Flash Flood Watch Today

Pre-sunrise colors looking toward Redington Pass at 5:30 am MST this morning.

Plot of CG flashes detected through 0733 UTC (1233 am) shows no flashes in eastern Pima County - above from Atmo and Vaisala. However, plot of ALERT rainfall observations shows light amounts scattered here and there though 8:00 am this morning (below - both north and south portions of the network). Here at house it appears that there was an early morning sprinkle.

The morning upper-air sounding from TWC/TUS (above) is nearly saturated above 600 mb, but lower levels are much drier and chopped up. Winds are easterly below 300 mb, with some speeds just over 20 kts. CAPE is quite limited.

The 12 UTC WRF-RR forecast for precipitation though noon tomorrow (above) shows a Tucson donut hole - ugh.

The morning forecast from the NWS is quite bullish (above and below) with high POPs through Tuesday and a flash flood watch for today.

Nice Rain Here

Heavy showers over west end of Catalinas at 6:00 pm MST yesterday afternoon.

Plot of detected CG flashes (above) for 24-hours ending at 1:03 am early this morning. Plot shows it was very active re thunderstorms across southeastern Arizona (from Atmo and Vaisala). Thunder rumbled here for several hours starting around 4:00 pm. ALERT plot below shows numerous sites with rainfall from Catalinas south through middle of network. We had 0.37" during a brief downpour here. The airport had 0.70" along with thunder and a severe gust to 58 mph; DM did not have strong winds and reported only 0.13" of rain. Atmo had 0.21" of rain.

The 500 mb analysis this morning (above) shows the anticyclone centered over west Texas. The morning sounding (below) shows several old boundary layers, and also indicates some CAPE with lifting needed. Winds are light southerly below 300 mb - so storms that form will be slow moving.

The 12 UTC WRF-RR forecast from Atmo (bottom) forecasts heavy rain amounts over parts of eastern Pima County through midnight tomorrow.

Showers Metro Area

Pre-dawn view of Catalinas at 5:00 am MST this morning.

There were scattered CG flashes in eastern Pima County yesterday (above plot of detected flashes from Vaisala and Atmo). There was widely scattered rainfall around the ALERT network through 9:00 am this morning (below). Nothing here at house

Forecast above is for rainfall through midnight tonight (from the 12 UTC run of the WRF-HRRR at Atmo). Plumes for QPF at the airport below are from 06 UTC runs of the GEFS models. Plumes continue to advertise a busy start to July.

Suppressed Again

Chaotic sky overhead this morning at 5:45 am MST.

Yesterday was again suppressed, as was forecast by the RF-RR (see previous post). Plot of detected CG flashes (above from Vaisala and Atmo- through 0703 UTC last night) shows only several flashes in all of Pima County. Plot of MesoWest rainfall through 7:30 am this morning (below) shows nothing over the metro area.

At 500 mb (above), yesterday's weak trough has pushed into New Mexico, leaving most of West under influence of trough over the Northwest. The anticyclone now has a single circulation center over southwest Texas.

The morning TWC/TUS  upper-air sounding (above) has some mid-level CAPE, but it's not clear if there'll be enough heating for some storms to develop. The 12 UTC forecast from the WRF-RR (below) keeps metro area dry through 5:00 pm tomorrow.

Suppressed Again Yesterday

Pink and purple skies to the east early this morning.

Yesterday was very suppressed, with no thunderstorms or rainfall across eastern Pima County - above plot of detected CG flashes through 0803 UTC today (from Vaisala and Atmo).

At 500 mb this morning (above) the anticyclone is weaker and centered over eastern New Mexico. A weak short-wave is brushing across the Arizona. The 12 UTC sounding from TWC/TUS (below) is similar to yesterday's. There are several old boundary layers below 500 mb, none of which exhibit much in the way of CAPE. 

The 12 UTC run of the WRF-RR at Atmo (below - valid through noon tomorrow) forecasts almost no rainfall across all of the southern 2/3rds of Arizona - more of the same.

Sprinkles Here

Nice colors over the Catalinas at about 5:25 am MST this morning.

