UDC 551.506.1:551.513(73)"1973.03" I WEATHER AND CIRCULATION OF MARCH 1973 I Record Heavy Precipitation Over the Central and Southern Great Plains
(figs. 1-3). Much of the circulation change can be attributed to an eastward displacement from February to March of major wave components at midlatitudes around the Northern Hemisphere. The blocking High north of Siberia was one of the more important features of the March circulation. This High was...
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| Language: | English |
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1973
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.395.1633 http://docs.lib.noaa.gov/rescue/mwr/101/mwr-101-06-0540.pdf |
| Summary: | (figs. 1-3). Much of the circulation change can be attributed to an eastward displacement from February to March of major wave components at midlatitudes around the Northern Hemisphere. The blocking High north of Siberia was one of the more important features of the March circulation. This High was instrumental in driving cold arctic air southward along the Asiatic coast and out over the warm water of the western Pacific. As a result, the southern portion of the preexisting western Pacific trough strengthened and a Low developed in the Bering Sea. Amplification of the mean trough in the western Pacific was accompanied by the building of a strong midlatitude ridge over the eastcentral part of the ocean. The mean 700-mb circulation over North America during March 1973 was essentially reversed from that of February (Dickson 1973). A broad double-trough became entrenched over the southwestern and central United States as mean height departures fell sharply over the western half of North America in March. A blocking ridge was present over eastern North America during March, having replaced a mean trough that moved eastward into 540 / Vol. 101, No. 6 1 Monthly Weather Review FIQURE l.--Mean 700-mb contours in decameters (dam) for March 1973. FIGURE 2.-Departure from normal of mean 700-mb height in meters (m) for March 1973. FIGURE 4.-Mean 700-mb geostrophic wind speed (mls) for March 1973. Solid arrows show the observed axes of maximum wind speed, and dashed lines show the normal. FIQURE 5.-Departure from normal of average surface temperature |
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