Mostly Down Day Yesterday

More middle clouds overhead today.

Visible satellite image at a bit after 7:00 am MST this morning (above) shows widespread debris cloudiness over eastern Arizona. Hurricane Hanna is nearing landfall around Corpus Christi this morning. Remains to be seen whether residual showers and cloudiness from the storm will reach this far northwest.

Yesterday had very limited thunderstorm activity, as is typical after a widespread rain day. Not sure why NWS hung on to POPs greater than 50% through most of day. Above shows radar echoes at 7:00 pm and below is detected CGs (from Atmo and Vaisala) for 24-hours ending at 8:00 am this morning.

Metro area ALERT reports for 24-hours ending at 8:00 am this morning is second below - few amounts and they are very light, except for one site in the Catalinas

The morning sounding from TWC (above, from NCAR RAP)  shows intrusion of dry air at low levels is currently destroying low-level CAPE. Winds are light, and so higher moisture may slosh back in during the day. Regardless, WRF forecasts are currently indicating very limited shower and storm activity in our area during next several days.

An aside - using the old meteorological definition of the start of monsoon (i.e. three consecutive days of average dewpoint 54 F or greater at airport) is preferable (to me), rather than just saying there is a "Monsoon Season" period beginning June 15th, as per current NWS practice. Plot of average daily dewpoint (below) at TUS indicates, by old definition, monsoon began here on July 22nd - about two weeks later than usual.

Quick Look At Today

Heavy clouds above continued over the Catalinas at about 9:00 am MST this morning, but blue skies were visible out to the west. Visible satellite image below is from 8:30 am - clouds over north Mexico and southeast Arizona, with Tropical Storm Hanna over in the GoM. Hanna may bring much increased PWs into northern Mexico over the weekend.

At 500 mb this morning (above), we continue on the far west edge of the large anticyclone over Oklahoma/Kansas border. A very weak trough extends from southern California southward to the mouth of the GoC. The morning sounding (below) from TWC continues with very high PW, and CAPE that will be present if we get some heating by afternoon. Note that winds continue to be light and variable below 300 mb, with no distinct steering flows.

Forecasts here for composite radar echoes both develop storms over eastern Pima County this afternoon - above is valid at 6:00 pm from the 12 UTC WRF-RR and below is valid at 5:00 pm from the 12 UTC WRF-NAM. The 06 UTC WRF-GFS was suppressed this afternoon, but then developed storms our area around 2:00 am on the 25th.

July 23rd - Finally A Significant Rain Event

Yesterday brought the first widespread rains to our area since the middle of March - the end of a four month local drought. Storms and rain were heaviest here during the morning hours and by early afternoon had diminished to to light showers and sprinkles. Image from campus above shows visibility restricted, probably less than a mile, during the heavy rains. Plot of detected CG flashes below (from Atmo and Vaisala) is for 24-hours ending at 2:00 am MST this morning - a very active day for much of Arizona.

Using rain reports here from both the ALERT network and also from Univ. of Utah's MesoWest. There were many reports over an inch in the north part of the ALERT area - here at house I measured 1.76". Note the 3.62"  and 3.18: amounts west of downtown. MesoWest plot at bottom shows reports for rest of southeast Arizona.

Finally, at end of day, a bit of sun poked through under the high, gray overcast.

Stormy Morning Parts Of Metro Area - Updated

Three-hour rain amounts ending at 10:30 am MST for north half of ALERT area. Very heavy rain and thunder here last 45 minutes or so, still moderate rain and I can't go out to read gauge.

Very heavy thunderstorm above is just to the east of the house at this time. Earlier storm drifted off Catalinas and there was a brief shower, with thunder rumbling, here that left 0.15" in the gauge - biggest rain event here since March 18th!

The NWS has issued a Flash Flood Watch (below) that is in effect until midnight tomorrow night.

Significant storms cover much of southeast Arizona at this time (radar chart above from 7:30 am MST). Plot of detected CG flashes (below, from Atmo and Vaisala) is for 24-hours ending at 7:30 - whites and pinks are flashes in past couple of hours. ALERT rain amounts ending at same time (second below) indicate several sites in Catalinas with amounts around an inch.

The 500 mb chart above (from University of Wyoming weather page) shows that we remain on the far west side of the large anticyclone centered over Oklahoma, while trough to west inched across much of Arizona. Note - I used the Wyoming 500 mb because those from NCAR RAP and NWS EMC were affected negatively by suspect heights at Chihuahua, Mexico, and Phoenix.

The morning TWC sounding (below) is very wet (1.77" PW) and with considerable CAPE. There are some clear skies out west, but it is not obvious whether any of that will inch eastward.

Great to find some rain in the gauge, after more than four months of local drought.

Two tropical systems of interest: above shows NHC morning forecast for current depression in the GoM with system expected to become a TS and head into south Texas and northern Mexico; below shows current forecast for Cat 3 hurricane Douglas as it heads westward toward Hawaii.

