CHAPTER 2
FORECASTING UPPER AIR
SYSTEMS
To prepare surface and upper air prognostic charts,
we must first make predictions of the weather systems
for these charts. Inasmuch as the current surface and
upper air charts reveal the current state of the weather,
so should the prognostic charts accurately reveal the
future state of the weather.
Preparing upper air and surface prognostic charts
dictates that the Aerographer’s Mate first begin with the
upper levels and then translate the prognosis downward
to the surface. The two are so interrelated that
consideration of the elements on one should not be made
independently of the other.
Prognostic charts are constructed at the Fleet
Numerical Meteorology and Oceanography Center
(FNMOC). The resultant products are transmitted over
their respective facsimile networks.
Overseas Meteorology and Oceanography
(METOC) units also construct and transmit prognostic
charts. We are all too often inclined to take these
products at face value. Since these prognostic charts are
generally for large areas, this practice could lead to an
erroneous forecast.
It is important that you, the Aerographer’s Mate, not
only understand the methods by which prognostic charts
are constructed, but you should also understand their
limitations as well. In this chapter we will discuss some
of the more common methods and rules for forecasting
upper air features. In the following chapter, methods
and techniques for progging upper air charts will be
considered. These methods can be used in constructing
your own prognostic charts where data are not available
and/or to check on the prognostic charts made by other
sources.
Before you read this chapter, you may find it
beneficial to review the AG2 TRAMAN, NAVEDTRA
10370, volume 1,
analysis concepts.
unit 8, which discusses upper air
GENERAL PROGNOSTIC
CONSIDERATIONS
LEARNING OBJECTIVES: Evaluate features
on upper level charts, and be familiar with the
various meteorological products available to
the forecaster in preparing upper level
prognostic charts.
The forecaster must consider all applicable
forecasting rules, draw upon experience, and consult all
available objective aids to produce the best possible
forecast from available data.
Forecasters should examine all aspects of the
weather picture from both the surface and aloft before
issuing their forecasts. Some conditions are deemed
less important, while others are emphasized.
Forecasters must depend heavily upon their knowledge
and experience as similar conditions yield similar
consequences. Some forecasters may decide to discard
a parameter, such as surface pressure, because through
their experience, or the experience of others, they may
decide that it is not a decisive factor.
An objective system of forecasting certain
atmospheric parameters may often exceed the skill of an
experienced forecaster. However, the objective process
should not necessarily y take precedence over a subjective
method, but rather the two should be used together to
arrive at the most accurate forecast.
HAND DRAWN ANALYSIS
Methods and procedures used in the analysis of
upper air charts were covered in the AG2 TRAMAN,
volume 1.
Accurately drawn analyses provide the
forecaster with the most important tool in constructing
an upper air prognostic chart. Such information as
windspeed and direction, temperature, dew point
depression, and heights are readily available for the
forecaster to integrate into any objective method for
producing a prognostic chart.
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