Briefing Process

I would like you to practice putting together a general weather briefing. The purpose will be to apply some of the things that we discussed in the class and find out new things. Ask the following questions to guide you in your discussion 1. What happened? 2. Why did it happen? 3. What is happening? 4. Why is it happening? 5. What is going to happen?

Before looking at charts, verify the time labels and make sure the date/time is correct and is what you are looking for. Occasionally charts are not updated on the web. You have to look at what you have downloaded or you may have the wrong chart. Always verify the product name. If you are looking for a 500mb height chart, make sure it says “500mb heights” somewhere on the chart.

For your practice, you can download the maps, import them to a word or powerpoint file and then discuss them. Another way would be to print them out and mark them up with a pen.

Look at upper level analysis charts • Examine yesterday’s 12 and 00 UTC and today’s 12 UTC 500 mb height chart and compare them • Find the locations of troughs and ridges and note the location in all three charts • Look for areas of • What kind of feature are we under right now? • Look at 200 and 250 mb analysis charts for today’s 12 UTC • Locate polar jet and subtropical jet if you can.

Satellite imagery • Look at the visible, infrared and images of the continental US • Zoom in to the CA/NV visible image • Look at specialty products such as /cirrus maps • Note down any sharp features, and areas of thick and thin cover • Do your best to interpret the types of you see in the images using cloud top • Can you identify any large scale highs or lows based on the clouds?

Radar • Look at the national radar plot. If there is something interesting, you can zoom in on that particular radar. • Are there distinct bands of ? • How do the precipitation features coincide with clouds that you observed in the satellite imagery?

Surface weather analysis • Get the latest surface synoptic analysis chart. They make the NOAA maps every 3 hours. Some commercial providers make them every hour but the fronts are updated only every 3 hours. Locate the position of any fronts, dry lines, highs, and lows. Notice areas with abnormally high or low dewpoints and think through how it compares to fronts and upper level features. • Look at dewpoint and maps of the continental US and then compare to the local Las Vegas Valley. • Look at the McCarran airport ASOS station meteogram chart. Notice trends in T, Td, , , cloud heights, tendency, and precipitation.

Soundings • Get the latest Desert Rock Airport sounding (DRA) and look at the skew-t plot. • Look at shape of T and Td lines and look for areas where they are close to each other and areas where they are far apart. • Notice the directions and speeds as a function of height () • Can you find any inversions?

Upper level forecasts • Go to the NCEP 500 mb forecast page and look for the 12 UTC vorticity/heights maps • Grab the analysis, 24-, 48-, 72- and 120-hr forecasts for the GFS model • Notice locations and movement of troughs, ridges and areas of vorticity • What kind of feature is coming our way over the next few days?

Surface forecasts • Go to the NCEP surface weather forecasts maps and grab the 24-, 48-hr and 3 day forecasts • Locate positions of fronts and compare with upper level forecasts maps • Examine QPF maps for probability of precipitation