DataStreme Activity 10B:

CYCLONE TRACK WEATHER

Do Now:

  1. Print this file.
  2. Print the Wednesday Image 1 and Image 2 Files.
  3. Print (when available) the Thursday, 16 November 2000, Daily Summary File.

To Do Activity:

  1. Read Chapter 10 in STUDY GUIDE, Part A: Narrative.
  2. Go to STUDY GUIDE, Part B: Applications. Start Activity 10B.
  3. Return here (Wednesday Activity B File) when told to do so.

Go To STUDY GUIDE - Activity 10B Now


WELCOME BACK: Procedure continued from STUDY GUIDE.

  1. This week's first activity, Activity 10A, showed a surface map defining a weather system in the upper Midwest with a cold front trailing to the Gulf of Mexico. That system slowly moved eastward finally providing only lingering effects to northern New England. Today's Activity 10B continues with the motion of that storm and the origins of the next system to affect the central US. We then look ahead to the future with a map of forecast conditions.

    Refer back to the Image 1 map of Activity 10A (12Z 13 NOV 2000). At that time the center of the storm circulation was located in [(Oklahoma-Kansas) (Minnesota-Wisconsin)].

  2. Image 1 of this Activity 10B is the surface map for 12Z 15 NOV 2000, 48 hours following the surface map of Activity A. On this Activity 10B Image 1 the remnants of the storm were located in New England with a low-pressure center. Compare the position of the storm center as marked by the Maine Low at 12Z 15 NOV with that of the Low center denoted in question 10, 48 hours previously. The low-pressure center had generally moved toward the [(east) (south)].

    The cold air mass affecting the eastern US was marked by a high-pressure center located near [(Illinois) (Mississippi)]. The eastward leading edge of the cold air mass at map time was shown by a [(warm) (cold)] front stretching from the Low across the Atlantic to just south of Florida. Precipitation lingered [(around) (far to the south of)] the low-pressure center in Maine. Lake-effect precipitation resulting from cold air flowing over relatively warm water can be seen to the south and east shores of Lakes Erie and Ontario.

  3. Three additional significant low-pressure systems are shown on the 12Z 15 NOV 2000 map. One storm is approaching the Northwest Pacific coast, another is found in south central Canada, and one is located in southeastern Colorado. The Colorado Low is expected to develop into the next system to affect the central US. The central pressure was dropping rapidly, 12 mb in the 12 hours prior to map time. The projected track of this storm is northeast with the trailing cold front separating cold air from the already cool air in the eastern US. The circulation between the High and the Low across northern Texas, Oklahoma and Kansas was generally from the [(north) (south)]. Comparing temperatures in Oklahoma to those further north suggests that this flow would produce [(cold) (warm)] air advection in that region.

  4. Image 2 is a DataStreme forecast map. It is a sample of the kinds of maps available in the "Forecasts" section of the DataStreme Homepage. These forecast conditions at stations across the country are produced by a computer model of the atmosphere using mathematical equations of the physical laws applying to fluid motions, starting from the observed conditions at a given time. This particular numerical weather prediction model producing the forecast shown is the Nested Grid Model (NGM), so named for the mathematical scheme used in the calculations.

    This forecast map was delivered on the DataStreme homepage as a "36 Hour" map, meaning it was a projection of weather conditions 36 hours into the future. The "Valid" time, shown on the printed map's upper left corner, is when these conditions are expected to exist. The Valid time of the map is 12Z 16 NOV 2000, consequently, the forecast would have been based on actual observations at [(00) (12)] Z on 15 NOV 2000.

  5. The forecast data for each station are presented in a "forecast station model" that is explained in the Homepage User's Guide, found in the Extras section on the DataStreme Homepage. The forecast conditions for the valid time of 12Z 16 NOV 2000 at Nashville, Tennessee (in central TN) were:


  6. Although weather systems are not shown on forecast maps, utilizing the hand-twist model and observing the wind directions, weather features may be approximately located. Winds having a general direction from the southeast are predicted across the Great Lakes. Winds having directions from the northwest are predicted across the Dakotas. Based on this circulation pattern, the low-pressure center was forecast to be located near [(northern Wisconsin) (eastern North Dakota)]. The weather symbols show that there is a good chance of [(freezing rain) (thunderstorms)] across Minnesota.

  7. The wind directions can also be used to anticipate the location of the cold front. Southerly winds and warm air advection are expected ahead of the cold front while northerly or westerly winds and cold air advection are expected behind the cold front. Based on these wind directions and their change across a narrow zone, the cold front is expected to stretch from [(Michigan to Alabama) (Wisconsin to Texas)].

  8. The lines on the forecast maps are isotherms. The weather symbol for freezing rain occurs where forecasted temperatures are generally [(below) (above)] 30 °F. The weather symbols for rain or thunderstorms occur where forecasted temperatures are [(below) (above)] 30 °F.

DataStreme forecast maps can be used to anticipate weather conditions in your area. Actual forecasts issued by the National Weather Service are produced by meteorologists beginning with this computer guidance material. Have students compare the forecast weather conditions for your location with those that actually occur at the forecast "valid time". You might also compare the DataStreme forecasts to those delivered by your NOAA Weather Radio station and local radio and television stations or newspapers. (Generally, weather forecasts appearing in newspapers are the least accurate due to the long lead time needed to meet their publication deadlines.)


Faxing Instructions:

After completing this week's applications, fax the following pages to your LIT mentor by Monday, 20 November 2000:

  1. Chapter 10 Progress Response Form,
  2. 10A and 10B Activity Response Form,
  3. STUDY GUIDE, Part B: Applications, page 10B-3.

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URL: datastreme/learn/b_act.html
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