Extratropical Highlights –June 2019

 

1. Northern Hemisphere

The 500-hPa circulation during June featured above-average heights over Alaska, the high latitudes of the North Atlantic, and eastern Europe, and below-average heights over the central North Pacific, the eastern North Atlantic, and central Russia (Fig. E9).

The main land-surface temperature signals included above-average temperatures in Alaska and much of Europe, with most areas recording departures in the upper 90^th percentile of occurrences (Fig. E1). The main precipitation signals included above-average totals in the central and eastern U.S., and below-average totals in central and eastern Europe (Fig. E3).

 

a. North America

The 500-hPa circulation during June featured above-average heights over the eastern North Pacific and Alaska U.S., and below-average heights over southeastern Canada (Fig. E9). This pattern was associated with a broad trough across the continental U.S., as indicated in both the 200-hPa wind (Fig. T21) and streamfunction (Fig. T22) fields. This trough contributed to above-average precipitation across the central and eastern U.S., with many locations recording totals in the upper 90^th percentile of occurrences (Fig. E3). It also contributed to several severe storm outbreaks across the central and southern U.S.

 

b. North Atlantic and Europe

The 500-hPa height pattern during June featured above-average heights over the high latitudes of the North Atlantic and eastern Europe, and below-average heights over the eastern North Atlantic (Fig. E9). This pattern contributed to well above-average surface temperatures in most of Europe, with many areas recording departures in the upper 90^th percentile of occurrences (Fig. E1). It also contributed to well below-average precipitation in central and eastern Europe, with some areas recording totals in the lowest 10^th percentile of occurrences (Fig. E3).

 

2. Southern Hemisphere

The 500-hPa height field during June featured above-average heights over eastern Australia, the central South Pacific, eastern South America, and the eastern Indian Ocean, and below-average heights over Antarctica (Fig. E15). This pattern contributed to well above-average surface temperatures in both southeastern South America and South Africa, with many locations recording departures in the upper 90^th percentile of occurrences (Fig. E1).