Weather forecast for the medium term to seasonal

GET A WEATHER FORECAST FOR YOUR NEEDS

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It is customary to classify the weather forecasts for the geographical extent of the area and the time interval. The following table shows schematically the distinction commonly used for the description and prediction of the main atmospheric phenomena:

	time Scale	Type of prediction	Extension of the geographical area
spatial scale			microscala			mesoscala			macroscala
spatial scale – second level			gamma (less than 20 m)	beta (from 20 m to 200 m)	alfa (from 200 m to 2 km)	gamma (from 2 to 40 km)	beta (from 40 to 100 km)	alfa (from 100 to 300 km)	beta (from 300 to 10 thousand kilometers)	alfa (until 40 thousand kilometers of Earth's circumference)
Type of prediction			–	–	local	provincial	regional	national	synoptic or continental	planetary or global
time interval Extension	less than 1 min	unpredictable	turbulence, dust devils
	1 min – 1 h	nowcasting “short”		thermal currents	single-cell storms, tornado	atmospheric gravity waves
	1 – 6 hours	nowcasting “long”			local winds	urban heat island, multicell thunderstorms, supercelle	squall line, convective systems (MCS)
	6 hours – 5 days	short term				breezes	orographic disturbances, cloud systems	tides, large convective systems (MCS)	tropical storms, hurricane
	1 – 3 weeks	middle term							fronts, baroclinic waves	long waves Rossby
	1 – 2 months	long term							teleconnections	intraseasonal oscillations (MJO)
	2 – 12 months	seasonal							seasonal anomalies, monsoons, polar vortex	the ITCZ ​​shifts
	1-2 years	annual							ENSO	climatic fluctuations, QBO
	over 2 years	climate							ENSO, oceanic thermal oscillations (AMO, PDO)	climate changes

 

It is understood how the two scales, spatial and temporal, are correlated and therefore, using one, the other is also implicitly meant to describe and predict atmospheric phenomena.

To be noted as the difference between weather and climate is here expressed gradually through a series of steps, in which, from the description of the atmospheric state at a certain time and in a precise place (definition of weather) we pass to the evaluation of the distribution of meteorological events on a monthly, annual, twentieth or thirty year basis in homogeneous geographical areas (definition of climate).

It is evident the usefulness of the combined use of weather and climate concepts to frame the events underway within a historical-statistical framework, although in many (for example certain media misinformers and various gullible believers) we simply forget one of the two elements or worse still confuse them, so much so as to arrive at extrapolating climatic conclusions from meteorological phenomena and vice versa.

The weather forecasts of Lungimira go up to the following 6 months and thus they cover the typical time interval of the medium-term forecasts, long-term and seasonal. In line with what has been said, these forecasts are not so detailed like short-term ones, but they assume the decade (10 days) as the temporal unity and the atmospheric variables are expressed through statistical functions (mean, median, percentiles, etc.). It is an intermediate measure of the state of the atmosphere, between the restricted one of weather and the extended one of climate, useful for obtaining important information regarding a near future: it is like lighting a radar by flying in the clouds; we point our eyes on the screen instead of on the window; the screen is much smaller and less detailed than the view from the window, but tells us what comes to us. In this case the “radar” of Lungimira uses all the main variables and atmospheric indices available to form a picture of the processes in progress and compare it with the historical-statistical data. The result is expressed in probabilistic terms since, due to the well-known law of the chaos of Lorenz, although starting from rigid initial conditions (Cauchy condition), it is not possible to determine the future weather more than a few days with sufficient precision, but it is possible to quantify the probability of occurrence of the various types of possible weather.