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Weather Reports and Forecast > Weather Maps > Flashcards

Weather Maps Flashcards

1
Q

The meteo society of Canada publishes two types of weather charts. What are they?

A

Surface and Upper Level charts

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2
Q

What is another name for Upper Level Charts?

A

Constant Pressure Chart

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3
Q

What are the two types of surface charts?

A
  • Surface analysis charts (give actual information observed at a specific time
  • Surface prognostic charts (give forecasted information)
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4
Q

On surface charts how are winds indicated?

A

An arrow shaft indicating degrees true in tens of degrees and velocity

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5
Q

How is the wind velocity indicated on a wind arrow on a surface chart?

A
  • Half feathers: 5KTS
  • Full feathers: 10KTS
  • Pennants (triangle): 50KTS
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6
Q

How high up are pressure patterns drawn on a surface analysis chart?

A

Surface to 3000AGL

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7
Q

What kind of weather is included in a surface anylysis chart?

A

Any weather visible from the surface up to any altitude is included.

But only pressure levels up to 3000ftAGL

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8
Q

What is important to rememeber about surface analysis charts?

A

The info in them can be a few hours old as it can take up to 3 hours for the map to be drawn

Information in these charts is based on information taken at 00Z, 06Z, 12Z, and 18Z

The good thing about these charts is they allow you to see how weather has been developing over time.

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9
Q

Station Surface Analysis Chart legend

A
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10
Q

Example of Station Surface Analysis

A
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11
Q

Example of Surface Analysis Chart

A
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12
Q

When are Upper Level charts issued?

A

00Z and 12Z

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13
Q

What are the two types of Upper Level Charts?

A

Analysis and Prognostic

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14
Q

What kind of weather do the Upper Level Analysis charts show?

A

Reported conditions aloft for wind speed and direction, temperature, moisture, frontal systems, and pressure systems

Are usually around 3 hours old by the time they are pusblished (same as surface analysis charts)

Fronts not included in these charts unless they extend up to the pressure level o that chart

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15
Q

What are the four Upper Level Analysis charts?

A

250mb
500mb
700mb
850mb

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16
Q

What are the two Prognostic Upper Level Charts?

A

Significan Weather
Significant Weather, High Level

17
Q

What are upper level charts often refered to constant pressure charts?

A

Because they are based on levels of constant pressure. Since you will always have your altimeter set to 29.92 in the areas these charts cover (Standard Pressure Region), we are no longer seeing the pressure at the surface and instead the H’s and L’s will show us areas where our true altitude will be higher or lower than indicated.

The GFA uses Sea Level Pressure

18
Q

The H’s and L’s on Upper Level charts are not depicting areas of high and low pressure…what are they depicting?

A

The height of specific pressure markers. In the picture, 700mb of pressure would be found at different altitudes based on the temperature of the air in different regions. In a colder region, reaching 700mb of atmospheric pressure may happen as early as 8000ft of altitude. In very hot regions, it may take you all the way to 11000ft to reach 700mb of pressure.

So the H’s and L’s represent areas where that map marker (250, 500, 750, 800) is higher or lower.

19
Q

The lines on upper level charts are not called isobars, they are called _______

A

Contours. Upper level charts are more like topographical hiking maps. The contrours show the heights of the atmosphere. The closer together the contours, the stronger the winds.

20
Q

What is a decameter?

A

10 meters. Altitudes on upper level charts are given in decameters instead of feet for some reason

21
Q

How do you convert decameters into feet?

A

Times the decameter number by 10 then times the answer by 3.

150 dM X 10 = 1500 x 3 = 4500

This isnt perfect, in fact its way off, the actual conversion of 150dM turns out to be closer to 5000ft but this is what they told us to use.

22
Q

What are the average altitudes for the most frequently used constant pressure levels?

A
23
Q

In Standard Altimeter regions, your true altitude will be constantly changing but why does this not matter?

A

Because everyone else also has their altimeter set to 29.92 so their altitudes change as well.

24
Q

How far apart are contour lines spaced apart?

A

6 decameters except on the 250mb chart where they are 12 decameters apart

25
Q

What are SIG WX charts?

A

Upper Prognostic weather charts
One is for the 700-400mb level. The other is for FL250 to FL630

26
Q

What does xxx on a hi-level SIG WX chart mean?

A

The cloud base or weather is below the height of the chart

27
Q

Upper level weather charts are issued ____ daily.

A

Two times daily at 0000Z and 1200Z

28
Q

OCNL means…?

A

between 25% and 50% of the time

29
Q

Surface Prognostic Charts are forecasts issued __ and __ hours before validity time

A

48 and 36

30
Q
A

Weather Reports and Forecast (8 decks)

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