Sunday, June 30, 2019

End Of June

Sunrise this morning behind Thimble Rock. Very warm morning (80 F here at 6:00 am MST) with increased PW and more humidity. Yesterday was hottest day of summer so far - 109 F at airport.

Thunderstorms yesterday afternoon stayed mostly locked onto mountains and avoided lower elevations. Flash density plot above (from and Vaisala) is for 24-hours ending at 6:15 am this morning. Only six stations in ALERT network had rainfall (0.04" or greater) with highest amount 0.24" in the Rincons.

PW has increased steadily at campus GPS site (above plot for seven days ending this morning) and has now reached an inch and a quarter. Perhaps a bit more thunderstorm activity this afternoon. Pattern has stagnated and we can now hope for a significant surge of low-level moisture into southern Arizona for better rain chances.

The IR satellite image below from 13 UTC appears (to me) to indicate that TS Barbara has formed near 110 W and 10 N - although the NHC has yet to declare this has happened.

Saturday, June 29, 2019

Brief Summary 28/29 June

View above from 3:00 pm MST yesterday afternoon (28 June) shows how high-based convection was around our area. Both TUS and DM reported thunderstorms but no measurable rainfall. I looked at ALERT and MesoWest and found only three sites in eastern Pima and Santa Cruz Counties with measurable rainfall. Max was about 0.15" at Florida Canyon (near or on the research grasslands on west side of the Santa Ritas).

Plot of CG flash density (below, from and ATMO) is for 24-hours ending at 6:45 am this morning. There was considerable CG flashes/thunderstorm activity, but very little rainfall - dangerous situation for wildfires. Plot indicates there may have been thunder here at house but I did not hear any.

Morning upper-air plot for TWC (from SPC - below) again shows a bit of middle-level CAPE and very dry low-levels. The wind field is very chopped-up below 300 mb. Another day with dry thunderstorms possible - WRF forecasts indicate most activity over higher elevations.

Friday, June 28, 2019

Early Afternoon Update

Thunderstorms have developed over portions of southeast Arizona to a greater extent than forecast by the 06 UTC WRF forecasts. Radar above is from 1:57 pm MST. Visible satellite image below is from 1:30 pm, while CG flash density (bottom from and Vaisala) is for 6-hours ending at 1:45 pm. Who will actually get measurable rain this afternoon?

Light Shower Here This Morning

View to north from campus at about 6:56 am MST this morning.

We had a light shower here this morning a bit before 6:30 am (Trace), and radar from that time (above) shows some showers over parts of the metro area. The morning sounding plot for TWC (below) indicates just a bit of CAPE above 500 mb.

Plot of 12-hours of detected CG flashes (from Atmo and Vaisala above ) ending at midnight last night indicates some thunderstorm activity west of Continental Divide with storms in parts of Cochise County. The MIMIC TPW analysis (below) for 6:00 am this morning continues to show amounts around an inch over southeastern Arizona (some from east and most from GoC). TS Alvin, southwest of Baja was upgraded briefly last evening to a Cat. 1 Hurricane by NHC.

The 06 UTC WRF-GFS forecast from Atmo (below on 1.8 km grid valid at 2:00 pm this afternoon) indicates some thunderstorm activity over Santa Cruz and eastern Pima County this afternoon. Rain at airport - perhaps.

Thursday, June 27, 2019

First Measurable Rain At Airport - Soon?

View south from Cabo San Lucas, Mexico, this morning at about 7:00 am MST.

The NWS forecast (below, from early am today) is for hot - period. Highs expected in 105 + F range each day - not pretty.

Plot above (from Atmo and Vaisala) is for 12-hours of CG flashes detected over Mexico, ending at 11:00 pm last night. Most thunderstorm activity north of Cabo Corrientes remains along and east of the Continental Divide. Also not a pretty picture for this late in June.

However, TS Alvin has helped push higher PW north up the GoC (MIMIC TPW analysis above from 5:00 am this morning) with values reaching around 1 inch now in southeastern Arizona. The trof in the northwest and the upper anticyclone are combining to provide southerly winds at 700 mb (plot below for 5:00 am this morning), which are favorable for continuing to push higher PW northward.

The QPF plumes from the 00 UTC GEFS (above) indicate a slight chance for very light amounts at airport beginning tomorrow afternoon and continuing through the Fourth of July. Last night's 06 UTC run of the WRF-GFS forecasts light amounts over parts of eastern Pima County through 12 UTC on the 29th.

So, the overall synoptic situation is continuing to ease toward the start of summer thunderstorms over southeastern Arizona.

Wednesday, June 26, 2019

Tropical Storm Alvin

Tropical Storm Alvin is southwest of Cabo Corrientes, moving westward. The NHC does not forecast that Alvin will intensify. Alvine is the first named storm of the season in the eastern, north Pacific.  Turns out that this is the third latest date for the first storm since 1966.

Tuesday, June 25, 2019

Look To South AM 25 June

First a look north to Jackson Hole golf course, where it will obviously be a busy day.

MIMIC TPW analysis for 8:00 am MST above shows that moist, tropical air remains south of 20 degrees north, with very dry conditions over the Southwest and northern Mexico.

Below (from Atmo and Vaisala) is plot of CG flashes for 12-hours ending at 8:45 am this morning. Thunderstorm activity west of Continental Divide remains far south of Cabo Corrientes.

At bottom is this morning's outlook for the Eastern Pacific from NHC. They are forecasting a high chance of Tropical Storm development during rest of week. A named storm would be Alvin, the first of the season. Last year, by June 27th, there had been 5 named storms, including 2 Cat. 4 hurricanes - so Eastern Pacific much quieter so far this season.

