National Overview - February 2000


NCDC transitioned to the nClimDiv dataset on Thursday, March 13, 2014. This was coincident with the release of the February 2014 monthly monitoring report. For details on this transition, please visit our public FTP site and our U.S. Climate Divisional Database site.

U.S. February Temp 1895-2000

The upper-air pattern remained progressive and active for most of the month with several deep, storm-producing troughs crossing the country from west to east. Pacific-borne systems dominated the month with limited intrusions of cooler arctic air.

A mean upper-level ridge in the central portion of the country provided warmer than normal temperatures from coast to coast with much warmer than normal temperatures from the central Rockies to the Ohio Valley and from the western Great Lakes to Texas. The prevalent onshore Pacific flow provided ample precipitation for Oregon, northern California and portions of the central and northern Rockies while the southwest, south, southeast, and the Atlantic coast were drier than normal. NA 500mb Map
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Additional information on hydrometeorological analysis and forecasting can be found at the Hydrometeorological Prediction Center's Web Page. The principles behind the 500 mb flow are briefly explained Here. BlueBar

Top of Page National Temperature - February

Preliminary data for February 2000 indicate that the monthly mean temperature averaged across the contiguous United States was warmer than normal and ranked as the third warmest February since 1895. Over 50% of the country was much warmer than normal while less than one percent of the country was much cooler than normal. The last six Februarys have averaged much above the long-term mean. US February Temp
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U.S. February Temperature Index, 1895-2000
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The preliminary national standardized temperature index ranked February 2000 as the second warmest February since 1895. The smoothed temperature value for February has been above the long-term mean since 1982.

The map to the right, based on approximately 250 airport stations, shows departures from the 1961-1990 normal of average temperatures for February 2000. Most of the country experienced much above normal temperatures for the month but areas west of the Rockies and the immediate coastal southeast averaged closer to normal. The Hawaiian stations averaged near normal and most of Alaska averaged much warmer than normal. U.S. February Temperature Departures

Animated TZ Map, 199903/200002
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The map animation provided to the left shows the geographical pattern of temperature anomalies for the last 12 months, compared to a base period of 1931-1990.
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Top of Page National Precipitation - February

U.S. February Precipitation, 1895-2000
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Based upon preliminary precipitation data, February 2000 ranked near the long-term mean. About ten percent of the country was much drier than normal while about 21% of the country was much wetter than normal.
The preliminary national standardized precipitation index also ranked February 2000 near the long-term mean. U.S. February Precipitation Index, 1895-2000
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U.S. February Surface Wetness
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Dominant high pressure over the country provided areas from the western Plains westward, with drier than normal surface conditions. Lower than average surface wetness, due to drought conditions, is evident in the lower Mississippi valley while some of the negative anomalies in the northwest are due to snowcover. Several storm systems provided wetter than normal conditions through convective-type precipitation for the central Plains, western Great Lakes, Ohio Valley, and the mid-Atlantic region.

The map below, based on approximately 250 airport stations, shows February 2000 total precipitation as a percent of the 1961-1990 station normals. Western Alaskan stations were wetter than normal while central and eastern locales within the state were drier than normal. All of the Hawaiian stations reported a drier than normal month. On the mainland U.S., stations were mostly drier than normal from the southwest through the southeast and up the Atlantic coastal region as well as the southern Appalachians. It was also dry in the western High Plains and the central Great Lakes region.

Above normal precipitation occurred at stations in the northern Rockies, Great Basin, all of California, north-central Texas, the central and northern Plains, and the Ohio Valley. U.S. February Precipitation Departures
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Long-term drought areal coverage (as measured by the Palmer Drought Index) increased when compared to January, with about 23% of the country in severe to extreme drought during February. The percent area of the country experiencing severe to extreme wetness has dropped steadily during the last six months and at the end of February was about five percent. The drought area expanded this month to its greatest extent since mid-1996 (see graph below left). However, several droughts in the past hundred years covered a much larger area for a much longer time (see graph below right). The February 2000 drought is only about two-thirds as extensive as the 1988 drought was at its peak.

USPA, 02/2000
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USPA 1900-01/2000-02
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Snowcover, 02/2000
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The snow cover anomaly map to the left reflects the general upper-level pattern across the U.S during February. The dominant ridge over the center of the country prevented the normal accumulation of snowfall for the central and southern Rockies and the Great Basin as well as portions of the central Plains. Weak upper-level impulses provided greater than normal snowfall anomalies over portions of the northern High Plains.

Most of the positive snowcover anomalies over the southern Great Lakes area, central Appalachians, and the mid-Atlantic region for February is due to snowfall which occurred late in January. Most of this snowcover melted by mid-month.

An animation of daily snowcover for North America is available.

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Top of Page Tornadoes - February

During February 2000, 49 tornadoes were documented across the contiguous United States. The 46-year average is 22. The most tornadoes observed in the February record was 83 in February 1971, while a record minimum of two tornadoes were observed in February 1964.

It should be pointed out that the preliminary tornado count is traditionally higher than the final count and that the tornado observations have generally improved with time as better observing practices and instrumentation (especially weather radar and satellites) were utilized.

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Current data are based on preliminary reports from River Forecast Center stations and First and Second Order airport stations obtained from the National Weather Service (NWS) Climate Prediction Center and real time Global Telecommunications System (GTS) monthly CLIMAT summaries. THE CURRENT DATA SHOULD BE USED WITH CAUTION. These preliminary data are useful for estimating how current anomalies compare to the historical record, however the actual values and rankings for the current year may change as the final data arrive at NCDC and are processed.

The following NCDC datasets are used for the historical U.S. data: the climate division drought database (TD-9640), and the hurricane datasets (TD-9636 and TD-9697). It should be noted that the climate division drought database consists of monthly data for 344 climate divisions in the contiguous United States. These divisional values are calculated from the 6000+ station Cooperative Observer network.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: National Overview for February 2000, published online March 2000, retrieved on October 2, 2014 from http://www.ncdc.noaa.gov/sotc/national/2000/2.