There are many various
types of
WEAHTER FORECAST; short-
term, mid- term, long- term; subjective and objective. They are available
on many different web pages but they are also of different qualities.
DHMZ web pages give you possibility of everyday weather "tracking", not
only of those subjective forecasts given by meteorologists for today
and tomorrow for Croatia (esp. Zagreb and the Adriatic), but also of those
objective computer made 7- days weather forecasts for Croatian cities
and worldwide.
Subjective
weather forecasts are written every day by our meteorologists, whose knowledge
is based not only on prognostic material but also on their experience.
They are the ones to decide on various weather symbols to be put on different
locations, on certain days.
Computer
weather forecast is a direct result of a prognostic model.
Weather symbols are specified from the forecast of cloudiness, type and
amount of precipitation on a certain day. If snow or rain symbol appears
it doesn´t mean that it will rain or snow all day long, only a part of
it. Mean cloudiness and precipitation is calculated from four successive
prognostic 6- hour terms (6, 12, 18 and 00 UTC). Maximum and minimum temperatures
are also direct model output, with no corrections from meteorologists.
Up- to- date analysis of weather forecast achievements showed that the
model temperature differs form its real value more than the official value
given by meteorologists (which has its reasons). Therefore those 7- days
forecasts can be taken only as time trend, ie. as the indicator for days
when colder or warmer weather than the average is expected, as well
as extreme precipitation. Also one mustn't forget that the longer the time
period, the less accurate the weather forecast.