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.

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.

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.

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.

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. 

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.

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.

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.

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. 

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".

More Re CG Lightning Flashes

Above shows detected CG flashes for 12-hours ending at 06 UTZ last night 9 (from weather.graphics and Vaisala). I noticed that there were a couple of flashes in northern Baja. Couldn't help wondering if the strikes occurred at the large wind farm near Tecate, Mexico (below).

Lightning Flash Density Past Week

May is going to come to a quiet end - although unusual cool has continued. Since the 21st six mornings brought low temperatures here at house down in the 40s. However, it looks like temperatures will be warming up as we begin June - NWS forecast indicates temperatures flirting with 100 F early next week here in Tucson.

The never-ending severe weather from the Plains to the East Coast has been the main story on national news for days now. I took a look at the CG flash density (from weather.graphics and Vaisala) for the past week ending at 7:00 am MST this morning. Plot above speaks for itself and is quite amazing.

Gusty Winds Today - Red Flag Warning

This morning's wind profile for TWC (above, right side) indicates strong winds of 30 to 50 kts from just above surface to above 600 mb. The BL will be well-mixed to around 700 mb by mid-day, bringing another afternoon with gusty winds.

Once again, the NWS webpage shows conflicting graphics (I know I'm mostly wasting my time on this, since it appears that neither Region or Headquarters care about this problem). The two graphics above indicate that the Tucson metro area is under a red flag warning today (this means that conditions are critical should a wildfire develop). But the weather story cartoon below shows the real details, with the red flag area entirely to our east and south.

The rainfall outlook for rest of May remains dismal, as per 00 UTC WRF-GFS forecast for precipitation through 5:00 am MST on June 1st (below, on 5.4 km grid).

More Wind For Last Week Of May

Nice view to west across Denver this morning, showing snow covered Rockies in distance (from Jack Hales webcam wall).

The 500 mb trough remains stuck over the West - above is this morning's 12 UTC forecast for 500 mb valid tomorrow morning at 12 UTC.  The trough continues to keep the subtropical ridge suppressed far to south over Mexico. Another dry short wave swings across Arizona tomorrow.

With the trough come more winds - just below is 06 UTC WRF-GFS forecast for 10-m winds valid at noon tomorrow. Second below is this morning's fire weather outlook from SPC, forecasting critical wildfire conditions over southeast Arizona and much of New Mexico for tomorrow. 

Will be good to get this unusual May behind us.

Trough Persists In West Through End Of Month

Stratus hanging to Kitt Peak this morning.

A line of weak, sprinkle showers did cross metro area early this am - radar above from 3:00 am MST.

Only amounts of 0.04" in ALERT network (below for 24-hours ending at 7:00 am) were in and near the mountains. In the city DM had a trace; nothing here that I could detect.

Mean 500 mn trough persists across West for rest of month as per model forecasts. Above is valid at 5:00 am this morning and below valid at 5:00 pm on Saturday June 1st. May will definitely come in cooler than normal.

Strong 500 mb Short Wave Over Arizona Tonight

California 500 mb low this morning is forecast to move southeastward and sharpen-up considerably. The very moisture-starved system will move slowly across Arizona tonight. The 12 UTC NAM forecast above is for 500 mb, valid at 06 UTC tonight. The forecast models do hint that there might be just enough middle-level moisture ahead of the short wave to support some sprinkle showers this evening into the night; but basically a very marginal system, except for strong winds ahead of it. Wind forecasts from nighttime WRF forecasts remain similar to forecasts I posted yesterday.

David Blanchard sent two links to videos taken mid-morning Monday the 20th of a weak tornado (some refer to tornadoes of this character as "landspouts" because of their similarities to waterspouts, e.g. spinning up along a weak convergence line). This appears to have been the case with this brief tornado, southwest of Tuba City and north-northeast of Flagstaff along Highway 89. Image above by Shawn Williams and below from Matthew Harrison.