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 the March Climate can be found at the respective Web Pages of the Southern Regional Climate Center and the Western Regional Climate Center.
Additional 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.
Table 1 shows precipitation and temperature ranks for each of the 9 regions and the nation for March 1999, the two-month period of February-March 1999, the six months of October 1998-March 1999, and the past 12 months, April 1998-March 1999.
PRECIPITATION AND TEMPERATURE RANKS, BASED
ON THE PERIOD 1895-1999. 1 = DRIEST/COLDEST,
105 = WETTEST/WARMEST FOR MARCH 1999,
105 = WETTEST/WARMEST FOR FEB-MAR 1999,
104 = WETTEST/WARMEST FOR OCT 1998-MAR 1999,
104 = WETTEST/WARMEST FOR APR 1998-MAR 1999.
MAR FEB-MAR OCT 1998- APR 1998-
REGION 1999 1999 MAR 1999 MAR 1999
------ ---- --------- --------- ---------
PRECIPITATION:
NORTHEAST 65 53 50 68
EAST NORTH CENTRAL 8 7 69 54
CENTRAL 22 22 61 87
SOUTHEAST 19 9 18 23
WEST NORTH CENTRAL 18 26 104 93
SOUTH 79 26 90 36
SOUTHWEST 9 3 41 42
NORTHWEST 32 93 99 101
WEST 35 62 41 74
NATIONAL 16 13 77 68
TEMPERATURE:
NORTHEAST 54 84 93 102
EAST NORTH CENTRAL 75 103 101 104
CENTRAL 32 74 94 101
SOUTHEAST 21 46 97 102
WEST NORTH CENTRAL 95 104 102 103
SOUTH 55 95 103 103
SOUTHWEST 91 100 103 100
NORTHWEST 59 66 80 95
WEST 55 62 54 33
NATIONAL 69 100 104 104
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 March, the 1961-1990 normal, and the March 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 0.71 1915 6.56 1936 3.14 3.52
EAST NORTH CENTRAL 0.21 1910 3.50 1977 1.89 0.86
CENTRAL 0.55 1910 6.91 1897 3.92 2.68
SOUTHEAST 1.54 1910 8.89 1980 4.75 3.15
WEST NORTH CENTRAL 0.39 1994 2.10 1987 1.02 0.69
SOUTH 0.89 1966 6.28 1973 2.83 3.26
SOUTHWEST 0.20 1956 2.90 1905 1.02 0.42
NORTHWEST 0.58 1965 5.46 1904 2.72 2.08
WEST 0.09 1914 6.28 1907 2.23 1.41
NATIONAL 0.91 1910 3.89 1973 2.47 1.94*
* PRELIMINARY VALUE, CONFIDENCE
INTERVAL + OR - 0.29 INCHES
TEMPERATURE (DEGREES F)
COLDEST WARMEST NORMAL 1999
REGION VALUE YEAR VALUE YEAR TEMP TEMP
------ ---------- ---------- ------ ------
NORTHEAST 25.1 1916 42.5 1946 33.4 33.2
EAST NORTH CENTRAL 18.8 1960 42.2 1910 29.9 32.5
CENTRAL 29.0 1960 53.0 1946 43.0 40.0
SOUTHEAST 44.9 1960 63.2 1945 54.7 52.1
WEST NORTH CENTRAL 19.1 1965 43.4 1910 31.2 35.8
SOUTH 43.7 1915 62.6 1907 53.6 53.5
SOUTHWEST 35.6 1917 49.0 1910 41.9 45.5
NORTHWEST 31.0 1917 46.0 1934 38.6 38.7
WEST 39.5 1897 55.0 1934 46.3 46.6
NATIONAL 36.1 1965 50.2 1910 42.4 43.3*
* PRELIMINARY VALUE, CONFIDENCE
INTERVAL + OR - 0.3 DEG. F.
Table 3 shows statistics for selected river basins: Precipitation rankings are for the hydrologic year-to-date, October-March 1998-1999, where 1 = driest, and 104 = 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.
