1. Meteorology Name: ____________________
DRAWING FRONTS
and the
DEVELOPMENT of the MID-LATITUDE LOW

2. Let's practice trying to draw them. We may need
to discuss the weather map symbols again. If so,
we have a worksheet for that!

3. Draw in the Cold front and the Warm front.
Draw in the Cold front and the Warm front.

4. Formation of Mid-Latitude Lows
The polar front is the boundary between ________________ air
masses in the polar easterlies and ______________ air masses
in the prevailing westerlies.
Polar air masses lie to the north of the ________________________.
_________________________ air masses lie to the south of it.
(sorry Brendon - different texts provide different
explanations for this)

5. In the first stage, there is a _____________________________ in the
These storms have a _____________________ -- they are not fixed in time and space;
they ________________________ as they trek _____________________ (in our latitudes),
almost as if you were holding a pinwheel and walking along with it.
In the first stage, there is a _____________________________ in the
_________________________ between the cold arctic/polar air and
warmer tropical air.

6. A kink or wave frequently forms somewhere
on the _______________________. There are many ways
such a wave can form.
One cause could be a
wave or kink in the _______________.
Another example
could be if a cold air mass
began moving __________________,
pushing part of the polar
front ahead of it.
The wave moves from _____________________________, like a wave
passing through a stage curtain shaken at one end.
_______________________________________________________.

7. southward. This creates a southward moving __________________________.
In the second stage, the front __________________________________ on the
west side of the wave, where polar air pushes __________________________
southward. This creates a southward moving __________________________.
On the east side of the wave, the polar front bulges
_______________________ as a _______________________.

8. Between the cold and warm fronts is a large amount of
______________________________ air. The warm air bulges into and over the
_________________________ air to form a region of ______________________.
The _________________ pressure is at the __________________ of the wave where
the ________________________________ meet.
A low, or ________________, has formed.

9. The isobars around a low are roughly ______________________________,
with a slight bend at the_______________________.

10. Winds whirl about the center of the low in a
_____________________________ direction in the Northern Hemisphere.

11. The whole system moves eastward, but the cold front
moves _____________________________ than the warm front.
The front that forms when the cold front overtakes
the warm front is called an ___________________________ front.

12. The warm air that had been stuck between the two colder
airmasses is ____________________ completely off the surface in an occluded front.
_______________________ continues until the low ___________________
and the two cold air masses mix across the ____________________ front.

13. A day or two after occlusion, the occluded front _______________________,
the winds subside and a ______________________ front forms along the
surface of the earth.

14. In summary, a low forms from
a ____________ in a
_______________________ front.
To form a fully
developed low takes
only ______________________.
Complete occlusion
usually takes an
additional _______________ or
more.

15. As a low passes to the north of a locality in the Northern
Hemisphere, the following weather changes occur:
A long period of _____________________________ in
advance of the ______________________.
2. _______________ and slow clearing after the warm
front passes. If the air is humid, showery
precipitation may occur, particularly nearer the
__________________________.
_____________________ precipitation around the time the
_________________________ passes.
4. ______________________ and rapid clearing, with a change
toward the weather characteristic of the newly
arrived ___________________________.
midlat_struct_mov.wmv

16. Don't think that these cyclones only strike the
northern latitudes.
December 13-14, an ___________________________________
(meaning one NOT in the tropics) dropped 2 feet of snow on
El Paso, TX and surroundings....
...paralyzing the city.

17. This storm was further fueled by cold
_____________ air rising above the
mountain areas bringing cold air over
the mountains and causing the
temperatures to fall below freezing.
Additionally, the _____________________________ flow of the low pulled
warm, moist air from the Gulf of Mexico and the Gulf of California high
into the atmosphere.

18. Upper-Air Flow
Throughout the life of a low-pressure system,
__________________________ is what controls the surface low's
_______________________________________.
At the Earth's surface, air is constantly _______________________ into the
low-pressure system. Instead of _______________________ the low,
however, lows often strengthen over time.

19. The upper-air flow should explain this unexpected fact.
If you look at a weather map, you will see that the
upper-air flow is seldom _____________________. Instead, it curves
back and forth like a winding road.
_______________ are like traffic
jams. As the air
approaches, it crowds
together and some air
________________ to the Earth's
surface.