Monday, July 06, 2020

More Of The Same

Nice sunrise this morning.

Weather graphic from NWS below says it all - not only for today, but for most of coming week.

Sunday, July 05, 2020

Rain In The Gauge - How Long?

View from Atmo this morning shows smoke from the Bighorn fire continuing to hang over the eastern Catalinas. Fire is now 75 percent contained, as firefighters do mop-up work - sadly, a huge portion of the Catalinas have been burned over during this disaster.

We are now almost through the first week of July and I'm wondering when there will be some meaningful rain in my gauge (by meaningful I mean around a quarter of an inch or more).

This morning's TWC sounding plot (above) has about an inch of PW, but only a tiny wedge of CAPE around 500 mb, as strong inversion just above shuts off likelihood of deep convection. Yesterday there were not even buildups over the mountains, as I had thought there might be.

Looked at the 06 UTC GEFS plumes this morning for the week ahead. Above are the plumes for T and PW. Temperatures trend upward during the week, while PW falls briefly and then holds near an inch for rest of week.

Plumes below are for CAPE and QPF at the airport. CAPE is forecast to be minimal, except by the operational GFS (blue). Outlook for QPF (rain) is also dismal - except late from the GFS (blue). Something seems awry in the GFS run, since it is a serious outlier, for some parameters, wrt the ensemble members.

Below is the 00 UTC WRF-GFS forecast for precipitation through 5:00 m MST on July 12th.

Certainly looks like a late start for the summer thunderstorm season here in the metro area.

Saturday, July 04, 2020

Crowded Day - Yellowstone NP

Many folks not staying sheltered this Fourth of July. Big lines of traffic at the North (above) and West (below) entrances to Yellowstone National Park.

Friday, July 03, 2020

Fourth Of July Weekend

View above is looking south from Kitt Peak yesterday afternoon at about 4:50 pm MST - looked promising. 

Down at bottom is view from Atmo at a bit after 8:00 am this morning, showing the low-hanging smoke from the Bighorn fire. 

Plot of detected CGs (above, from Atmo and Vaisala) is for 24-hours ending at 2:30 am this morning. The active thunderstorms stayed south along the edges of metro area. The airport reported thunder, gusts to 44 mph and 0.06"; DM had thunder, gusts to 40 mph, but only a Trace of rain; here at house we had south gusts 35 to 45 mph and a light shower around 6:00 pm - total in gauge was 0.02". This is significant because it is first rain in gauge since the 0.04" on April 11th. No meaningful rain here since middle of March. Plot below is 24-hour rainfall ending at 8:00 am this morning. There were a couple of sites down toward Sonoita with over an inch.  

PW remains high this morning (1.30 inches) and TWC sounding (above) continues to have some CAPE.  The WRF runs do not forecast storms because of warm mid-level temperatures and slowly decreasing PW. However, there may well be some storms over the mountains this afternoon.

The GEFS plumes from 06 UTC (above yesterday and below today) illustrate nicely how the models have been jumping around. The chance for rain on night of Fourth (above) has gone totally missing on today's runs.

It now looks like July will be off to a dry start for most of Arizona - second below is the 00 UTC WRF-GFS forecast for total precipitation through 5:00 pm on July 10th - not pretty.

Thursday, July 02, 2020

Morning Showers

Two photos here (top and bottom) looking toward Thimble Rock before and after sunrise. Smoke from Bighorn fire along mountains left of Thimble Rock.

Yesterday there was a slight sprinkle here at house around 6:00 pm MST, starting July off with a Trace. The airport and DM both reported thunderstorms yesterday afternoon, with Traces of rain and gusty winds.

This morning's sounding plot for TWC (above) indicates PW has indeed increased, and is up to 1.17 inches. Although surface CAPE is zero, the old boundary layer above the surface has a sliver of CAPE and there are showers in the general area. Composite radar image below is from 8:25 am with most showers east and south of the metro area. Shower area is shifting slowly northward.

The NWS has issued a flash flood watch, as per their morning forecast for the airport - 2nd below.

Looks like today is probably our best chance for some measurable rainfall around the metro area, through the Fourth. Perhaps another chance developing on Sunday the fifth.

Wednesday, July 01, 2020

Perhaps Storms Tomorrow

Couple of active spots of the Bighorn fire were visible from campus yesterday afternoon. The fire has burned southeast all the way to Redington Road and remains active this morning. Fire has grown to about 120,000 acres, and is a bit more than 50% contained (this morning's fire map below).

The morning sounding above from TWC is quite stable and has just 16 mm of PW. However, forecast models continue to bring GoC moisture into Arizona later today and tonight. Forecast sounding for TWC (below, from 12 UTC run of the WRF-RR as are WRF forecasts below), indicates a doubling of PW and some CAPE by 4:30 pm MST tomorrow afternoon.

The QPF plumes from 06 UTC GEFS (above for airport) indicate slight chances for storms and rain late tonight. Chances increase for Fourth of July night, although average amount remains quite low.

The 12 UTC WRF-RR forecast is more aggressive wrt convection and rain on the 2nd than is the GEFS and the earlier WRF forecasts from last night. Forecast radar echoes above valid at 6:30 pm tomorrow. Total rainfall forecast below is valid through midnight tomorrow night. (Note color bars for both are below in yesterday's post.)

Tuesday, June 30, 2020

Models Wobbling

View of Catalinas at about 8:30 am MST this morning shows high-based cumulus field and only a bit of smoke along right side of image.

Forecast above is from the 12 UTC WRF-RR at Atmo and is valid at 5:00 pm tomorrow afternoon. Model forecasts a very nice return of moisture from GoC into southern Arizona.

However, models forecast only slight amounts of precipitation at most. Above is from same model run for precipitation through 5:00 am on July 2nd. The forecast of precipitation below is from 06 UTC GFS and is valid through same period - keeps all precipitation south of border. Apparently warm temperatures in middle levels keep convective activity fairly suppressed - much different than yesterday's forecasts which indicated good chances for decent storms to start July (see previous post).

The forecast plumes for QPF at the airport (bottom) are a mess, and indicate at best a chance for light showers any time from tomorrow afternoon through mid-week next week. Nothing much positive for a wet start to July in any of these forecasts.