the West Coast, extending eastward into Arizona, and with increased chances for below-average temperatures along the Gulf Coast into New Mexico.

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