National Oceanic and Atmospheric Administration

National Climatic Data Center, 17 November 1999

• Climate of 1999: October Overview
• Detailed Climate Perspectives . . .
  • Global Analysis
    
  • Global Regional Analyses
    
  • U.S. National Analysis
    
  • U.S. Regional/Statewide Analyses
  • Extreme Events
• 1999 Monthly Reports

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 October 1999, the two-month period of September-October 1999, the six months of May-October 1999, and the past 12 months, November 1998-October 1999.

             PRECIPITATION AND TEMPERATURE RANKS, BASED
             ON THE PERIOD 1895-1999.  1 = DRIEST/COLDEST,
             105 = WETTEST/WARMEST FOR OCTOBER 1999,
             105 = WETTEST/WARMEST FOR SEP-OCT 1999,
             105 = WETTEST/WARMEST FOR MAY-OCT 1999,
             104 = WETTEST/WARMEST FOR NOV 1998-OCT 1999.

                        OCT    SEP-OCT    MAY-OCT   NOV 1998-
    REGION              1999     1999       1999    OCT 1999
    ------              ----  ---------  ---------  ---------

              PRECIPITATION:

   NORTHEAST             48      103         57         42
   EAST NORTH CENTRAL    13       14         77         88
   CENTRAL               25       13          9         20

   SOUTHEAST             72       89         61         31
   WEST NORTH CENTRAL    13       36         76         82
   SOUTH                 30       27         29         51

   SOUTHWEST              5       17         89         71
   NORTHWEST             43       15         21         95
   WEST                  27       20         18         40

   NATIONAL              18       26         33         51

              TEMPERATURE:

   NORTHEAST             26       66         96         99
   EAST NORTH CENTRAL    46       47         72        100
   CENTRAL               47       46         63         92

   SOUTHEAST             51       33         44         96
   WEST NORTH CENTRAL    64       43         48         94
   SOUTH                 49       41         60        100

   SOUTHWEST             76       59         57         98
   NORTHWEST             64       67         42         71
   WEST                  98      100         76         63

   NATIONAL              65       59         67        101

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 October, the 1961-1990 normal, and the October 1999 value for each of the 9 regions and the contiguous U.S. for precipitation and temperature. It should be noted that the 1999 values will change when the final data are processed.

                             PRECIPITATION (INCHES)
                           DRIEST     WETTEST   NORMAL  1999
       REGION            VALUE YEAR VALUE YEAR   PCPN   PCPN
       ------            ---------- ----------  ------ ------

      NORTHEAST           0.44 1924  6.96 1995   3.35   2.95
      EAST NORTH CENTRAL  0.25 1952  4.66 1984   2.47   1.22
      CENTRAL             0.53 1963  7.15 1919   3.04   2.06

      SOUTHEAST           0.53 1963  7.33 1959   3.16   3.74
      WEST NORTH CENTRAL  0.13 1952  2.95 1998   1.09   0.52
      SOUTH               0.12 1952  7.07 1984   2.89   1.88

      SOUTHWEST           0.02 1952  3.67 1972   1.12   0.25
      NORTHWEST           0.14 1987  5.20 1950   2.05   1.93
      WEST                0.01 1917  2.86 1962   1.01   0.44

      NATIONAL            0.54 1952  3.72 1941   2.16   1.52*

                          * PRELIMINARY VALUE, CONFIDENCE
                            INTERVAL + OR - 0.21 INCHES

                             TEMPERATURE (DEGREES F)
                           COLDEST    WARMEST   NORMAL  1999
       REGION            VALUE YEAR VALUE YEAR   TEMP   TEMP
       ------            ---------- ----------  ------ ------

      NORTHEAST           42.7 1925  56.0 1947   48.9   47.8
      EAST NORTH CENTRAL  37.5 1925  57.6 1963   47.8   47.5
      CENTRAL             48.2 1917  62.9 1947   55.2   55.6

      SOUTHEAST           58.2 1987  72.8 1919   63.4   63.8
      WEST NORTH CENTRAL  35.5 1925  53.9 1963   45.9   46.9
      SOUTH               56.7 1976  69.9 1947   63.4   64.0

      SOUTHWEST           48.6 1984  59.4 1950   53.4   54.8
      NORTHWEST           42.3 1919  53.9 1988   47.7   48.6
      WEST                51.8 1916  62.1 1988   56.9   60.3

      NATIONAL            49.7 1925  59.8 1963   54.4   55.2*

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

Table 3 shows statistics for selected river basins: Precipitation rankings are for October 1999, where 1 = driest, and 105 = wettest, based on the period 1895 to 1999. 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 October 1999.