Once again there are limited observations this morning: the ALERT network is still not functioning, and MesoWest is not fully back on line yet.

Plot of detected CG flashes through 0703 UTC last night (above from Vaisala and Atmo) shows limited CG activity over eastern Pima County. There were lightning flashes visible here around midnight, but only a sprinkle around 6:00 am this morning. TUS reported thunder but no rain, DM reported a Trace, and Atmo had 0.17" right around midnight last night.

The morning 500 mb analysis (above) continues to show a large anticyclone covering much of the southern 2/3rds of the country. Two centers of circulation are over west Texas and also near the Four Corners. A weak, inverted trough was over southwestern Arizona. 

The morning upper-air sounding from TWC/TUS (below) shows a deep layer of nearly saturated air above 600 mb, but really chopped-up conditions below. Winds aloft are mostly southerly with light speeds. 

The morning 12 UTC run of the WRF-RR at Atmo forecasts almost nothing across southern Arizona through noon tomorrow (above). However, the 06 UTC GFS forecasts considerable precipitation across Arizona for the week ending 12 UTC on July 2nd (below). So we'll possibly have a very wet start to July, as a long Holiday weekend approaches.

Limited Data Today

Lightning flash north of the Catalinas about 3:30 am MST this early morning.

Yesterday the WRF runs in the morning (see previous post) kept things very suppressed across the metro area following Saturday's heavy rain event. For some reason the NWS kept POPs at the airport at 50% during the day and through the evening. TUS and DM had a Trace, but the metro area was generally suppressed - nothing here or at Atmo. This is best illustrated by the plot of detected CG flashes (below - from Atmo and Vaisala) valid through 0703 UTC. (Note the ALERT network is displaying old data this morning, and that MesoWest is down for maintenance today.)

The 500 mb analysis this morning (above) shows a large anticyclone with light winds - main center is over west Texas, with a small secondary center near the Four Corners.  Plumes from the 06 UTC GEFS runs (below) indicate continued, but light showers for the airport.

Heavy Storms Here

View of heavy thunderstorm over north portion of city from downtown at 3:10 pm MST yesterday.

Plot of detected CG flashes from Atmo and Vaisala (above) is for 24 hours ending at 0803 UTC last night - note that flashes were concentrated over the north portion of eastern Pima County. Time series of T and Td (below) from Atmo shows the dramatic temperature drop as the rainfall began.

ALERT data (above and below) indicate that rainfall was also concentrated over the west to north parts of the metro area with heaviest amounts extending from southwest across the metro area to the Catalinas. Here at house we had 1.39" in the gauge. The airport reported 0.37" and DM had a Trace; however Atmo came in with 2.06"! Angel Otarola reported right at 3 inches from his location a couple of miles east of here.

Sounding this morning from TWC/TUS (above) shows a classic, post-storm, onion shape. It will be very hard for the dry, sub-cloud layer to mix out today. The forecast from the 12 UTC run of the WRF-RR at Atmo (below) shows eastern Pima County mostly dry through 6:00 am tomorrow morning.

No Rain Here

View of the Catalinas at 6:30 MST this morning showing heavily overcast skies.

Plot of detected CG flashes (above - from Atmo and Vaisala) through 0703 UTC last night shows a donut hole over much of the metro area. There were some strikes near enough that we heard some rumbles of thunder here at the house.

There were a few ALERT sites (above and below) that recorded rainfall through 6:30 am MST this morning. These were mostly over the southeast portion of the network, where a couple of sites had over an inch of rain. Not even a sprinkle occurred here at the house. The airport reported a severe thunderstorm with gusts to 73 mph and 0.35"; DM had gusts to 35 mph and 0.11"; and Atmo had gusts to 46 mph but no rainfall. I did not notice really strong winds here - probably had gusts to around 30 mph.

Plumes from the 06 UTC runs of the GEFS (above for QPF at the airport and below for CAPE) are shown here. Light showers are indicated almost daily for the coming week and CAPE remains quite high.

This morning's forecast from the NWS (above) indicates POPs of 50 to 60 percent for each period through Monday. The long-range GFS forecast through noon next Saturday (below) shows heavy precipitation amounts across the entire state.