Thunderstorm
Warnings for Ammunition Plants.-A
large number of munitions plants completed for processing high-explosive
materials in 1940-41, required protection from the weather, especially
thunderstorms. At the request of plant officials, the Weather Bureau
organized a Severe Storm-warning Service to issue advisories to plant
officials. During the approach of thunderstorms, such advices enabled
the plants to evacuate war workers so that they would be safe in the
event lightning struck, thus setting off high-explosive materials.
On the other hand, the information provided by the service permitted
employees to resume work as soon as the danger passed, thus keeping
the loss of man-hours of work to a minimum. The assurance of the workers
that plant officials and the Bureau were looking after their safety
during dangerous weather situations played a large part in maintaining
the employees' morale.
The severe
storm-warning plan was organized by recruiting observers stationed
at several points in all directions from ammunition plant. Reports
of thunderstorms approaching their vicinity were telephoned to a central
Weather Bureau station or to an office in the plant. Such reports
were then interpreted by meteorologists or designated plant officials
and advices issued to superintendents for use in evacuating civilian
workers to shelter.
Some
munitions plants were located in sparsely inhabited country where
it was impracticable to obtain sufficient observers to make reports
of approaching storms. In such cases, plant superintendents provided
trucks with short-wave radio communications facilities to patrol areas
in the vicinity of a plant to report the approach of thunderstorms
or the existence of other meteorological phenomena which might cause
hazards to operation.
The service
rendered proved so effective that by December 1942 forecasts, warnings,
and advices were being furnished to over 100 plants engaged in manufacturing
or storing ammunition and military supplies. By June 1945 nearly 200
storm-reporting networks were in operation and providing service to
about 327 Army and Navy air fields, training camps, and other military
installations, in addition to plant engaged in war production.
Considerable
research is being carried on in the use of radar equipment for detecting
the location, movement and intensity of thunderstorms, hurricanes
and other meteorological phenomena. The severe storm-warning service
being continued in peacetime may be reorganized eventually by the
installation of radar equipment at Weather Bureau offices, and in
plants where lightning is a hazard so as to provide the same service
as above described without the large number of reporting observers.
Special
Forecasts and Warnings for Military Purposes.-- In
1940, and continuing through the war years, the rapid growth of the
Defense Program and the mobilization for war beginning in 1941, required
unprecedented specialization in the issuance of weather forecasts
to serve military and domestic needs which far surpassed similar service
provided by the Weather Bureau in peacetime. Accordingly, priority
was given the issuance of special weather forecasts required by the
military forces.
In addition
to the usual weather and temperature forecasts, special forecasts
were prepared in detail and issued to include indications of quantitative
amounts of rain, snow, and sleet expected; the occurrence and intensity
of thunderstorms, hail and dust storms; estimates of direction, velocity,
and duration of winds, both surface and aloft; the expectancy, occurrence
and duration of fog and haze; limits of visibility; aloft, including
forecasts of degree days expected during the heating seasons, and
river stages and ice conditions on the Great lakes and other numerous
rivers of the United States to determine the opening and closing of
navigation seasons. In one case, the Army Air Forces asked for and
was furnished a special forecast giving the date when the Danube River
would become frozen at Budapest, Hungary. Storm, hurricane and flood
warnings were issued as heretofore but much expanded to assure greater
protection of lives and property, especially at military bases and
industrial plants engaged in the war effort.
These
special forecasts and warnings were furnished to Army ordnance plants,
Army and Navy flying fields; to the Army for carrying on large scale
maneuvers; to amphibious commands for training and reconnaissance
in detecting enemy submarines; to Army Engineers for use in the construction
of many types of military installations; to Army glider detachments
in training and maneuvers; to barrage-balloon and smoke detachments
engaged in training maneuvers; to port authorities for loading and
unloading in the dispatching of convoys; to Chemical Warfare units
for training and in conducting experiments; to interceptor commands
for defense purposes; to providing grounds and coast artillery units
for ballistic purposes; to research units engaged in the development
of new weapons of war; to the Army Air Forces to determine the arrival
of Japanese incendiary balloons on the west coast; to navy Frontier
commands and Army and Navy weather centrals and field offices in the
United States for planning various other types military operations
of strategic importance.
In addition,
military and civilian organizations received all storm, hurricane,
and flood warnings issued by the U. S. Weather Bureau for use in protecting
lives and property and moving strategic military equipment when necessary
before the approach of disastrous storms.
An interesting
example of a special forecast follows; in September 1942 the U. S.
navy assigned the airplane carrier USS Wolverine on Lake Michigan
to the training of Navy pilots. About a year later, the USS Sable
joined the USS Wolverine in this program. Weather service consisting
of flight forecasts, weather reports, storm warnings, and weather
summaries, was supplied to the Navy by the Chicago Forecast Center.
These data were turned over to the Navy after being placed in secret
cipher and delivered to the carriers by motorboat service supplied
by the Navy. Radio was also employed occasionally.
Should
such a service be required for a future emergency, the organization
for making it effective would probably be developed along similar
lines making use of any newly-developed communications facilities
and other technique.
Still
another special service was developed early in 1945 to assist the
United States Forest Service and the Western Defense Command with
forecasts and weather information to determine the expected arrival
and course of Japanese balloon-bombs in western pacific coastal areas.
These incendiary and anti-personnel bombs and balloons were released
in Japan in large numbers, and the Forest Service was faced with the
problem of protecting valuable national forest areas against fires
resulting therefrom. The Weather Bureau office at San Francisco prepared
daily forecasts of upper winds at various levels over the Pacific
Ocean and contiguous areas in the western states. A meteorological
cryptographic system was devised to furnish advices to Forest Service
officials at San Francisco, Seattle, and Boise for use in maintaining
daily watches for balloons. In addition, this same information served
the Western Defense Command in planning interceptor flights off the
west Coast.
