The most significant storm of the season crossed California, delivering drought-easing rainfall to coastal areas and beneficial snow in the Sierra Nevada. In addition, rain in California’s agricultural regions temporarily eased irrigation requirements and aided drought-stressed rangeland and winter grains. However, spring and summer runoff prospects improved only slightly, as pre-storm snowpack values were near record lows and because drought-parched soils soaked up most of the available moisture. In addition, the storm moved too far south to provide optimal amounts of moisture in California’s key watershed areas, with the heaviest precipitation occurring in coastal and southern California rather than the Sierra Nevada. The remainder of the West also experienced stormy weather, with some of the heaviest precipitation occurring in central Arizona. Meanwhile, water-supply prospects further improved under a generally wet regime across the northern tier of the West. East of the Rockies, heavy rain was mostly confined to the Gulf Coast region. In early March, a late-winter storm unfolded across parts of the Plains, Midwest, mid-South, and mid-Atlantic States, where varying amounts of snow and sleet fell in advance of a record-setting March cold outbreak. By the morning of March 3, more than half (57%) of the contiguous U.S. was covered by snow, according to NOAA’s National Operational Hydrologic Remote Sensing Center.
Alaska, Hawaii, and Puerto Rico
As generally dry weather covered both Alaska and Puerto Rico, there were no changes to the depictions of dryness and drought. Parts of western Alaska experienced record-setting warmth, while cold conditions prevailed in the southeastern part of the state. On February 27, Anchorage (49°F) and Bethel (46°F) posted daily-record highs. Two days later, King Salmon (52°F) notched a record-breaking high for March 1. Meanwhile, dryness (D0) was apparent at several time scales in south-central Puerto Rico. In recent weeks, drier-than-normal conditions have begun to develop on other parts of Puerto Rico, including western portions of the northern coast—and this region will need to be watched for possible D0 development. Meanwhile, generous cold frontal rains continued to erode dryness and drought in Hawaii. As a result, drought (D1) was removed from Kahoolawe, while abnormal dryness (D0) was eliminated from Lanai. In addition, severe drought (D2) completely disappeared from Maui for the first time since the summer of 2011, and from the Big Island for the first time since the summer of 2008. Interestingly, windward sections of the Big Island have turned drier in recent weeks due to weak trade winds, and saw some D0 expansion. In Hilo, for example, February rainfall totaled just 2.57 inches (27% of normal). Meanwhile, extreme drought (D3) persisted on central Molokai, where conservation measures within the Molokai Irrigation System continued to require all non-homestead water users to cut consumption by 30%.
Central and Southern Plains
Generally light, wintry precipitation prevented further drought expansion on the central Plains. On March 2, USDA reported that 31% of the winter wheat in Oklahoma was rated in very poor to poor condition, up from 24% a month earlier. Kansas wheat was 22% very poor to poor, up from 20% at the end of January. Nebraska’s winter wheat was unchanged at 18% very poor to poor. When the wheat crop entered dormancy in late 2013, very poor to poor ratings were lower than 10% in all of those states. However, some of the perceived harm to the wheat may not have been explicitly caused by drought, but rather the cumulative effects of a harsh winter featuring wild temperature swings, occasional high winds, and exposure to extreme cold without the benefit of a protective snow cover. Drought was still a concern, though, especially in western sections of those states. On March 2, topsoil moisture was rated 87% very short to short in Oklahoma, along with 57% in Nebraska and 55% in Kansas. Rangeland and pastures were rated 46% very poor to poor in Oklahoma, reflective of both short- and long-term drought.
In Texas, there were a variety of changes to the drought depiction, both improvement and deterioration. Recent precipitation was heaviest across southern and eastern Texas, where there were widespread changes for the better. General, slight deterioration was noted—with a few exceptions—across northern and western Texas. The portion of the Texas winter wheat crop rated in very poor to poor condition stood at 46% on March 2, up from 28% in late-November 2013. Additionally, 52% of Texas’ rangeland and pastures were rated very poor to poor on March 2, up from 30% just over 3 months ago. Spring planting is underway across Deep South Texas (e.g. Texas corn was 8% planted, statewide, by March 2), and moisture will be needed soon as fieldwork moves northward. On March 2, statewide topsoil moisture was rated 78% very short to short in Texas, with numbers topping 90% in several northern and western districts.
Rain, sleet, and snow in early March mostly arrested the expansion of abnormal dryness (D0) across the lower half of the Mississippi Valley. During the 7-day drought-monitoring period, precipitation totaled 0.23 inch in Joplin, Missouri, and 0.55 inch in Shreveport, Louisiana. Despite the moisture, year-to-date (January 1 – March 4) precipitation totaled 1.06 inch (22% of normal) in Joplin and 3.85 inches (40%) in Shreveport, Louisiana.
