Drought news

US Drought Monitor February 4, 2014
US Drought Monitor February 4, 2014

Click here to go to the US Drought Monitor website. Here’s an excerpt:

Summary

During the past 7-days, the persistent, amplified ridge that had dominated weather conditions across the western contiguous U.S. (CONUS) collapsed, which allowed Pacific storm systems to move eastward across the region. Moderate to heavy precipitation (0.5-3.0 inches liquid equivalent, locally heavier) was observed over the higher elevations of the Coastal Ranges, the Cascades, the Sierras, the Bitterroots, the Wasatch, and near the Colorado Front Range. Lower elevations across much of the West generally received light precipitation (0.5-inch or less), including the coastal areas of far southern California. Moderate to heavy precipitation (0.5-3.0 inches liquid equivalent, locally heavier) was also observed across portions of the Midwest, Ohio Valley, Great Lakes, southern New England, mid-Atlantic and southern Atlantic Coast states, Gulf Coast region, Tennessee Valley, Lower Mississippi Valley, and the ArkLaTex region. Temperatures during the past week were primarily below-normal east of the Continental Divide, and above-normal west of the Divide, though there were a few exceptions. East of the Divide, New England and Florida reported above-normal mean temperatures, while west of the Divide, Washington state was below-normal for the week…

Southern and Central Plains

Though light to moderate precipitation (under 2.0 inches) fell over parts of western, far southern, eastern, and northern Texas, many areas received little to no precipitation during the past week (though a few locations in the ArkLaTex region received 2-3 inches of rain). The precipitation that did fall helped to alleviate some of the short-term dryness. However, reservoirs along the Colorado River, as a whole, are at their lowest level (as a percent of normal) for this time of year ever, as is true of total water storage across the state. These factors prompted a number of 1-category improvements and degradations to the Texas drought depiction. In far western Oklahoma, extreme drought (D3) was expanded northward to include Roger Mills County. The latest precipitation event produced only about a tenth of an inch (radar estimated) from Roger Mills County southward across southwestern Oklahoma. There were a high number of days in January with extremely low relative humidity, mean temperatures close to normal, and wind. The January PNP was 20 percent of normal for the state as a whole (Mesonet), and the state-wide average precipitation was 0.29-inch. This was the 8th driest January on record. In Kansas, the state-wide average precipitation (PNP) for January was only 34 percent of normal. Reassessment of conditions will be needed next week after this current storm system passes through the area. In south-central Nebraska, a small drought-free area was downgraded to abnormal dryness (D0), in response to continuing dryness…

Southwest

Most of Arizona and New Mexico received little if any precipitation during the past 7-days. A predominantly dry pattern has been in place since the very beneficial and welcome late-season monsoon rains last September. Impacts are somewhat limited at this time due to lower evapo-transpiration (ET) rates during winter, but an increased snowpack in the next two months is needed to preclude more serious problems. SNOTEL Snow Water Equivalent (SWE), as of February 5, 2014, is mostly well below normal across the Mogollon Rim area (ranging from 14-41 percent), and in the White Mountains of eastern Arizona (SWE 26-36 percent of normal). The mountainous terrain of western and central Colorado received moderate to heavy precipitation (0.5-4.0 inches) during the past week, while the high plains of eastern Colorado generally received less than a half-inch of precipitation. As time is needed to evaluate regional impacts across the Southwest, it was decided not to alter the depiction this week…

The West

Though several inches of precipitation (liquid equivalent) fell over the northern one-half to two-thirds of California this week (locally 3-4 inches in the central Sierras), significantly more precipitation will be needed to justify improvement with the depiction. The central and southern Sierras report up to 4 inches of SWE, while the northern Sierras report only an inch. The precipitation received this week only keeps the snowpack/water supply from falling further behind. Reservoirs continue to go down. An 8-station index for the northern Sierras (which represents an average of 8 precipitation gauges that span the area from Lake Tahoe to up above Lake Shasta), indicates precipitation amounts of 4.5 inches since the beginning of the Water Year (Oct 1). Last year at this time, 34.3 inches of precipitation fell, while the average to date is 26.4 inches. The only change to the depiction in California this week was to slightly increase the coverage of exceptional drought (D4) conditions across most of San Luis Obispo County. Two of the larger reservoirs in the County, near the border with Monterey County, are at 5-percent capacity (Lake Nacimiento and Lake San Antonio). The City of Cambria is implementing water restrictions for residents, while many cattle owners are selling off their herds due to lack of feed and water. The higher elevations of western Washington and western Oregon received 2-5 inches of precipitation (liquid equivalent, locally heavier) during the past week, though as is the case with California, significantly more precipitation will be needed to overcome longer-term deficits. Finally, in western Montana, the valley areas have been fairly dry recently, while the mountainous areas have received significant precipitation. Given support from the latest short-term and long-term drought blends, and the recent dryness (ACIS 30-day and 60-day PNPs ranging from about 20-50 percent of normal in this area), the drought-free area in southwestern Montana was downgraded to abnormal dryness (D0)…

Looking Ahead

During February 6-10, 2014, very heavy precipitation (as much as 7-9 inches, liquid equivalent) is predicted in northern California, and 3-4 inches in western Oregon. This will go a long way in helping to mitigate some of the drought conditions in these areas, though reassessment of conditions next week will be needed to determine the extent of any potential improvements in the Drought Monitor depiction. Along the Southeast coast including northern Florida, 1.0-1.5 inches of rain is expected during the period which will be beneficial to the small areas of abnormal dryness (D0) in that region. With the exception of 3-4 inches of precipitation anticipated over the central Rockies and Wasatch Range, most other areas of the CONUS can expect a half-inch or less of precipitation within the next 5 days.

For the ensuing 5-day period, February 11-15, 2014, there are elevated odds of above-median precipitation for most of the northern and eastern Lower 48 states, and the Alaska Panhandle. Probabilities for above-median precipitation rise up to 60-percent in the Pacific Northwest, and 50-percent over the Gulf and Atlantic Coast states. Below-median precipitation is favored for southern California, much of the Southwest and southern Rockies, the central and southern High Plains, and most of Alaska.

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