Aviation Weather Review & Go-No Decision Chart

v. 3.0 Revised: 4 April 2005

All of the data and products listed below derive from one of the following portals meteorological information:

• NWS Aviation Page.
• ADDS. Aviation Digital Data Service. Probably the most complete site available for pilots and is the foundation for the NWS aviation page.
• UCAR RAP Weather Page. University Corporation for Atmospheric Research (UCAR)-Research Applications Program(RAP). RAP is one of the major aviation applications research organizations in the country; research has resulted in the ADDS Aviation Data Site, Terminal Doppler Radar (TDWR), NWS’s Structural Icing Program, & many other significant aviation wx applications. This site contains additional data beyond the ADDS site.
• Unisys Weather Page. An excellent site maintained by the Unisys Corp and used for general weather information and data.
• AOPA Members Weather Page. Requires username and pw.

WxBriefPage . .. . Course Outline .

Before proceeding, a couple of points about this table might be helpful. First, my objective with this process is twofold. First I want to provide you a process of sorting through lots of information so that you become familiar with current weather information from a visual perspective, that is I would like for you to begin to build a mental picture of atmospheric processes. Second, once you begin to picture weather in 3-D, then you can begin to understand better forecasts and weather briefings that project future states of clouds, winds, temperatures, icing, and other things that are critical you a safe and efficient flight.

You can click here for METARs and TAFs of the local COS or CO region in map format or CO Radar/Stlt Otherwise, try the sequence listed below in whatever time frame you’re working and see if these few bits of data might help visualizing weather.

Which time frame are you interested in reviewing: Routine Weather Review 5 days to 48 hours < 24 h <12h <6h

