The Challenges and Complexities of Weather Forecasting, by
Weather forecasting is a complex and often challenging skill that
involves observing and processing vast amounts of data. Weather systems can range from small, short
lived thunderstorms only a few miles in diameter that last a couple hours to large scale rain and
snow storms up to a thousand miles in diameter and lasting for days.
Forecasting ultimately is a three step
process. These include:
When a forecaster comes on duty, their
first order of business is to become familiar with what is currently happening in the weather. This
includes looking at satellite imagery, surface data, precipitation reports, and getting a briefing
from other forecasters on duty. The next order of business is to project weather changes into the
future to derive a forecast. Short range forecasting, looking a few hours into the future, typically
depends on closely observing how weather systems are currently evolving and tracking, and projecting
their movement into the future based on what is understood about dynamics of the atmosphere.
Forecasts out beyond a day rely more on numerical weather modeling. Numerical forecast models
compile data from surface observations, weather balloons and satellite imagery to create a computer
generated simulation of the weather into the future. The model simulations use dynamic equations
that express how the atmosphere will respond to changes in temperature, pressure and humidity over
time. Forecasters deal with many forecast models that are run several times a day and must decide
which ones to rely on based on how well they seem to be handling current weather, how realistic
their output is, and how consistent the forecast models are being from one run to the next. The
forecaster may even decide that no model can be relied on at that time.
Once the forecasters have created a
forecast that they are reasonably confident in, their next role is to deliver that forecast in a way
that people can understand and appropriately respond to. The mission of the National Weather Service
is to communicate forecasts in a way that helps save lives and protect property. When the potential
exists for a weather event that may impact our forecast area, a weather watch will be issued such as
a winter storm watch, a high wind watch or a thunderstorm watch. When a watch is issued, those who
may be impacted are advised to stay closely tuned to updated forecasts for potential warnings. A
weather warning means the warned event is expected and people in the affected area should prepare.
National Weather Service warnings often include “call to action” statements which alert
the public on how to prepare for the expected weather.
Following a significant weather event,
forecasters will call weather spotters throughout their forecast area to ascertain the impact of a
weather event on the area. They will gather information on how much rain or snow fell, and if any
damage occurred due to weather. By reviewing the impact of an event, forecasters can learn how well
their forecast verified as well as what may have happened that was unexpected, and thereby be able
to improve on future forecasts.