execute block first before last line of the method - objective-c

Question

The line of code inside blocks in objective c is executed later after executing other lines of code in the same method.
My query is:
There is a method named :
-(NSDictionary*)callingWeatherService{
NSString *urlString = #"http://api.openweathermap.org/data/2.5/weather?q=London,uk";
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString]];
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
operation.responseSerializer = [AFJSONResponseSerializer serializer];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
// 3
self.dictionary = (NSDictionary *)responseObject;
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
// 4
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:#"Error Retrieving Weather"
message:[error localizedDescription]
delegate:nil
cancelButtonTitle:#"Ok"
otherButtonTitles:nil];
[alertView show];
}];
// 5
[operation start];
return self.dictionary;
}
But the statement return self.dictionary; gets executed first before block execution so dictionary is returned as nil;
Is there any solution that statement return self.dictionary; is executed only after block execution. I need this approach for a specific purpose.
Don't want to use delegates, I had already used delegates inside afnetworking blocks for getting dictionary data.

Answer 1

The short answer is no - blocks are designed to be performed asynchronously, meaning that you never know when they complete. It would be really dumb to change this behavior.
Either use delegates, or use KVO assigned to the dictionary variable or NSNotifications. If I were you I would definitely use delegates.