River
Stages and Flood Forecasting.-Extensive, and in many cases,
record high floods occurred over large sections of the United States
during the war years. Accordingly, it was essential for the Weather
Bureau to strengthen its flood warning service for over 80 river district
forecast centers to protect vital industries, geared to war production,
from loss by floods.
To do
this task, the Weather Bureau, early in 1941, enlisted the cooperation
of the Army Engineers to supply data on the location of War plants
in operation as well as those under construction where potential flood
hazards existed. In addition, studies of flood expectancies were made,
and new river and rainfall stations were established to supply reports
from flood areas. It was on this basis that the flood forecast service
of the Weather Bureau was intensified and proved so effective that
forecasts and warnings were issued also for the protection of military
bases. Air fields, and for military maneuvers which involved the building
of pontoon bridges, and fording of streams by troops and mobile equipment.
The forecasts and warnings were telegraphed to the Army Weather Group
Headquarters for relay to their installations via Army communication
channels. Similar service was also provided to the Office of Defense
Transportation, War Production Board, War Food Administration, Corps
of Engineers, American Red Cross, American Waterways, and others in
addition to domestic interests and the general public.
Extended
Forecasts for Warfare.-At the outbreak of the war Weather
Bureau research and development was largely directed to the preparation
of advisory forecasts mostly for periods of five days in advance,
accompanied by research directed toward their improvement and to provide
forecast for as many days in advance as possible, for ocean and foreign
land areas as well as for the continental United States.
The research
activities were organized into three sections, the Extended Forecast
Section, the Special Forecast Section, and the Verification and Research
Section. The functions of the first two units were to develop techniques
for forecasting weather for periods up to five and six days in advance,
and to apply these techniques to the preparation of experimental advisory
forecasts for the United States and the Atlantic and pacific Ocean
areas on a regular, twice-weekly schedule. The Verification and Research
Section was organized to verify all forecasts and to conduct statistical
research in connection with improving extended forecasting methods.
It soon
became evident that investigations in extended forecasting would require
many more past years of Northern Hemisphere analyzed weather maps
than were available. Since these maps were needed also for other purposes,
a special project was initiated for the purpose of preparing a historical
series of well-analyzed maps for the Northern Hemisphere and for other
areas. This project is described elsewhere.
In addition
to the extended and long-range forecast investigations, cooperative
research projects were continued at universities on problems of special
importance to the war. In the early part of the war these projects
were not well coordinated with similar projects supported directly
by the Army or Navy, but joint support and direction of the research
was later provided by the three agencies working through the Joint
Meteorological Committee.
In cooperation
with the meteorological services of the Army and Navy and with university
meteorological departments, research in extended and long-range forecasting
was carried out along every line of attack that seemed to offer reasonable
opportunity for contribution. All long-range forecasting techniques
which had been proposed to the Bureau were examined. In many cases,
a quick survey of the proposed basis for forecasting was sufficient
to justify discarding it as a possibility for exploitation within
a reasonable time. Many of the methods thus discarded were unscientific
in the extreme. Some others could not be given tests adequate to demonstrate
conclusively their soundness or unsoundness, simple because of the
enormous processing of data that would be required. Principal emphasis
was placed by the Weather Bureau on the following six lines of attack,
with other lines of attack being investigated by the Army, Navy or
universities.
1.
The "General Circulation" Method of Forecasting.-Basic development
of this method of forecasting was begun in 1938 at the Massachusetts
Institute of Technology by a unit working in cooperation with the
Weather Bureau and the Bureau of Agricultural Economics of the Department
of Agriculture. In 1941, the unit was transferred to the Washington
office of the Weather Bureau, where its functions have been to prepare
extended forecasts for periods of six days in advance, and to carry
on research designed to improve these forecasts. In March 1942 experimental
work was begun on the extension of the forecast period to a month
in advance.
The forecasts
for five-day periods cover the elements of average temperature and
total precipitation for areas within the United States. In addition,
prognostic weather maps are prepared for each day of a six-day period,
covering the greater portion of the Northern Hemisphere. These forecasts
have been prepared twice weekly, and distributed to all Weather Bureau
forecast centers and to the Army and navy weather services. Many special
forecasts for practice maneuvers, special flights, and other special
operations were prepared at the request of the Army and Navy. In this
connection, Mr. J. Namias and Mr. K. E. Smith of the Section received
citations from navy Secretary Frank Knox for their work in forecasting
for the Allied invasion of North Africa.
The research
carried on by the Extended Forecast Section has included numerous
projects aimed at improvement of the forecasts. The forecasting procedure
calls for the preparation of prognostic mean-pressure maps for sea
level and the 10,000-foot level for the period three to seven days
in the future. Having given these prognostic maps and the most recent
daily observed map, estimates are made of the average temperature,
total precipitation, and other weather elements through the five-day
period. Thus the forecast consists of two steps, (a) preparation of
prognostic maps of the atmospheric circulation pattern and (b) interpretation
of these maps in terms of specific weather elements. Research has
been directed at improving the accuracy of both steps, and a member
of papers have been prepared on the results. These were furnished
to Army and Navy meteorologists who were working along similar lines
to develop extended forecasting procedures for operational purposes
in the various theaters of war. One of the most important papers,
"Methods of Extended Forecasting," by Mr. Jerome Namias, summarizes
in detail the method of preparing forecasts for six days in advance.
This paper was widely distributed to meteorologists of the Allied
Forces, and to universities in this country training meteorologists
for the Army and Navy.
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