Thursday, April 30, 2020

End Of April

Mild (68 F at airport at 6:00 am MST) at sunrise, with high clouds overhead, on last day of April. Past month has been dry, with only 0.04" of rain here at house - on April 11th. April through June are usually our three driest months of the year - so about two more months of this before we can look forward to the thunderstorm season. 

Image down at bottom shows freeways nearly deserted near LAX on this foggy, "Stay-At-Home" morning.

Banner from NWS yesterday afternoon - official high at airport yesterday was 101 F - first hundred degree day coming about three weeks to a month earlier than normal (depending upon which time period is considered, as per above).

Coming week will be high and dry (as per below), with afternoon highs upper 90s to low 100s and no chances for rainfall. Second below is forecast of total precipitation through 5:00 pm May 7th (from 00 UTC WRF-GFS last evening).

Saturday, April 25, 2020

Clear Skies Continue/ Temps Flirt With 100F

Another morning with clear skies - wondering when we'll have clouds to watch!

Temperatures in the afternoons have been hot and flirting with the 100's - NWS forecasts several days during the coming week to be at or just above 100F. There remains little hope for rainfall (06 UTC GEFS QPF for airport above).

Unfolded sky view from Mt. Lemmon below - No those are not clouds at left. Looks like a bird made a direct hit on the all-sky camera lens.

Wednesday, April 22, 2020

Today Is The 50th Earth Day

Much progress since 1970, although some backsliding occurring recent years.

Monday, April 20, 2020

More Of Same This Week

Campus view north from Professor Emeritus Wyant's office (Optical Sciences) shows a completely deserted campus, that remains shut down because of the virus pandemic.

Bottom is view of Jackson, Wyoming, golf course with just a bit of snow left on the course.

Little to report locally. Gusty winds (forecast above from 06 UTC WRF-GFS is for winds at 4:00 pm MST tomorrow) combined with very dry conditions have led NWS to issue a Fire Weather Watch for southeast Arizona, with metro Tucson area just west of watch area (see NWS webpage for complete details).

Forecast below for total precipitation is from 00 UTC WRF-GFS and is valid through 5:00 pm on the 27th. Temperatures will be summer-like, approaching 100 F, by the end of the week.

Saturday, April 18, 2020

Windy At Times With Temperatures Inching Upward

Another mostly sunny sunrise in what's continuing to be a very dry April here. View above from Atmo at a bit after 6:30 am MST. At bottom is the leaning "Stick of Truth" at Grand Targhee Resort, in Wyoming on west side of Tetons - looks like the duct tape repair is not hacking it.

Little to report, except more of the same with occasional windy periods and temperatures creeping up toward the 90s. Wind forecast above (from 06 UTC run of WRF-NAM) valid at 1:00 PM this afternoon. The 06 UTC GEFS plumes for temperature below provide a hint of what's ahead for us in coming weeks.

Friday, April 17, 2020

Dry For Rest Of April

Clouds over the Catalinas this morning. Down at bottom: view of a snowy morning in Denver, and also Old Faithful being faithful.

GEFS models forecasting no precipitation for Tucson through end of month. Below is GFS 06 UTC forecast for total precipitation through midnight last day of April.

Tuesday, April 14, 2020

Mild And Dry With Some Gusty Winds

Pre-sunrise clear skies over our area this morning. Down at bottom - vivid sunrise colors at Skunk Bay on Puget Sound, Washington.

Severe thunderstorms and tornadoes across the Southeast on Sunday and Monday resulted in major damage and more than 30 fatalities. Storm reports from SPC for Easter Sunday below.

This morning's 500 mb chart (above from GEFS for 12 UTC) is dominated by large-scale trough over much of the continent and a blocking ridge over the eastern Pacific and Alaska. The MIMIC analysis of PW (below for 12 UTC this morning) indicates extremely dry air dominating over most of continental U.S., including our area.

GEFS plumes for winds at TUS (above) indicate several more periods of gusty winds into the middle of next week. Gusts of 25 to 40+ mph were common yesterday afternoon across all of southeast Arizona.

Forecast below shows total precipitation forecast by 00 UTC GFS out through midnight next Monday night. Our very dry April will continue for at least another week.

Sunday, April 12, 2020

Easter Sunday 2020

Easter bunny in the sky - not my photo. Still some clouds and stratus around at sunrise this morning, as per image down at bottom.

Scattered light rains yesterday afternoon produced 0.04" here for the first rain of April. Amounts across the ALERT network (above and below) were mostly less than a quarter of an inch. Airport had 0.07" and Atmo recorded 0.03".

There were some embedded thunderstorms around, as per detected CG flashes through midnight (above from Atmo and Vaisala), but there was a big hole over our area.

Looks like a dry week ahead for southern Arizona, but some more precipitation for the north half of state - below is 06 UTC GFS forecast for total precipitation through noon next Sunday, the 19th.

Saturday, April 11, 2020

Showers For Easter Weekend

Red sunrise this morning highlighted clouds over the Catalinas above. Below is view at 7:00 am MST of heavy clouds over the GoC southwest of Puerto Penasco, Mexico.

The morning 500 mb analysis for 12 UTC (above from SPC site) shows that the closed low has moved about as predicted for several days, and is centered about right over Yuma.

Visible satellite image from 7:00 am (above) shows clouds associated with the circulation - the closed middle and upper-level low will move along the Borderlands today, bringing us a chance for showers continuing into the night. Showers currently developing over mountains locally. Plot of detected CG flashes (from Atmo and Vaisala below) shows that thunderstorms have moved into far southwestern Pima County during past 3 hours.

The 06 UTC SREF  plumes for QPF at TUS (above from SPC website) continue showing 100 percent of the ensemble models predicting rainfall - but amounts continue to average only around a tenth inch or so. Thunderstorms would likely produce amounts somewhat higher, if they occur over parts of metro area. 

Regardless an unsettled start to the weekend, but clearing skies likely for Easter Sunday.

Finally, the SPC is outlooking a significant outbreak of severe thunderstorms for the Southeast tomorrow (below).

Friday, April 10, 2020

Waiting For Bit Of Rain


Pristine, clear skies in the view south from Kitt Peak this morning.

Down at bottom is current "Weather Story" from NWS at San Diego, where rains of 5 to 7 inches have already fallen over much of their forecast area. Very significant event underway for extreme Southern California as the 500 mb low this morning (below) remains over southern California.

Models continue to forecast the low to move south and eastward across Arizona tomorrow bringing us a chance of showers, and perhaps thunderstorms. Forecast above is from the 06 UTC WRF-GFS and is for radar echoes at noon tomorrow (Saturday the 11th).

Total QPF forecast from the same WRF run above through noon on Easter Sunday. Plumes below for QPF from the SPC plume viewer. Event continues to be forecast to occur tomorrow afternoon and continue into the night. Forecast amounts for southeast Arizona remain light - about a tenth or so posible at airport.