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 northwest 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.

Eastern Pacific Tropical Storm

The eastern Pacific is fairly active as we head into June - above. Tropical Storm Amanda is the first of this season.

Her center is just to the east of the stroger storm cluster in the 1350 UTC IR image above. The storm is far southwest of Baja and poses no threat to land. The forecast from NHS early this morning is shown below. It keeps Amanda at TS levels as she drifts generally westward.

Storms Yesterday

View of heavy storm over the Catalinas and foothills at 5:45 pm MST yesterday afternoon.

Plot of CG flashes detected during 24-hours ending at 7:30 am this morning. Note the abundant activity across eastern Pima County.

Rain from the ALERT network (above) for 24-hours ending at 7:00 am this morning, and for same period from CoCoRaHS at Atmos Science page CSU, Ft. Collins CO, across low-elevations of the metro area (below). Here at house we had two brief showers between 3:00 pm and 6:00 pm yesterday afternoon. There was thunder and wind to around 30 to 35 mph with the second shower. Total rainfall was only 0.07" here.

Very Isolated Showers

 Update - only four ALERT sites had rainfall yesterday of 0.04" or more (one of these had 0.08"). Sites were in the Catalinas, plus one at far southwest corner of network.  In sum, a very quiet day across the metro area.