Water Supply Outlook for Alberta

May 2002

Fall Precipitation (September 1 to October 31, 2001)

Fall Precipitation was below-normal to much-below-normal in most areas of the province (Figure 1) with southern areas recording much-below-normal values (Figure 2). As a result of the low precipitation totals (Figure 3), soil moisture conditions remain very dry in most areas of the province. A map showing soil moisture conditions in the province is available from the Alberta Agriculture website located at:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/cl5882
 

April 2002 Precipitation

Precipitation was generally above-normal in the province during the month of April (Figure 4) with the exception of the extreme north and the southeastern corner, which recorded much-below-normal precipitation (Figure 5). Higher elevations recorded above-normal snowfall during April (Figure 6).
 

Winter Precipitation (November 1, 2001 to April 30, 2002)

Winter precipitation (November 1, 2001 to April 30, 2002) is near normal in most areas west of a Grande-Prairie-Whitecourt-Red Deer-Lethbridge line and below-normal in areas east of this line (Figure 7). Precipitation in April helped raise winter totals closer to normal values, particularly in southern Alberta (Figure 8). Areas along the eastern side of the province have received much-below-normal precipitation to date and the higher elevations in the mountains, which have recorded above-normal values (Figure 9).
 

Long-Lead Precipitation Outlook

Environment Canada's long-lead precipitation forecast issued on March 1 for the March to May period indicates above-normal precipitation in the entire province. The forecast for the summer period (June to August) is for above-normal precipitation in southern areas of Alberta and normal precipitation elsewhere. Environment Canada's long-lead precipitation outlook is available from their website located at:
http://weatheroffice.ec.gc.ca/saisons/index_e.html.

The National Oceanic and Atmospheric Administration (NOAA) is forecasting an equal chance of below-normal, normal or above-normal for the month of May. NOAA is forecasting below-normal precipitation for the southern portion of the province during the summer (June through August) period. NOAA's long-lead precipitation outlook is available from their website located at:
http://www.cpc.ncep.noaa.gov/products/predictions/90day/.

NOAA is forecasting that a warm event episode (El Nino) will likely develop in the tropical Pacific during the next few months. The significance of an El Nino event to the province of Alberta is that winter precipitation is typically below-normal during such events. The last major El Nino event occurred in the winter of 1997-98.


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