Exercise 4A – Ground Truth the Official Grids, Assess
Guidance Trends and set a Forecast Policy
Objectives
1.
Compare the Temperature, Dewpoint Temperature and Wind forecast grids with the latest
surface observations.
2.
Show latest model guidance and view fire weather forecast parameters.
3.
Use DifferenceGrids to assess guidance trends.
4.
Set a (rough) forecast policy.
5.
For each parameter, decide if the Official Grids or the latest standard guidance is the best
starting point for a time period.
Overview
In Exercise 4A you will ground truth the near-term official Fcst Grids relating to fire weather. You
will also assess the guidance trends relating to fire weather in order to make a decision on whether
to keep the current Fcst Grids or load new model guidance. In the forecast office the policy
decisions and grid editing strategies will be completed in consultation with the other forecasters.
Preliminary
Open GFE in Practice Mode, and ensure you are in the Weather Element Group called Fire
Danger. These instructions are based on GFE version 3.14.
The Exercise
Step 1 – Ground truth the Temperature, Dewpoint Temperature and Wind Grids
You can use the following techniques:
•
DifferenceGrids [[FF33]] (between Fcst and Obs) for Temperature and Dewpoint
•
Overlaying Wind Grids
•
Comparing Official Grids with observations in IDV and/or AIFS Applications
(This is only for real time situations as the data is not available for the Case Studies)
Are the Official Grids close enough to reality or do we need a forecast update?
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Step 2 – Show latest model guidance and assess fire weather forecast parameters
Task:
•
Change weather element groups to view different parameters and the relevant guidance (e.g.
Wind and Temperature groups)
•
If some guidance is not available, load it using ShowGuidance [[FF22]]
•
View the guidance by selecting the grids below the blue line in the Grid Manager
•
Use IDV, Kenny or web interfaces, if available, to view other fire weather data
How do the fire weather parameters from the different models
compare? Are you confident about the forecast for this event?
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Step 3 – Assess guidance trends
A useful method for assessing guidance trends is the DifferenceGrids procedure [[FF33]], which you
will be familiar with from earlier stages of training.
Task:
•
Create some Difference Grids for Temperature and Dewpoint Temperature (and Wind
magnitude if suitable) then view the Grids to assess how the guidance has changed from run to
run
•
To compare wind fields from different model runs, use ShowGuidance to display the runs
and overlay the fields you wish to compare.
Now that you have looked at the official Fcst grids, latest model data and the guidance trends in
detail you can make a rough forecast policy map and decide whether the Official grids or the latest
guidance is the best starting point for your forecast.
You may wish to load the latest model guidance for Wind, Temperature or Dewpoint Temperature
for a particular time period. Details of how to do this are contained in Step 4.
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Step 4 – If required, load the latest model guidance
Use the Populate Copy Selected Grids From procedure
Task:
•
Select the Temperature, Dewpoint Temperature and Wind grids as appropriate for desired
time periods
Note: in the new GUI, select multiple weather elements in the Grid Manger by Ctrl + Left
Click on required weather elements. In the old GUI, multiple weather elements are selected by
clicking on the box beside the weather element name in the grid manager.
•
From the Populate menu select Copy Selected Grids From
•
Click on Run/Dismiss
Note: You may need to use DeleteByInterval [[FF66]] (or via the Edit menu) to ensure that your
guidance grids have the correct validity period
Additional Information/Resources
•
Smart Tool Documentation
Checklist
•
Compare the Temperature, Dewpoint Temperature and Wind grids with the latest observations.
•
Show latest model guidance and assess fire weather forecast parameters (Wind, Temperature
and Dewpoint Temperature).
•
Use DifferenceGrids to look at guidance trends.
•
Set a (rough) forecast policy
•
For each parameter, decide if the Official Grids or the latest standard guidance is the best
starting point for a time period.
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