California and National Drought Summary for October 11, 2016

Summary

October 14, 2016 - Hurricane Matthew approached the east coast of Florida as a category 4 hurricane, having many bracing for the impact during this last week. The eye of the storm stayed offshore for the most part, but did bring with it intense rain and associated flooding along with wind damage. Some reports of 14+ inches of rain were noted in South Carolina and North Carolina, but these rains did not impact any of the drought regions of the Southeast. The storm pushed rain up the east coast and into southern New England. Significant rain also fell with a slow-moving storm system that impacted much of southeast Kansas and northeast Oklahoma, but it stalled out as it approached the Ozarks. The Pacific Northwest continues to stay active with multiple storms coming ashore and bringing rain along the coastal areas of Washington and Oregon and into the northern Rocky Mountains. Most of the rest of the United States was dry this week and the significant dryness over the Southeast during the last several months is starting to rapidly deteriorate conditions there with widespread impacts.

The Northeast and Mid-Atlantic

Rain bands associated with Hurricane Matthew pushed up into the Mid-Atlantic and into southern New England. Enough precipitation was recorded that portions of southern and northeast New Jersey had a slight improvement to the abnormally dry and moderate drought conditions there. Southeast Massachusetts also received good rains this last week, which was enough to ease the drought intensity, as extreme and severe drought conditions were improved a category and drought was removed from Nantucket and Martha’s Vineyard. Other portions of these regions remained dry and had drought intensify and expand this week. Abnormally dry conditions were introduced over much of the remaining portions of New England that were not already labeled as such. All areas except extreme northern Maine are now in abnormally dry or drought status. Moderate drought was expanded over eastern New York and Vermont while severe drought was expanded in southern New York and northern New Jersey. Along with the dryness in the region, temperatures remained normal to slightly above normal throughout this area this week.

Southeast

A strong delineation line between areas of ample moisture and significant drought areas continues to strengthen. With the impact of Hurricane Matthew, the coastal regions from south Florida northward into the Carolinas continue to be very wet with significant drought only a few hundred miles to the west. Temperatures were cooler than normal this week for those areas receiving the rain from Matthew, and all other areas continued to be 2-4 degrees above normal. Very dry conditions over the last 2-3 months have allowed for drought to develop and intensify quite rapidly in the typically moist climate of the region. Mississippi, Alabama, Georgia, southern Tennessee, and the western portions of the Carolinas all have had drought degradations this week of a full category in most instances. Almost all of Mississippi, Alabama and Tennessee along with the western three-quarters of Georgia are now being depicted as abnormally dry or worse. Over the last 6 months, Oneonta and Scottsboro, Alabama, have had their driest period on record, based upon 83 and 102 years of record, respectively. In Tennessee, both Ridgeside and Chattanooga have had their driest last 6-month period on record, based upon the last 89 and 138 year periods of record, respectively. Most areas in the D4 regions of Alabama, Georgia and Tennessee are top 10 driest on record for the last 6 months. Along with the dryness, almost all areas in Mississippi, Alabama, Tennessee, and Georgia are seeing a record number of 90 degree days over the past 6 months as well. This week continued the rapid expansion of drought intensity in this region, with new areas of extreme drought in Mississippi and Alabama as well as the expansion of exceptional drought. Significant impacts are already being reported to the agricultural sector and hydrological issues are developing rapidly. Over the last 6 months, precipitation deficits of 12-16 inches below normal are widespread through this region along with temperatures 4-6 degrees above normal.

Midwest

Most of the Midwest was dry this week, allowing for harvest activities to take off in full force. Some areas of western Iowa and northern Missouri did record up to 3 inches of rain for the week and most areas were 4-6 degrees above normal. Abnormally dry conditions were introduced into much of southern Kentucky this week and into the boot-heel of Missouri too. Moderate drought was introduced in eastern Kentucky while pockets of dryness are scattered in the region. No other changes were made this week.

High Plains

Temperatures were cooler than normal over most of the region this week with portions of North Dakota 6-9 degrees below normal. Areas of western and eastern Nebraska, along with eastern Kansas, were wetter than normal, with portions of southeast Kansas recording over 5 inches of rain. Drought is not much of an issue in the region and the only change this week was some removal of abnormally dry conditions over western Nebraska.

South

Much of the region was dry this last week, with only areas along the Red River between Texas and Oklahoma and areas of northeast Oklahoma recording above-normal precipitation. Temperatures were normal to slightly above normal in the eastern portions of the region, where departures were 2-4 degrees above normal. Moderate drought expanded over much of northeast Texas, southeast Oklahoma, southeast Arkansas and eastern Louisiana as well as in southeast Arkansas and northeast Louisiana. Abnormally dry conditions also expanded over east Texas, Arkansas, and Louisiana. Conditions over the last 4-6 weeks have dried out considerably with impacts being experienced in the drought areas.

West

Cooler than normal temperatures were experienced over much of the West this week as departures of 3-6 degrees below normal were common. Most areas were dry outside of the Pacific Northwest and into the northern Rocky Mountains, where several storms impacted the region. Improvements to the abnormally dry conditions were made over western Washington and western Wyoming this week and a full category improvement was made to the drought areas of Montana.

Hawaii, Alaska and Puerto Rico

No changes were made this week for Alaska, Hawaii or Puerto Rico.

Looking Ahead

Over the next 5-7 days, the storm pattern will continue to impact the Pacific Northwest, with significant rain anticipated along the coastal region from northern California to Washington. These storms will also impact the interior Northwest into central Montana and western Wyoming, bringing widespread precipitation. The Midwest and Great Lakes regions will also see precipitation as well as portions of the southern Plains. The Southeast looks to remain dry into the Mid-Atlantic. Temperatures are anticipated to be warmer than normal over much of the country, with only the areas of the Pacific Northwest being cooler than normal due to the anticipated precipitation. Departures will range from 12-15 degrees above normal for daily high temperatures over the Texas and Oklahoma panhandles to 9-12 degrees below normal over northern California.

The 6-10 day outlooks show that the warm October is anticipated to continue. Almost the entire country (outside of the Great Basin and Central Rocky Mountain regions) has a higher probability of warmer than normal temperatures, with the highest likelihood over the Southeast and Mid-Atlantic. Higher probabilities of above-normal precipitation exist for the Pacific Northwest and interior Northwest, High Plains, Midwest, Northeast and the western side of the Mississippi River Valley. Below-normal precipitation is anticipated over much of the Southeast and into Florida.

Author(s):
Brian Fuchs, National Drought Mitigation Center

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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, typically <6 months (e.g. agricultural, grasslands)

L ... Long-Term, typically >6 months (e.g. hydrology, ecology)
Source: National Drought Mitigation Center