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

  MISSOURI BASIN                      5          0.0%   23.6%
  PACIFIC NORTHWEST BASIN            47          0.0%    0.6%
  CALIFORNIA RIVER BASIN             37          8.8%    0.0%

  GREAT BASIN                         5          0.0%    0.0%
  UPPER COLORADO BASIN                4          0.0%    0.0%
  LOWER COLORADO BASIN                2          0.0%    0.0%
  RIO GRANDE BASIN                   13          0.0%    3.9%

  ARKANSAS-WHITE-RED BASIN           31          0.0%   26.6%
  TEXAS GULF COAST BASIN             27          0.0%    0.0%
  SOURIS-RED-RAINY BASIN             17          0.0%   90.3%
  UPPER MISSISSIPPI BASIN            13          0.0%    0.0%

  LOWER MISSISSIPPI BASIN            61          0.0%    0.0%
  GREAT LAKES BASIN                  26          4.4%    0.0%
  OHIO RIVER BASIN                   38         49.4%    0.0%
  TENNESSEE RIVER BASIN              36          0.0%    0.0%

  NEW ENGLAND BASIN                  64          0.0%    0.0%
  MID-ATLANTIC BASIN                 41          3.7%    0.0%
  SOUTH ATLANTIC-GULF BASIN          79          2.6%    8.7%

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

Table 4 shows precipitation and temperature ranks for each of the 9 regions and the nation for the year-to-date, January-October 1999, based on the period 1895-1999. 1 = DRIEST/COLDEST, 105 = WETTEST/HOTTEST.

       REGION                PRECIPITATION  TEMPERATURE
       ------                -------------  -----------

      NORTHEAST                   80             94
      EAST NORTH CENTRAL          90             99
      CENTRAL                     21             80

      SOUTHEAST                   37             76
      WEST NORTH CENTRAL          81             90
      SOUTH                       43             92

      SOUTHWEST                   79             97
      NORTHWEST                   65             68
      WEST                        45             70

      NATIONAL                    50             96

Table 5 shows historical extremes for January-October, the 1961-1990 normal, and the January-October 1999 value for each of the 9 regions and the contiguous U.S. for precipitation and temperature.

                             PRECIPITATION (INCHES)
                           DRIEST     WETTEST   NORMAL  1999
       REGION            VALUE YEAR VALUE YEAR   PCPN   PCPN
       ------            ---------- ----------  ------ ------

      NORTHEAST          26.40 1957 44.79 1996  34.34  36.27
      EAST NORTH CENTRAL 18.10 1910 33.27 1951  27.17  29.93
      CENTRAL            26.58 1930 44.82 1898  36.08  32.93

      SOUTHEAST          31.56 1954 54.83 1929  43.86  41.82
      WEST NORTH CENTRAL 10.32 1934 21.38 1915  15.53  16.93
      SOUTH              20.41 1956 41.23 1973  30.60  29.05

      SOUTHWEST           7.05 1956 20.24 1941  11.78  13.08
      NORTHWEST          13.30 1929 25.43 1950  19.69  20.26
      WEST                5.98 1966 22.96 1998  11.96  11.03

      NATIONAL           20.39 1934 28.56 1998  24.84  24.74

                             TEMPERATURE (DEGREES F)
                           COLDEST    WARMEST   NORMAL  1999
       REGION            VALUE YEAR VALUE YEAR   TEMP   TEMP
       ------            ---------- ----------  ------ ------

      NORTHEAST           46.5 1907  51.9 1998   48.8   50.7
      EAST NORTH CENTRAL  42.8 1917  51.1 1921   47.0   49.0
      CENTRAL             53.9 1979  60.1 1921   56.2   57.7

