Monsoon Forecast Discussions 2023

   Synopsis This is the second part of a forecast discussion regarding a strong Pacific Storm expected to impact Arizona starting this evening and persisting into Wednesday morning. The first round of moderate to heavy rain is expected to begin this evening and persist into the early morning hours tomorrow. A few sporadic lightning flashes are possible within the heaviest rain bands, but better instability tomorrow afternoon will promote a greater chance of thunderstorms particularly across Eastern Arizona. Snow levels will remain above 7000 feet with this storm.   Current Conditions Current radar and IR satellite imagery as well as lightning detection networks indicate a large area of showers with a few embedded lightning strikes across the western half of Arizona moving rapidly eastward. This area of precipitation is associated with PVA ahead of a shortwave and a region of strong upper level divergence due to left exit region dynamics as indicated by the current SPC 300mb and 500mb a

  Synopsis This is the first part of a forecast discussion regarding a strong Pacific Storm expected to impact Arizona starting this evening and persisting into Wednesday morning. The first round of moderate to heavy rain is expected to begin this evening and persist into the early morning hours tomorrow. Snow levels will remain above 7000 feet with this storm.   Current Conditions Regional visible satellite imagery overlaid with GOES GLM flashes indicates a band of heavy showers moving through far Southern California with a few sporadic lightning strikes just off the coast of San Diego this morning.  Visible satellite imagery overlaid with GLM flashes courtesy of College of Dupage. Current SPC 300mb analysis displays a strong jet streak just off the SoCal coast with a region of upper level divergence over far Southern California associated with the left exit region dynamics. SPC 300mb analysis as of 18:00z. Current SPC 500mb analysis shows a shortwave trough just off the SoCal coast w