PRECIPITATION % AREA % AREA
RIVER BASIN RANK DRY WET
----------- ------------- ------ ------
MISSOURI BASIN 103 0.0% 19.1%
PACIFIC NORTHWEST BASIN 99 0.0% 31.0%
CALIFORNIA RIVER BASIN 46 0.0% 20.9%
GREAT BASIN 32 0.0% 0.0%
UPPER COLORADO BASIN 35 0.0% 0.0%
LOWER COLORADO BASIN 14 32.4% 0.0%
RIO GRANDE BASIN 74 0.0% 0.0%
ARKANSAS-WHITE-RED BASIN 100 0.0% 3.7%
TEXAS GULF COAST BASIN 87 0.0% 0.0%
SOURIS-RED-RAINY BASIN 104 0.0% 56.0%
UPPER MISSISSIPPI BASIN 75 4.8% 4.2%
LOWER MISSISSIPPI BASIN 60 0.0% 0.0%
GREAT LAKES BASIN 36 4.1% 0.0%
OHIO RIVER BASIN 49 0.0% 0.0%
TENNESSEE RIVER BASIN 58 0.0% 0.0%
NEW ENGLAND BASIN 67 0.0% 7.7%
MID-ATLANTIC BASIN 32 14.3% 2.7%
SOUTH ATLANTIC-GULF BASIN 19 9.7% 0.0%
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-March 1999, based on the period 1895-1999. 1 = DRIEST/COLDEST, 105 = WETTEST/HOTTEST.
REGION PRECIPITATION TEMPERATURE
------ ------------- -----------
NORTHEAST 95 83
EAST NORTH CENTRAL 36 95
CENTRAL 63 73
SOUTHEAST 31 67
WEST NORTH CENTRAL 37 101
SOUTH 60 99
SOUTHWEST 4 102
NORTHWEST 94 85
WEST 53 73
NATIONAL 57 100
Table 5 shows historical extremes for January-March, the 1961-1990 normal, and the January-March 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 6.10 1957 14.04 1900 8.63 11.68
EAST NORTH CENTRAL 1.64 1958 6.13 1998 3.95 3.58
CENTRAL 4.82 1941 16.22 1950 9.08 10.31
SOUTHEAST 6.28 1907 19.95 1998 13.03 10.84
WEST NORTH CENTRAL 1.46 1968 3.22 1987 2.18 2.05
SOUTH 3.71 1967 12.30 1990 7.22 7.50
SOUTHWEST 0.66 1972 6.65 1905 2.64 1.33
NORTHWEST 4.79 1985 14.74 1904 9.38 11.88
WEST 3.03 1972 15.17 1995 7.08 7.31
NATIONAL 5.04 1910 9.54 1998 6.52 6.66
TEMPERATURE (DEGREES F)
COLDEST WARMEST NORMAL 1999
REGION VALUE YEAR VALUE YEAR TEMP TEMP
------ ---------- ---------- ------ ------
NORTHEAST 20.5 1904 32.4 1998 25.9 28.3
EAST NORTH CENTRAL 10.6 1912 28.4 1987 20.2 24.4
CENTRAL 26.2 1978 41.9 1990 34.5 37.0
SOUTHEAST 43.2 1978 54.7 1990 48.6 50.7
WEST NORTH CENTRAL 14.6 1936 31.9 1992 23.3 29.0
SOUTH 40.3 1978 53.2 1907 46.5 50.8
SOUTHWEST 31.4 1937 42.2 1986 36.3 40.8
NORTHWEST 26.5 1949 40.3 1934 33.5 35.4
WEST 34.9 1949 48.1 1986 42.5 43.5
NATIONAL 31.2 1979 40.2 1921 35.5 39.1
March 1999 Regional Temperature and Precipitation
| Preliminary data ranked March 1999 as the 15th warmest March on record for the Southwest Region. The dominant upper-level flow kept cooler air north of the region for most of the month. The last eight months of March have been at- to much-above the long term mean.
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Preliminary data ranked March 1999 as the 21st coolest March on record for the Southeast Region. During the second and fourth weeks of the month, significant polar air intrusions provided for the cooler than normal conditions.
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| Based upon preliminary data, March 1999 was the 27th wettest March on record for the South Region.
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March 1999 was the 8th driest March since 1895 for the East-North Central Region, based upon preliminary data. Just last year, during the El Niño event, the region experienced the fourth wettest March on record.
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January-March 1999 Temperature and Precipitation
| The year-to-date, January-March 1999, was the 4th warmest January-March period on record for the Southwest Region. The dominant storm track has been north of the region thus allowing for warmer than normal temperatures. The last 11 such periods have been above- to much-above the long term mean.
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Preliminary data ranked January-March 1999 as the 33rd warmest January-March on record for the Central Region.
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| January-March 1999 was the 11th wettest January-March on record for the Northeast Region.
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Preliminary data ranked January-March 1999 as the 4th driest January-March on record for the Southwest Region. The same upper-level flow pattern which kept the region dry during March (see above) had persisted during most of the year-to-date as well. Nearly all precipitation episodes had been moving north of the region.
