Transcript Class introduction / background (Powerpoint)

ATOC 6700
Weather Forecasting Discussion
ATOC 6700
Weather Forecasting Discussion
THIS CLASS IS NOT
ABOUT WEATHER FORECASTING
OK… So what is this class about?
• It is a critical thinking class
• Understand the “black box” of scientific data
– What types of data do you use in your research?
– What types of data will we use this semester?
• Determine if the data you are working with
makes sense based on physical principles
– Build on the knowledge you’ve gained in taking the
ATOC core classes
OK… So what is this class about?
• Draw conclusions from the available data
– What do you use your data for in your research?
– In this class we’ll use the available data to make short
duration weather forecasts
• Defend your conclusions
– As a scientist you need to be able to explain and
defend the conclusions you’ve drawn from your data
and analysis
– We’ll do the same thing in ATOC 6700
• Analyze additional data as it becomes available
and reassess your conclusions
– What were you right or wrong about in your initial
analysis?
Student Introductions
• Tell us:
– Your name and where you are from
– Your year in ATOC graduate program
– The topic of your research and your advisor
ATOC 6700 Goals
• Apply theoretical concepts from ATOC core
classes (esp. ATOC 5050 and 5060) to real-world
mid-latitude weather
• Develop a physically based conceptual model, or
“story”, to relate atmospheric processes to the
weather observed at specific locations
• You will have incomplete data as you develop
your model/story – this is the same challenge you
will face in your research
How will we achieve these goals?
• Introduction to forecasting
– During the first 3 weeks of the semester Professor Cassano will review the
key factors to consider when making a weather forecast
– Professor Cassano will lead the weekly forecast discussion during this
period
• Weekly weather discussion (Forecast Discussion Handout)
– Review previous week’s forecast and identify aspects of forecast that were
or were not well forecast
– Identify the key weather elements that will impact the upcoming forecast
• Forecasting contest
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Forecast daily high and low temperature
Forecast daily precipitation category
Forecasts for 6 to 54 hours in the future (day 1 and 2)
Forecast for Denver, CO and Chicago, IL
Forecasting contest entry page
• Written forecast analysis (Forecast Discussion Handout)
– Five times during the semester you will submit a written analysis of your
forecast for one forecast city
• Key weather elements you expected to impact the city
• Impact of these weather elements on the sensible weather in the forecast city
• Class schedule
ATOC 6700 Expectations
• You should plan on:
– Spending at least 1 hour the morning before class
reviewing the current weather and model
forecasts
– Spending at least 1 hour per week preparing your
forecasts
– Spending 1 hour per week assessing your forecast
for the following week’s in-class discussion
– Actively contributing to the weekly weather
discussions
– Preparing 5 written forecast discussions
Weather Forecasting Review
ATOC 6700
28 August 2013
Numerical Forecasts
• Model output statistics (MOS) and other
gridded numerical forecast products are the
basis for modern weather forecasts
Numerical Forecasts
• Model output statistics (MOS) and other
gridded numerical forecast products are the
basis for modern weather forecasts
• We want to use these to make our weekly
forecasts, but…
• We also want to understand why the MOS
numbers change in time as they do.
– We don’t want to use MOS as a black box
• What are the processes that lead to changes
in temperature and drive precipitation?
Key Weather Elements
• Upper level features
– Troughs / ridges
• PVA / NVA
– Jet stream
• Air mass characteristics
– Temperature and moisture
• Surface features
– Surface low and high pressure centers
– Fronts
• Local effects
Key Weather Elements
• Upper level features
– Troughs / ridges
• PVA / NVA
– Jet stream
• Air mass characteristics
– Temperature and moisture
• Surface features
– Surface low and high pressure centers
– Fronts
• Local effects
Why are these important for
forecasting the weather?
• Rising / sinking motion
– Cloud and precipitation development
• Divergence / convergence
– Forces vertical motion
– Surface pressure
• Temperature advection / air mass change
• Wind shift (frontal)
• Rising motion (frontal)
Forecasting Local Weather
• Temperature
– Air mass temperature / CAA / WAA
– Clouds – day vs. night
– Winds – day vs. night
– Time of year
– Recent precipitation / soil moisture / snow cover
– Local effects on temperature (topography)
– Humidity / fog impacts on temperature
Forecasting Local Weather
• Cloud cover
– Moisture
– Rising or sinking motion
– Frontal clouds
– Convective clouds
– Other types of clouds
Forecasting Local Weather
• Wind
– Near surface wind and SLP
• Or look at 850 or 700 mb maps for indication of surface
winds at DEN
– Upslope vs. downslope winds
– Topographic effects on winds (wind storms)
Forecasting Local Weather
• Precipitation
– Moisture availability
– Dynamic forcing
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Troughs / ridges / PVA / NVA
Jet stream
Fronts
Low pressure center
– Local forcing
• Topography
Weather Products Available Online
• ATOC 6700 web page
– Week in Review – Observations
– Week in Review – Guidance Review
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NCAR Real-time Weather Data
NCEP Models
Forecast Model Animator
National Weather Service web pages
University of Wyoming Weather Web
Plymouth State Weather Center
Observational Weather Products
• Surface data
– Maps (NCAR Real-time Weather Data,
NWS North American Surface Analysis )
– Text list of time series (Plymouth State)
– Meteograms (Plymouth State)
• Upper air maps (University of Wyoming)
– What levels are of interest for forecasting?
– What can we learn from each upper air map?
• Soundings (University of Wyoming)
Observational Weather Products
• Satellite images
(NCAR Real-time Weather Data)
• Radar (NCAR Real-time Weather Data)
• Severe weather
– Thunderstorms (Storm Prediction Center)
– Hurricanes (National Hurricane Center)
NWP Products
• Model forecast maps
– Which maps are of interest for forecasting?
– NCEP Models
– Forecast Model Animator
– NCAR Real-time Weather Data
– University of Wyoming
• Model output statistics (MOS)
– Ex. DEN NAM MOS
NWS Products
• Zone Forecast
– DEN
– ORD
• Grid Forecast
– DEN
– ORD
• Forecast Discussion
– DEN
– ORD