      SOUTHEAST           63.0 1940  67.2 1925   64.6   65.8
      WEST NORTH CENTRAL  43.0 1917  50.3 1934   46.9   48.3
      SOUTH               63.2 1979  67.7 1911   64.8   66.6

      SOUTHWEST           51.9 1917  57.8 1934   54.8   56.2
      NORTHWEST           46.7 1955  53.0 1934   49.4   49.5
      WEST                55.4 1912  60.5 1934   57.6   57.7

      NATIONAL            53.4 1912  57.7 1934   55.3   56.7

The Tropics: A Historical Perspective

The sixth hurricane of the Atlantic tropical season formed on 14 October, from a tropical storm first noted south of western Cuba just one day before. Hurricane Irene drifted northward and crossed the Florida Keys, east of Key West, on the 15th. The hurricane made landfall near Cape Sabel early the same afternoon with highest sustained winds of 85 miles per hour. Irene produced widespread rainfall amounts of 6 to 12 inches with Boynton Beach, on Florida's east coast south of West Palm Beach, reporting 17.45 inches. Wind gusts of 85 mph were reported from both Miami and Homestead.

larger image

Irene re-emerged over the Atlantic near Vero Beach and moved north toward the Carolinas. On the 17th and 18th, Irene insulted the eastern Carolinas with up to 8 inches of rainfall while the center paralleled the coast about 100 miles offshore. Portions of eastern North and South Carolina were inundated by floodwaters from Hurricane Floyd just one month earlier.

Hurricane Irene is the sixth hurricane in just over three years to impact eastern North Carolina. The others were Bertha (7/96), Fran (9/96), Bonnie (8/98), Dennis (8/99) and Floyd (9/99).

For the latest forecasts, warnings, and analyses for the tropical Atlantic and the tropical Eastern North Pacific, visit the National Hurricane Center's web site. For maps of U.S. landfalling major hurricanes and special reports on recent noteworthy storms visit the NCDC Hurricanes page. Additional satellite images and loops of Dennis and Floyd are located at the NCDC Online Images web site. Additional information, including near real-time data can be found at the Weather Underground tropical page.

October 1999 Temperature and Precipitation

Based upon preliminary data, October 1999 was the eighth warmest October on record for the West Region. Eight of the last thirteen such months have been warmer to much warmer than the long-term mean.

larger image

larger image

Preliminary data for the Northeast Region ranked October 1999 as the 25th coolest October since 1895. October temperatures have averaged at to below normal for the Northeast Region since 1986.

High pressure dominated the Southwest Region of the United States during October keeping most precipitation north and east of the region. October 1999 was the fifth driest such month since 1895 for the region.

larger image

larger image

Preliminary October precipitation data for the Primary Hard Red Winter Wheat Belt indicate that the five-month growing season was off to a dry start. October 1999 was the 13th driest such month since 1895.

October 1999 Statewide Temperature and Precipitation

Larger Map

October 1999 was the third warmest such month since 1895 for Nevada. Eight other states ranked within the warm-third of the historical distribution. No state ranked within the top ten cool portion of the distribution while fourteen states ranked within the cool third.

No state ranked within the top ten wet portion of the historical distribution while only five ranked within the wet third portion. Five states ranked within the top ten dry portion of the distribution including: Arizona - Driest Utah - second driest Nebraska - fifth driest Iowa - ninth driest Colorado - tenth driest

Larger Map

January-October 1999 Temperature and Precipitation

Based upon preliminary data, the year-to-date 1999 was the seventh warmest such ten-month period on record for the East-North Central Region. Just last year the region had the second warmest such ten-month period on record.

larger image

larger image

Preliminary data for the East-North Central Region ranked January-October 1999 as the 16th wettest such ten-month period since 1895. The last ten such ten-month periods have been near- to much above the long-term mean.

January-October 1999 was the 21st driest such ten-month period since records began in 1895 for the Central Region and the first such period since 1992 to be below the long-term mean for precipitation.

larger image

January-October 1999 Statewide Temperature and Precipitation

Larger Map

Eleven states were within the top ten warm portion of the historical distribution for temperature for January-October 1999, including: Rhode Island - 3rd warmest New Hampshire - 4th warmest Maine - 5th warmest Massachusetts - 6th warmest Wisconsin - 6th warmest No state ranked within the top-ten cool portion of the distribution.

