The Lake Charles echo. [volume] (Lake Charles, Parish of Calcasieu, La.) 1876-1898, 1884-12-27
COLD WAVES.
How tEley Come South, and
why.


How tEhey Come South, am,
why.
New Orleans City Item:
A casual encounter with Assistan
Signal Observer Boyer developed SOM
facts which are of almost universal in
tercst, not to say Importance, in thi
section: ....s. ....-.. ...-.....
Item-Now, Mr., Boyer, we hear 50
much about the approach of colo
waves; can you explain that to usl
Mr.. B.-Certainly. The words cold
wave must be taken. in their litera
sense, for it is nothing less than ar
enormous cold, dry, atmospheric wave
which advances upon us from the
North during the winter months. ,.
ltem-You say that this wave sd
vances southwark. Can you give the
readers of the Item an explanation Of
the cause Of this7 '.1
Mr.. B.-The answer to that queS-
tion is rather difficult, as there ara
several theories sxtant which endeavor
to show the cause of this southeast
erly course Of cold waves. Certainly,
| have my own ideas upon the subject,
but do not wish to express them
here. .a
Item - How does the Weather
Bureau predict the approach of this
wave ....... ... .......
Mr.. B.-The chief Office at Wash
ington receives tri.daily reports from
stations extending throughout the
United States, and sven into Canada:
Upon the receipt of these reports "iso-
thermal lines" which are lines con-
Meeting all places of equal tempera-
ture, and "iIobaric lineI," which are
lines connecting places of equal ba-
rometric pressure, are drawn upon
maps. At mere glance these maps
will show The position of a cold wave
and all storm centres.
Item-What part in weather pre-
dieting does the terms high barome-
ter, or low pressure, take I
Mr.. B.-The terms areas of high
barometer and high pressure are syn.
onymous; as are also the terms low
barometer and low pressure, and |
may here state that they are the fac.
tors in all weather predictions.
Item-About how lSng does it take
a cold wave to reach New Orleans
from some given point in the North 7
Mr.. BIN predicting the rate of
speed Of cold wave the hight of the
barometer, or atmospheric pressure on
the different regions, must be taken
into consideration, Suppose, for in
stance, au area of high barometer
appears in the Northwest, the high
barometer being the result Of a cold
and dry atmosphere, At the same
time, along the Gulf States, the tenn
perature has been warm and the at
mosphere humid. Now we are all
cognizant of the fact that warm sir |
is much lighter than cold air and that |
humid air is lighter than dry one,
consequently the barometer falls in |
the Gulf States, which indicates de- |
preston in the atmosphere. The cold,
dry, high pressure area of the North
west rushes down upon us to till up |
this depression, causing our northers.
Suppose, on the other hand, our at
is unusually dry, and the
barometer considerably above the nor
NAL, 1t can be seen that the onward
course of the cold wave or high pres
sure area would be checked, Natur-
ally it would seek the path of least
and the pressure in the Gulf
States would be the means, perhaps, Of
DETECTING it by sending it more to the
eastward. .H ..
Item-But how about the given
points /
Mr.. B.-Please Wait. am Ceming
% that now, Let US take Bismarck,
OAK, as the given point in the North.
have found, upon going ever our
'scoTds and reports, that II averages
lb0ut three days from the time the
irst effects of the cold wave are felt
It Bismarck to the tims the first effects
lre felt in New Orleans. Here is an
Instance: The temperature at Bis
narck began to fall some time during
he morning of November 10. The
which then Stood at about
'0. 90 inches, began to rise very rapidly
Until the nth, when the msximum
leight was Teached-about 3e,57
nches--with the Temperature at II
1t New Orleans, on the morning Of
he 18th, the barometer was nearly
tationary, at 30.l4 inches. Six or
light hours after it began to fall, until
he morning of the 18th, when the
Vind suddenly shifted to the north,
by rain and q falling tenn
,erRture. t.
Item--Csn you give me any local
,remonitory signsl l.
Mr., B.-After the minimum Of .
old wave has passed us, the wind will
,e noticed TO yeer slowly around from
leFth TO east, the barometer falling
teadily while the temperature in
reases. The wind generally remains
tatiopary at the east or southeast
,oints, sometimes for several days.
Rains follow the Wind, Yhich then be
rims 10 move steadily towards the
oulb and southwest, a sudden shift
o the northwest and north brings US
mother northsr. II may be Of inter
st to kppw that at New 0Flsans the
Vinds most likely to bring rain are
rom east to south, while those from
ysst 10 north are the least likely to be
ollowed by rain.