Monday, July 28, 2025

Showers This Evening?


Pre-sunrise color at 5:30 am MST this morning, looking toward Redington Pass.


There were no detected CG flashes across Arizona yesterday, as shown by the 24-hour plot (above, from Atmo) ending at 1033 UTC (0333 am).


This morning's seven day outlook from the NHC (above) shows an active Pacific, including Cat. 1 Hurricane Iona over the Central Pacific. Off the southwestern coast of Mexico, there is a 90 percent chance that a depression or storm will develop by the end of the week.


Large anticyclone continues to dominate
much of eastern US (above, from SPC). There is a large, inverted trough over northern Mexico; however, the missing 500 mb data over New Mexico and Colorado keep us from knowing how far north this feature extends.


Forecast from the 15 UTC run of the WRF-HRRR at Atmo (above) shows just a bit of light shower activity over Pima County through midnight. The current morning forecast from the NWS Office is shown below. Forecast indicates 20 to 50 precent POPS for all periods through coming seven days.

Saturday, July 26, 2025

Possible Showers At End Of Month


Sunrise, with a bit of contrail, looking toward Redington Pass at about 6:00 am MST.


Yesterday was a rare July day with no detected CG flashes across the entire state, as per plot above for 24-hours ending at 0703 UTC (a bit after midnight last night - from Atmo).


The QPF plumes from the 06 UTC GEFS runs (above, for airport) keep things dry until first part of next week.The total precipitation forecast from the 06 UTC run of the WRF-GFS at Atmo (below) shows no rainfall in Arizona through noon on Monday.


The 06 UTC GFS forecast for 500 mb (below, valid at 06 UTC on the 29th) shows a huge anticyclone dominating most of the country with an inverted trough approaching eastern Arizona, which will bring the showers indicated on the GEFS QPF plumes.

Wednesday, July 23, 2025

Light Showers Here


Some pre-dawn color this morning looking toward Redington Pass at 5:45 am MST. Down at bottom is view looking the same direction, showing a bright, partial rainbow at 6:40 pm yesterday.


Plot of detected CG flashes (for 24-hours ending at 0803 UTC - 0103 am - from Atmo) shows abundant lightning across eastern Pima County. There was frequent thunder here but only a light, late afternoon, shower. Plot of ALERT Network data (below - for 24-hours ending at 7:00 am this morning) indicates mostly light amounts of rainfall. Atmo reported 0.27"; we had 0.04"; TUS had 0.01" and DM reported thunder with gusts to 36 mph but only a Trace of rain. Note the heavy amounts around and south of Vail.



The 06 UTC plumes for QPF at the airport (above) indicate a long dry period into early next week. The plumes for temperature (below) indicate warming temperatures, until early next week. The GEFS POPs (second below) indicate 50 to 60 percent chances for showers early next week, toward the end of July.



Tuesday, July 22, 2025

Showers Across Area


Buildups over the Catalinas at 8:00 am MST this morning.


Plot of detected CG flashes (above from Atmo) shows almost no activity over eastern Pima County. However, precipitation was widspead across the ALERT Network (below and second below) for 24-hours ending at 8:00 am this morning. Amounts were mostly light, except in southern parts of the network. Here at the house there was 0.17" during a midafternoon shower; TUS had 0.13"; DM reported 0.08"; and Atmo had 0.19".




Forecast above (from the 12 UTC WRF-RR run at Atmo) indicates rainfall through midnight for much of eastern Pima County. Current forecast from the NWS Forecast Office is shown below. 

Monday, July 21, 2025

Showers In The Forecast


Clouds over the Catalinas at 7:20 am MST this morning.

The 06 UTC plumes for QPF at the airport (above) from the 06 UTC GEFS runs. Precipitaton peaks tonight and tomorrow. Plumes for temperature below indicate mild today and tomorrow and then heating up the rest of the week.



Precipitation forecast through midnight tonight (from the 12 UTC run of the WRF-RR at Atmo - above) indicates heavy precipitation for eastern Pima County - a bit earlier than the GEFS plumes, which indicate max POPs tomorrow (below).



NWS forecast graphic (above) and am details (below) also focus on best chances for rain being today.

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.