Marine Weather and Tide Forecast for Rillito, AZ

DISCUSSION
Latest WV satellite imagery shows our area under NE flow aloft as a mid-upper level high pressure is located to our NW from southern California into southern Nevada. Still have some remnant mid/upper level clouds hanging on across Santa Cruz/Cochise Counties as a weak mid level disturbance pushes to the southwest.
These clouds have slowed convective development down that way early this afternoon. Meanwhile, the rest of southeast Arizona is under clear to partly cloudy skies and visible satellite imagery shows cloud build-ups on the Sky Islands from Tucson northeastward.
Elsewhere, a few thunderstorms have formed across the White Mountains and we'll continue to see those moving to the southwest, though moisture in this area is much more limited. Given the moisture content today along with the well mixed dry sub-cloud layer, strong outflow winds and blowing dust will be the primary threat with thunderstorms across the region. Latest trends off the HRRR are latching onto the slower development across SW Cochise County, with scattered thunderstorms forming initially in the higher terrain from Tucson eastward then pushing into valleys. Meanwhile, the activity coming off the White Mountains will push into Graham County, then tend to lose a bit of their punch as they continue to move to the SW. By later this evening, more widespread thunderstorm activity will be focused from northern Sonora into the T.O. Nation and this will help to reinforce the moisture for Tuesday.

Tuesday is shaping up to be an active day across much of our forecast area. The combination of favorable easterly flow as the mid- upper level high shifts into northern Arizona and PWAT values increasing to about 1.2 to 1.6 inches along with MLCAPE values of 1000 to 1500 J/KG will result in more widespread thunderstorm development. The higher atmospheric moisture content with a bit slower storm motion compared to today will result in a transition to storms with areas of heavy rainfall with flash flooding potential being the primary threat. 12Z HRRR shows neighborhood probabilities (40-km) of 1" or more of rain at 50-90% with a couple of localized spots of 10% chance of 3" or more focused on the Tucson Metro and locales into Santa Cruz and much of Cochise Counties. Given the higher rainfall rates expected Tuesday with some cell mergers and the fact that not all areas have seen heavy rain yet, we went ahead and hoisted a Flash Flood Watch across Central and Eastern Pima County, Santa Cruz County and Cochise County Tuesday afternoon and evening. This also closely matches the WPC slight risk for Excessive Rainfall for Tuesday.

For Wednesday while there is considerable moisture, we are more likely to be on the subsident backside of an MCV which would tend to result in less activity compared to Tuesday, especially if Tuesday is as active as we anticipate it to be.

For the remainder of the week into the weekend, the pattern will be dominated by an upper low off the central/northern Baja peninsula moving to the north with southerly flow continuing in our area.
However, some drying is expected during this period with PWAT values returning to normal levels. Thus, expect typical day-to-day variability in daily monsoon activity for later in the week and weekend.

Temperatures will drop to below normal levels Wednesday and Thursday, then gradually warming back up with highs slightly above normal this weekend into next week.

AVIATION
Valid through 16/00Z. SCT-BKN 7-11k ft AGL BKN 12-15k ft AGL thru the period. SCT -TSRA/-SHRA in the White Mountains north of KSAD and along higher terrain from KOLS through KDUG moving W-SW across Southeast Arizona thru 15/04Z. Thunderstorms possible in KTUS vicinity between 14/22Z and 15/04Z. Another round of SCT TSRA/SHRA is expected aft 15/19Z for much of southeast Arizona. Wind gusts of 40-50 kts with 1-3SM VSBY in BLDU are possible with the thunderstorms today, especially near KSAD. Otherwise, SFC winds mainly less than 10 kts. Aviation discussion not updated for TAF amendments.

FIRE WEATHER
A more active monsoon pattern this week.
Deeper atmospheric moisture moving into the will increase the potential for heavy rainfall and localized flash flooding, especially on Tuesday. Temperatures will remain above normal through Tuesday, then drop back down to near or slightly below normal by mid week. Winds will remain westerly from 10-15 mph, with occasional gusts at or above 25 mph. Afternoon RH values in the low lying areas will be between 10-15% this afternoon, then 20-30% through the remainder of the week.

TWC WATCHES/WARNINGS/ADVISORIES
Flood Watch from Tuesday afternoon through Tuesday evening for AZZ502>504-507-508-512>515.