Numerical weather predictions

Question 1

What are the 2 configurations of the Global environmental multiscale model?

Answer 1

Regional

global

Question 2

What are the differences between the 2 configurations?

Answer 2

Forecast duration:48 hrs regional, 120 hrs global

Resolution: Regional uses a smaller resolution

Question 3

what are the different charts displayed in the 4 panel global and regional models?

Answer 3

• 500 hpa vorticity
• 850hpa (0 hour only)
• 700 hpa (humidity)
• MSL (thickness)
• Quantative Precipitation forecast (from +12H)

Question 4

How many times daily are they prepared and based on which data?

Answer 4

twice daily, based on the 0000z and 1200z data

Question 5

What does the 850hpa chart depict?

Answer 5

Isotherms at 5 degree intervals, and a phase change zone between -2.5 and 2.5 degrees. temperature maxima and minima are denoted by + and -

Question 6

What does the 500hpa chart depict?

Answer 6

isopleths of absolute vorticity, vorticity maxima and minima are denoted by + and -

Question 7

what does the 700hpa (humidity) chart depict?

Answer 7

• isopleths of average relative humidity

- areas with relative humidity of 70% or more are lightly stipled and over 90% are heavily stipled

Question 8

what does the MSL (thickness) chart depict?

Answer 8

-1000-500 hpa thickness isopleths

Question 9

what does the QPF chart depict?

Answer 9

• isohyets represent 1,5,10,25,50,100 mm accumulations

- they are the accumulations forecast during the preceeding 12 hours

Question 10

List the 2 types of regional aviation models

Answer 10

• Icing/Turbulence

- clouds

Question 11

What 4 charts are shown on the icing/turbulence models?

Answer 11

• Icing and freezing level
• Momentum flux
• High level turbulence and trop height
• Mid level turbulence

Question 12

What is shown on the cloud charts

Answer 12

ceiling

Question 13

When are the regional aviation model icing/turbulence charts issued?

Answer 13

based on 0000z and 1200z data and valid for Hr+6,+12,+18,+24

Question 14

What does the icing and freezing level chart depict?

Answer 14

Freezing level and supercooled water

Question 15

What does the momentum flux chart depict?

Answer 15

isopleths of surface stress, with a correlation of:
.75 = moderate turbulence
1.5 = severe turbulence
3.0 = extreme turbulence

Question 16

What does the high level turbulence and trop chart depict?

Answer 16

• Tropopause heights

- isopleths of maximum deformation vertical shear index from 400hpa to 200hpa

Question 17

What does the mid level turbulence depict?

Answer 17

-Isopleths of maximum deformation vertical shear index from 700hpa to 400hpa

Question 18

What does the ceiling chart depict?

Answer 18

Low and mid level ceilings up to 24000ft.

Question 19

What are the 5 types of FX messages?

Answer 19

• Main weather discusion
• Extended range forecast discussion
• Operational Run status
• Trenton military
• American FX

Question 20

how often is the main weather discussion issued and how long does it cover?

Answer 20

twice daily, at 0930z and 2100z

-48 hrs

Question 21

How are the forecast discussions different from the models?

Answer 21

They explain a human point of view of a weather forecast compared to a computer

Question 22

How often is the extended forecast discussion issued and how long does it cover?

Answer 22

once daily at 0730

-from 48hrs to 120hrs

Question 23

how often is the operational run status issued?

Answer 23

twice daily

Question 24

how often is the trenton military discussion released?

Answer 24

once daily and updated as required

Question 25

How often are the american FX issued?

Answer 25

twice daily and updated as required