Tuesday, December 31, 2019

Cloudy End To 2019

Colorful sunrise here to end the year. However, conditions are rather dreary with extensive cloud cover - as per 6:30 am IR image below and two early morning webcam views at bottom. Yesterday was dreary also, as high cloud cover moved in by 10:00 am MST and persisted rest of day.

Outlook for precipitation remains dim, as per GFS forecast (above) for totals through next ten days.

Monday, December 30, 2019

Mild And Dry Start For New Year

Fair skies locally above, but some altocumulus over the Superstitions at bottom.

Forecast from NWS below indicates a mild week ahead with highs basically in 60s and lows 30s F - not much on the weather horizon yet for 2020.

Sunday, December 29, 2019

Clear And Cold Morning

Clear and cold this morning - low here was 25F. Photo above is at sunset last night - by neighbor John Ferner. Below is Sawmill Restaurant in Summerhaven about 11:45 am MST this morning. 

Views of snow on mountains from Tucson above and Flagstaff below.

Juvenile Roadrunner below, fluffed up in the cold in nearby backyard.

Saturday, December 28, 2019

So Much For Sunshine

View above shows continued heavy clouds locally, with snow showers over the Catalinas. Visible satellite image below at 3:41 pm MST shows that clearing just did not move across eastern Pima County as expected - see post below.

Continued Damp And Dreary.

Heavy clouds continue over the Catalinas, but 8:45 am MST satellite image below shows clear skies to our west. Hopefully the sun will come out by afternoon.

Rainfall across entire area yesterday and into the night. Light showers before sunrise across this part of town. Measured 0.39" yesterday, plus another 0.11" during night - so half an inch total here.

The deep, 500 mb trough (above) is moving eastward. We are on back side now and can look for improving conditions. Webcam views below are of heavy snow falling in downtown Denver (top), ahead of the trough. But a beautiful sunrise at Mt. Whitney behind the trough (bottom). Christmas week has certainly been wet - total rain here at house since 23rd has been 0.96".

Friday, December 27, 2019

Rainy/Snowy Morning Again

A dark and rainy morning here in Tucson. Amounts at low elevations range 0.20 to 0.40 inches currently, with rain still falling. View of Flagstaff at bottom is from about an hour ago - plenty of snow up there.

The NWS KEMX radar composite image above indicates echoes mainly around 25 to 30 dBZ. But this is a bit misleading since the radar elevation is over 5,00 ft MSL. The freezing level is very low (the 12 UTC TWC sounding below indicates the freezing level is right around 850 mb), so the echoes are mainly in the ice and the rain is below the elevation of the radar beam. Also, the snow level is quite low on the mountains.

The PHX radar second below is sampling both rain and ice because of its lower elevation (about 4,00 ft lower than Tucson radar).

Thursday, December 26, 2019

Another Quick-Hitting Storm Headed Our Way

Snow falling above is at Big Bear Lake, California - which is in the mountains east of San Bernardino.

A closed 500 mb low west of LA  is forecast to move quickly eastward across southern Arizona tomorrow. Forecast above is from 06 UTC WRF-GFS on 5.4 km grid and indicates the low just east of Yuma (with second center west of Flagstaff) at 5:00 am MST tomorrow morning.

Below are 09 UTC plumes for rainfall amount at TUS - event begins late tonight and continues through day tomorrow. Amounts forecast locally are around half an inch - similar to the Christmas storm.

Forecasts from 06 UTC WRF-GFS are for: rainfall above and snowfall below are from now through 2:pm tomorrow afternoon. Snow levels will drop to low levels toward Benson and Sonoita. Travel south on 83 toward Sonoita could be a bit treacherous tomorrow morning.

Winter Weather Advisory For Tucson

Map above from NWS indicates Tucson is in a winter weather advisory (purple area) for snow accumulations and hazardous travel conditions.

The point forecast for the airport (above) also indicates that we are in the winter weather advisory, although forecast is for rain only at TUS.

Below is a different graphic from NWS Tucson webpage - note that winter weather advisory is actually only for areas above 4,500 ft msl elevation.

It is mind-boggling to me that NWS Region and Headquarter levels remain unconcerned that their graphics programs are outdated, and sometimes generate possibly confusing pictures for general users who visit local office websites.

Christmas Precipitation Event

Photos here from campus are for: 10:00 am MST on Christmas Eve; and noon on Christmas day.  Note the low angle rainbow at noon!

Down at bottom is later on Christmas, a bit after 5:00 pm. Christmas afternoon was quite beautiful.

Above are ALERT data for the two-day event. Most of rain fell on Christmas Eve with just a few hundredths  on Christmas morning. Here at house we had 0.42" on the 24th and 0.04" yesterday morning.All sites in network had precipitation, with snow at the high elevations. Quite a few sites measured over half an inch of rain - mostly around the Catalinas. But, there were also three reports of half inch plus down at the far southern sites.

Tuesday, December 24, 2019

Christmas Eve Morning

Ragged clouds hanging over the city this morning. Radar a bit before 6:30 am (below) shows a band of showers west of the metro area. Down at bottom is pre-dawn view of the Courthouse square in Prescott. 

Only two sites in the ALERT network (Three Points and near the Desert Museum, west of the city and under the heavier radar echoes - yellow to orange) have recorded 0.04". Slight sprinkle here around 5:00 am and that's it so far.

Forecasts here from the 06 UTC run of the WRF-GFS model at Atmo: above shows forecast radar echoes at 10:00 am MST this morning; below is forecast of precipitation amounts through 5:00 pm on Christmas Day; second below is forecast snowfall amounts through 10:00 am tomorrow morning. White Christmas likely in Rim Country and mountains. 

Monday, December 23, 2019

Damp Holiday Week

Ragged clouds hang over the City and the Catalinas at about 6:45 am MST this morning - above. Down at bottom are views of the bright, pre-dawn lights at Cabo San Lucas and Ketchikan, Alaska.

Very unsettled week on tap as a 500 mb short wave swings across the state tomorrow followed by another at end of week. The 500 mb forecast (above from 06 UTC WRF-GFS runs, as are all WRF graphics here) shows the first short wave over the lower Colorado River Basin at 11:00 am tomorrow morning.

The GEFS plumes (below) for rainfall at airport below forecast two periods of significant precipitation during the week - Christmas Eve and around Friday.

The WRF forecast for composite radar echoes above is valid at 11:00 am tomorrow morning. The forecast sounding below is for the same time. There is little CAPE in the forecast, but the deep, saturated layer could support a rumble or two of thunder, in addition to the rains. Second below is the WRF forecast of precipitation amounts from now through noon on Christmas day.

Certainly appears that last minute, pre-Christmas chores would best be done today.