Chance Of Sprinkles

Heavy cloud cover across the metro area at about 7:00 am MST this Sunday morning.

The 12 UTC TWC/TUS sounding (above) shows a moist layer in mid-levels from 350 to 650 mb, but with very dry low-levels. At 500 mb there is a weak trough from southwest Utah down to northern Baja. This feature will move across Arizona today, bringing clearing with it. However, as it moves eastward, there is a very slight chance for sprinkles this morning. The coming week, now to Christmas, will be mostly cool and dry.

Frosty Morning

 

The Geminid meteor shower is underway. The Atmo webcam pointed at the Rincons caught one at 6:00 am MST this morning. Down at bottom is pre-sunrise view of the Rincons at 7:00 am.

There was some light frost here at the house this morning, and our low was 26 F - first time low has gone below 30 F this winter. Temperatures were cold and mostly freezing or colder - morning lows from MesoWest are shown above.

The 06 UTC GEFS plumes for temperature this week are shown above. We can look forward to a gradual warm-up beginning tomorrow. Current NWS forecast for today and tomorrow is shown below.

Widespread Rain Event

Mostly clear skies at 7:53 am MST this morning. There was a light dusting of snow on the Catalina foothills with greater amounts up at higher elevations.

The 500 mb analysis this morning (above) shows the closed low has moved eastward and is centered over southeast Wyoming - not southeast Colorado as the analysis indicates. Note the 100 kt wind speed over southwest Kansas.

Shown here are event totals for rainfall from the ALERT network. There was a second, light period of precipitation after dark last night, but bulk of precipitation was with the morning rain. Note the numerous reports of more than half an inch. Here at the house we had 0.34" in the morning, and then another 0.04" around midnight - total of 0.38" for the event. 

Plumes for temperature (above from 06 UTC GEFS) indicate two more cold mornings and then moderating temperatures. Low temperature here this morning was 32 F, but it will likely drop into the 20s F tomorrow and Thursday mornings. Current NWS forecast for the airport shown below.

Finally a look ahead. The GFS forecast below is valid at 18 UTC on Christmas Day and indicates a large surface high will dominate the central US, but with some rain and snow in the Northwest and the Northeast. 

Rainy Morning

Chilly, windy morning across the metro with areas of moderate to heavy rain. Temperatures at low elevations in 40s and 50s F and winds gusting 30 to 40 mph. View above looking toward Catalinas from campus at 7:45 am MST, and view at bottom shows snow cover at the General Store in Summerhaven at 7:30 am.

The 500 mb analysis shows that forecasts over the weekend for this level were generally accurate - low center currently over southern Idaho, with embedded shortwaves over Arizona and central California. Radar below (1st tilt) is from 7:45 am MST, showing strong echoes across much of the metro area.

Rain amounts across the ALERT network (above and below) are for three hours ending at 8:00 am this morning. Don't have amount for here since it's raining fairly heavily and I haven't been out to the gauge. More later.

Nasty Day Tomorrow

View of Rincons at 5:45 am MST this morning.

GFS 12 UTC forecast for 500 mb level at 5:00 pm tomorrow evening, with cyclone over Utah and strong trough and winds impacting Arizona - jet forecast to be nearly overhead.

The GEFS plumes from 06 UTC (above) indicate some snow mixed with the rain at the airport.

The 12 UTC WRF-RR this morning indicates snow inching into the southeast metro area - forecast is for accumulation through noon on Tuesday. 

Morning forecasts from the NWS keep snow accumulations on the mountains (above) with high rain POPS for the airport (below). Should be very interesting day tomorrow,

Big Changes Next Week

View of the Catalinas at 7:35 am MST tis morning shows scattered clouds and some haze/dirty air over the metro area.

The GFS 500 mb forecast valid for 12 UTC this morning (above) shows a weak trough across southern California that will move across Arizona during the next 36 hours. By next Monday/Tuesday a very strong trough will dig into the West - GFS forecast below valid at 5:00 pm on next Monday.

Plumes from 00 UTC last evening (above for QPF and below for precipitation type) indicate chances for significant precipitation on Monday. Note that the forecast below for precipitation type indicates slight chances for a bit of snow mixed with the rain.

Precipitation forecast above shows GFS totals through 5:00 am next Wednesday morning. Current forecast from the NWS (below) indicates very high POPs for Monday the 12th, and our second December precipitation event.

Significant Rain Event

It's a foggy, dreary morning after yesterday's rainfall. View from campus toward the Catalinas above at 7:45 am MST. At bottom is view from Continental (south of Tucson along I-19) looking toward the east. The NWS issued a dense fog advisory last evening that extends into this morning.

The ALERT maps here are for the entire event, which began Saturday morning and continued into yesterday afternoon. Note that almost all sites had over half an inch and many sites had over an inch. Note the Mt. Lemmon report of 6.30". Here at house the total was 0.69"; Atmo had 0.54"; TUS reported 0.69"; and DM had 0.65". There were no detected CG flashes anywhere in Arizona for the 24-hours ending at 7:30 am this morning. 

Looks like the coming week will be fair and mild for southeastern Arizona.

Rain Update

Light to sometimes moderate rain continues across the metro area this morning. The rain began yesterday morning around 9:30 am MST and has continued since then.

Radar above (second tilt) is from 7:10 am this morning. There were some thunderstorms yesterday afternoon (plot of detected CG flashes below from Atmo and Vaisala) as per below for 24-hours ending at 0633 UTC last night.

Rain amounts for 24-hours through 7:30 am in the ALERT network are shown above and below. Reports are generally in range of 0.25 to 0.60 inches. Here at house we had received 0.40" at 7:30 and moderate rain was continuing. This is first rain since October 23rd, and most significant amounts since October 6th. It is a very welcome event!

First Rain Of Winter?

Morning views at 7:00 am MST today of Catalinas top and Rincons down at bottom.

Forecast models and NWS outlooks are indicating a significant rain event for southeast Arizona tomorrow. Weekend outlook from NWS (above) indicates a half to an inch of rain possible for the metro area. The NWS forecast for the airport (below) indicates 80% POPS for tomorrow and tomorrow night. Given our long spell of dryness going back into October, this would be a much needed event.

Plumes (from the 06 UTC runs of the GEFS - above) indicate a huge increase in PW beginning tonight that peaks well over an inch tomorrow and Sunday. The plumes for rainfall at the airport (below) average around half an inch, but with some members forecasting much more.

Forecast below is from the 12 UTC WRF-RR at Atmo - that model forecasts 1.3 inches for the airport through 5:00 am on Sunday morning. It appears that there will finally be some weather to watch here in southeast Arizona.