A late start but as a cooler than normal Southern California has turned around so will the monsoon in Arizona and evidence is finally there to warn of a strong upswing in the state-wide monsoon levels as we close the month off and go into September so read on for details.
The Arizona Monsoon usually peaks around this time. However, during certain years we see a later start to it and a September peak. This looks very likely this year just as it was last year. In September the monsoonal moisture comes from two different atmospheric profiles. The first one is the Eastern Pacific Hurricanes getting moisture streaming north of them and into the monsoon ridge. The second is when the jet stream starts to become active again as the polar jet is affected by the solar heating and sends cutoff lows down into California. These cutoff lows can bring up tropical moisture from hurricanes in the Eastern Pacific. September can be a very dynamic month as we can very well see a repeat of last September across the state where it all come together in the month of September to finish off the monsoon season.
Remember, unless I issue a SEVERE THUNDERSTORM WATCH in the metros you can bet on mainly isolated activity. Nothing gets by me and we will take it one day at a time as events line-up.
Stay tuned to official forecasts here at Arizona Weather Force