Saturday, April 22, 2017

Earth Day 2017 - Sad And Challenging



After decades of improvement, we have to revise Pogo's famous statement from 1971 - We have new enemies and they are Trump and his billionaire cronies he's brought into our swamp.






Friday, April 21, 2017

Hot Weekend In The Deserts


Forecast models indicate a hot weekend for the Sonoran and Mojave Deserts, as a 500 mb short-wave ridge passes by. The forecast above is from the 06 UTC WRF-NAM forecast run at Atmo and is for 2-m temperatures at 03:00 pm MST on Sunday afternoon.


In the longer-term, a strong 500 mb short wave is forecast into the Southwest by the last weekend of the month. Above forecast is from the operational ECMWF forecast from 00 UTC last evening.


The NWS GEFS plumes indicate a windy week (above and below from 06 UTC forecast runs), as per the 10-m winds shown above. Some members forecast quite strong speeds for next Thursday and Friday. Several of the members also forecast a bit of precipitation for the airport (below). At this point we can probably bank more on the winds than on the rain chances.




Thursday, April 20, 2017

Nice Morning Here In Tucson

Was quite nice at sunrise today as we head into another warm and dry day. Issues for rest of month are mainly two - will it rain before May begins?; and will it break 100 F? Looks like the high temperatures this weekend will flirt with 100 F, but outlook for rain continues dim. Since the 19th of February, it has only rained here at house on two days, with a grand total of 0.08". Photos below from my morning walk today.


Vermilion Flycatcher.


Cooper's Hawk with crescent moon above and Palo Verde tree with yellow snow below.


Saturday, April 15, 2017

Tornadoes Around Dimmitt, Texas


A couple of supercells did develop late yesterday near Dimmitt, Texas. They produced a number of tornadoes that danced around wind energy turbines, as per images by S. Speransky above and below.



The Amarillo 00 UTC sounding (above) continues to indicate the nasty weak wind layer, but with stronger flow above and a SRH rich environment up to 4 km. Lubbock radar about 02 UTC at bottom shows two supercells north-northwest of the radar. Chasers in the right spot had quite a show.






Friday, April 14, 2017

Mid-April Weather Doldrums


The weather doldrums seem to have spread from southern Arizona across much of the CONUS for mid-April. Above map (which is blurry in all versions for unknown reasons) shows severe thunderstorm reports to SPC yesterday - April 13th. There were only two. Weak tornadoes were reported near Bend, Oregon, and Wichita Falls, Texas, and that was it.

The large-scale pattern is dominated by a split flow regime that leaves the Plains under a weak trough in southern branch, below a bent-back ridge that extends from Minnesota northwestward toward Alaska. The pattern has resulted in strange vertical wind profiles that are not supportive of organized thunderstorm systems.



The sounding from Dodge City, Kansas, this morning provides a nice example. There is considerable CAPE above 700 mb, but a strong low-level jet gives way to wind speeds of 15 to 20 kts from 500 to 300 mb. This produces the bizarre hodograph shown below - strongly veering jet below 2 km, topped by weirdness resembling an accordion. Not exactly a classic Plains supercell hodograph.

Locally, not much in sight except for some windy afternoons - rain seems far away in the model forecasts.





Tuesday, April 11, 2017

The Latest Test for the White House? Pulling Off Its Easter Egg Roll

Guess my April Fools' Day post wasn't too far off. Below from NY Times article this am.
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Sunday, April 09, 2017

Short-Lived Lenticulars With Irridesence

We were at Santa Rita Abbey yesterday and I observed small, lenticular clouds forming and then dissipating, turbulently, in very rapid sequence. I had never seen anything like this and any insights much appreciated. First photo in sequence below was at 01:03 pm MST and last was at 01:19 pm (the complete sequence has about 20 photos in it). There were about 8 to 10 separate clouds involved in the sequence.










Friday, April 07, 2017

No Comment Needed


Fire Weather Watch





For a broader perspective I've added the Day 2 Fire WX Outlook above from the SPC.


Will revisit one of my recurrent gripes this morning. The NWS has issued a Fire Weather Watch for portions of southeast Arizona on Saturday. The graphic above at the main NWS web page indicates that Nogales, Green Valley, and Tucson, and points further west, are under this watch area. The high-resolution, gridded forecast for the airport (below) indicates that the watch is in effect at the airport.


But, if one clicks on the detailed hazards or Weather Story links one gets a different story that indicates the watch begins east of Tucson and I-19. This is more than a bit confusing and, in my opinion, is unacceptably sloppy in this era of detailed and fancy forecast graphics. When will NWS catch up with rest of world?





