Basics of PredictionBasics of Prediction

Meteorology 415Meteorology 415

Fall 2012Fall 2012

Basics of PredictionBasics of Prediction

Remember the importance of the Remember the importance of the diurnal cyclediurnal cycle Temperature variation is dependent on:Temperature variation is dependent on:

Cloud cover, thicknessCloud cover, thickness Precipitation Precipitation Wind (mixing)Wind (mixing) Thermal advectionThermal advection

Boundary Layer Dynamics:Boundary Layer Dynamics: Thermal inertia - depthThermal inertia - depth Momentum – amount of transport and Momentum – amount of transport and

mixingmixing

Basics of PredictionBasics of Prediction

Fundamentals of temperature lag and how it varies with season (summer vs fall)

Basics of PredictionBasics of Prediction

Importance of diurnal variation based on elevation

Basics of PredictionBasics of Prediction

Wind speed is directly related to time of day – lowest speeds after sunset.

Basics of PredictionBasics of Prediction

The depth of the Planetary Boundary Layer is a function of day of year

Basics of PredictionBasics of Prediction

Diurnal tides due to thermal inertia

Basics of PredictionBasics of Prediction

The Effects of PBL depth are much broader than ‘the weather’

Basics of PredictionBasics of Prediction

The Nocturnal Low-Level Jet is related to diurnal variations forced by the surface

Basics of PredictionBasics of Prediction

MOS takes into consideration diurnal MOS takes into consideration diurnal cycles, so when advection trumps cycles, so when advection trumps the cycle (such as wintertime fronts)the cycle (such as wintertime fronts)…the guidance may only pick up on …the guidance may only pick up on part of the reversal in these cycles.part of the reversal in these cycles.

Remember that these cycles are Remember that these cycles are modified by elevation and time of the modified by elevation and time of the year – this will prove helpful when year – this will prove helpful when forecasting for Canada and/or Europe forecasting for Canada and/or Europe where there is no MOS.where there is no MOS.