(Gladys) Szeman Lam

Alexander Serebreny

Metr356

10/1/04

 

Notes For October 1st 2004

 

Assignments

Midterm: October 11

Bring Scantron Form #882 and Number 2 Pencil

Midterm is 50 questions, mutliple choice, covers material from beginning of semester

Only material discussed in class is covered

May include:

      Interpreting Weather Maps
      High/Low Pressure
      Fog

Guest Instructor Week of 10 October
Elizabeth Frieberg, MS in Applied Geosciences Candidate

Class meets Monday 4 October and Friday 8 October (no class Wednesday)

Attendence at these class sections will be mandatory

Subject matter: In-class Exercises Relating To Summer Pressure, Wind and Cloud Patterns -- Advection Fog

Subject matter for these sessions fair game for midterm

Sea Level Pressure

            -Looking at the high and low pressure of the wind

            -Wind speed greater than 20 kts

                        -On the map, shows in blue that the wind speed is greater than 10

            - Locally the air goes from areas of high pressure to low pressure

Temperature Pattern

- Warm air coming from subtropics

- Cold air coming from Canada

Dew Point Temperature

            -Temperatures are so low, that they canÕt generate thunderstorms

- A tongue of higher dew points is advancing into the Northern Great Plains from the South.

Fronts

            -The map shows the cold and the stationary front

-The curvy front in the northern U.S. is there because the mountains there are holding the front

            -ItÕs much warmer in the lower south part the U.S.

            -The North American Thermal Low is associated with warm temperatures at the

               ground.

Satelite over U.S.

            -The invert satellite shows clouds (thunderstorms)

            -The infrared satellite shows fog off the coast

Winds

            -At the surface most winds are 5-30 mph

            -At about 40,000 feet up (300mb level) winds exceed 70 knots.

            -Winds are much faster at the upper part of the lower atmosphere.

            -The winds are also at a different direction

Clouds and wind at different elevations in the Summer

-Fog is a reproducible part of our summer pattern every year

-ÒAdvection FogÓ is a feature of our climate

-Within 200m elevation shows the depth of the fog layer from the visible satellite image (on 8/14/97)

            -The fog is still outlined on the coast from the satellite image

            -The map shows Salinas valley filled with fog.

            -The Berkeley and Oakland hills are taller then the fog on this day.

            -The upper layer of the stratus cloud (fog) is called Marine Layer

-Some cirrus clouds over the Bay Area can be traced back to thunderstorms that formed over the mountains in the Sierra.

Cross-section of winds
            -As the map shows, most of the winds are blown in from the ocean

-This air starts off from warmer temperatures and higher pressure and is pulled towards areas of lower pressure.

North American Ocean

-The ocean temperature near the western U.S. and around the Bay are pretty much cold

            -Besides the current, the cold temperatures at the coast are due to upwelling. 

Homework Discussion

            -Must be written to 3 pages

            -Graphics are not counted part of the pages

            -See website for more information: http://tornado.sfsu.edu/geosciences/classes/m356/Writing_Assignments/Writing_Assignment1_F04.htm