Through climate analysis, National Climatic Data Center scientists have identified nine climatically consistent regions within the contiguous United States which are useful for putting current climate anomalies into an historical perspective.

Additional information about current climate anomalies can be found at the respective Web Pages of the Southern Regional Climate Center, Western Regional Climate Center, Midwest Regional Climate Center, Southeast Regional Climate Center, High Plains Regional Climate Center, and the Northeast Regional Climate Center.

Table 1 shows precipitation and temperature ranks for each of the 9 regions and the nation for January 2000, the two-month period of December 1999-January 2000, the six months of August 1999-January 2000, and the past 12 months, February 1999-January 2000.

               PRECIPITATION AND TEMPERATURE RANKS, BASED
               ON THE PERIOD 1895-2000.  1 = DRIEST/COLDEST,
               106 = WETTEST/WARMEST FOR JAN 2000,
               105 = WETTEST/WARMEST FOR DEC 1999-JAN 2000,
               105 = WETTEST/WARMEST FOR AUG 1999-JAN 2000,
               105 = WETTEST/WARMEST FOR FEB 1999-JAN 2000.

                          JAN   DEC 1999-  AUG 1999-  FEB 1999-
      REGION              2000  JAN 2000   JAN 2000   JAN 2000
      ------              ----  ---------  ---------  ---------

                PRECIPITATION:

     NORTHEAST             57       27         91         37
     EAST NORTH CENTRAL    34       20          8         64
     CENTRAL               34       29          8          7

     SOUTHEAST             60       26         55         21
     WEST NORTH CENTRAL    98       94         56         77
     SOUTH                 16       17          2         11

     SOUTHWEST             39       17         22         65
     NORTHWEST             72       56         49         63
     WEST                  69       34         17         23

     NATIONAL              37       14          7         20

                TEMPERATURE:

     NORTHEAST             61       78         90        102
     EAST NORTH CENTRAL    85       95         94        103
     CENTRAL               66       76         86         94

     SOUTHEAST             52       55         70         69
     WEST NORTH CENTRAL    97      105        105        105
     SOUTH                 95       99         96         98

     SOUTHWEST             99       96        101        101
     NORTHWEST             86       88        101         79
     WEST                 103       98        101         81

     NATIONAL              97      104        103        103

It should be emphasized that all of the temperature and precipitation ranks in Tables 1 through 5 are based on preliminary data. The ranks will change when the final data are processed.

Table 2 shows historical extremes for January, the 1961-1990 normal, and the January 2000 value for each of the 9 regions and the contiguous U.S. for precipitation and temperature. It should be noted that the 2000 values will change when the final data are processed.

                            PRECIPITATION (INCHES)
                         DRIEST     WETTEST   NORMAL  2000
     REGION            VALUE YEAR VALUE YEAR   PCPN   PCPN
     ------            ---------- ----------  ------ ------

    NORTHEAST           0.87 1981  7.22 1979   2.84   3.00
    EAST NORTH CENTRAL  0.32 1961  2.47 1916   1.11   0.85
    CENTRAL             0.72 1981  9.61 1937   2.52   2.19

    SOUTHEAST           0.92 1927  7.73 1936   4.13   3.91
    WEST NORTH CENTRAL  0.16 1961  1.25 1949   0.61   0.98
    SOUTH               0.53 1914  5.34 1932   2.09   1.24

    SOUTHWEST           0.20 1924  3.00 1916   0.82   0.69
    NORTHWEST           0.43 1985  7.81 1953   3.80   4.36
    WEST                0.28 1984 10.67 1916   2.58   3.47

    NATIONAL            0.92 1981  3.87 1916   2.07   2.01*

                        * PRELIMINARY VALUE, CONFIDENCE
                          INTERVAL + OR - 0.34 INCHES

                           TEMPERATURE (DEGREES F)
                         COLDEST    WARMEST   NORMAL  2000
     REGION            VALUE YEAR VALUE YEAR   TEMP   TEMP
     ------            ---------- ----------  ------ ------

    NORTHEAST           12.3 1918  33.8 1932   21.1   23.2
    EAST NORTH CENTRAL  -1.3 1912  25.4 1990   13.0   19.6
    CENTRAL             15.1 1977  40.0 1933   28.2   32.0

