State of the Climate
Drought
November 2007

National Oceanic and Atmospheric Administration

National Climatic Data Center

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Contents Of This Report:

National Drought Overview
Detailed Drought Discussion
State/Regional/National Moisture Status
Pre-Instrumental Perspective

National Overview

Based on the Palmer Drought Index, severe to extreme drought affected about 23 percent of the contiguous United States as of the end of November 2007, an increase of about 2 percent compared to last month. By contrast, about 9 percent of the contiguous U.S. fell in the severely to extremely wet categories.
About 38 percent of the contiguous U.S. fell in the moderate to extreme drought categories (based on the Palmer Drought Index) at the end of November.
On a broad scale, the previous two decades (1980s and 1990s) were characterized by unusual wetness with short periods of extensive droughts, whereas the 1930s and 1950s were characterized by prolonged periods of extensive droughts with little wetness (moderate to extreme drought graphic, severe to extreme drought graphic).

A file containing the national monthly percent area severely dry and wet from 1900 to present is available for the severe to extreme and moderate to extreme categories.
Historical temperature, precipitation, and Palmer drought data from 1895 to present for climate divisions, states, and regions in the contiguous U.S. are available at the Climate Division: Temperature-Precipitation-Drought Data page in files having names that start with "drd964x" and ending with "txt" (without the quotes).

Detailed Drought Discussion

November 2007 was an unusually dry month for much of the country. Nationally, this November ranked as the 13th driest November in the 1895-present record. On a regional basis, the dryness was concentrated in the central and northern Plains eastward to the western Great Lakes and westward to the intermountain West. Other dry areas included much of California and the mid-Atlantic to Deep South, central stations in Alaska, the southeastern Hawaiian islands, and southeastern Puerto Rico. As a result, drought expanded or intensified in parts of the three core drought areas:

in the West,
across the northern portions of the western Great Lakes, and
in the mid-Atlantic to the Southeast.

November 2007 Statewide Precipitation Ranks

Near-record dryness occurred in several states this month, with South Carolina having a rank of second driest November and Iowa and Wisconsin ranking third driest. The persistent dryness throughout much of 2007 has resulted in record dry conditions for several states for certain periods:

driest January-November and many other periods for North Carolina
driest July-November for South Carolina
driest February-November for Tennessee

November 2007 Palmer Hydrological Drought Index

About 63 percent of the western U.S. (Rockies westward) fell in the moderate to extreme drought category, an increase over last month, and about 42 percent fell in the severe to extreme category (as defined by the Palmer Drought Index) by the end of this month.

The persistent dryness has depleted soil moisture, ravaged pastures, and dried up streams. Soil moisture and streamflow (both modeled and observed) were most severely affected in the three core drought areas: the Southeast, upper Great Lakes, and West.

9 Month Standardized Precipitation Index, March-November 2007

A more detailed drought discussion can be found below.

SOUTHEAST DROUGHT
According to the Southeast Regional Climate Center, drought continued to be the top climate story for almost all the Southeast in November. The end of November is also the end of the North Atlantic hurricane season. Earlier hopes that hurricanes would bring relief, partly encouraged in September by Hurricane Humberto in Alabama and Georgia and tropical storm Gabrielle in eastern North Carolina, were unfulfilled. Indeed, in November the dominance of the Bermuda high pressure system, helping to steer rain-bearing storms away from the region, seemed to be even more marked. For numerous stations around the Southeast November 2007 was the driest November in many years. For several stations in Virginia and the Carolinas it was the driest on record. Most notable was the record for downtown Charleston, SC, where November 2007 had zero rain. The old November record was 0.21 inch set in 1996, and the only other month which has recorded zero precipitation was October 2000. Farther south the lack of rain was less spectacular, it merely being the driest November for the past few decades. If the current circulation pattern persists, however, some spots might be on the way to new annual records. For example, the total rainfall so far this year, January through November, in Huntsville, Alabama was the lowest since 1914.

Early in the month drought was still concentrated, as for previous months, in the southern Appalachian Mountains. An expansion, especially southward and eastward, took place followed by a slight retreat for much of the area. The slight amelioration in the middle of the month in Southern Florida however, was reversed, and severe drought returned to that area.

According to the end-of-November U.S. Drought Monitor discussion:

USDA reports indicate that 81 percent of North Carolina's pastures were rated in very poor to poor condition on November 25, and pastures rated very poor to poor stood at 75 percent in Virginia, 74 percent in South Carolina, and 71 percent in Georgia.
Another drought-related agricultural impact was delayed emergence of winter wheat. Wheat planting was ahead of the 5-year average in Georgia and North Carolina, while emergence trailed the normal pace. In South Carolina, half of the wheat was planted (vs. the 5-year average of 58 percent) by November 25, but the crop was only 19 percent emerged (vs. the average of 43 percent).

