EAA Triple Five Flier EAA Triple Five Flier Newsletter | Page 5

Rewriting Aviation Weather
©2016 Rose Marie Kern

Greetings and Happy Holidays to all!
For those of you with more than a passing interest in the weather side of aviation, I thought I
would point out that the National Weather Service has just updated the AC 00-45 (Aviation
Weather Service order) to version H. This version is significantly different than its predecessor. The NWS has been rampantly making changes as instrumentation and computer technologies leap forward. They have created a plethora of new weather “products” – charts and
graphics relevant to aviation.
The document also indicates that many older type charts will be phased out as the newer ones
come online. For instance, the traditional Weather Depiction Chart and Constant Pressure
Analysis charts are being phased out and replaced with the CVA (Ceiling and Visibility Analysis) and the Upper Air Constant Pressure Level Forecasts.
Textual information for AIRMETS and Area Forec asts is being replaced by graphical AIRMETS and Forecasts. The use of graphics has been determined to be more useful to pilots and
all the weather products are moving in that direction.
Some of the more interesting highlights include whole new sections devoted to Space Weather
analysis and specialized Helicopter weather charts. Extensive revision has been done to sections devoted to Alaska and Hawaii. The order also indicates that a reorganization, and in some
cases, re-naming of departments has taken place.
The Radar Section has been gutted and re-written with many new images and descriptions of
how radar is depicted and interpreted. It also mentions upcoming radar products still in development. Freezing level graphics are vastly improved and graphical images have been added to
show winds aloft information. Radiosonde data and analysis models include SKEW-T diagrams for forecast modeling.
In the past there were many types of textual weather overviews that are now replaced by the
Meteorological Impact Statement. The various surface analysis charts are now combined into a
Unified Surface Analysis Chart that spans the globe. This model will make it easier to predict
major storm movements and hurricanes.
Pilots will still see any PIREPS entered into the system by ATC or Flight Service, but the database will also show AIREPs. An AIREP is a PIREP in ICAO format that has been automatically entered by equipment onboard an aircraft. The information gives the lat/long of the aircraft
and its flight level along with temperature, wind, and turbulence data. Instead of UA you will
see ARP and UUA (urgent reports) will be encoded as ARS.
radiation levels

5