: a thunderstorm cluster moves west, often off the coast of Africa. Most don?t get any stronger.
easterly wave stg. 2
wiggle in winds. 85% of major Atlantic hurricanes start as easterly waves, but most waves don?t become hurricanes.
tropical depression stage 3 How many closed isobars
weak low-pressure area with sustained (constant) winds below 39 mph. At least 1 closed isobar
tropical storm stage 4
Tropical Storm: strong low-pressure center with sustained winds between 39-73 mph. Gets a name! About 50% of tropical storms intensify further to? CLOSED ISOBARS
stage 5 hurricane
Hurricane: intense very circular low-pressure center with sustained winds at or above 74 mph. Often develops an ?eye,? especially as it intensifies beyond minimal hurricane status.
?The End?: hurricane usually either dies over land (away from warm water) or becomes part of an extratropical weather system.
What factors control the strength of a hurricane?
Ocean temperatures (above 80°F, good for growth)
Vertical wind shear (jet streams bad for growth, unlike thunderstorms/tornadoes)
wind, hurricanes are low pressure areas extreem pressure gradents causes sustainted winds in the eye wall up to 200mph
the exact same thing as weater balloon except it takes measurements as it falls down from the plane through the hurricane.
winds of what side are the fastest of the hurricane
another hurricane hazard
when a hurricane makes landfall tornadoes associated with hruricanes are usually tornadoes created by friction
non supercell tornadoes that form in the right front qudrant
High winds push ocean water ahead of the storm, causing a ?wall of water? as high as three stories
Weakening hurricanes over land can produce enormous amounts of rain, especially if they interact with mid-latitude weather systems or cross over mountains
rain water flood
kills the most people in a hurricane. as they weaken and move over land
record setting hurricane season
2005 we ran out of names fro the hurricanes so we had to use letters from the greek alphabet
winds >74mph possible hurricane within 36 hours
winds >74mph hurricane is24 hours away
3 steps to weather forecast
1) Data collection 2) Data analysis 3) Produce forecast (prediction)
In U.S., it is NCEP and National Weather Service (NWS) Headquarters in Silver Spring, MD errors are removed data is plotted on a map and analyzed`
This type of forecasting is called numerical weather forecasting
Use computer model forecasts as basis for own forecast
Forecasts based on long-term averages
Assess current conditions, assume that either these conditions will occur in the future or that a current trend will manifest itself
The ?amount? of a variable is specifically stated Example: ?The high temperature will be 72°F with 0.5? of rain?
A categorical amount is forecasted, no numerical values Example: ?It will not rain today. Temperatures will be below normal
Chance that something will occur Usually issued with precipitation forecasts Example: ?There is a 60% chance of rain today?
long range forecast
Long-Range forecasts Upcoming season (90 days in advance) or more Can only issue most likely outcomes ?Will be drier than normal?, or ?warmer than normal? Issued by the Climate Prediction Center (CPC)
why are some forecasts bad?
Data is sparse Only 74 upper air stations, not close enough Observations not taken frequently enough Computer models do not handle certain things well Anything smaller in scale (parameterized), like thunderstorms, wind turbulence, etc. Snow cover Weather is changing rapidly Forecasts are for periods longer than 3 days
why are some forecasts good?
Models are getting better and better Computers are faster, more computations can be performed, resolution is increasing Weather isn?t changing very rapidly Forecasters are receiving better training 3 days or less
analysis of air flow relative to the temperature distribution helps identify areas of low level uplift.
useful in predicting the movement of air mass thunderstorms
most wideley used
300 and 200mb maps
best for defining the number and posiion of rossby waves and for analysing jet stream patterns
Want to see the other 33 Flashcards in final deck 2?JOIN TODAY FOR FREE!