National Climatic Data Center, 14 January 2003

• December Precipitation
• Precipitation Departures
• Last 3 months (Oct-Dec)
• Year-to-Date (Jan-Dec)

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• U.S.Temperatures
• North America Snow Season

December Precipitation

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The graph to the left is a time series depicting precipitation averaged across the contiguous U.S. Based upon preliminary precipitation data, December 2002 was much wetter than average, ranking 9th wettest - only the second significantly wetter than average month in the last two and a half years . There has been no significant trend in mean national December precipitation over the last century.

There was considerable regional variability in precipitation across the country. Three states in the southern half of the country (California, Arkansas and Florida), received much above average rainfall in December, while 2 states (Michigan, and Nebraska) received much below average rainfall this month. Iowa had its driest December on record. This follows on the heels of a dry November for the Middle and Upper Mississippi Valley, and combined rankings for the last 2 months show that Nebraska and South Dakota were the driest such 2 months on record and that the East North Central Region was much drier than average. Sustained drought alleviation continued in many eastern states and the long-term drought in much of the east is now over. Some long-term dryness still remains from Georgia to Virginia, however this is no longer severe and is expected to dissipate with El Nino-related precipitation continuing to be above normal in the Southeast.

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Some precipitation fell as snow in December, especially in the New England region and along the east coast. More details of snowfall in December can be found on the snow season page

Thunderstorms Produce Severe Weather in Missouri

Thunderstorms preceding a strong cold front pushed into the U.S. Mississippi Valley on the 17th, producing severe weather and tornadoes. Three people were killed in Missouri and Arkansas with more than 40 injuries (Associated Press). A powerful Pacific storm system plowed into the western United States during the 13th-16th, producing high winds, heavy rains, significant mountain snowfall and causing 9 deaths (Associated Press). Rainfall amounts exceeding 254 mm (10 inches) occurred in parts of California, and wind gusts over 70 km/hr (~40 knots or 45 mph) produced up to 1.9 million power outages during the period (Pacific Gas & Electric).

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The graph to the left is a time series depicting precipitation from October-December averaged across the primary hard red winter wheat belt. The growing season runs from October to February for the hard red winter wheat and preliminary data indicate that precipitation was above average for the first 3 months of the growing season in 2002.

Precipitation Departures

The map below, based on more than 500 airport stations, shows December 2002 total precipitation as a percent of the 1971-2000 station normals. Above normal precipitation generally occurred in the West, Gulf states and along the east coast. The north central part of the country was anomalously dry as well as Alaska, Hawaii and parts of the Southwest U.S.

A large storm system impacted the west coast during the 13th-16th December 2002 and caused many 24-hour rainfall records to fall, especially in California. San Francisco airport received 2 consecutive 24-hour rainfall record totals on the 13th and 14th of December. On the 13th, 2.47 inches of rain smashed the old record of 0.45 inches set in 1968, and on the 14th 0.88 inches exceeded the old record by 0.05 inches. Contrasting the heavy precipitation in the west, parts of the Midwest set new records for dryness. In Des Moines, Iowa, 53 consecutive days without rain (ending on January 4th, 2003) broke the old record for the number of dry days (45). And in Kansas City, MO, the record for the driest December was equalled with a total of only 0.03 inches of rainfall during the month. For more records during December 2002, see NCDC's Extremes Page.

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Three months, October-December 2002

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The graph to the left is a time series depicting precipitation averaged across the contiguous U.S. Based upon preliminary precipitation data, October-December 2002 was much wetter than average, ranking 11th wettest in the last 108 years. This belies considerable regional variability as can be seen from the maps below and contrasts with the last 3 October-December periods.

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Nine states along the Gulf coast and eastern seaboard received much above average precipitation over October-December 2002. Several divisions had record precipitation totals for the period. Montana was the only state to average much below normal precipitation for the three months though general dryness was seen throughout the Northwest, North Central and Central regions and also portions of the Great Lakes.

National Precipitation - January-December 2002

A comprehensive annual assessment of the U.S. climate is available in preliminary form and will be in final form on January 23rd.
larger image	The graph to the left is a time series depicting precipitation averaged across the contiguous U.S. Based upon preliminary precipitation data, January-December 2002 was slightly drier than average, ranking 41st driest in the last 108 such periods. The last 4 years have averaged slightly to much below the long term mean precipitation.

Record dryness occurred in Colorado from January to December, 2002. The pattern of state-averaged annual precipitation can be seen in the map to the right. Five other states ranked in the top ten driest such periods. More information on drought analysis for these states and others can be found on NCDC's Drought Pages. Mississippi and West Virginia had their 11th wettest year on record while New York state had its 12th. Much of the annual precipitation along the Gulf coast and eastern states fell in the second half of the year.

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Questions?

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: questions@ncdc.noaa.gov

For further information on the historical climate perspective presented in this report, contact:

Catherine Godfrey NOAA/National Climatic Data Center 151 Patton Avenue Asheville, NC 28801-5001 fax: 828-271-4328 email: Catherine.S.Godfrey@noaa.gov

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

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