CVA presents simplified area maps of ceiling, visibility and flight category as outlined below:
|VFR||Visual Flight Rules||ceiling ≥1000 feet||and||visibility ≥ 3 statute miles (sm)|
|IFR||Instrument Flight Rules||ceiling < 1,000 feet||and/or||visibility < 3 statute miles|
As explained further in the overview section , CVA's ceiling and visibility fields are derived through nearest-neighbor interpolation of METAR data. This interpolation process, in effect, "stretches" limited-area METAR observations across the broader domain between stations and accounts for terrain effects on ceiling height. The resulting fields help to visualize the "likely" conditions at range from METARs. However, the reliability of these fields degrades as distance from a METAR site increases. Thus, users should apply cautious practical judgment in considering the representativeness of the product as distance from a METAR site increases.
Each regional display includes station plots showing the current ceiling and visibility observations reported at selected METAR stations. To avoid overcrowding, the display shows only a subset of the total number of stations available. Station plot content is shown in the figure below.
Refer to the following links for a complete list of METAR stations and associated station plots:
Here is a list of the URL options: