National Overview - January 2002


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.

Top of Page National Temperatures

National Temperature Time Series
larger image
The graph to the left shows monthly mean temperature averaged across the contiguous United States based on long-term data from the U.S. Historical Climatology Network (USHCN). The value is estimated from preliminary Climate Division data using the first difference approach. January 2002 ranked as the seventh warmest January in the 1895 to present record. The preliminary nationally averaged temperature was 35.4° F (1.9° C) which was 4.5° F (2.5° C) above the long-term mean. The January temperature values from 1895 through 2002 are available.
It is interesting to note that January temperatures in the last five years were above normal.

The Mean 500mb Height and Anomalies chart shows no large negative or postive anomalies over the contiguous United States. A prominent upper level ridge of high pressure anchored over the eastern half of the United States during January promoted unseasonably mild weather across the country east of the Rockies. Seasonably cool temperatures were common across the Inter-Mountain West.

A more detailed analysis including how statewide and regionwide temperatures compare to other years is available.

State Temperature Ranks
larger image

Top of Page Temperature Departures

The map to the right, based on approximately 250 airport stations, shows departures from the 1961-1990 normal temperatures for January 2002. Only portions of northern Utah and southern California had negative temperature anomalies greater than 1.8° F (1° C). Most of the rest of the contiguous states experienced unusually warm weather, with the largest positive anomalies of 9° F (5° C) or greater over Montana eastward through the northeastern quarter of the country. The bulk of Alaska had large positive anomalies with some negative anomalies on the west coast. Temperatures in Puerto Rico and Hawaii were near average. National Temperature Departures
larger image
Percent of Normal Day-to-Day Temperature Variability
larger image
The unusually warm departures of monthly mean temperature were associated with above normal persistence of daily temperatures. This is reflected in below normal day-to-day temperature variability particularly in the Northeast, as seen both in the map to the left and in an animated map of daily temperature anomalies.
Visual Text Separator

Top of Page National Precipitation

National Precipitation Time Series
larger image
The graph to the left is a time series depicting precipitation averaged across the nation. Based upon preliminary precipitation data, January 2002 was slightly below average, ranking near the middle of the historical distribution. While nationally averaged precipitation was near the long term mean, there was considerable regional variability. Arizona and Minnesota were notably dry receiving much below normal precipitation for the month.
On the 2nd and 3rd, a rare southern winter storm left its mark in seven states from Lousiana to Virginia. A dusting to as much as 14 inches (35.6 cm) of snow caused thousands of traffic accidents, closed schools and businesses and cut power to tens of thousands (AP). On the 7th, a separate system dropped up to a foot (30.5 cm) of heavy, wet snow in West Virginia, contributing to one death and leaving thousands in the dark (AP). In Washington and Oregon, two-day heavy rains totalling up to 6.5 inches (165.1 mm) sent rivers out of their banks and prompted mudslides that blocked traffic. Later in the month, more than 8 inches (203.2 mm) of rain fell in Tennessee and was blamed for the deaths of five people. The Tennessee Emergency Management Agency said that nearly one quarter on Tennessee's counties experienced flood damage from this event. (AP) State Precipitation Ranks
larger image
Rainfall caused flooding in northern Alabama as well, with seven day totals surpassing 7 inches (177.8 mm). Heavy rains closed roads, flooded creeks and rivers and forced residents to evacuate in Lauderdale County. (AP) Late in the month (on the 27th) heavy snows fell in the Pacific Northwest and were blamed for the deaths of two motorists. (AP) On the 29th, record rainfall fell at several Hawaii recording stations and severe storms caused millions of dollars in flood damage. The Hilo airport shattered their January 24-hour rainfall record of 9.51 inches (241.6 cm). The new record was 12.47 inches (316.7 mm).

A more detailed analysis including how statewide and regionwide precipitation compares to other years is available.


Top of Page Precipitation Anomalies

The map to the right, based on approximately 250 airport stations, shows January 2002 total precipitation as a percent of the 1961-1990 station normals. Above normal precipitation generally occurred in coastal Washington and Oregon, a large area centered around the Southern Plains, along the Mississippi Valley and in North Carolina. The rest of the country was mostly dry. Northern and southeastern Alaska were dry as well, with the rest of Alaska and Hawaii being wet. Puerto Rico was near normal. National Precipitation Departures
larger image

Top of Page National Snow Cover

National Snow Cover
animation
The map to the left shows national snow cover on January 3rd after a storm left portions of Georgia, South Carolina, North Carolina and Virginia blanketed in snow. Areas of north central North Carolina received up to 14 inches (35.6 cm) of snow. In South Carolina, the governor activated the National Guard to assist stranded drivers. A separate storm system left areas of West Virginia under up to a foot (30.5 cm) of new snow, contributing to one death and cutting power to thousands of residents (AP). Late in the month on the 27th, snowstorms in the Pacific Northwest were blamed for the deaths of two motorists in western Washington (AP).
Visual Text Separator

Top of Page November-January Temperatures

National Temperature Time Series- 3 month
larger image
The graph to the left shows monthly mean temperature averaged across the contiguous United States based on long-term data from the U.S. Historical Climatology Network (USHCN). The value is estimated from preliminary Climate Division data using the first difference approach. November-January 2002 ranked as the warmest such period in the 1895 to present record. The preliminary nationally averaged temperature was 39.9° F (4.4° C) which was 4.3° F (2.4° C) above the long-term mean.
November 2001-January 2002 ranked as the warmest November-January nationally in the 1895-2002 record. This is due largely to an extensive area of much above normal temperatures, and the lack of very cold temperatures, during each of these three months. As seen in the graph to the right, two-thirds of the contiguous U.S. was unusually warm in November 2001, followed by about a fifth of the country unusually warm in both December and January. State Temperature Ranks
larger image
Statewide Temperature Ranks
larger image
November 2001-January 2002 ranked as the warmest November-January nationally in the 1895-2002 record. The second warmest November-January occurred just two years ago, in 1999-2000, while the third warmest occurred back in the drought decade of the 1930s, 1933-1934. The statewide pattern of warmth for these top three November-January periods is shown on the accompanying maps. The 2001-2002 November-January warmth (the orange and red much above normal shadings on the maps) occurred from the northern and central Great Plains states to the east coast.
State Temperature Ranks
larger image
State Temperature Ranks
larger image

During 1999-2000, the warmth was centered from the Mississippi River to the west coast. On both of these maps, none of the Lower 48 States averaged below normal. During 1933-1934, the unusual warmth stretched from the Southeast to the entire west coast, with a pocket of very cold temperatures in the Northeast.

Citing This Report

NOAA National Climatic Data Center, State of the Climate: National Overview for January 2002, published online February 2002, retrieved on August 30, 2014 from http://www.ncdc.noaa.gov/sotc/national/2002/1.