Reading the last part of METARS?

[a-v-8er]

Could someone explain how to interpret the code that can be on a METAR that reads "58033" (5appp)

5 = pressure tendancy the last 3 hours
a = ?
p =
p =
p =

I don't understand the "a" but assume the last three digits "ppp" corresponds to the change in hPa.

If someone else could please fill in the blanks. Thanks in advance!

 

[skiddriver]

a = characteristics of barometric tendency

ATMOSPHERIC PRESSURE NOW HIGHER THAN 3 HOURS AGO.
0 Increasing, then decreasing.
1 Increasing, then steady; or increasing, then increasing more slowly.
2 Increasing steadily or unsteadily.
3 Decreasing or steady, then increasing; or increasing, then increasing more rapidly.
ATMOSPHERIC PRESSURE NOW THE SAME AS 3 HOURS AGO.
0 Increasing, then decreasing.
4 Steady.
5 Decreasing, then increasing.
ATMOSPHERIC PRESSURE NOW LOWER THAN 3 HOURS AGO.
5 Decreasing, then increasing.
6 Decreasing, then steady; or decreasing, then decreasing more slowly.
7 Decreasing steadily or unsteadily.
8 Steady or increasing, then decreasing; or decreasing, then decreasing more rapidly.

ppp = the absolute value of the change of either the station pressure or the altimeter in the past 3 hours coded in tenths of hectopascals and using the tens, units, and tenths digits

e.g., a steady increase of 3.2 hectopascals in the past 3 hours would be coded 52032.


I didn't have this in my memory bank. You can find the source info at this link.

http://www2.faa.gov/atpubs/SWO/chapter_15.htm#Figure 15-9. Characteristics of Barometer Tendency

 

[a-v-8er]

Thanks!

 

[wxman]

Wow, glad to see that someone is actually interested in knowing what that stuff means. I've been a certified weather observer for 14 years, and a flight instructor for 7 years. Most pilots could care less what anything after A2992 means.

 

[Limeyflyer]

I got drilled on those definitions on my CFII ride by the FEDS. Luckily I studied them. Still sucked though.

 

[huncowboy]

skiddriver,

thanks for the link!!!!!!!!! Awesome!!!

 

[turboshark]

metar decoders needed?

id have to agree with the weather observer. from what i can say to this is...."id need to see my metar decoder to figure this out." is strange that the rest of the metar is understandable except for the trash at the end. go figure..........