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Welcome to the Dynamic Weather Forecaster

Introduction

Weather forecasting is commonly used in introductory college meteorology instruction to engage students in analyzing meteorological data. The educational challenge is to model a learning tool on the scientific foundation used in professional forecasting, including parameters that give a complete view of the weather beyond high and low temperature and chance of precipitation. The use of the Dynamic Weather Forecaster (DWF) minimizes technical challenges for instructors and students while significantly improving learning. The forecasting behavior of 201 students enrolled in an introductory meteorology course at Iowa State University in spring 2008 shows that DWF results are a reliable predictor of the students' performance in exams and in the overall course. Developed as an open-source application, the Dynamic Weather Forecaster (DWF) is administered through a server on the Iowa State University campus.

The DWF currently works with U.S. weather data supplied by Unidata. It could be altered to work globally since Unidata also supplies data from around the world, but questions about fronts would have to be eliminated since these data are not available outside the U.S. In addition, some modifications would be needed to allow users to choose times other than 12z and 18z to correspond with local sunrise and noon.

Purpose

The Dynamic Weather Forecaster exercise is open, free and available to any instructor who would like to have their class forecast the weather using the same tools and parameters used by scientists.

The instructor enrolls the students in a DWF class and creates the dynamic forecast including the duration of the assignment (e.g., one semester). Students submit their forecast for the weather for the next day, and each submission is automatically closed at midnight local time. The supplied assignment consists of 13 questions but can be modified to meet local needs. The student first selects the 4-letter International Civil Aviation Organization identifier for the weather station for which the forecast is done; this code determines which data will be used to score the forecast. Students are asked to forecast the 12 UTC (Coordinated Universal Time or Zulu) and 18 UTC temperature; the potential of clouds, fronts, and advection to affect temperature; wind speed and direction; and three main precipitation factors (moisture content, frontal position, instability). Detailed explanations, a glossary, and forecasting tips are hyperlinked to each question.

Objective techniques have been developed to allow automated verification of the 13 questions using a real-time weather data feed supplied to Iowa State University by University Corporation for Atmospheric Research's Unidata program. Partial credit is given for each incorrect question answered (1/3 points); full credit (max. 36 points) is given for temperature values ±5F, wind speed ±5 knots, wind direction within 90 degrees of the actual direction, and frontal positions within 140 miles of the reporting station. Any direction is validated as correct when there is no wind. The effect of clouds on the 12Z and 18Z is evaluated based on the percentage of cloud cover for the six hours preceding 12Z and four hours preceding 18Z. A cloud coverage of at least 75% will affect the 12Z (nighttime) temperature during the six hours preceding it by inhibiting radiational loss. A cloud coverage of at least 75% during the four hours preceding 18Z, when radiational heating is more intense, will affect 18Z temperatures. No points are given for the station code (item 1).  The scoring scheme may be modified as well.

Getting Started

On-campus users may create the exercise through the iState portal. Off-campus users need to have a class created for them by an on-campus user.  Follow the links below for instructions.

Managing your class (on-campus users)
Managing your class (off-campus users)

For students: after you have logged in, select Assignments from the Options tab. The Forecasting assignment will appear in the next page. Click on the hyperlink to get started. If your instructor has selected to also use the Archive Forecasts set that are available through the DWF portal, links to these sets will also appear under the Forecasting link.

Forecasting the Weather

The assignment consists of the following 13 items:

Item 1

Enter the station code for the site for which you will be forecasting.

Item 2

Questions 2-5 all refer to conditions expected at 12z.

What will be the 12Z temperature (°F) tomorrow?

Item 3

Cloud cover to inhibit radiational cooling tonight will:

be significant
not be significant

Item 4

A frontal passage by 12Z tomorrow may also affect the temperature. I predict there will have been the passage of (within about 140 miles of the reporting station):

a warm front
a cold front
an occluded front
a stationary front
no front

Item 5

Advection may also change temperature. I predict 12Z temperature change will:

be affected by warm air advection.
be affected by cold air advection.
not be significantly affected by advection.

Item 6

Questions 6-11 all refer to conditions expected at 18z.

What will be the 18Z temperature (°F) tomorrow?

Item 7

For 18Z tomorrow, I predict cloudiness will:

hold down the daytime temperature.
not affect the daytime temperature.

Item 8

A frontal passage by 18Z tomorrow may also affect the temperature. I predict there will have been the passage of (within about 140 miles of the reporting station):

a warm front
a cold front
an occluded front
a stationary front
no front

Item 9

Advection may also change temperature. I predict 18Z temperature change will:

be affected by warm air advection.
be affected by cold air advection.
not be significantly affected by advection.

Item 10

Enter the expected wind speed at 18Z (knots)

Item 11

Select wind direction at 18Z

N
NE
E
SE
S
SW
W
NW

Item 12

Will there be precipitation between 12Z tomorrow and 12Z the next day?

Yes
No

Item 13

The following factors will favor precipitation between 12Z tomorrow and 12Z the next day.
Marking the box means YES. It is possible to have any combination including all NOs.

Moisture Supply
Frontal Position
Unstable Atmosphere