Wednesday, July 16, 2025

Heavy Rains Across Region


View from campus at 0737 am MST this morning shows rain over north part of city, obscuring foothills and mountains.


Plot of detected CG flashes for 24-hours ending at 1433 UTC (0733 am - above from Atmo) this morning shows numerous flashes over our part of Pima County.


ALERT data for 24-hours ending at 7:50 am (above and below) shows numerous sites exceeding an inch and two very heavy amounts toward southwest end of the Catalinas. The airport reported  1.29"; DM had 1.25"; we had 1.10" here; and Atmo reported only 0.69". I estimate that about 0.60" fell here before midnight, with about 0.50" after midnight.




QPF plumes from SPC (above) keep the rain going at the airport through rest of day, and then shut things down for a couple of days. The morning 500 mb analysis (plagued by all the missing sites) indicates a broad, inverted trough across the south half of Arizona. Finally, a nice event breaks the dry spell that covered most of first half of July.

Tuesday, July 15, 2025

Thunder But Little Rain


View of Catalinas at 5:40 am MST, with some sunrise color at eastern edge.


Plot of detected CG flashes (above from Atmo) for 24-hours ending at 0733 UTC indicates an active cluster of storms to the northeast of here. Storms mostly affected the Catalinas and also portions of mid-town, as per ALERT plots (below for 24-hours ending at 7:00 am).

We had frequent thunder here, but only a brief, light shower just before 4:30 pm that produced only 0.01". DM reported a Trace; NWS and Atmo had no rain.  Winds were strong with gusts to 45 mph at DM; gusts to 36 mph at the airport; and I estimated 30 to 35 mph here.



The GEFS plumes for QPF (above from 06 UTC runs) continue to indicate an active week with frequent, but light showers. The GFS goes wild this evening, indicating almost an inch of rain in a heavy shower. GEFS POPS for the airport (below) hit almost 90 percent this evening.

Will eagerly watch how things develop today.



The 12 UTC WRF-HRRR forecasts an inch of rain at the airport through 1:00 am tonight (above) and the NWS issued a Flash Flood Watch (below) valid this afternoon and evening. Current morning forecast from NWS Forecast Office for the airport is at the bottom.


Monday, July 14, 2025

Dry Spell Hits 11 Days


View of Catalinas at 8:00 am MST this morning, showing a few high clouds over the mountains.


Another day with no detected CG flashes (above, from Atmo) over all of Pima County. There was again no rainfall anywhere in the ALERT Network and none here. Last rain here at house was on the 3rd, 11 days ago, which is a long dry spell for July.


 Rainfall forecast from the 06 UTC WRF-HRRR run (above, valid through 6:00 am tomorrow morning) indicates precipitation over the mountains and southern portion of eastern Pima County. Morning forecast from the NWS Forecast Office (below) calls for 40 percent POPs today, increasing to 70 percent for Tuesday night.

Long-term outlook from the GFS through the 30th of July (below) keeps Tucson just at northern end of heavy precipitation plume that covers western Mexico.

Friday, July 11, 2025

Another Dry Day

 

The full, Hunters' moon rising near Redington Pass at 10:00 pm MST last evening.


IR image this moring from 6:12 am (above) shows clear skies across Arizona. The plot of detected CG flashes for 24-hours ending at a bit after midnight last night (below - from Atmo), indicates one isolated thunderstorm across all of Arizona, over the Chiricahuas. Yesterday was another day with no precipitation reported across the entire ALERT Network.



Map of forecast high temperatures for today, from the NWS Forecast Office (above) indicates 105 F for Tucson. Yesterday's high was 109 F and Wednesday's high was 113 F - tying the record high for the date.


The GEFS plumes for QPF from 06 UTC last night (above) continue to indicate chances for showers next week. The preciptation type plot (below) indicates POPs reaching 40 percent late in the week.

Thursday, July 10, 2025

Mostly Dry

View of the Catalinas at 08:30 am MST this morning.

