Basics of Prediction Meteorology 415 Fall 2012

Basics of Prediction Remember the importance of the diurnal cycle Remember the importance of the diurnal cycle Temperature variation is dependent on: Temperature variation is dependent on: Cloud cover, thickness Cloud cover, thickness Precipitation Precipitation Wind (mixing) Wind (mixing) Thermal advection Thermal advection Boundary Layer Dynamics: Boundary Layer Dynamics: Thermal inertia - depth Thermal inertia - depth Momentum – amount of transport and mixing Momentum – amount of transport and mixing

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

Basics of Prediction Importance of diurnal variation based on elevation

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

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

Basics of Prediction Diurnal tides due to thermal inertia

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

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

Basics of Prediction MOS takes into consideration diurnal cycles, so when advection trumps the cycle (such as wintertime fronts)…the guidance may only pick up on part of the reversal in these cycles. MOS takes into consideration diurnal cycles, so when advection trumps the cycle (such as wintertime fronts)…the guidance may only pick up on part of the reversal in these cycles. Remember that these cycles are modified by elevation and time of the year – this will prove helpful when forecasting for Canada and/or Europe where there is no MOS. Remember that these cycles are modified by elevation and time of the year – this will prove helpful when forecasting for Canada and/or Europe where there is no MOS.