#Drought news: 180-day #precipitation deficits remain the largest (more than 6 inches) across southwest #Colorado

Click on a thumbnail graphic to view a gallery of drought data from the US Drought Monitor.

Click here to go to the US Drought Monitor Website hosted by the Colorado Climate Center. Here’s an excerpt:

This Week’s Drought Summary

An area of upper-level low pressure entered southern California by December 26 and then progressed east across the Four Corners region. This upper-level low resulted in heavy rain and high-elevation snow from southern California east to southwest Colorado and New Mexico. A surface low developed across the south-central Great Plains on December 28 with a subsequent track northeast to the upper Mississippi Valley and Great Lakes. Heavy snow fell to the northwest of this low pressure system, while moderate to heavy rainfall accompanied the cold front as it shifted east from the Great Plains to the East Coast. Following the heavy precipitation across the Pacific Northwest during mid to late December, precipitation average below normal during the final week of December. Enhanced onshore flow resulted in periods of heavy precipitation along the Alaska Panhandle, but longer-term precipitation deficits persist. A low pressure system and trailing front brought locally heavy rain and damaging winds to parts of the Hawaiian Islands this past week…

High Plains

A low pressure system developed across the southern Great Plains on Dec 28 and then tracked northeast to Iowa and Minnesota. Along and northwest of the surface low track, beneficial precipitation (0.5 to 1.5 inches) fell from the western half of Kansas north to southern and eastern Nebraska. This recent precipitation prompted a 1 to 2-category improvements to the short-term drought areas in Kansas. A 2-category improvement was justified where more than 1 inch of precipitation occurred and 90-day precipitation is either at or above normal. However, severe drought (D2) continues west of Garden City and Liberal, Kansas. In contrast to the improving conditions for Kansas, abnormal dryness (D0) was extended north across western Wyoming where 90-day precipitation deficits are 2 to 6 inches. Drought impacts were modified to long-term only in southwest Colorado due to recent snowfall. Snow water content is running 125 to 135 percent of normal as of December 29, but 6-month SPI values support the severe drought (D2) category in southwest Colorado…

West

A vigorous upper-level trough crossed southern California and the desert Southwest from December 25 to 27. Widespread moderate to heavy rain and high-elevation snow (0.5 to 2 inches, liquid equivalent) accompanied this upper-level trough. Snowfall amounts exceeded two feet in the mountains of southern California, while 4 to 12 inches was recorded in the higher elevations of Arizona. This recent precipitation along with support from longer-term SPI values resulted in a 1-category improvement to Dx levels in parts of Arizona and southwest Utah. 180-day precipitation deficits remain the largest (more than 6 inches) across southwest Colorado.

Drier weather returned to the Pacific Northwest during the final week of December. Following the period of heavy precipitation during mid to late December, no changes were made to the ongoing abnormal dryness (D0) and short-term moderate drought (D1) areas. Water year to date (since October 1) precipitation deficits of more than 12 inches, 28-day stream flows in the lowest 10th percentile, and basin average snow water content less than 50 percent support the short-term moderate drought (D1) across parts of Oregon and Washington…

South

As an upper-level trough ejected from the desert Southwest, a surface low developed over the southern Great Plains. Beneficial rainfall (more than 1 inch) resulted in improving conditions across the eastern Oklahoma Panhandle and northwest Oklahoma. Moderate (D1) to severe (D2) drought continues across southwest Oklahoma and adjacent areas of the Texas Panhandle and northwest Texas which received lighter rainfall amounts (0.75 inches of less). Changes to the drought depiction across the remainder of Texas included a slight reduction in D0/D1 in central and southwest parts of the state, based on recent rainfall and lack of short-term dryness. Although it was a dry week across deep southern Texas, a reassessment of indicators supported a slight reduction of severe (D2) drought. A small area of severe (D2) drought was added to Burleson County, based on 120-day indicators. On December 29, a cold front crossed the lower Mississippi Valley where 0.5 to 2 inches of rainfall occurred. The heaviest rain fell to the north and east of the ongoing D0 to D2 areas…

Looking Ahead

During the next 5 days (January 2 to 6), another surface low is forecast to develop across the southern Great Plain on January 2. This surface low and trailing cold are likely to bring heavy rainfall (1 to 3 inches) to the lower Mississippi Valley and Tennessee Valley with more modest amounts (1 inch or less) along the East Coast. A low pressure system with onshore flow is expected to bring rain and high-elevation snow to the Pacific Northwest, beginning of January 4. Although rainfall of around an inch is forecast along the Texas Gulf Coast during the next week, dry weather is likely across the remainder of Texas. Mild temperatures are forecast to prevail across the continental U.S. during the first week of January 2020, while bitterly cold temperatures persist throughout Alaska.

The CPC 6-10 day extended range outlook (January 6 to 10, 2020) indicates a slight tilt in the odds for above normal precipitation across much of the central and northeastern U.S. Below normal precipitation is favored for the Southeast along with California and the Southwest. The highest confidence in the temperature outlook exists across Alaska where below normal temperatures are likely to persist into the second week of January. Below normal temperatures are favored for the Great Basin and Rockies, while a warming trend is anticipated across the south-central and eastern U.S.

US Drought Monitor one week change map ending December 31, 2019.

Just for grins here’s a gallery of early January Drought Monitor national maps for the past few years.

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