Skip Navigation Links 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center

HOME > Expert Assessments > Climate Diagnostics Bulletin


Extratropical Highlights - May 2001

1. Northern Hemisphere
The Northern Hemisphere circulation featured several persistent anomalies during May (Figs. E10, E12, E13), including above-average heights at 500-hPa over the northern and eastern North Pacific, eastern Canada, and the eastern North Atlantic, and below-average heights over Alaska, the central North Atlantic and western Russia. Over North America the anomalous circulation contributed to significantly above-average surface temperatures over the western United States and eastern Canada, and to below-average temperatures across Alaska (Fig. E1). Above-average surface temperatures were also observed over much of Europe and central Russia during the month. The anomalous circulation also contributed to a continuation of below-average rainfall and excessive long-term rainfall deficits across Florida and portions of the Gulf Coast (Fig. E3, E5). Elsewhere, above-average rains were recorded during May in southern China, southeastern Asia, and western Russia (Figs. E3, E4).

2. Southern Hemisphere

The primary Southern Hemisphere surface anomaly during May reflected significantly below-average rainfall across the eastern half of Australia, with totals in many locations dropping below the 10th percentile (Fig. E3, bottom). This dryness was partly associated with anomalous upper-level convergence (Fig. T23) and sinking motion in the region upstream of the mean midlatitude trough (Fig. E16), which was situated along the east coast of the continent and spanned both the middle and subtropical latitudes. The dryness in northeastern Australia (Fig. E4) was also associated with an overall northward shift in the primary region of tropical convection to well north of the continent (Fig. T25).

NOAA/ National Weather Service
NOAA Center for Weather and Climate Prediction
Climate Prediction Center
5830 University Research Court
College Park, Maryland 20740
Page Author: Climate Prediction Center Internet Team
Page last modified: August 24, 2007
Information Quality
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities