20160505

Another strong cold upper low with limited moisture moves over Arizona during the day tomorrow, very much like the previous system from about a week ago.

12z WRFNAM

Like the previous system, there will only be limited moisture available, but it does look like there is enough to support showers and a few storms over the western 1/3 of the domain.

 Some CAPE is present during the late afternoon around Phoenix and to the west and south, where moisture is slightly elevated.  Moderate inverted V profile will again indicates some of the areas of convection will have strong gusty winds.

Areas of showers and a few thunderstorms are present by afternoon over the western 1/3 of Arizona.  Stronger storms are restricted to SW Arizona where there is more moisture and CAPE available.   The WRFNAM and WRFGFS differ in the timing with the WRFGFS forming storms closer to the Phoenix area as early as 3pm while the WRFNAM holds off until early evening.

12z WRFGFS

Areas of SW Arizona and towards the Phoenix area and down into Pinal county could see localized gusty winds and some blowing dust as well as some lightning.  I don't have the WRF lightning forecast operational yet so I can't be more specific.  The bad spot is again going to be far SE Arizona along I-10 west of San Simon.  Winds in the 30+ knot range with higher gusts are forecast.

Unlike the previous system, showers with a few weak storms continue into the late evening over central Arizona.

Recent model runs indicate storms around the Phoenix area around 4-6pm with around 10-15F cooling from the activity.  Much cooler in the Phoenix area tomorrow.