National Climatic Data Center, 10 February 2005

Regional Overview

The January precipitation pattern at the primary stations in Alaska was mixed but mostly wetter than normal at the interior stations and drier than normal at the coastal stations. The pattern was also mixed in Hawaii. In Puerto Rico, the south central and northwestern parts of the island were drier than normal, based on National Weather Service radar estimates of precipitation and on Cooperative station precipitation reports for the last 4 weeks. January streamflow averaged near normal for Hawaii and higher than normal for Puerto Rico.

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Long-term moisture deficits persisted in many areas. Much of the northern Rockies was dry at the 12 to 24 month timescales. Many Alaska stations, especially in the interior and southern coastal regions, were drier than normal at the 12 month timescale. Severe moisture deficits were evident at the 36 to 60 month timescales across much of the West into the northern High Plains and central Plains. These long-term hydrological drought conditions are reflected in the February 1 United States Drought Monitor map. Below-normal precipitation also persisted at the 60 month timescale across parts of the Southeast and extreme northeastern New England.

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Some regional highlights:

• Oregon had the ninth driest January and November-January in the 111-year record
• End-of-month and monthly averaged soil moisture conditions were drier than normal across parts of the northern Rockies and central and northern Plains, the Pacific Northwest, and the coastal Southeast, based on model computations (CPC-1, CPC-2, MRCC). The models also indicated dry soil moisture conditions in eastern Alaska, Hawaii, and near the surface and at depth across parts of the central Plains to the Great Lakes.
• Streamflow levels were below seasonal norms across a few parts of the Pacific Northwest, central and northern Rockies and Great Plains, and coastal Southeast, both as computed by models and based on USGS observations.
• Snow water content of the western mountain snowpack contrasted sharply from south to north. Basin-averaged end-of-January snowpacks in parts of Arizona, Nevada, central California and Utah were above average, while snowpacks in Oregon, Washington, Idaho, Montana and the east slopes of the northern Rockies were significantly below average. This pattern, which is also apparent in basin-averaged water-year-to-date precipitation anomalies, reflected a southerly track of winter storms across the region for the last five months. As reported by the USDA, several individual stations in the remote high altitude SNOTEL network set new record lows (in the north) and highs (in the south) for both snow water content and water-year-to-date accumulated precipitation.
• Reservoir levels in most of the western states continued well below seasonal normals. Although long-term (out to 5-years) moisture conditions remained dry across much of the West, drought conditions improved during the last 5 months. The percent area of the western U.S. (Rockies westward) experiencing moderate to extreme drought (as defined by the Palmer Drought Index) decreased from about 67% in July 2004 to under 10% by December. Intensification of drought in the Pacific Northwest (November, January) resulted in an expansion of the western drought area to about 18% by the end of January.

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• Palmer Drought Indices,
• Standardized Precipitation Index,
• airport station percent of normal precipitation maps,
• statewide precipitation rank maps,
• Cooperative station percent of normal precipitation maps,
• satellite-based observations of vegetative health,
• National Weather Service model calculations of
  • soil moisture,
  • runoff,
  • evaporation,
• National Weather Service model calculations of soil moisture using the Leaky Bucket Model,
• Midwest Regional Climate Center model calculations of soil moisture,
• percent of average maps for the SNOTEL stations in the western mountains provided by the Western Regional Climate Center
  • hydrologic year precipitation
  • snow water equivalent of snowpack,
• snow course snowpack observations in the western mountains provided by the USDA NRCS
• streamflow maps maintained by the USGS.

A detailed review of drought and moisture conditions is available for the following regions and states:

• Northwest region
• Southwest region
• Idaho
• Montana
• Oregon
• Washington
• Wyoming

• West North Central region
• Nebraska
• North Dakota
• South Dakota

• Southeast region
• Alabama
• Florida
• Georgia
• Maine
• North Carolina
• South Carolina

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Additional Contacts:

For additional information on current and past wildfire seasons please see the National Interagency Fire Center web site or the U.S. Forest Service Fire and Aviation web site.

NCDC's Drought Recovery Page shows the precipitation required to end or ameliorate droughts and the probability of receiving the required precipitation.

Additional climate monitoring graphics can be found at the Climate Prediction Center's monitoring pages:

• Weekly, Monthly, 3-Month, 12-Month Monitoring
• El Nino, Drought, Snow Cover, and Degree Day Monitoring
• Weekly Drought Monitoring
• Soil Moisture Monitoring

Precipitation and modeled soil moisture anomaly maps for the Midwest U.S. can be found at the Midwest Regional Climate Center's monitoring page.

Drought conditions on the Canadian prairies can be found at the Agriculture and Agri-Food Canada Drought Watch page.

• 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.info@noaa.gov
  
  
  
• For further information on the historical climate perspective presented in this report, contact:
  Richard Heim
  NOAA/National Climatic Data Center
  151 Patton Avenue
  Asheville, NC 28801-5001
  fax: 828-271-4328
  email: Richard.Heim@noaa.gov
  
  
  -or-
  
  
  Jay Lawrimore
  NOAA/National Climatic Data Center
  151 Patton Avenue
  Asheville, NC 28801-5001
  fax: 828-271-4328
  email: Jay.Lawrimore@noaa.gov