In late November, the USDA declared 58 counties in Florida as primary natural disaster areas due to drought.

WESTERN DROUGHT

As summarized by the Western Regional Climate Center, November precipitation across the West was generally below normal except for parts of western Montana, eastern Oregon and portions of Southern California and Arizona. The Southwest was dry until the final day of the month. Palm Springs had no rain through the first 29 days but ended up 468 percent of normal for the month with 1.28 inches falling on the 30th. Most monthly totals in Arizona all occurred on the final day of the month. In Hawaii, thanks to a Kona low on the 4th, parts of Oahu received over 10 inches of rain. Honolulu measured 3.81 inches on the 4th which was 0.39 inch more than the total they had received for January-October 2007 (3.42 inches).

Map showing West Region November 2007 Percent of Normal Precipitation

December 1st snowpack was well below normal in all regions especially in the Sierra Nevada with most locations reporting no snow at all. Roswell, NM, and El Paso, TX, have measured more snowfall this season than ski resorts at Lake Tahoe. Isolated locations of Montana, Washington and Oregon had near 90 percent of normal snowpack.

MIDWEST DROUGHT
As explained by the Midwest Regional Climate Center, dry weather persisted across most of the region west of the Mississippi River, where November precipitation was less than 25 percent of normal, and as low as 5 to 10 percent of normal in northwestern Iowa and southwestern Minnesota. Parts of the Ohio Valley and a band from east-central Illinois through the northern half of Ohio received normal to above normal precipitation. Heavy rainfall in Kentucky the second and fourth weeks of the month significantly reduced drought impacts in the southeastern portion of the state, and at the end of the month Extreme Drought (as defined by the U.S. Drought Monitor) existed in all or parts of only nine counties in Kentucky.

NORTHEAST DROUGHT
As noted by the Northeast Regional Climate Center, moderate drought conditions continued in eastern Connecticut, Rhode Island, central Maryland and southern Delaware, while severe drought conditions persisted in southwestern West Virginia and Maryland's Eastern Shore. Precipitation totals varied from north to south, with Delaware the driest, at 43% of normal, and Maine the wettest, with 181% of the normal November precipitation.

OTHER AREAS
According to the end-of-November U.S. Drought Monitor discussion:

In Texas, the percentage of the winter wheat crop rated very poor to poor by USDA rose from 29 percent on October 28 to 53 percent on November 25. During the same 4-week period, Oklahoma wheat rated very poor to poor increased from 18 to 30 percent, while Kansas and Colorado wheat rated very poor to poor climbed from 10 to 15 percent. By November 25, topsoil moisture rated very short to short in Kansas stood at 100 percent in the southwest, 86 percent in the south-central region, 82 percent in the west-central region, and 72 percent in the northwest. (The Kansas state average was 53 percent very short to short on topsoil moisture.) Wheat was struggling to grow on the southern High Plains, where Texas' emergence stood at 70 percent on November 25, compared to the 5-year average of 85 percent. Similarly, Oklahoma's wheat was 83 percent emerged, compared to the 5-year average of 95 percent.
Another complication of the Plains' dry autumn has been a rash of grass fires. During the week ending November 23, the Aetna fire burned 5,000 acres of vegetation in southern Kansas, while the Wild Hog fires (two separate incidents) charred at least 3,400 acres in northern Texas.

State/Regional/National Moisture Status

A detailed review of drought and moisture conditions is available for all contiguous U.S. states, the nine standard regions, and the nation (contiguous U.S.):

STATES:

Alabama	Arizona	Arkansas	California	Colorado	Connecticut
Delaware	Florida	Georgia	Idaho	Illinois	Indiana
Iowa	Kansas	Kentucky	Louisiana	Maine	Maryland
Massachusetts	Michigan	Minnesota	Mississippi	Missouri	Montana
Nebraska	Nevada	New Hampshire	New Jersey	New Mexico	New York
North Carolina	North Dakota	Ohio	Oklahoma	Oregon	Pennsylvania
Rhode Island	South Carolina	South Dakota	Tennessee	Texas	Utah
Vermont	Virginia	Washington	West Virginia	Wisconsin	Wyoming

REGIONS:

Northeast Region	East North Central Region	Central Region
Southeast Region	West North Central Region	South Region
Southwest Region	Northwest Region	West Region