Storms continued to take aim at the Pacific Northwest this week, bringing multiple rounds of heavy rain along the coast and lower elevations, and snow to the mountains. Many locations along the coast have measured rain nearly every day this year.
While the heaviest rains fell outside of most of the region’s current drought areas, parts of western Oregon have received 125% to 300% of normal precipitation since the beginning of the year, helping to chip away at long-term drought conditions.
A winter storm brought snow to Rockies and eastern New Mexico before moving eastward. Several locations from far southeastern New Mexico into western, central and eastern Texas, northern Louisiana and Mississippi were blanketed by at least 6 inches of snow.
Dryness continued to deteriorate conditions in locations such as Southern California, south-central Oregon, north-central Kansas, and south Texas. In all, the percent area of the Lower 48 experiencing moderate drought or worse stands at 44.85%, down from 45.76% last week.
Last week’s winter storm brought snow to northern Alabama and to the mountains of western North Carolina and Virginia. Most other places, with the exception of the Florida Peninsula and eastern Virginia, received rain.
The area remains drought-free this week with areas of normal dryness in areas where rainfall deficits exist out to 90 days. With temperatures 3 to 8 degrees colder than normal, these deficits aren’t yet showing up in streamflow and soil moisture.
The South was hit with another winter storm this week, spreading rain and snow from Texas to Mississippi. Widespread snow fell across much of East Texas and northern Louisiana, with totals generally ranging from 2 to 5 inches, with isolated higher amounts near 6 inches across portions of deep East Texas and west-central Louisiana.
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As a result, one-category improvements were made across much of the state. The rain and snow even helped chip away at the extreme (D3) and exceptional (D4) areas in the western part of the state as soil moisture and groundwater began to improve.
Drought conditions deteriorated in far South Texas, which has experienced warmer than normal temperatures, combined with rainfall less than 25% of normal over the last 90 days. To the east, rain and snow helped improve parts of the abnormally dry areas in southwest Arkansas and central Mississippi.
The Midwest saw a continuation of relatively mild temperatures and below-normal rain and snow. Temperatures ranged from near normal in the south to more than 15 degrees above normal in the north.
The warm, dry week led to an expansion of moderate drought (D1) in northeast Minnesota and a broad expansion of abnormal dryness (D0) from northeast Iowa through northern Wisconsin and into the Upper Peninsula of Michigan. Here, precipitation shortages exist out to 60 days and soil moisture has continued to dry out.
The only improvement occurred to D1 in Illinois, where precipitation deficits, streamflow, and soil moisture improved.
Like the upper Midwest, much of the High Plains experienced relatively warm, dry conditions. Temperatures ranged from 4 degrees above normal in north-central Kansas to more 20 degrees above normal in north-central Minnesota.
These conditions led to expansions of moderate drought (D1) in northeast Wyoming and western North Dakota and in north-central Kansas as precipitation deficits continued to build and soil moisture decreased.
The only improvements were made in southeast Colorado, where widespread precipitation, which was near to above-average for the entire month, lessened precipitation deficits and replenished soil moisture.
While the Pacific Northwest saw continued wet weather, the Southwest remained dry. One-category improvements were made in west Oregon, where 125% to 300% of normal precipitation has fallen since the beginning of the year. This has led to improvements in streamflow and groundwater.
East of the Cascades, water year-to-date precipitation is well below normal, resulting in extremely low streamflows and degradations to exceptional (D3) drought in south-central Oregon.
In the Southwest, moderate (D2) and extreme (D3) drought expanded in central California where water year-to-date precipitation is less than 25% of normal. With the exception of an expansion of abnormal dryness (D0) in northern Montana, the rest of the West remained unchanged.
Once again, many state drought teams noted that in areas where rain and snow fell, it wasn’t enough to increase moisture availability. In areas where it didn’t, such as the Southwest, the conditions either didn’t yet warrant additional degradations or, because they were already in exceptional drought (D4), could not be degraded further.
Snowpack and snow-water equivalent are well below normal and soils are dry. Ranchers have noted that natural forage is insufficient or depleted.
Most of the region remained relatively dry this week. Light rain and snow either missed or didn’t accumulate enough to improve drought and abnormally dry areas.
Changes to the map include an expansion of abnormal dryness (D0) and moderate drought (D1) in northern New York, where precipitation deficits are more than 6 inches over the last six months, causing decreases in soil moisture and groundwater. D0 also expanded across northern New Hampshire.
Alaska, Hawaii, and Puerto Rico
In Alaska, above-normal precipitation resulted in the removal of abnormally dry (D0) conditions on Kodiak Island. Snowfall in much of the interior has been below normal since mid-November, leading to an expansion of D0 from the Wrangell Mountains into the northeast Brooks Range. A second D0 area extends into the Upper Tanana Valley and the north side of the Alaska Range as far west as Denali National Park.
In Hawaii, generally light winds and dry conditions prevailed over much of the past week. Changes to the map include the introduction of exceptional (D4) drought on Molokai as vegetation health declined and there were reports of cattle and deer deaths. Thunderstorms in Maui missed the hardest hit drought areas, leading to an expansion of extreme (D3) drought from the central valley northward to include Kahului. Finally, severe drought (D2) was expanded on the Big Island over the lower Kohala slopes.
The National Weather Service Weather Prediction Center forecast for the remainder of the week calls for snow across the Upper Midwest. Widespread precipitation is also forecast in New England this weekend, which is likely to fall as rain along the coast and snow through the interior.
Areas of ongoing drought in California, Oregon, Washington, and Idaho are forecast to remain dry into the middle of next week.
Looking farther ahead to Jan. 19-23, the Climate Prediction Center Outlooks favor colder than normal temperatures in the western Great Plains and Rocky Mountains, as well as other parts of the West. Warmer than normal temperatures are expected in roughly the eastern half of the Lower 48.
The greatest chances for above-normal precipitation are in eastern Montana, northeast Wyoming, and adjacent western North Dakota and South Dakota, and from southeast Texas through northwest Georgia.
The Pacific Coast, as well as much of inland central and northern California, Oregon, and Washington, are favored to receive below-normal precipitation, as are south Florida and northern New England.