Yesterday’s Weather

Fairly quiet overall for the Southwest. A few storms formed in Eastern New Mexico but they were weak with only minor microbursts less than 30 kts. Arizona saw 110+ F temperatures in the deserts due to subsidence.   

Analysis

250 mb shows strong westerly winds continue across the region dragging in dry air across the region.

At 500 mb, the upper level ridge is still north of Guaymas with westerlies over the region. Warm air aloft is also spreading across the region with temperatues of -5C.

At 700 mb, the ridge is west of Guaymas and extends into the Pacific acoss the Baja Peninsula. Very dry air is on the north side of the ridge with Phoenix sounding showing dewpoint temperature of -14C.  At the surface,  a weak cold front is dropping south across far northeast New Mexico. 

The National Weather Service in Tucson has shifted the 12Z sounding to 18Z for the monsoon. The Phoenix sounding shows no CAPE with very dry air aloft. When using this and other similar soundings its best to used mixed layer CAPE as it smooths out the “bad” data such as the high surface dew point that is there from modification of the boundary layer from irrigation sprinkler systems. Also, when we actually get storms they will also modify the sounding. 

Today

The dry air aloft is suppressing convection across the region. The front in northeast New Mexico moves southward and will move down to southeast New Mexico by Wednesday morning. There is an increase in CAPE but it cannot overcome the CIN from all the dry air aloft so no thunderstorms will be able to form. The rest the area will remain free of convection and will have to deal with the hot temperatures. 

Tomorrow

This will be another down day across the region as the warm and dry air aloft will suppress any convection. The front in eastern New Mexico moves into west Texas. Still too much CIN to overcome, so it will be another hot day and temperatures will go up a couple of degrees from Tuesday.

Outlook to later this week

Thursday will be the hottest day of the week with temperatures near 114 degrees in the Phoenix and 115 degrees Gila Bend region. Temperatures will then slowly cool as the jet stream drops south with temperatures dropping about 5 to 10 degrees with the most cooling in Arizona deserts.

Tomorrow, we’ll comment more on the possibility of convection and precipiation in New Mexico on Thursday.

Discussion written by Pat Holbrook