Saturday, March 16, 2024

Quick Summary



View of Table Mountain and Finger Rock at 7:40 am MST this morning.


Plot of detected CG flashes yesterday (above - from Atmo and Vaisala) for 24-hours ending at 0803 UTC today. There were just a few flashes in Pima County, but TUS and DM both noted thunder around 6:00 pm.


Precipitation reports from the ALERT network (above and below for 24-hours ending at 7:30 am this morning. Amounts were generally light, with a bit of a donut hole over metro Tucson. Here at the house there were off-and-on showers that left only 0.03" in the gauge; TUS had 0.01" while Atmo and DM both reported 0.04".


The GEFS plumes for QPF from the 06 UTC GEFS indicate chances for another very light event tomorrow and again around Tuesday. Note that the plumes yesterday over-did the event - see previous post. The temperature plumes (below) indicate gradual warming through the coming week.

Friday, March 15, 2024

Showers West Of Metro Area



View of pre-sunrise colors looking toward the Rincons at 6:35 am MST this morning. View at bottom is looking toward the Catalinas at 6:40 am.

At 500 mb this morning (above) the closed low is centered somewhere near Yuma. The low is forecast to linger over Arizona into early next week. The GFS forecast below is valid at 00 UTC on St. Patrick's Day.

This morning there are showers west of interstates, that are moving rapidly northward. The precipitation forecast from the 12 UTC WRF-RR (below) is valid for the period ending at midnight tonight. Widespread rain/snow covers all of Pima County. The morning NWS forecast for the airport is giving a 60 percent chance of measurable rainfall today.


Thursday, March 14, 2024

Showers Likely Tomorrow



View of Rincons before sunrise this morning.

Analysis for 500 mb at 12 UTC this morning (from SPC). Note that closed circulation is actually over southwest Utah, rather position indicated on analysis. Forecast from 06 UTC GFS (below) moves the low center to southwest Arizona  by 12 UTC tomorrow morning.

Plumes from the GEFS for the 06 UTC runs - above for QPF at airport and below T at the airport. Most of rain event is forecast during the day tomorrow. Temperatures drop considerably for tomorrow also.

Forecast above is from the 12 UTC WRF-RR run at Atmo - shown is precipitation forecast by the model through noon on Saturday. Current morning forecast from the TUS Forecast Office is shown below.

Tuesday, March 12, 2024

Showers Possible By End Of Week



View looking toward Rincons/Redington Pass at 6:55 am MST this morning.

The GEFS plumes for rainfall amounts at airport (from 06 UTC runs - above) indicate showery periods into early next week. Note the wide range of values and timing, so things are a bit uncertain at this time. The plumes from same runs for winds (below) indicate the possibility of some gustiness and stronger speeds for tomorrow and Thursday.


The GFS 500 mb forecast (above from 06 UTC run shows a strong, closed low over Arizona and southern California at 12 UTC on the 15th (Friday).


The precipitation forecast from the 06 UTC WRF-GFS run (above) indicates light precipitation amounts for eastern Pima County through 11:00 pm on the 16th (Saturday). The morning NWS TUS forecast for the airport is shown below for Thursday through Saturday, with highest POPs on Friday. It should be an interesting end-of-week and weekend.

Monday, March 11, 2024

Winter Summaries


Nasty driving conditions on I-10 morning of February 28th.

Winter overview - Rainfall here at house was 4.74" for December through February. This was the third wettest winter season here since 1999. Wettest winter was 2007/08 with 5.75", and second wettest was 2019/20 with 5.05".

For comparison, the driest winters here have been: 1999/00 with 0.31"; 2021/22 with 0.61"; and 2013/14 with 0.67".

Friday, March 08, 2024

Widespread Precipitation



View at 7:15 am MST this morning looking toward Catalinas. At bottom is view of snowy conditions in Summerhaven at 7:00 am.

Plot of detected CG flashes for 24-hours ending at 1123 UTC this morning (from Atmo and Vaisala) shows that there was widespread thunderstorm activity across much of Pima County yesterday afternoon. Airport reported thunder, but nearby DM did not.

There was essentially 100 percent coverage across the ALERT network for 24-hours ending at 10:30 am this morning (above and below). Many sites reported over half an inch, with two sites in Catalinas reporting over an inch.

Here at house we had 0.39". The airport reported 0.52"; Atmo had 0.48"; and DM had 1 inch. All-in-all a nice early March precipitation event.


Thursday, March 07, 2024

Showers Likely



A bit of pre-sunrise color this morning looking toward Redington Pass at 6:15 am MST.


The 500 mb analysis for the continental US (above) shows the trough that will affect us today and tomorrow currently stretching, north to south, across Nevada and far southern California. The current upper-air sounding from TUS/TWC (below) continues to show very strong westerly winds aloft. However, the sounding is currently very stable and dry - no CAPE and less than a quarter of inch of precipitable water. A special noon sounding could prove very useful today.



The MIMIC 1300 UTC analysis of total PW (above) does show a band of more moist air out to our west. The GEFS plumes from 06 UTC for QPF at the airport (below) all indicate rainfall beginning mid-day and extending into Friday afternoon. Average amount at the airport continues around a third of an inch.

Forecast above shows total precipitation forecast by the 09 UTC WRF-HRRR at Atmo with accumulated rain and high elevation snow across all of eastern Pima County. Current morning forecast graphic/statement from the NWS Forecast Office is shown below.