20160623

Increased storm activity is expected starting tomorrow as moisture increases.  Moisture has been increasing over northwest Mexico over the past few days resulting in much more afternoon and evening convective activity over the Sierra Madre.  This diurnal pattern is forecast to continue which will result in increasing moisture across southern Arizona due to outflow type surges.

Day 1
Not much activity expected in spite of increasing moisture as much of southeastern Arizona is cloudy thus reducing heating.  Most model runs missed this area of clouds and showers with only the 6z WRFGFS having any significant amounts present.  Even the models that have too much heating predict very little deep convection except along the AZ-NM border.

Day 2
A substantial increase in moisture is forecast for southeastern Arizona by tomorrow with much of the increase coming in the lower part of the atmosphere as 850mb Td over 10 degrees are over much of that part of the state.   However, this big increase in moisture is only forecast by the WRF runs that use the GFS.  The WRFNAMs are somewhat drier.

WRFGFS

 Other negatives include poor steering and possible debris clouds holding back heating.  In spite of these, the WRFGFS has over 1000 J/Kg CAPE and fairly deeply mixed PBL at Tucson.

The best case shows strong storm near the Tucson area by mid to late afternoon.  The previous WRFGFS runs area similar.  The WRFNAM runs also have strong storms somewhat farther south, near the border.  As steering is weak, individual storms don't move much. 

12z WRFGFS

Strong winds are likely in and close to the storms but no major outflows are expected in Pinal or Maricopa counties.

Due to slow storm motion, some areas could see some high amounts of precipitation (1.5 inches)

12Z WRFGFS

 Extended
Moisture continues to slowly increase along with chances of deep convection.  Beginning Sunday, mid level flow becomes mainly easterly with 10-15 knots as the high becomes centered over the 4 Corners and a large TUTT feature over the Big Bend continues to slowly move to the west. thus increasing the possibility of organized convection making it's way to the lower deserts for during the start of the week.