January-October 1999 was the ninth driest such ten-month period since 1895 for West Virginia. January-October 1999 was the eighth wettest such ten-month period on record for Minnesota and the tenth wettest January-October since 1895 for North Dakota.

Larger Map

November 1998-October 1999 Statewide Temperature and Precipitation

Larger Map

Twenty-two states were within the top ten warm portion of the historical distribution for temperature for the running twelve month period. Some November 1998-October 1999 ranks included: New Hampshire - second warmest Rhode Island - second warmest Maine - third warmest Vermont - third warmest Only California ranked within the cool third portion of the historical distribution.

Four states were within the top 10 wet portion of the distribution for the November 1998-October 1999 period including: North Dakota - fourth wettest Washington - fourth wettest Minnesota - fifth wettest Kansas - tenth wettest Three states ranked within the top ten dry portion of the distribution for the same period. They included the sixth driest such period for West Virginia, the seventh driest for Georgia, and the tenth driest such twelve-month period since 1895 for Ohio.

Larger Map

It should be emphasized that all of the temperature and precipitation ranks on these maps are based on preliminary data. The ranks will change when the final data are processed.

Palmer Drought Indices

The Palmer Z Index shows how monthly moisture conditions depart from normal (short-term drought and wetness). The October pattern shows extremely wet conditions across portions of Florida and eastern North Carolina brought by Hurricane Irene. Extremely dry conditions stretched from the southern Great Lakes and Ohio Valley into the central Great Plains, and also afflicted much of the southwestern U.S. 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.

larger animated image

The Palmer Drought Index maps show long-term (cumulative) drought and wet conditions. The severe drought of 1999 continued from the central Appalachians to the Ohio Valley and over parts of the Southeast, but it had ended over the Northeast and coastal mid-Atlantic. Long-term conditions were in the very moist category in waterlogged eastern North Carolina. The central and northern Great Plains experienced unusually moist conditions during spring and early summer, but very dry conditions beginning in July 1999 eroded the eastern edge of the long-term moist area. 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.

larger animated image

The Palmer Crop Moisture Index is computed on a weekly basis by the National Weather Service's Climate Prediction Center and is useful for following the impact of precipitation anomalies on agriculture. The Animated Crop Moisture Index maps show the weekly change in topsoil moisture conditions for 1999 through the end of October. On these Crop Moisture Index maps, the red shading denotes dry conditions while the green shading indicates wet conditions.

Crop Moisture Index Legend: -3.00 and below (severely dry) -2.00 to -2.99 (excessively dry) -1.00 to -1.99 (abnormally dry) -0.99 to +0.99 (mid-range) +1.00 to +1.99 (abnormally moist) +2.00 to +2.99 (wet) +3.00 and above (excessively wet)

larger animated image

Streamflow and Drought

Preliminary streamflow measurements by the United States Geological Survey reveal unusually low daily streamflows associated with the drought from the southern Great Lakes to the southern Appalachians during October. River stages were above normal during the month in the wet areas of the northern Plains and east coast.

Explanation: New record high for day 90th percentile 75th - 89th percentile 25th - 74th percentile 10th - 24th percentile 10th percentile New record low for day

larger animated image

More streamflow information can be found at the United States Geological Survey's web page.

Missouri Precipitation Deficit

Severe short-term drought occurred during October 1999 in the central Plains states, with Nebraska having the fifth driest October since 1895, Iowa the ninth driest October, Kansas 13th driest, and Missouri 18th driest. Conditions averaged statewide across Missouri have been dry for each of the last four months. In 1999, Missouri has had the 15th driest September-October, seventh driest August-October, and fourth driest July-October. The dryness of the last four months contrasts with the overall wet conditions of the previous twelve months and has resulted in a neutral (near zero) long-term Palmer drought index for the Show-Me state.

larger image

larger image

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

NCDC / Climate Research / Climate of 1999 / October / U.S. Regional/Statewide / Search / Help