UA WRF Forecast Discussions

Synopsis A low pressure system in Southern California will gradually move eastward into Arizona leading to unsettled weather through Wednesday night. Precipitation will mainly impact the higher terrain in Northern Arizona today and tomorrow with precipitation chances increasing in Southern Arizona on Wednesday. Rainfall amounts will be light and variable with a trace to 0.25 inches in the lower deserts and between 0.25 and 0.75 inches over the higher terrain with locally higher amounts possible along favorable southwestern facing slopes of the Mogollon Rim. Snow levels will remain mainly above 4000 feet today and tomorrow with total 72-hour snow accumulations ranging  from a dusting to 4 inches, but locally higher amounts are possible over the tallest peaks of Northern Arizona. On Wednesday, snow levels will likely drop to 3000-3500 feet which means some higher valley locales could receive a dusting of snow.  Current Conditions As of 11AM MST, visible satellite imagery an...

Synopsis An upper level closed low, currently centered over the lower Colorado River Valley, will continue to dig southward into Northern Mexico throughout the day today. This feature is expected to provide Arizona with cold temperatures, strong winds, and scattered, light precipitation late tonight through Wednesday. Easterly winds on the order of 20 to 40 knots are expected across the region with strongest wind speeds over the higher terrain and in Southeastern Arizona late tonight through Wednesday afternoon.  Even though this upper level low is dynamically robust, it is quite moisture starved leading to only light precipitation accumulations.  Snow levels will be relatively low with some light snowfall possible in some of the valley locations mainly east of Tucson and above 3000 feet. Snow accumulations over the high terrain will be light with only 1 to 3 inches possible. Besides precipitation chances, Wednesday will be a chilly day across Ari...

  Synopsis A mid latitude trough is expected to continue to dig southeastward along the West Coast throughout the day today and eventually reach Arizona later tonight. This feature will allow 500mb heights to fall leading to much cooler temperatures as well as a chance for valley rain showers and mountain snow across mainly the eastern half of the state. In addition, UA WRF model soundings forecast a relatively shallow layer of instability (CAPE on the order of 100 to 300 J/kg) tomorrow across the region, so an isolated low-topped thunderstorm or two is possible. Rainfall amounts are expected to be light, with between a trace to 0.10 inches in the lower deserts, and between 0.25 and 0.50 inches over the higher terrain with highest amounts possible along the southwestern facing slopes of the Mogollon Rim and White Mountains. Snow levels will remain above 6000 feet with a trace to 6 inches expected with locally higher amounts possible over the tallest peaks.    Current Cond...