    SOUTHEAST           35.0 1977  57.7 1950   44.1   45.6
    WEST NORTH CENTRAL   0.1 1937  26.6 1986   16.5   24.5
    SOUTH               31.1 1940  50.7 1923   40.7   46.9

    SOUTHWEST           20.8 1937  38.2 1986   31.2   36.7
    NORTHWEST           13.4 1949  37.4 1953   28.5   31.6
    WEST                24.4 1937  45.5 1986   38.4   43.0

    NATIONAL            22.4 1979  37.1 1953   29.9   35.0*

                       * PRELIMINARY VALUE, CONFIDENCE
                          INTERVAL + OR - 0.3 DEG. F.

 

Table 3 shows statistics for selected river basins: Precipitation rankings are for October 1999-January 2000, where 1 = driest, and 106 = wettest, based on the period 1895 to 2000. Also shown is the areal percent of the basin experiencing severe or extreme long-term (Palmer) drought, and areal percent of the basin experiencing severe or extreme long-term (Palmer) wet conditions, as of January 2000.

                       PRECIPITATION  % AREA  % AREA
   RIVER BASIN                       RANK        DRY     WET
   -----------                   -------------  ------  ------

   MISSOURI BASIN                     10          1.4%   18.5%
   PACIFIC NORTHWEST BASIN            59          0.0%    1.2%
   CALIFORNIA RIVER BASIN             26         37.6%    0.0%

   GREAT BASIN                         3          0.8%    0.0%
   UPPER COLORADO BASIN                7          0.0%    0.0%
   LOWER COLORADO BASIN                1         63.6%    0.0%
   RIO GRANDE BASIN                    3         36.2%    3.9%

   ARKANSAS-WHITE-RED BASIN           26          0.0%   16.3%
   TEXAS GULF COAST BASIN              6         34.5%    0.0%
   SOURIS-RED-RAINY BASIN              1          0.0%    8.4%
   UPPER MISSISSIPPI BASIN             5         23.1%    0.0%

   LOWER MISSISSIPPI BASIN             6         54.2%    0.0%
   GREAT LAKES BASIN                  17         18.9%    0.0%
   OHIO RIVER BASIN                   23         64.0%    0.0%
   TENNESSEE RIVER BASIN              13         39.6%    0.0%

   NEW ENGLAND BASIN                  47          0.0%    0.0%
   MID-ATLANTIC BASIN                 29          7.0%    0.0%
   SOUTH ATLANTIC-GULF BASIN          38          2.6%    3.6%

The river basin regions are defined by the U.S. Water Resources Council.

January 2000 Temperature and Precipitation

Based upon preliminary data, January 2000 was the fourth warmest January on record for the West region. High pressure dominated the region and kept cool air further north. January 2000 was the seventh consecutive January with much above normal temperatures.

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High pressure dominated the South region of the United States during January keeping most precipitation north and east of the area. January 2000 was the 16th driest such month since 1895.

Preliminary January precipitation data for the Primary Hard Red Winter Wheat Belt indicate that the five-month growing season (The growing season runs October-February.) continues to be dry. The October 1999-January 2000 period was the 16th driest such growing season to-date since 1895. The region had the wettest such period on record just last year.

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January 2000 Statewide Temperature and Precipitation

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Twenty-three states ranked within the warm-third portion of the historical distribution for January 2000 while nine states ranked within the top ten warm. It was the second warmest January since 1895 for Arizona. Other rankings include: California - 4th warmest New Mexico - 5th warmest Nevada - 6th warmest Oklahoma - 6th warmest Utah - 6th warmest Wyoming - 6th warmest No state ranked within the cool-third of the historical distribution.

It was the sixth driest January on record for West Virginia and the ninth driest January since 1895 for Louisiana, the only two states within the top ten dry portion of the distribution. Twelve other states ranked within the dry-third portion of the distribution. It was the second wettest January on record for Wyoming and the fourth wettest January on record for Montana.. Eight other states ranked within the wet-third portion of the distribution.

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Palmer Drought Indices

The Palmer Z Index shows how monthly moisture conditions depart from normal (short-term drought and wetness). The January 2000 pattern shows extremely dry conditions over portions of the Southwest, south central Arkansas, and a good portion of Louisiana. The Palmer Z Index indicates that wet conditions occurred along portions of the Pacific Coast, and in parts of the northern Rockies.

