ATOC 6700 Weather Forecasting Discussion

Student Introductions Tell us: – Your name – Your year in ATOC graduate program – The topic of your research

Course Goals Apply theoretical concepts from ATOC core classes (esp. ATOC 5050 and 5060) to real-world mid-latitude weather Attempt to develop a cohesive “story” to relate atmospheric processes to the weather observed at specific locations You will have incomplete data as you develop your story – this is the same challenge you will face in your research

Course Approach Weekly weather discussion led by students – What are the key weather elements that will influence the weather at our forecast cities? – How will these weather elements impact the sensible weather at our forecast cities for the next several days? Forecasting contest Critique past forecasts to learn sources of forecast errors – Weekly forecast analysis write-up

How will we achieve these goals? Weekly weather discussion (handout)handout – Forecast review – Discussion of past week’s significant weather (optional) – Forecast discussion Forecasting contest – 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 Forecasting contest entry page Written forecast analysis (handout)handout – 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 – What did you forecast and what verified? – What aspects of your forecast were correct / incorrect?

ATOC 6700 Expectations You should plan on: – Spending at least 1 hour per week preparing your forecasts – Spending 1 to 2 hours per week assessing your forecast and preparing your written forecast analysis – Contributing to the weekly weather discussions – Leading one weekly weather discussion during the semester, which will require several hours preparation

Weather Forecasting Review ATOC August 2013

Key Weather Elements Troughs / ridges – PVA / NVA Jet stream Fronts Low and high pressure centers

Key Weather Elements Troughs / ridges – PVA / NVA Jet stream Fronts Low and high pressure centers

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

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 Troughs / ridges / PVA / NVA Jet stream Fronts Low pressure center – Local forcing Topography

Weather Terms Refresher A weather term primer is available on the class web page (at the bottom of the Weather Links page)weather term primer

Weather Products Available Online ATOC 6700 web page NCAR Real-time Weather Data University of Wyoming Weather Web Plymouth State Weather Center NCEP Models Forecast Model Animator National Weather Service web pages Week in Review – Observations Week in Review – Guidance Review

Observational Weather Products Surface data – Maps (NCAR Real-time Weather Data, NWS North American Surface Analysis )NCAR Real-time Weather Data NWS North American Surface Analysis – Text list of time series (Plymouth State)Plymouth State – Meteograms (Plymouth State)Plymouth State Upper air maps (University of Wyoming)University of Wyoming – What levels are of interest for forecasting? – What can we learn from each upper air map? Soundings (University of Wyoming)University of Wyoming

Observational Weather Products Satellite images (NCAR Real-time Weather Data)NCAR Real-time Weather Data Radar (NCAR Real-time Weather Data)NCAR Real-time Weather Data Severe weather – Thunderstorms (Storm Prediction Center)Storm Prediction Center – Hurricanes (National Hurricane Center)National Hurricane Center

NWP Products Model forecast maps – Which maps are of interest for forecasting? – NCEP Models NCEP Models – Forecast Model Animator Forecast Model Animator – NCAR Real-time Weather Data NCAR Real-time Weather Data – University of Wyoming University of Wyoming Model output statistics (MOS) – Ex. DEN NAM MOSDEN NAM MOS – Reading MOS products Reading MOS products

NWS Products Zone Forecast – DEN DEN – ORD ORD Grid Forecast – DEN DEN – ORD ORD Forecast Discussion – DEN DEN – ORD ORD