Meteo 003: Lab 12
Question 1.
a) Identify centers of high and low
pressure in maps
b) There are three forces that can
affect the wind direction. They are …
Friction is greatest over rough
surfaces.
Question 1.
c) The parcel will initially cool at the dry adiabatic lapse rate. What will the temperature
need to be for a cloud to form?
Estimate the parcel’s starting elevation from the legend (yellow)
d) The parcel cools at the moist adiabatic lapse
rate the rest of the way.
• Is the parcel warmer or cooler than the
environment?
Warmer -> Positively Buoyant -> Continue rising
Colder -> Negatively Buoyant -> Sink back down
Question 1.
e)
• The parcel is unsaturated now and
descends from 3500 m to 1600 m.
• Warms at the dry adiabatic lapse rate
(10ᵒC/km) during descent
Question 2.
a) Lapse rate between two layers can be computed as follows:
−(𝑇850 −𝑇𝑠𝑓𝑐 )ᵒ𝐶
Γ=
𝐻
Make sure to convert the temperatures to degree Celsius. To determine the
stability of the layer, compare the lapse rate to the dry and moist adiabatic
lapse rates.
• Stable: Γ < 6ᵒC/km (Γ𝑚 )
• Conditionally Unstable: 6ᵒC/km < Γ < 10ᵒC/km
• Unstable: Γ > 10ᵒC/km (Γ𝑑 )
Reference lapse rates in your response
Question 2.
b) What ingredients are needed for lake effect rain/snow?
c) What is the role of wind direction?
d) When is lake effect snow most likely to occur? Are any of the ingredients needed
for lake effect snow present during this time of the year (November)?
Question 3.
Question 4.
a) Isopleth…
b) Note that nearly all precipitation in midlatitudes starts out as snow…
• Snow: Below freezing the entire descent
• Sleet: Small warm layer melts snow then
refreezes as an ice pellet in lower cold
layer
• Freezing Rain: Warm layer melts snow but
cannot refreeze in shallower lower cold
layer near ground
Question 5.
 Identify regions of the mid-latitude
cyclone.
 What kind of air masses are colliding at
frontal boundaries? Recall that fronts are
named after the advancing air mass.
 What is the role of the steepness of
different fronts on the development of
and intensity of precipitation (steady
snow versus thunderstorms, for
example)? Gently lifting a parcel vs fast
ascent…
 See Chapter 13!
.A
L
.B
.C
.E
.D
I.
H.
.G
.F
Lab Assingment #12
DUE THURSDAY DURING OFFICE HOURS!
Astrid (ais5396@psu.edu): 10-11 AM and 1-2 PM in 623 Walker
Josh (jig5374@psu.edu): 2-3 PM in 6th Floor Walker Wx Center
Zach (zmg5025@psu.edu): 4-5 PM in 6th Floor Walker Wx Center