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The animated maps show the geographical pattern of the moisture anomalies for the last 12 months. On these maps, the red shading denotes dry conditions while the green shading indicates wet conditions.

The Palmer Drought Index maps show long-term (cumulative) drought and wet spell conditions. The drought in the mid-west continued in January while areal coverage and intensity remained nearly unchanged. Drought conditions in the Southwest expanded during January as did drought conditions in the central and southern Mississippi Valley. During the preceding twelve months, the area of wet conditions in the Great Plains steadily decreased in size until only a few areas, mainly in South Dakota and Colorado, remained wet at the end of January.

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The animated maps show how the geographical pattern of the long-term moisture conditions has changed over the last 12 months. On these maps, the red shading denotes drought conditions while the green shading indicates wet conditions.

Preliminary streamflow measurements by the United States Geological Survey revealed persistently low daily streamflows associated with drought from the Great Lakes to the southern Plains and Southeast during November. More streamflow information can be found at the United States Geological Survey's web page.

Central and South Regions Precipitation Deficits

The Central and South regions of the U.S. have experienced extremely dry conditions for each of the last seven months.

In the Central region (which stretches from the Ohio to Tennessee Valleys, and central Appalachians to the mid-Mississippi Valley), the present dry spell follows a 12-month period (July 1998-June 1999) of alternating wet and dry months (see bottom left graph). July 1999 - January 2000 ranked as the fifth driest such seven-month period on record. In the graph below right, the dark blue curve shows the values for each year, and the smooth red curve shows the decade-scale variations.

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In the South region (which stretches from Kansas to Texas, then eastward to Mississippi), the present dry spell follows a 12-month period (July 1998-June 1999) that was generally wet (see bottom left graph). July 1999 - January 2000 ranked as the driest such seven-month period since 1895, and exceeds the worst years of the 1950's. However, the southern Plains drought of the 1950's was characterized by year-after-year of extremely dry conditions, as seen in the graph below right. Other statistics for the South region: second driest August-January, fifth driest September-January, seventh driest October-January, eighth driest November-January, and 17th driest December-January on record. January 2000 was the 16th driest such month since 1895.

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Current and historical drought information can be found at the Web Page for the National Drought Mitigation Center. The Center monitors current droughts both in the United States and worldwide.

Damage due to the drought has been summarized by NOAA and the Office of Global Programs in the Climatological Impacts section of the Climate Information Project. Crop impact information can be found at the USDA NASS (National Agricultural Statistics Service) and Weekly Weather and Crop Bulletin pages. Drought statements by local National Weather Service Offices can be found at the NWS Hydrologic Information Center. Drought threat assessments and other information can be found at NOAA's Drought Information Center.

For more information, refer to ...

References:

Thomas R. Karl and Albert J. Koscielny, 1982: "Drought in the United States: 1895-1981." Journal of Climatology, vol. 2, pp. 313-329.

Thomas R. Karl and Walter James Koss, 1984: "Regional and National Monthly, Seasonal, and Annual Temperature Weighted by Area, 1895-1983." Historical Climatology Series 4-3, National Climatic Data Center, Asheville, NC, 38 pp.

NOAA's National Climatic Data Center is the world's largest active archive of weather data. The preliminary temperature and precipitation rankings are available from the center by calling: 828-271-4800.

Historical precipitation and temperature ranking maps are also available on the Internet at: http://nic.fb4.noaa.gov/products/analysis_monitoring/regional_monitoring/usa.html.

NOAA works closely with the academic and science communities on climate-related research projects to increase the understanding of El Niño and improve forecasting techniques. NOAA's Climate Prediction Center monitors, analyzes and predicts climate events ranging from weeks to seasons for the nation. NOAA also operates the network of data buoys and satellites that provide vital information about the ocean waters, and initiates research projects to improve future climate forecasts. The long lead climate outlooks are available on the Internet at: http://nic.fb4.noaa.gov.

For all climate questions other than questions concerning this report, please contact the National Climatic Data Center's Climate Services Division:

Climate Services Division
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4876
phone: 828-271-4800
email: ncdc.orders@noaa.gov

William Brown
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: william.brown@noaa.gov

Mike Changery
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: mchangry@ncdc.noaa.gov

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