Farther north, mostly dry, extremely cold weather covered the Midwestern areas of lingering dryness (D0) and moderate to severe drought (D1 to D2), resulting in no changes to the depiction. Minneapolis-St. Paul, Minnesota reported its 50th day with a below 0°F reading on March 3, the most in any winter at that location since 1977-78.
Cold, dry weather resulted in no change in the depiction of lingering Northeastern dryness (D0). Much of the region remains encased in snow, following several earlier storms, with depths on March 5 reported at 10 inches in Hartford, Connecticut, and 9 inches in Manchester, New Hampshire. In coming weeks, the effect of the snow on soils that are still dry from long-term precipitation deficits will depend on conditions during the spring thaw.
Additional rain near the Gulf Coast led to the removal of abnormal dryness (D0) from western Florida and a reduction in coverage in southern Alabama. At the same time, year-to-date rainfall deficits led to the introduction of some D0 in east-central Alabama. Anniston, Alabama, near the edge of the new dry area, reported precipitation of 7.49 inches (73% of normal) from January 1 – March 4.
A blockbuster storm struck California as the calendar turned from February to March, averting a record-breaking season for dryness. From February 26 – March 2, the potent storm—and a weaker, initial system—accounted for more than 75 percent of the season-to-date precipitation in California locations such as Burbank (4.78 of 5.28 inches); downtown Los Angeles (4.52 of 5.72 inches); Camarillo (3.66 of 4.85 inches); and Sandberg (3.04 of 3.93 inches). However, after the precipitation ended, season-to-date (July 1 – March 4) totals were just 40 percent of normal in Burbank, Camarillo, and Sandberg, and 49 percent of normal in downtown Los Angeles. At the height of the second storm, on February 28, Los Angeles—with 2.24 inches—experienced its wettest day since March 20, 2011. Los Angeles also received at least an inch of rain on 3 consecutive days (February 27 – March 1) for the first time since December 18-20, 2010. Benefits from the storms extended northward along the California coast and into some northern areas of the state, leading to a modest reduction in the coverage of extreme to exceptional drought (D3 to D4). However, short-term benefits from the storms were mostly offset by still-large, 3-year precipitation deficits, low reservoir levels, and a sub-par snowpack.
The California Department of Water Sources reported a slight jump in the water equivalency of the high-elevation Sierra Nevada snowpack. The water content, which averaged just 5 inches (22 percent of the late-February normal) prior to the two storms, climbed to 8 inches (33 percent) by March 5. The snowfall was heaviest in the southern Sierra Nevada, where a slight reduction in the coverage of extreme to exceptional drought (D3 to D4) resulted.
Arizona, in particular, also benefited from the second storm, although snow levels were quite high. Flagstaff, Arizona, nearly 7,000 feet above sea level, received 1.13 inches of precipitation on March 1-2, but only 1.1 inches of snow. Due to heavy precipitation, mainly in central Arizona, some reductions in drought intensity were noted. Some heavy precipitation spilled into northern and western New Mexico, but several other areas of the state remained mostly dry and experienced further drought deterioration. There were few changes to the drought depiction across the Intermountain West, mainly because recent precipitation failed to significantly dent existing seasonal deficits. In the Northwest, however, rain and snow continued to chip away at dryness and drought. For example, dryness (D0) was removed from portions of the northern Cascades. One exception to the Northwestern improvement was the rain-shadow areas east of the Washington Cascades, where severe drought (D2) was expanded. Precipitation in Washington from October 1 – March 4 totaled just 1.85 inches (38% of normal) in Wenatchee; 1.95 inches (37%) in Moses Lake; and 3.01 inches (35%) in Omak.
From March 6 - 10, a barrage of Pacific moisture will maintain mild, wet conditions in the Northwest, leading to possible flooding as far east as the northern Rockies. Five-day precipitation totals could reach 4 to 8 inches in the Pacific Northwest and 2 to 4 inches in the northern Rockies—although lighter amounts will occur in rain-shadow areas east of the Cascades. Although some precipitation will graze northern California, central and southern portions of the state will experience warm, mostly dry weather. Meanwhile, a series of disturbances will result in showers across the Deep South, where 5-day rainfall could reach 1 to 3 inches. On March 7, some snow or freezing rain may occur east of the southern Appalachians, as moisture interacts with lingering cold air. Elsewhere, cold weather will linger for several more days across the eastern half of the U.S., although a marked warming trend can be expected early next week. The NWS 6- to 10-day outlook for March 11 - 15 calls for below-normal temperatures across the eastern half of the U.S., while warmer-than-normal weather will prevail in the West. Meanwhile, near- to below-normal precipitation across the majority of the nation will contrast with wetter-than-normal conditions in southern Florida and from the Great Lakes region into the Northeast.