Hello everyone, just practicing reading the MSL chart ,

Fig 48
I believe that RP is a trough, JK is a cold front but there is a solid line MN
MN is a solid line it seems to be the protruberances from a High and therefore I presume it is a Ridge but I cannot find it in BOM or other charts
Can someone help

Also can someone please validate
A = Low , B = High C = Coll
There are numbers in squares 10, 20, 30 etc can someone please assist me with what these are?

Fig 49
A = Low
B = High
C = Coll
Similarly
JK cold front
MN ridge
PR = trough

Again there are multiple numbers in square boxes what are these for? are they to lable the value of the isobars?

Regards

Ravi