724. 
that the front should remain inactive as far as cloudiness 
and precipitation are concerned. 
A glance at Fig. 4 shows that the cold high has moved 
from northwestern Montana to northeastern Kansas, 
in accordance with the steering indicated by the upper- 
level flow. 
It is the ease with which a truly comprehensive 
picture of the synoptic situation may be gained which 
commends the method of combined analysis presented 
here. With other methods the same results may, of 
1020 
10400 
0630Z OCTOBER 26,1949 
AAAAGOLD FRONT 
@aaeaWARM FRONT 
Oy-My STATIONARY FRONT 
aA A OCCLUDED FRONT 
AAA A GOLD FRONT ALOFT 
OBSERVATIONS AND ANALYSIS 
required to make two- or three-day forecasts need maps 
covering considerably more area of the earth’s surface 
than is needed for shorter-period forecasts. If this addi- 
tional area is achieved by increasing the size of the map, 
the map soon becomes so large that it is difficult to 
perceive the relationship between changes on opposite 
sides of the world. Such concepts as the spread of energy 
downstream from a newly formed storm or the creation 
of new troughs whose location is indicated by constant 
vorticity currents remain imaccessible to the synoptic 
310) 
/ > 1029 
Fic. 4—Combined sea-level and 700-mb analysis for the United States at 0630Z, October 26, 1949. 
course, be obtained in time. But the authors feel that the 
saving of time and energy effected by this method is of 
sufficient significance to warrant its inclusion in the 
standard operational procedure used for analysis. 
Before leaving the problem of how best to facilitate 
the comprehensive, three-dimensional visualization of a 
synoptic situation, one further point should be con- 
sidered: the total area of the meteorological map base 
being used must be so restricted in extent as to insure 
ease In superimposition together with ease in compre- 
hension. A map whose areal dimensions are greater than 
about three feet square is difficult to handle and is too 
large in scope to see all at once. Meteorologists who are 
meteorologist unless his working charts are small enough 
so that he can study a large area simultaneously. 
Although small-size, large-area maps are needed by 
the forecaster for predictions of two to three days or 
longer, the analyst who is responsible for a detailed 
analysis of a limited portion of the earth’s surface, or 
the forecaster concerned with a local forecast, usually 
needs a different map base. This latter base must have 
a scale large enough so that the data from all the ob- 
servational stations in the region may be conveniently 
represented on the map, since detailed data are neces- 
sary for the analyst to be able to locate pressure jumps, 
nascent waves on fronts, and poorly marked fronts. 
