PRACTICAL TRAINING EXERCISE
Once again you must make arrangements withyour supervisor, duty forecaster, or chief to com-plete this training exercise. This exercise takes from 1 to 2 hours to complete, depending upon the synoptic conditions affecting your ship or sta-tion. Additionally, you need 3 to 5 days worth of analyzed surface charts and access to current teletype data. Proceed as follows:
1. Take the most recent analyzed surfaceanalysis and locate all cold fronts, warm fronts, stationary fronts, and occluded frontal systems. Remember, each front represents the boundary between air masses of different properties. Discuss the air masses with the person helping you. Then, identify and label each air mass as to properties, source region, and direction of movement (tra-jectory). To get an accurate evaluation of the source region and direction of air mass movement, look back at the previous surface charts. The past positions and direction of movement of the fron-tal systems provide you with this information. From this, determine if the air mass is colder or warmer than the underlying surface and if any of the air masses have undergone modification. Label the air masses as k or w and modified as applicable.
2. With a knowledge of the trajectory andthermodynamics of the air masses, you can now determine their stability. Study the weather and types of clouds associated with the air masses and determine if the air masses are stable or unstable. Don’t be afraid to ask questions and seek help from the person helping you. No one expects you to be able to do this on your own—yet.
3. Look at each front again and compare theanalyzed fronts with the definitions for the various types of fronts. Try to visualize a cold front DISPLACING warm air, a warm front REPLACING colder air, the quasi-stationary front, and the occluded front in which the cold front has overtaken a warm front. Discuss the relationship of the fronts to their associated air masses. Try to visualize how the fronts slope.
4. Study the lows associated with the frontsand the movement of the fronts with and around the cyclonic centers. Look back on the charts to see if a wave cyclone has formed or dissipated along a slow-moving or stationary front. Deter-mine if the wave is stable or unstable. You should be able to find a wave cyclone that has developed along the front and has, over time, developed into a classic occluded cyclone. If not, have your chief or duty forecaster show or explain to you the com-plete cycle. He maybe able to find a chart series that shows this.
5. Have your chief or duty forecaster showyou the vertical structure, winds, and isotherms of the various fronts on upper air charts. Note the direction of wind flow and isotherm packing along the front that indicated the slope of the front and the intensity of the weather associated with each type of front. Locate a satellite photograph that depicts the cloud shields of the various types of fronts.
NOTE TO THE SUPERVISOR, DUTYFORECASTER, OR CHIEF: The trainee does not have knowledge of satellite analysis. It would be extremely helpful if you point out some signi-ficant feature on available satellite pictures, such as a bulge on a front indicating wave formation, cold slot associated with an occlusion, and other significant features.
6. Study the plotted weather on the surfacechart or aviation hourly for various stations ahead of, at, and behind all the fronts. Look for the following surface characteristics:
a. Wind shifts across the front
b. Pressure tendencies
c. Temperature changes
d. Dew-point changes
e. Clouds and weather at and behind thefront
f. Prefrontal weather and instability lines
Compare these conditions with past charts anddetermine if these fronts have undergone any modification. Pay special attention to those fronts that have recently moved onshore or offshore, those fronts that have just moved out of moun-tainous regions, and those fronts approaching large bodies of open water.
With the knowledge you have just gained fromthis exercise, you should be able to look at a sur-face chart with a new perspective, Don’t just glance at the chart in the future. Try to spend some time while on watch to really study the sur-face chart, its air masses, fronts, and cyclones.
Make an effort to keep abreast of previous andcurrent synoptic conditions. The more you know about these features and their history, the easier it will be to develop a forecast.
Aerographer’s Mate 3 and 2,NAVEDTRA 10363-E1, Naval Education and Training Pro-gram Development Center, Pensacola, Fla., 1976.
Aerographer’s Mate 1 and C,NAVEDTRA 10362-B, Naval Education and Training Program Development Center, Pensacola, Fla., 1974
Forecasting for the Mid-Latitudes,NAVEDTRA 40501, Naval Education and Training Sup-port Center, Pacific, San Diego, Ca., 1978.
Glossary of Meteorology,American Meteoro-logical Society, Boston, Mass., 1959.
Handbook of Meteorology,NAVEDTRA 50-110R-42, McGraw-Hill Book Company, Inc., N.Y., 1945.
Meteorology for Army Aviators,United States Army Aviation Center, Fort Rucker, Ala., 1981.
Petterssen, Sverre, Introduction to Meteorology, McGraw-Hill Book Company, Inc., N. Y., 1958.
The Use of the Skew T, Log P Diagram in Analysis and Forecasting, Department of the Air Force, 1979.
Willett, Hurd C., Descriptive Meteorology, NAVPER 50-1B-502, Academic Press, Inc., N. Y., 1952.