Understanding Local Diurnal Winds Sea Breezes and Land
Understanding Local Diurnal Winds • Sea Breezes and Land Breezes dependent on the differences in heating and cooling between land water. • Upslope and downslope winds forced by the differences in heating and cooling between terrain and lowlands.
Sea and Land Breezes
Return Flow
Return Flow
Sea Breeze Front: leading edge of cooler air
Can See the Influence of Sea and Land Breezes on Clouds
Washington Coast Sea Breeze Front
Colliding Sea Breezes Can Produce Strong Upward Motion
Fig. 7 -7, p. 176
Sea Breeze Winds Along the Southern Oregon Coast • Gusts frequently reach 30 -35 knots during the summer during the afternoon. • Very painful to stay on the beach! • Strong pressure gradient normal to the coast between the warm land areas and the cold upwelling water.
2 -minute average July-August winds along the Northwest coast.
Southern Oregon Coast Near Brookings
Summer Diurnal Winds
The Sound Breeze Viewed Using Ferry Data
Picture take in Sequim looking N Strong Regional Sea Breeze Winds During the Summer
Land Breezes Tend to Be Weak in the Northwest • Why? Because the land rarely cools down more than the water. • Local minimum temperatures generally in the low to mid-50 s…similar to the temperature of the Sound and the Pacific Ocean. • But it can happen in winter during unusually cold periods.
Land Breeze example during a cold period.
Slope Winds
Slope Winds Upslope Flow on Heated Slopes Downslope Flow on Cooled Slopes
Low temperatures are generally cooler in low spots on cold, cloud-free nights.
Eastern Washington Slope flows
Fig. 7 -11, p. 178
rm a W L L Valley breeze W arm C l oo H H Co ol Mountain breeze Editable Text Fig. 7 -11, p. 178
Fig. 7 -12, p. 179
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