Time Frame	Questions to Ask	Things to Review	Decisions to Make & Remarks
Routine Wx Review	The main purpose of this review is to get a feel for cloud features and weather patterns seen on satellite imagery, upper air, surface, & what you might experience if you were flying into those areas. After looking at the large or synoptic scale charts, review METARs/TAFs in the COS area as well as the Mesoscale Sfc Chart for the DEN-COS region.	0.1 Hemisphere loops-Uwisc. 0.2 28km EIR Western Pacific Ocean Region 0.3 NWS SEA Fcst Office SatPage 1.0 Current IR loop--NWS. or 1.1. Current IR loop--Unisys 1.2 Current WV loop--Unisys 2.0 Current 700 MB 500 MB 300 MB 3.0 Current Synoptic Surface Chart 4.0 Sig wx--CONUS—NWS Av Pg 5.0 Current SIGMET/AIRMET 6.0 Current Radar Composite Loop 7.0 4 panel 12/24 h Sig wx prog charts 8.0 METARs TAFs COS Sfc Chart	No decisions needed—just routinely review this information and begin to develop a mental image of the weather.
5 days to 48 h period Establish a base line abt your intended departure, enroute & destinations weather.	Similar to the above, but here you begin to make tentative decisions based on what you review in terms of critical weather as you approach 48 h to ETD. 1. What is the current situation at my departure, destination (s), & enroute airports? 2-4 Are there organized cloud patterns (comma clouds, waves) on the synoptic scale IR stlt loop? Vsb data will help you refine the types of clouds and precipitation associated with the cloud pattern. . Does the Vsb data suggest convection, embedded convection within organized cloud areas? How do these patterns compare with upper air & sfc charts? 5.0 Do you see organized convection on the Doppler radar? 6-7 Are there significant surface features present that may affect my flight in the nxt 48 h to 5 days? What is forecast, in general terms, for your departure, destinations, & enroute sites? (This link (7.0) takes you to the COS 7-day forecast; some forecast offices also provide a more detailed, numerical 48 h forecast called the Element Meteogram. You can then select your destinations, alternates, or locations along your route from the box at the top of the 7-day forecast page.) 8.0 If you’re interested, you can review the latest Numerical Model output from what is termed the Aviation Model.	1.1 Sig wx--CONUS—NWS Av Pg 1.2 Current SIGMET/AIRMET 2.1 Current IR loop--NWS. or 2.2. Current IR loop--Unisys 2.3 Current region visible satellite data 3.0 700 MB 500 MB 300 MB 4.0 Current Synoptic Surface Chart 5.0 Current Radar Composite Loop 6.0 Latest Sfc Progs—ADDS Prog Charts 7.0 Winds aloft fcst (FD). Select an area. 7.1 Or Wnds aloft fcst from ADDS (3.5 d) 8.0 NWS 7-day fcst for KCOS 9.0 TSTMS: Outlooks Sigmet Watches 10.0 Aviation NWP Model Output 12h-5 d	1. Should I change my departure day/time based on what I reviewed?
GO NO GO At or less than 24 h to ETD.	Under construction Tailored aviation forecasts are not issued beyond 24 h due to uncertainty in making detailed forecasts. So, from this time to ETD, you can blend the trends you have observed into detailed forecasts to provide much greater skill in decision-making. This period is when you want to take the most time to review and use your skills in making a GO NO GO decision. 1-6. These steps are the same as in the > 24 h period, but you must pay particular attention to potential hazards that may affect your plans. 7-8. Are there conditions beyond your piloting skills, certification, and/or aircraft capabilities that suggest you cancel or delay your flight? If you’re at the 24 h period, you should at least consider alternate routes or dates if sig wx is a factor. 9.0 Is there a potential for icing along your route, based on the patterns you see and the Current Icing Potential (CIP) charts? It may be best consider this for periods beginning < 12 h before ETD. Are there organized pressure patterns, wind signatures, fronts, or areas were T-Td < 5 deg on the regional sfc charts?	1.1 Sig wx--CONUS—NWS Av Pg 1.2 Current SIGMET/AIRMET 2.1 Current IR loop--NWS. or 2.2. Current IR loop--Unisys 2.3 Current region visible satellite data. 3.0 700 MB 500 MB 300 MB 4.0 Current Synoptic Surface Chart 5.0 Review the composite radar image 6.0 Latest Sfc Progs—ADDS Prog Charts 7.0 4 panel 12/24 h Sig wx prog charts 8.0 Area Forecast Select a region 9.0 TSTMS: Outlooks Sigmet Watches 9.0 Winds aloft fcst (FD). Select an area. 9.1 Or Wnds aloft fcst from ADDS (3.5 d) 10.0 Latest Doppler Radar data by site. 11.0 Review TAFs. or Regional Information 11.1 CO/WY Heckman’s pg; 11.2 South TX Wx Brief Page
GO NO GO At or less than 12 h to ETD.	We’re now interested in getting information that focuses on shorter time scales and narrowed to our departure, enroute, & destination/alternates weather. We move from the larger, synoptic scale to a regional review of data.	1.1 Sig wx--CONUS—NWS Av Pg 1.2 Current SIGMET/AIRMET 2.1 Current IR loop--NWS. or 2.2. Current IR loop--Unisys 2.3 Current region visible satellite data. 3.0 700 MB 500 MB 300 MB 4.0 Current Synoptic Surface Chart 4.1 PIREPS 5.0 Review the composite radar image 6.0 Latest Sfc Progs—ADDS Prog Charts 7.0 4 panel 12/24 h Sig wx prog charts 8.0 Area Forecast Select a region 9.0 TSTMS: Outlooks Sigmet Watches 10.0 Winds aloft fcst (FD). Select an area. 10.1 Or Wnds aloft fcst from ADDS 11.0 Current Regional METARs & Sfc chart 12.0 Regional Satellite Data ADDS 13.0 Regional Doppler Radar Data ADDS 14.0 Review TAFs. or Heckman’s pg 15.0 Current Icing Potential (CIP).
GO NO GO At or less than 06 h to ETD.	We’re now interested in as much detail as we can gain about our departure, enroute, & destination. Our decisions here focus on: “Can we take off based on our limitations?” “Will we be able to maintain VFR or VFR on Top”, or “Will there be hazards to IFR such as icing or turbulence?” You want to know what’s going on “right now” and how will that change in the next few hours.	1.1 Sig wx--CONUS—NWS Av Pg 1.2 Current SIGMET/AIRMET 2.1 Current IR loop--NWS. or 2.2. Current IR loop--Unisys 3.0 Winds aloft fcst (FD). Select an area. 3.1 Or Wnds aloft fcst from ADDS 4.0 A Quick Look at a specific region[1] 5.0 Current region visible satellite data. 6.0 Review TAFs. or Heckman’s pg 6.1 PIREPS 7.0 Current Icing Potential (CIP). 8.0 TSTMS: Outlooks Sigmet Watches 9.0 PIREPS 10.0 Review TAFs. or Heckman’s pg

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[1] For this version of the table, I have selected the Colorado Region. You can select specific regions from the ADDS site as you flight plan for other routes and destinations.