Lesson 502 Numerical Weather Predictions

Question 1

List the two configurations of Global Environmental Multiscale (GEM) model.

Answer 1

Regional

Global

Question 2

What are the differences between the regional and global configurations? (3 each)

Answer 2

Regional: short term (up to 48 hours), twice daily (00 and 12Z), smaller resolution 15 km.
Global: long term (up to 144 hours), 12Z, larger resolution.

Question 3

Name the five different panels on the regional and global models.

Answer 3

850 hPa (0 hour only)
500 hPa (vorticity)
700 hPa (humidity)
MSL (thickness)
Thickness - precipitation

Question 4

List the two types of regional aviation GEMs.

Answer 4

Icing/turbulence

Clouds

Question 5

Name the content of the panels on the regional models.

Answer 5

Icing and freezing level in upper left
Momentum flux or surface stress in lower left
High level turbulence and tropopause height in upper right
Mid-level turbulence in lower right
CLOUD CHART: Ceiling

Question 6

What is the correlation between surface stress levels and turbulence?

Answer 6

0. 75 Pa - moderate mechanical turbulence
1. 50 Pa - severe mechanical turbulence
2. 00 Pa - extreme mechanical turbulence

Question 7

On high level turbulence and tropopause height charts, the correlation between the deformation vertical shear index (DVSI) and turbulence intensities are:

Answer 7

0-29 - no turbulence 
30-49 - light
50-149 - moderate
150-249 - severe
250 or more - extreme

Question 8

On the aviation regional ceiling chart, low clouds with opacity of _______ or more of the sky and a base of less than _______ ft are indicated with a ________ stippling and a thin _________ line.

Answer 8

6/10
6500 ft
Light
Dashed

Question 9

On the regional aviation ceiling chart, middle clouds with opacity of _______ or more of the sky and with a base between _______ and ________ ft above MSL are indicated with a ________ stippling and a thick line. Tops above 24000 ft are plotted as _____.

Answer 9

6/10
6500 and 24000 ft
Dark stippling
99

Question 10

FX messages are forecast discussions. What are the five types available to FSS?
OTEAM

Answer 10

Operational run status
Trenton forecast discussion 
Extended range forecast discussion 
American FX
Main weather discussion