Name: ___________________________________________
Treasure Hunt#5
Mountain Meteorology
Due: Wed. 9 April 2014
MetEd Articles#4-8 [Terrain-Forced Flows, Pt II]
Score:____________/ 25
(1) Explain how wind observations in gap flow situations are at odds with the Funnel or Venturi Effect
explanation for gap flows {found in MetEd module#4}.
(2) Name the parameter that approximates the distance upstream from a barrier that the terrain influences
the winds and give a typical range (distance range) for this parameter {found in MetEd module#4}.
(3) Name the two types of pressure gradients that tend to produce the strongest winds over the exit of a gap
{found in MetEd module#4}.
(4) Where is a weather phenomenon known as the “Silver Thaw” located and describe how it is related to
gap flow {found in MetEd module#4}?
(5) Using the gap wind calculator, how does changing the length of the gap change the resulting wind at
the gap exit {found in MetEd module#4}? If the gap exit wind speeds change, why? If not, why not?
(6) In order to get a heavy snow event in the Eastern Foothills and High Plains of Colorado, through what
pressure level must the moisture extend from the surface {found in MetEd module#5}?
(7) In order to get a heavy snow event in the Eastern Foothills and High Plains of Colorado, from what
direction should the winds be at the 700 hPa level{found in MetEd module#5}?
(8) Do you see evidence in the model fields of a barrier jet on the eastern slopes of the Rockies during the
first 36 hours of the model forecast for the March 2003 event {found in MetEd module#5}? If so, what
model products help to identify its presence?
(9) What is primarily responsible for the model-produced MSLP nosing (or ridging) southward in a wedgeshape down the eastern slopes of the Rockies on 18 March 2003 {found in MetEd module#5}?
(10) What process is primarily responsible for the tightening of the north-south, low-level pressure
gradient north of the surface low from 2100 – 2100 UTC 17-18 Mar 2003{found in MetEd module#5}?
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(11) The trapped cold air of a CAD event may influence the ________ of the overlying air mass, and affect
the fields of ________, ________, and ________. {fill in the blanks} {found in MetEd module#6}.
(12) Name two of the elements that are REQUIRED for a cold air damming event {found in MetEd
module#6}.
(13) Under which type of stratification and wind speed conditions is terrain blocking most effective for
initiating cold air damming{found in MetEd module#6}?
(14) List the three main mechanisms that produce the low-level cold air mass in the initial stages of a cold
air damming event {found in MetEd module#6}.
(15) Name two forecast clues used to predict the conclusion of a cold air damming event {found in MetEd
module#6}.
(16) In examining the SLP pattern associated with a coastal jet, how does the pressure gradient change as
one approaches the coast from offsore {found in MetEd module#7}?
(17) In a vertical cross section oriented across the coastline, what causes the near-vertical isentropes near
shore associated with the coastal jet {found in MetEd module#7}?
(18) Name two of the three ways in which the coastal mountains contribute to the structure of the coastal
jet {found in MetEd module#7}.
(19) Name the type of SSTs (cold or warm) found in the vicinity of the coastal jet and list one mechanism
responsible for the presence of these SSTs{found in MetEd module#7}.
(20) The coastal jet has along-coast variations in speed. Where are the highest wind speeds found relative
to coastal points and capes and what hydraulic feature is found immediately downwind of coastal points
and capes {found in MetEd module#7}?
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(21) Give a brief definition of a coastally trapped wind reversal (CTWR) and list other names by which
they are known {found in MetEd module#8}.
(22) With the passage of a CTWR, temperature at the surface typically ________, while the SLP reaches a
minimum ________ the reversal in wind direction {fill in the blanks}{found in MetEd module#8}.
(23) Describe the observational evidence related to the wind and propagation speeds that indicates that a
CTWR is not due merely to advection, but is a disturbance {found in MetEd module#8}. Name the type of
wave having similarities to the CTWR.
(24) If you were trying to predict the onset of a CTWR, what change in the Pacific (subtropical) High
might give you a hint that a CTWR might be ready to form{found in MetEd module#8}?
(25) On the mesoscale, the formation of an offshore low is forced by ________ at low levels and its center
________ as the CTWR evolves {fill in the blanks}{found in MetEd module#8}.
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