NCDC: U.S. Regional Drought Watch

NCDC / Climate Mon. / Climate-2004 / Apr / U.S. Drought / Regional / Search / Help

Climate of 2004 - April
U.S. Regional Drought Watch

National Climatic Data Center, 13 May 2004

Global Analysis / Global Hazards / United States / U.S. Drought / National Drought Overview / Extremes
Use these links to access detailed analyses of Global and U.S. data.

Regional Drought Overview / Additional Contacts / Questions

Regional Overview

April was dry across much of the Far West, from the northern Rockies across the Great Plains to the southern Great Lakes, and in the Southeast. Above-normal precipitation across the southern and central Rockies and adjoining Plains states brought short-term drought relief to those areas. Much of Alaska was drier than normal, but wetter than normal conditions prevailed at the primary stations along the southern coastal band and the southern interior regions. The rainfall pattern in Hawaii was mixed. The primary stations in Puerto Rico were generally drier than normal, especially for the last 4 weeks, but the pattern was mixed at 8 weeks.

Click here for map showing Palmer Z Index

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Wet conditions during April in the Northeast and Southwest brought relief from recent (and long-term) dry spells in those areas. This month marked the second and third consecutive dry months, respectively, for the West and Northwest regions. April 2004 ranked as the 22nd and 25th driest April, respectively, in the 110-year record for the West North Central and East North Central regions. Six of the last seven months have averaged near to much drier than normal for the Southeast. This recent dryness, combined with the prolonged dryness that occurred from 1998-2002, has resulted in the reappearance in the Southeast of an area of drought based on the Palmer Drought Index (February, March, April).

This month's short-term dryness compounded the long-term moisture deficits (last 9 to 24 to 36 to 60 months) in many areas.

Click here for map showing Current Month Palmer Hydrological Drought Index

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Some regional highlights:

Several states had the tenth driest, or drier, month or season for:
- April (Indiana)
- February-April (Indiana, Maine, Washington)
- driest January-April (Maine)
- November-April (South Carolina)
- May-April (Idaho, Montana)
Soil moisture conditions:
- End-of-month soil moisture conditions were much drier than normal in the Southeast and parts of the Midwest and West, based on model computations.
- USDA topsoil moisture observations were dry to very dry (both observed and compared to recent climatologies) in states in the Southeast, New England, Great Lakes to northern Plains, and parts of the West.
According to early May USDA reports, more than 30 percent of the pasture and range land was in poor or very poor condition in the Rocky Mountain states and adjoining central and northern Plains states. Several other states had poor or very poor condition percentages that were higher than seasonal norms.
Hotter than normal temperatures and an early snowmelt season exacerbated drought conditions across much of the West.
- High elevation SNOTEL station reports and snow course observations reveal a much below-average mountain snowpack. Western streams and reservoirs depend on water from spring snowmelt.
- Reservoirs in most of the western states were still low or depleted.
- Streamflow levels were below seasonal norms, especially in the northern Rockies, both as computed by models and based on USGS observations.
- The percent area of the western U.S. (Rockies westward) experiencing moderate to extreme drought (as defined by the Palmer Drought Index) decreased slightly during April to about 61%. While this is not near record historical levels, it is still comparable to the major droughts of the 20th Century.

These overall conditions are evident in the following indicators:

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
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 conditions is available for the following regions and states:

Click here for map showing the nine U.S. standard regions

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Click here for graph showing Western U.S. Percent Area in Moderate to Extreme Drought

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Click here for map showing Percent of Normal Precipitation

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Additional Contacts:

Damage due to the drought has been summarized by NOAA and the Office of Global Programs in the Climatological Impacts section of the Climate Information Project. Crop impact information can be found at the USDA NASS (National Agricultural Statistics Service) and Weekly Weather and Crop Bulletin pages. Drought statements by local National Weather Service Offices can be found at the NWS Hydrologic Information Center. Drought threat assessments and other information can be found at NOAA's Drought Information Center. Additional drought information can be found at the National Drought Mitigation Center, the USDA's National Agricultural Library, the interim National Drought Council, and the NOAA Paleoclimatology Program. The following states have set up web pages detailing current drought conditions and/or their plans to handle drought emergencies:

Colorado - Delaware - Delaware River Basin (DE-NJ-NY-PA) - Florida Panhandle - Georgia - Hawaii - Idaho - Kentucky - Maine - Maryland - Missouri-1 - Missouri-2 - Montana-1 - Montana-2 - Nebraska - New Jersey-1 - New Jersey-2 - New Jersey-3 - New Mexico - North Carolina - Oklahoma-1 - Oklahoma-2 - Oklahoma-3 - Oregon - Pennsylvania-1 - Pennsylvania-2 - Pennsylvania-3 - South Carolina - Texas - Vermont - Virginia - Washington - Wyoming

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:

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

NCDC / Climate Mon. / Climate-2004 / Apr / U.S. Drought / Regional / Search / Help

http://www.ncdc.noaa.gov/oa/climate/research/2004/apr/drought-regional-overview.html
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Last Updated Tuesday, 29-Nov-2005 14:04:15 EST by Richard.Heim@noaa.gov
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