Unsettled Weekend

Nice color over the Rincons (top) and Catalinas (bottom) a bit before 6:30 am MST this morning.

Plumes for QPF (from 06 UTC GEFS runs - above) continue to indicate a wet and active weekend. The chances for rain at the airport from same runs (below) indicate high POPs for the 11th and 12th. 

Current morning forecast from the NWS for the airport is below.

The Tropics remain very active, as shown in the TPW image for 15 UTC (above). TS Rachel is west of Baja; Hurricane Simon is off the Mexican Coast; and Hurricane Isaias is headed for a landfall on the Florida Panhandle (current NHC outlook shown below).

Complicated Situation

Pre-sunrise glow over the Rincons a bit before 6:00 am MST this morning. View at bottom shows crescent moonrise, looking same direction at a bit before 5:00 am.

There are two tropical storms over the eastern Pacific this morning. Former Hurricane Rachel (above) is much weakened and it is forecast to turn northeast and be over the lower Colorado River Basin by Sunday. To the South, TS Simon is forecast to rapidly become a major hurricane and move toward Cabo Corrientes by Sunday. Thus, there will be lower pressure both to north and south of GoC, competing to pull moisture both northward and southward.

The TPW image (below, from 15 UTC) shows Rachel, Simon, and also Hurricane Isaias over the Gulf of Mexico. Currently, high PWs extend about halfway up the GoC, so a real tug-of-war is setting up for the weekend. At this time, it is not clear to me whether Rachel or Simon will dominate the moisture transports.

The NWS take on this is a bit different than mine, as per graphic above. The current NWS forecast for the airport (below) puts the emphasis on Saturday, with POPs at 50 to 60 percent. Regardless, it should be an interesting weekend here. Note that hurricane in GoM is fcst to move rapidly northward and strike the eastern Gulf Coast area by tomorrow evening.

Fair Weather

Views of the Rincons at 5:45 am MST (above), and of the Catalinas at 6:45 am (bottom - both on October 5th). Outlook from NWS for coming work week (below) indicates mild and dry conditions continuing.

Heavy Rain Here

Downpour on campus yesterday morning at 9:45 am MST.

Widespread reports of over an inch across the ALERT Network for 24-hours ending at 7:30 am this morning (above). Here at the house there was 0.90" in the gauge. Atmo reported 0.79", while DM had 0.34" and the airport noted 0.31".

The NWS morning forecast for the airport (below) calls for an extended period of tranquil weather as October begins.

Rainy Morning

Showers along the Catalinas at 6:30 am MST this morning.

ALERT reports as of  7:00 am (above) showing mostly light amounts. Here at house there was 0.08" in the gauge at 7:00 am (however, it is raining again as I write this). The airport reported 0.04"; DM had 0.03"; and Atmo had 0.08". Plot of detected CG flashes (below - from Atmo) indicates widespread thunderstorm activity across Pima County this morning.

QPF plumes from SPC this morning (above) call for fairly significant rain here today. The current forecast from the NWS Forecast Office for the airport is below, calling for 100% POPs today. Latest advisory re Hurricane Polo from NHC is at bottom.

Flash Flood Watch

 

IR image from 18 UTC today showing heavy cloud cover over northern Mexico and much of the Southwest. Hurricane Polo is approaching southern Baja at this time, maintaining Cat. 3 strength (96 to 112 kt).

GFS forecast from 12 UTC run for 500 mb at 18 UTC today. Below is forecast from same run for 500 mb valid at 00 UTC tomorrow afternoon. Note the powerful short-wave across Arizona.

The NWS has issued a FF Watch for much of Arizona (above) valid from now until 11 PM tomorrow night. Current morning forecast for the airport shown below.

Morning Outlook from NHC for track of Hurricane Polo shown below. Storm is forecast to dissipate southeast of Tucson tomorrow afternoon.

Hurricane Polo

IR view of Category 5 (140 kt) Hurricane Polo at 1405 UTC this morning off the southwest coast of Mexico.

Forecasts of Polo's possible tracks above, from the GEFS runs at 06 UTC this morning. Once Polo crosses GoC, its remnants are forecast to cross northern Sonora just southeast of Tucson. The offical morning track forecast from NHC is shown below. Should be an interesting few days next week, assuming the forecasts are reasonably accurate.

Quick Look Today

Heavy overcast this morning shown in 8:00 am MST view of Catalinas.

Only rain reported within the ALERT Network for 24-hours ending at 8:00 am occurred in the far southwest corner of the array (above).

Plumes for rainfall at TUS (above - from SPC) indicate chances for light showers today. The current NWS forecast for the airport (below) indicates POPs of 30 percent today and tonight. No rain here at the house for over a week now.