500 hpa and prog charts Flashcards

1
Q

How long after observation time are the 500 vorticity and 500 thickness charts transmitted?

A

vorticity - 2 hrs

Thickness - 3.5 hrs

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2
Q

what are the letters or symbols used to indicate a vorticity maxima and a minima?

A

Maxima - C or +

Minima - A or -

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3
Q

Define Isopleth

A

Line of equal or constant value of a given quantity

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4
Q

The smaller the quadrilateral, the ______ the advection

A

greater

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5
Q

when isopleths are parallel to the contour lines, what is the advection value?

A

0

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6
Q

Define positive vorticity advection

A

Advection of higher values of vorticity, which is often associated with upward motion of the air.

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7
Q

What does negative vorticty advection represent?

A

Lower levels of vorticity moving towards higher levels of vorticity

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8
Q

NVA is associated with _______ and PVA is associated with _________

A

NVA - Convergence

PVA - Divergence

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9
Q

PVA is indicitive of:

A

Falling pressure, rising motion, and instability

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10
Q

The thickness pattern on the 500hpa chart reflects the :

A

Mean temperature of the layer between 500hpa and 1000 hpa and is proportional to the mean temperature of the air below 18000ft

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11
Q

Warm thickness advection supports:

A

Cyclogenesis

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12
Q

Fronts are usually located on the _____ of the thickness field.

A

warm.

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13
Q

the area between the 534 and 540 dashed lines is stippled to indicate ______ and is colored ______

A

change of phase state

yellow

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14
Q

The low to mid sfc prog chart (sfc to 400mb) contains:

A
  • Pressure centers, surface fronts
  • Surface positions of tropical storms
  • significant clouds
  • turbulence, freezing lvl, and icing
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15
Q

the comox sfc prog chart is issued for the period of __________

A

12, 24 and 36 hr

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16
Q

the CMC sig wx prog (400mb to 700mb) is prepared ____ times daily and is transmitted _____ after the GFAs.

A

4 times

1 hr

17
Q

The mid level prog contains:

A
  • surface presure centers, tropical storms, frontal positions
  • Significant cloud, turbulence, freezing lvl and icing
18
Q

The forecast wind chart for FL240 contains winds and temps for FL ______ and is produced by:

A

FL 240, 340 and 450

WAFC in washington, DC

19
Q

List the steps necessary for interpolating conditions between 2 points on an analyzed weather chart

A
  • Recognize the chart
  • Understand the plotting model
  • Proportional distance
  • Topography/local effects
    RUPT
20
Q

Define local effect

A

Localized weather caused by the interaction between the atmosphere and the earth’s topography

21
Q

The significance of localized weather is:

A

the localized weather doesn’t fit the synoptic picture

22
Q

what scale is a local effect?

A

mesoscale

23
Q

List the significant factors that contribute to the formation of local effects

A

Moisture
Stability
Circulation

24
Q

List the local effects that occur near water bodies

A
Moisture source
Streamers
Thermal lows
Moderated temperature extremes
Land/Sea breezes
Convergence zones
Fog/stratus
25
Q

List the local effects that occur over higher terrain

A
Orographic clouds
Wind
Persistent radiation fog
Persistent freezing rain
Windshear
26
Q

List the local effects that occur near cities/industrial areas

A

Poor visibility

Ice fog

27
Q

List the steps required to address discrepancies between current and forecast weather, prior to calling the forecast office:

A

Identify discrepancies
Determine MANAIR requirements
Apply local procedures

28
Q

What are the shortcuts to pull up upper air plots on FWGS

A
TA - Temp, t-12
TB - temp, pressure, Td
AN - tephigram
PB - sig and mandatory winds
PA - sig winds only
UP - entire upper air plot