Forecasts
Published April 25, 2012

Seasonal Drought Outlook

 (through July)
Data Source(s): NOAA–Climate Prediction Center (CPC)

This summary is partially excerpted and edited from the April 19 Seasonal Drought Outlook technical discussion produced by the NOAA-Climate Prediction Center (CPC) and written by forecaster R. Tinker.

In the southwestern and western U.S., drought is expected to persist or intensify in many regions and develop in the central Rocky Mountains (Figure 11). This forecast is based in part on the dry conditions the Southwest and California typically experience during April through June. The period is also expected to be warmer than average, which, in conjunction with typically windy weather, can enhance dry conditions by increasing evaporation and transpiration. In addition, current mountain snowpacks—the source of much of the region’s water supply—are below average at every snow monitoring site currently reporting in Arizona, New Mexico, Utah, Colorado, and Wyoming. As a result, the landscape likely will be subject to a longer dry season, and summer streamflows will very likely be below average.

The only exception to persisting or intensifying drought is in southern New Mexico and Arizona, where the onset of monsoon rains in late June and early July should provide some drought improvement. The onset date of the monsoon and total precipitation during July–September are difficult to forecast. However, on average, the monsoon begins between June 26 and July 3 in southwestern New Mexico and between July 3 and July 10 in southeastern Arizona. The CPC assigns a high confidence to this forecast.

Map of United states Seasonal Drought Outlook
Notes:

The delineated areas in the Seasonal Drought Outlook are defined subjectively and are based on expert assessment of numerous indicators, including the official precipitation outlooks, various medium- and short-range forecasts , models such as the 6-10 day and 8-14 day forecasts,  soil moisture tools, and climatology.

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