While July began with rain here on the 2nd and 3rd, it has been dry ever since, with not even a sprinkle.


Two sites in the ALERT network reported light rainfall during the 24-hours ending at 08:30 am (above). The plot of detected CG flashes (below, from Atmo) for 24-hours ending at 0903 UTC (0203 am MST) shows no flashes in Pima County, and just scattered flashes in southeast Arizona - very quiet for July.


The 06 UTC GEFS plumes for QPF (below) indicate a chance for light showers beginning early next week.

Wednesday, July 09, 2025

Isolated Storms Yesterday


Storm off to the northeast of main metro area yesterday afternoon produced rain, some heavy, toward and across Redington Pass (above and below). Image above from campus at 5:00 pm MST and ALERT precipitation below for for 24-hours through 7:00 am this morning. Note that Sunday and Monday were completely suppressed with no rainfall anywhere across the ALERT Network.



Current morning forecast from NWS (above) highlights the Extreme Heat Warning that is effect today. Seven-day rainfall totals from the 06 UTC GFS forecast (below) keep Tucson area just along the northern edge of the heavy precipitation plume that extends across all of western Mexico.

Sunday, July 06, 2025

Isolated Storms Yesterday

 


There were isolated storms and showers around yesterday afternoon. These occurred mainly over the Catalinas and Redington Pass area.

 There were also storms over the far southwest portion of the Alert network. See graphics above and below.

Saturday, July 05, 2025

Very Suppressed On The Fourth


It was very quiet and suppressed yesterday - view above is from 5:00 pm MST on the Fourth.


Detected CG flashes (through 0853 UTC above - from Atmo) remained far to our south along the Borderlands. There was one report of 0.04" on the MesoWest precip site through 8:00 am this morning (below). Report could be valid since there was a decaying, weak radar echo in that area.



Current forevast for rest of weekend from the NWS is above. Note that every forecast period through the coming seven days has POPs of 20 to 40 percent. The rainfall forecast from the 12 UTC WRF-RR run at Atmo (below) keeps the precipitation through 6:00 pm tomorrow mostly south of the main metro area.

Friday, July 04, 2025

Heavy Storms On 3rd


Heavy storm over this part of the metro area at 2:20 pm CST yesterday afternoon.Widespread CG flash activity across eastern Pima County yesterday shown in graphic below for 24-hours ending at 0933 UTC (0233 am MST) - from Atmo site at Univ. of Arizona.


Rainfall across parts of MesoWest network for 24-hours ending at 7:00 am MST this morning (below). Here at the house the storm pictured above left 0.62" in my gauge. Note that heavy rain amounts occurred over a small area around here and just north of the Rillito.



Looks like much less activity today as per 06 UTC QPF plumes (above) and forecast from the WRF-HRRR run from 12 UTC this morning (below) valid through 10:00 pm tonight - from Atmo web site.

Thursday, July 03, 2025

Scattered Showers Yesterday


Dark skies with some showers around yesterday afternoon at 2:00 pm.


MesoWest rainfall reports for 24-hours ending at 7:00 am MST this morning. Amounts were generally light, although 5 sites (2 in Catalinas, 2 in Santa Cruz County, and 1 above had more than an inch). Here at the house we had a light, afternoon shower that left only 0.02" in the gauge. The airport reported 0.38" (and a gust to 47 mph); DM had 0.01"; and Atmo reported 0.03". There were widespread CG flashes detected across most Arizona (plot below shows CG flshes detected through 0803 UTC early this morning).




Plot of Total Precipitable Water (above for 13 UTC this morning) shows that high values had spread across much of Arizona. The remnants of Hurricane Flossie are southwest of Baja.

Plumes from the GEFS runs at 06 UTC (above for QPF and below for temperature - both at airport) show light showers around for much of the coming week. The temperature plumes show a gradual heat-up into the 100s F is on tap as we head deeper into July.

Current NWS forecast for today and Fourth of July is shown at bottom.