Extratropical Highlights –July
2019
1. Northern Hemisphere
The 500-hPa circulation during July
featured above-average heights over Alaska, the northeastern U.S., and
Greenland, and below-average heights over the central North Atlantic and western
Russia (Fig. E9).
The main land-surface temperature signals included above-average temperatures in
Alaska, the southwestern and eastern U.S., and southern Europe (Fig. E1). The
main precipitation signals included above-average totals in southern China, and
below-average totals in the northeastern and mid-Atlantic regions of the U.S. (Fig. E3).
a. North America
The 500-hPa circulation during July
featured above-average heights over Alaska and the northeastern U.S. (Fig. E9).
This pattern contributed to above-average surface temperatures in Alaska and in
the eastern U.S. (Fig. E1). Much of Alaska recorded temperatures in the
upper 90th percentile of occurrences.
Also during July, below-average
precipitation was recorded in the northeastern and mid-Atlantic regions of the
U.S. (Fig. E3).
Area-averaged totals in both regions were in the lowest 20th
percentile of occurrences (Fig. E5).
2. Southern Hemisphere
The 500-hPa height field during July
featured above-average heights over southern Australia, the central South
Pacific, the high latitudes of the South Atlantic, and the eastern Indian Ocean. It also featured below-average heights over
the high latitudes of the eastern South Pacific and in the area south of Africa
(Fig. E15).
In southern Australia, the above-average heights contributed to anomalously
warm (Fig. E1)
and dry (Fig. E3)
conditions, with many locations recording rainfall totals in the lower 30th
percentile of occurrences.