Monday, June 24, 2019

The Most Difficult Month

T. S. Eliot called April the cruellest month (The Wasteland), but here in the Sonoran Desert June is the most difficult month (at least for me). View above is from campus of the Catalinas at about 3:00 pm MST - June 24th. Hard to imagine skies more clear. The visible image below is from 2:00 pm - only some isolated Cu over high terrain (there is a bit of hard-to-see smoke from the Woodbury wildfire near Roosevelt Lake - this fire has now burned over 100,000 acres). 

The heat of the per-monsoon period, along with little chance of rainfall, make June very difficult until the onset of summer thunderstorms. Precipitation forecast at bottom is from 12 UTC WRF-GFS and is of total rainfall through noon on July 1st. June gloom in San Diego sounds pretty good right now.

Friday, June 21, 2019

Start Of Astronomical Summer Today

Had a fall early am on Fathers' Day and have been out-of-action this week.

Today is the summer solstice and start of astronomical summer, but day-to-day continues dry with high temperatures around 100 F.

The current dewpoint tracker from NWS (above) shows nasty drying trend. The plot below of detected CG flashes over Mexico (from Atmo and Vaisala) ends at 12 UTC this morning, and shows most thunderstorm activity remaining along and east of Continental Divide.

The 500 mb pattern continues troughy in West, but models forecast patterns by end of month that are looking more monsoonal. 

Friday, June 14, 2019

100+ Heat Continues

There was bit of color at sunrise today - first time in quite a while. This pales in comparison with today's sunrise in Loveland, Colorado (bottom). Taken by son Jason looking east from Mariana Buttes golf course, which is west of the city.

String of 100+ F days continues here (began last Sunday) and forecast for today from NWS is 102 F. 

Yesterday and Wednesday the high at airport reached 107 F. The extended range forecasts, however, develop a weak trough over the West and things cool off some.

Tuesday, June 11, 2019

Some Rain In Early June

Back edge of line of showers and thunderstorms at about 6:30 pm MST yesterday evening.

Light showers, with some thunderstorms embedded, moved across parts of the metro area late in afternoon. View above at about 6:20 pm shows small shower that was moving eastward along the Foothills. This activity produced a low rumble of thunder and rainfall of 0.04" here at house. The airport and DM both reported thunder with a Trace of rain.

Plot below of detected CG flashes (for 24-hours ending at 5:00 am this morning - from Atmo and Vaisala) indicates a narrow band of thunderstorms across Santa Cruz County and east-central Pima County. Only 5 stations in the ALERT network recorded 0.04" or more - max 0.16" at two sites.

Unusual event for early June and now we've got some heat to deal with.

Monday, June 10, 2019

Miscellany For 10 June

This was the warmest morning at sunrise since sometime last summer. Here at house, temperature was 76 F at 6:30 am MST. The low at the airport reached only 80 F. Warm temperatures due to the heavy clouds during the night, as per view from campus above.

Yesterday was first day of 100 F highs, with the airport reaching 101 F. Plot above (from MesoWest) shows highs yesterday from all their networks (this means there are a number of home weather stations shown). There are a few obvious problems - as per 89 F just north of airport and a 113 F hiding up in the Oro Valley area (a station out near Ajo reported 272 F).

South view from Kitt Peak at bit after 7:00 am (below) shows clear west and clouds east.

A weak, 500 mb short wave, moving through the larger=scale ridge, brushed southern Arizona and northwestern Mexico during the night. This produced southerly winds up the GoC and brought a push of higher PW air (values up to almost an inch and a half) as far north as southeastern Arizona (the MIMIC TPW analysis above is for 6:00 am).

The higher PW brought some CAPE to northwestern Mexico, with thunderstorms as far north as Hermosilla area - an interesting and somewhat surprising development for June 9th. Plot below of detected CG flashes, from Atmo and Vaisala, is for 12-hours ending 3:00 am. Perhaps a flash even in Cochise County.

Saturday, June 08, 2019

First Day Of 100 + Temperature Near

View of Catalinas at 7:26 am this morning - mostly clear skies with some middle cloud drifting over the highest part of the mountains.

The airport has not yet recorded a high temperature of 100 F or higher this year. However, the current morning forecast from NWS for the airport (below) indicates 100 F tomorrow (as well as higher temperatures rest of week). This happens as 500 mb heights slowly increase over the Southwest. 

Regardless of exact date, this will be the latest for first 100 F day since at least 1982.

On the Eastern Pacific scale, the CG flash activity has inched northward - above is 12- hour CG flashes for period ending at 12 UTC this morning. Thunderstorms west of the Continental Divide occurred almost north to Cabo Corrientes.

The 500 mb forecast below is valid at 06 UTC on Tuesday the 11th - note that mid-level easterlies are also inching northward toward the southern end of the GoC.

At bottom is reference map - Cabo Corrientes is shaded light green at the lower right of the map. 

Saturday, June 01, 2019

Start Of Meteorological Summer

Today is the first day of meteorological summer and the start of June.

Summary for May here at house: There were two precipitation events: 0.23" on the 12/13th and 0.05" on the 20th - total for month only 0.28".

Even this low total amounted to the third wettest May here in last 20 years.

May precipitation from ALERT is shown above - fewer than 10 sites had more than half an inch. At least two sites recorded precipitation less than 0.04".

However, rainfall at the airport was the outlier amount with 1.22" - second wettest day in May during period of records (amount was about 600 % of normal) occurred when a localized thunderstorm produced most of this and also wind gusts over 50 mph.

Here at house there were seven days with morning low in the 40s.

Rainfall in June here is highly variable - five months with 0.00" but also two months coming in at over 2.00".