National Drought Summary -- March 22, 2018

The discussion in the Looking Ahead section is simply a description of what the official national guidance from the National Weather Service (NWS) National Centers for Environmental Prediction is depicting for current areas of dryness and drought. The NWS forecast products utilized include the HPC 5-day QPF and 5-day Mean Temperature progs, the 6-10 Day Outlooks of Temperature and Precipitation Probability, and the 8-14 Day Outlooks of Temperature and Precipitation Probability, valid as of late Wednesday afternoon of the USDM release week. The NWS forecast web page used for this section is: http://www.cpc.ncep.noaa.gov/products/forecasts/.

Moderate precipitation fell in a wide swath covering an area from Kansas and Nebraska, eastward into parts of the Midwest and Mid-Atlantic regions. Additionally, moderate precipitation fell in the South and Southeast. Locally higher amounts fell in northern Florida late in the USDM period. Moisture laden systems continued to provide much needed precipitation to coastal California and the Sierra. Light to moderate precipitation fell in the Northeast, High Plains, and parts of the Rockies. The drought stricken areas of the Four Corners and the Southern Plains saw little to no precipitation.


Alaska, Hawaii, and Puerto Rico

Less-than-normal snow fell in February in southwest Alaska which has continued into March. While good snows have fallen in eastern Prince William Sound and the Kenai Peninsula, snow water equivalents are still running below normal. Streamflows at 1, 7, 14, and 28-days in the south are 10-30 percent of normal. The northern section of Alaska’s D0 was trimmed back in response to the above normal precipitation at 30 and 60-days.

Drought or abnormally dry conditions do not exist for Hawaii or Puerto Rico this week.


High Plains

Precipitation was a mixture of above and below normal across the region during the USDM period. Precipitation surpluses of 0.25 to 1 inch was widespread across much of the western Dakotas, eastern Wyoming, much of Nebraska, the northeastern corner of Colorado and parts of western Kansas. The eastern Dakotas, north central Wyoming and much of southern Colorado had precipitation deficits of 0.25 inch during the period. Winter wheat conditions were rated 55% poor to very poor in Kansas where 60-day precipitation departures are as much as 3 inches below normal. Recent precipitation allowed for D0 to be removed in northern Nebraska and parts of western Minnesota. Moderate drought (D1) was trimmed back in central North Dakota. Extreme drought (D3) was expanded southern Colorado.


Midwest

Precipitation was generally below normal (less than 1.0 inch deficits) across the region during the USDM period. Precipitation during the last 30 days has been above normal for most of the region limiting drought to just Iowa and Missouri. Heavy precipitation did fall in parts of Missouri during the USDM period allowing for contraction of some abnormally dry conditions (D0). Additionally, D0 was contracted in southern Iowa due to the recent precipitation. Deteriorating conditions in Wisconsin prompted the introduction of D0 in the northern part of the state into the Upper Peninsula of Michigan.


Northeast

The Northeast endured another nor’easter this week – its third in as many weeks. As much as 2 feet of snow fell in the region. Drought/dryness was confined to Maryland where 30-day precipitation deficits are 1-2” below normal. No changes to the USDM depiction were made in this region.


South

Precipitation was generally below normal (0.25-1.0 inch deficits) across the region during the USDM period. During the last 30 days, much of Texas was running about 1 inch below normal for the period while the rest of the region was as much as 10 inches above normal. The dryness is beginning to affect agriculture, plant and wildlife. It was reported that cotton and corn growers in the Rio Grande Valley may begin to irrigate earlier than normal due to the abnormally dry conditions in the area. According to the USDA, 60% of wheat in Texas was in poor to very poor condition while 66% of topsoil moisture across the state was short to very short. Moderate drought was expanded in western and parts of southern Texas. Severe drought was expanded in western Texas. Drought and dryness is not currently effecting the majority of the other states of the region.


Southeast

Precipitation was generally below normal (0.25-1.0 inch deficits) across the region aside from some high amounts (1-5 inches total) in the Panhandle of Florida and parts of Mississippi and Louisiana during the USDM period. Precipitation deficits of 1-3 inches during the last 30 days exist for much of the Southeast. The largest impact is the high risk of fire danger, especially in south Florida, where more than 3,000 acres were recently charred in the Big Cypress National Preserve and a fire in Picayune Strand State Forest scorched more than 10,000 acres. A burn ban remains in effect in Brevard County, Florida. Drought was contracted in northern Florida where the heaviest precipitation fell during the USDM period. The drought depiction improved up to 2 categories in parts of this area. In south Florida moderate drought expanded slightly. Drought depiction in the rest of the region was status quo, except for some small modifications in northern Alabama, eastern Georgia, and north central North Carolina. Drought depiction in the rest of the region was status quo, except for some small modifications in northern Alabama, eastern Georgia, and north central North Carolina.


West

Precipitation amounts during the USDM period were above normal in parts of Montana, much of Idaho, eastern Oregon, northern Utah and Nevada, and much of California. Below-normal precipitation occurred elsewhere, but was most notable in the Desert Southwest and coastal Pacific Northwest. Precipitation departures for the 30- and 60-day time periods are apparent in most of the region. The important water year-to-date precipitation amounts were running above normal in the north but running at least 25-50 percent below normal for much of the region. Mountain snowpack is less than 25 percent of normal across much of the Sierra Nevada and Intermountain West. Extreme drought (D3) was expanded in Arizona.


Looking Ahead:

During the next 5 days, precipitation amounts are forecast to be high in much of California along with the risk of flooding. Precipitation amounts may approach 2 inches in the Intermountain West, Northwest, and parts of the High Plains. Elsewhere, a large swath totaling 0.25-2.00 inches of precipitation is projected to fall in parts of the Midwest and Northeast. The drought stricken Four Corners region, western Texas and eastern Colorado is expected to continue to be dry.

The 6-10 day outlook from the Climate Prediction Center calls for an increased chance of below-normal precipitation in the West while the highest probability of precipitation is forecast for the South. The probability of above-normal temperatures are also highest in the South. Below-normal temperatures are most likely to occur across the western third of the U.S.


Authors:

Richard Heim, NOAA, NCEI

Chris Fenimore, NOAA, NCEI



Dryness Categories
D0...Abnormally Dry...used for areas showing dryness but not yet in drought, or for areas recovering from drought.

Drought Intensity Categories
D1...Moderate Drought
D2...Severe Drought
D3...Extreme Drought
D4...Exceptional Drought

Drought or Dryness Types
S...Short-term
L...Long-term
SL...Short- and long-term