Afternoon Showers Parts Of Metro Area

Bright skies over the Catalinas this morning, but with some bubbling cumulus already happening.

The outflows mentioned yesterday did impact the metro area with winds (gusts to 32 mph at TUS and gusts to 37 mph at DM AFB), but they also triggered some light showers over parts of the city.

The plot of detected CG flashes (below, from Atmo and Vaisala) is for 24-hours ending at 8:00 am MST this morning. There were some flashes in eastern Pima County but most thunderstorm activity was to the west and south in Mexico. We may had a rumble of thunder here, but if so it was from an in cloud flash.

For comparison here are rainfall reports for 24-hours ending at 8:00 am from MesoWest above and from the ALERT network below. ALERT sites captured more sires with around a quarter of an inch east of downtown. Here at the house we had sprinkles around 8:00 pm but with only a Trace. This is the only year in my records here when there has been so little July rainfall through the 21st (still at 0.03").

This morning's TWC sounding below has nearly an inch and a half of PW following a northward push of low-level moisture from the GoC yesterday. However, there still is only a small amount of CAPE for the mixed BL. Again, there are virtually no steering winds, but strong southwest winds above 350 mb to bring anvils our way. 

Just looked at two 12 UTC WRF forecasts. The RR version forecasts showers and thunderstorms over metro area after dark this evening. The NAM version forecasts a huge area of afternoon and evening anvil over eastern Pima County, followed by light showers before sunrise.

Quick Look 21 July

View south from Kitt Peak at a bit after 8:15 am MST this morning shows showers just off to the west. These are part of a line of light, nearly stationary showers that extends from around Florence to Kitt Peak and on into Mexico. Visible image from 7:30 am below shows that this line of showers extends northward all the way into southern Utah.

The morning sounding from TWC (above) remains short of low-level moisture and has essentially no CAPE. Winds below 350 mb are mostly light and variable. Yet another disappointing sounding.

Two forecasts for later today from the 06 UTC WRF-GFS - above is forecast for composite radar echoes valid at 5:00 pm - anvils again over our area. However, winds are forecast to become strong and gusty as outflows from storms to our southwest and northeast converge over the metro area.

While we are in a bit of a PW min area at 6:00 am this morning (below), the WRF forecasts indicate an increase this evening as the outflows move into eastern Pima County.

This morning's forecast from NWS  is shown at bottom for Thursday to Saturday - PoPs of 50 to 60 percent indicated for all periods. This is a very strong forecast, since widespread storms one day tend to lead to minimal activity the following day - time will tell, but I certainly hope for the first substantial rainfall here at house by the weekend.

More Clouds/No Rain Yet

Another morning with heavy middle clouds; early morning temperatures holding in low to mid 80s F - with dewpoints in low 50s. Yesterday there were no thunderstorms over the entire southwest half of Arizona - our miserable July continues.

Image at bottom taken during early morning thunderstorm in Las Vegas, Nevada, today.

Visible satellite image from 7:30 am MST this morning shows much of Arizona with middle-level cloud cover.

This morning's sounding from TWC continues much the same as yesterday's - there is a sliver of CAPE above 600 mb today, and some easterly winds around 500 mb - so a glimmer of hope. 

However, the 06 UTC WRF-GFS forecast indicates another down day here in southeastern Arizona - radar forecast below from 06 UTC WRF-GFS is valid at 5:00 pm today.

Forecast plumes above from 06 UTC GEFS for QPF at airport - the operational GFS is seriously different than the ensemble forecasts. The ensembles hold some hope for light afternoon showers, but the operational forecast (blue) is very wet. Current morning forecast from NWS (below for last half of week) indicates that the forecast office is trending similar to the operational GFS.

Dry July Drags On

Heavy middle cloud overcast this morning is providing a little relief from the series of of very warm early mornings. However, it was still 83 F at 6:00 am MST this morning.

Southeast Arizona was almost totally suppressed yesterday, as per plot of detected CG flashes (from Atmo and Vaisala - below) though 2:00 am this morning. There were few reports of precipitation in southeast Arizona, about 10 reports that I could find, and all were less than 0.05", except for a report of 0.30 " at Bisbee.

Visible satellite image this morning at about 7:30 am shows band of cloudiness curving all the way from northwest Arizona to south end of GoC. Radar indicates there may be some light sprinkles over Arizona.

Header graphic at the NWS this morning (below) is for "Southeast Arizona" and is slightly different than point forecast for airport.

This morning the TWC sounding remains essentially without CAPE, and the 500 mb analysis continues weak and unorganized for the Southwest, although a weak anticyclone is present somewhere near the Four Corners. The GEFS plumes from 06 UTC this morning (above) do hold out some hope for the coming week, especially after Thursday. In the short term PW decreases - forecast below from 06 UTC WRF-GFS is valid at 5:00 am on Tuesday morning. 

Coming week looks like a mixed bag that will hopefully bring storms and rain late.