Tuesday, April 04, 2017

Severe Winds In Arizona Yesterday


The main severe thunderstorm activity yesterday was the continuing outbreak of storms, with deadly tornadoes in the Southeast. However, thunderstorms developed yesterday ahead of a strong, 500 mb shortwave that crossed northern portions of the state. Regional radar above shows thunderstorms near Las Vegas around 02:00 pm MST. Outflow from these storms enhanced the already strong winds along a cold front, producing severe winds in far northwest Arizona (SPC reports from yesterday below) and also along I-17 near Arcosanti.

The flash density for CGs during the past 24-hours is shown at bottom (from weather.graphics and Vaisala), indicating considerable thunderstorm activity from southern Nevada eastward across much of Arizona and New Mexico. Nothing locally, except more winds and dust and pollen continuing to make things miserable for allergy sufferers. 



Monday, April 03, 2017

March Summary/First Week Of April More Of Same

March 2017 was a very warm, windy, and dusty month, but one with almost no precipitation here in southeastern Arizona. Rainfall here along the Rillito in the north part of the City of Tucson amounted to only 0.06" during the early morning hours of March 28th. There were Trace sprinkles on two other days. This was the second driest March in my 18 years of records here - driest was 0.03" in 2013. Four of the last seven years have seen 0.08" or less here - certainly a dry trend for recent years.

There may have been thunder early on the 28th, or the storms may have stayed a bit too far south.

Only 6 mornings had lows in the 30s F and two of those days dropped to 32 F. Of interest early in month was the morning low of 34 F here followed by an afternoon high at airport of 87 F on the 8th. A summary of heat records for the warmest Tucson March on record is available from the NWS at:  

http://www.wrh.noaa.gov/twc/climate/monthly/mar17.php


The first full week of April (today through 05:00 pm MST next Monday) starts out much like March. The GEFS temperature plumes for the week are above (note that there is a substantial cool bias in these models and the morning forecast from the NWS indicates high temperatures at the airport of 91 F on the 6th and 7th, before a cool front passes on the weekend. Gusty winds are indicated during a number of afternoons (just below).

The 00 UTC WRF-GFS forecast of precipitation for the coming week is shown at bottom. California's VERY wet cool season continues unabated over the northern half of the state, while dry conditions rule down here.





Saturday, April 01, 2017

This Year's Easter Egg Roll


In a surprise tweet from President Trump this morning he shared his plans to shift this year's traditional White House Easter Egg Roll to one of his golf properties. The event would probably be staged at either his New York City course or at the course at Mal-a-Lago in Florida - photos of the two possible venues shown below. The President states that he wants no "losers" rolling his great looking Faberge eggs.





Friday, March 31, 2017

Intense Surface Low Blasts The Southwest


An intense surface low dug into the Southwest yesterday, bringing high winds and dust across much of Southern California, and Arizona. At 05:00 pm MST yesterday (above) the low was centered somewhere near Bullhead City, Arizona. This morning the surface cyclone is centered along the Arizona/Utah border, west of the Four Corners. Winds yesterday gusted in 70 to 80 mph range over parts of the Mojave Desert, before shifting eastward across Arizona during the night. The airport recorded 45 mph around midnight.


View a bit after 06:00 am this morning to the north of Kitt Peak (above) shows dust extending upward to near the bases of the middle cloud layer. There were light sprinkles across the metro area and composite radar below is from just before 07:00 am. View at bottom from campus captures a mix of clouds, dust, and light showers. Here at the house there were dirty sprinkles between 06:30 and 07:00 am.

Wind gusts across Arizona were generally in 30 to 60 mph range. Some of the higher gusts I noted when I scanned the observations this morning include: 80+ mph at the 4-M telescope on Kitt Peak; 72 mph at the Hachita Valley RAWS in southwest corner of New Mexico; Flagstaff 66 mph; Guthrie RAWS 65 mph; and 61 mph at Ft. Huachuca. 





Tuesday, March 28, 2017

Early Morning Showers


Guess I was distracted by Al running around at University of Oklahoma yesterday. Turns out that a couple of ensemble member forecasts got the very low POPs event of early this morning. Regional radar above is from 03:00 am MST. Airport and DM had thunderstorms in addition to the light showers. TUS reported 0.21" and DM had 0.11", while we had 0.06" here at house.

The 06 UTC WRF-GFS caught up with what was happening and its forecast for 04:00 am is below - but of course by the time that forecast ran, the showers were moving into the metro area. The atmosphere out-performed the models this time around.



Portion of ALERT network shown above is 6-hour precipitation ending at 06:00 am this morning - rainfall mostly centered over core metro area, with amounts generally less than a tenth of an inch. 

The showers mainly cleaned out most of the dust and pollen, so that it was a beautiful early morning with clean and sparkling skies - below.