Local Outlook

Sunrise east of the Catalinas this morning.

The local NWS outlook here is for a chance of severe thunderstorms with damaging winds (above). However, SPC outlook for today keeps severe storm risks far to northeast of our area. The current NWS forecast for the airport is second below.

Update And Monsoon "Start"

View looking toward the Rincons at around 4:30 am MST this morning.

There is an article in the the morning paper that states the 2026 monsoon has arrived, right on time. However, this is based on the NWS definition of a "Monsoon Season" running from June 15th to September 30th. This definition ignores the actual meteorological conditions that might be prevailing.

Yesterday's 0.19" of rainfall presents an example of the problems of the seasonal definition.

The rainfall was associated with a weak shortwave that sneaked in from the Pacific - consider the 500 mb charts from the 06 UTC GFS forecasts.

The 500 mb chart for this morning (above) shows the weak disturbance over Arizona. The 7-day forecast (below) shows the typical monsoon high at 500 mb situated across central Baja, with a weak trough still across Arizona. The fourteen day forecast (bottom) indicates a large trough dominating the western US at 500 mb. There is no indication in the forecasts of the typical Four-Corners anticyclone that defines the summer monsoon circulation at 500 mb. So, if the forecasts are accurate, the start of the summer monsoon, from my perspective, remains several weeks away.

Stormy

Skies clearing at 11:00 am MST. Current rainfall reports across eastern portions of the ALERT Network (below) indicate amounts up to just over an inch. Here at house there is currently just 0.19" in the gauge.

Several periods of showers and some thunder beginning yesterday evening and continuing this morning. At 6:45 am (view above) there was only 0.06" in the gauge but more rain has fallen since. Will update things later today. Plot of detected CG flashes (below - from Atmo) shows considerable activity over eastern Pima County through 1443 UTC.

Mysterious Radar Echoes

Map above shows the Goldwater Range and the Army's Yuma Proving round, with I-8 stretching through a narrow corridor from Gila Bend to Yuma.

Tuesday afternoon (June 9th) I noticed some radar echoes out northeast of Yuma around 3:45 pm MST (above and below). The echoes were only present in the lowest two tilts of data and were moving north-northeastward. Skies were, however, perfect clear - see concurrent visible satellite image - second below. Note that bird and insect migrations usually occur in the evening and during the night. So what was going on?

I assume that some exercise or activity at Yuma Proving Ground injected chaff into the near-surface atmosphere. Below is some kind of big armament out at Yuma Proving ground. The echoes dissipated after an hour or so. There was no similar activity yesterday afternoon. There was also no mention of the strange echoes in either the Tucson or Phoenix NWS weather discussions covering the relevant times. This event was also reminiscent of the high-level chaff releases that the Air Force used to do over the Goldwater Range. 

Moonrise and Sunrise

Rising quarter moon, looking toward the Rincons about 2:30 am this morning. View at bottom is a bit before sunrise.

Plumes from GEFS rins at 06 UTC this morning. Above shows QPF amounts at the airport, indicating chances for light showers around the weekend.

The plumes for PW exceed and inch over the weekend (above); and POPs for the airport (below) stay under 30 percent. Will have to watch how the plume forecasts evolve as weekend approaches.

Tropical Storms Boris and Cristina

 

Tropical Storm Boris has developed early this morning over the eastern Pacific. As the NHC graphic (above) shows, Boris is just south of the coast of southern Mexico. The storm is forecast to be  short-lived and to move ashore this afternoon. 

Updated at 1800 UTC today 8 June: The NHC has upgraded the second disturbance in the eastern Pacific to Tropical Storm Cristina. Current track forecast shown below.

Summer Outlook

View toward the Rincons at 5:30 am this morning - a bit after sunrise.

This spring (Mar, Apr, and May) was relatively dry here with only a total of 0.66" of rain. Since 1999 this was the 11th driest spring. The wettest spring here was 2004 with 2.71", while the driest was in 2018 with only 0.03" for the three months.

The current NWS Climate Prediction Center (CPC) outlook for this summer is below - they expect the warmth over the West to continue, along with a slight chance for above normal rainfall. Of course, one big storm day here can determine the character of the entire summer - so we will watch to see how things evolve.