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| Preliminary data indicate that precipitation averaged across the Primary Corn and Soybean agricultural belt was below normal for the first month of the six-month growing season and ranked as the 20th driest March on record.
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March 1999 Statewide Temperature and Precipitation
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Based upon preliminary data, March 1999 was the 9th warmest March for Montana and the tenth warmest March on record for Colorado. Fifteen other states ranked within the warm-third portion of the historical distribution. No state ranked within the top-ten cool portion of the distribution while 14 states ranked within the cool-third.
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| Based upon preliminary data, March 1999 was the third driest March on record for Wisconsin, fifth driest for Michigan, sixth driest for Colorado and Nevada, and seventh driest for Utah. Eighteen other states ranked within the dry-third of the distribution. No state ranked within the top-ten wet portion while only four ranked within the wet-third.
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January-March 1999 Statewide Temperature and Precipitation
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Fifteen states ranked within the top-ten warm portion of the distribution for the year-to-date, January-March 1999. The year-to-date was the third warmest January-March for New Mexico, fourth warmest for Colorado and Wyoming, fifth warmest for Montana, Nebraska and Utah, and sixth warmest for Arizona. Twenty-two other states ranked within the warm-third portion of the distribution. No state ranked within the cool-third portion of the distribution for the year-to-date.
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| Six states ranked within the top-ten wet portion of the historical distribution for the year-to-date, January-March 1999, including the fifth wettest January-March on record for Connecticut and the sixth wettest for New Hampshire. Thirteen other states ranked within the wet-third portion of the distribution for the three-month period. It was the third driest January-March on record for Arizona and the sixth driest such period since 1895 for Colorado. Eight other states ranked within the dry-third portion of the historical distribution.
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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.
March 1999 brought a change in the temperature pattern to the United States, when compared to February 1999. As noted earlier, March temperatures averaged cooler than normal along the Pacific coast and across the Southeast to Ohio Valley, while unusually warm average temperatures dominated much of the Rockies and northern Plains states and into New England. The animated maps show the geographical pattern of temperature anomalies for the last 12 months.
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On these standardized temperature anomaly maps, red indicates areas with mean monthly temperatures much warmer than normal (top 10 percentile), tan indicates warmer than normal (70-90 percentile), light blue indicates colder than normal (10-30 percentile), and dark blue indicates much colder than normal (bottom 10 percentile).
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The Palmer Z Index, below, shows how monthly moisture conditions depart from normal (short-term drought and wetness). March 1999 was unusually wet in parts of the northern and central Plains, and unusually dry across much of the western U.S., the Great Lakes to Ohio Valley, and into the Southeast.
| The animated maps show the geographical pattern of the moisture anomalies for the last 12 months. On these Z Index maps, the red shading denotes dry conditions while the green shading indicates wet conditions.
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The Palmer Drought Index Maps show long-term (cumulative) drought and wet conditions. Long-term wetness decreased across much of the United States during March 1999, but wet spell conditions continued across much of the Pacific Coast, northern and central Plains, and parts of New England. Long-term drought conditions intensified in the Southwest, Great Lakes, and from the Southeast to Mid-Atlantic states.
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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 Palmer Drought Index maps, the red shading denotes drought conditions while the green shading indicates wet conditions.
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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 change in topsoil moisture conditions during the first 13 weeks of 1999. Unusually wet conditions occurred from Texas to the Ohio Valley at the beginning of March, however much of the country experienced a drying trend during the last few weeks of this 3-month period. On these Crop Moisture Index maps, the red shading denotes dry conditions while the green shading indicates wet conditions.
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Florida Statewide Precipitation Deficit
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Moderate to severe long-term drought plagued Florida during March, a situation which has been developing over the past several months. Statewide precipitation averaged for both February and March over two inches below normal. In fact, precipitation has averaged below normal for eight of the last 12 months.
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| Based upon preliminary data, February-March 1999 was the fifth driest February-March period on record for Florida. The second wettest such two-month period since 1895 occurred just last year. February-March 1998 had abundant rainfall, a signature of El Niño conditions.
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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 or on the World Wide Web at: http:/www.ncdc.noaa.gov/ol/documentlibrary/cvb.html
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 further information, contact:
William Brown
NOAA/National Climatic Data Center
151 Patton Avenue
Asheville, NC 28801-5001
fax: 828-271-4328
email: william.brown@noaa.gov
-or-
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 Monitoring / Climate of 1999 / Help
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