Marine Weather and Tide Forecast for South Tucson, AZ

DISCUSSION
Overnight, showers and perhaps a rumble of thunder continue as a weak disturbance interacts with increasing moisture and elevated instability. Rainfall amounts overnight will remain light, but some localized areas could pick up a quick 0.25" or so through the morning. Over the past hour, lightning has picked up just south of the border, with these isolated storms moving into southern AZ.

Tropical Storm Rachel continues to track northeastward toward Baja, bringing tropical moisture and dynamic forcing into Southern Arizona. While gradient winds have lessened slightly in recent guidance, strong, gusty winds are still expected. A Wind Advisory remains in place from Tucson westward for Sunday.
Expect south to southwest winds of 25–35 mph with gusts of 45–55+ mph, with localized higher gusts possible near any convective activity. For the Wind Adv east for eastern Pima, portions of Santa Cruz, and SE Pinal COs, S/SW sustained winds of 25-35 mph, with gusts around 45 mph likely. Once again, localized wind gusts to 60 mph will be possible due to a threat for isolated strong to severe thunderstorms.

While there could be a brief lull from mid morning into early afternoon, increasing moisture transported north into AZ from Rachel's interaction with an upper level trof will increase coverage of showers and storms.

Severe potential exists this afternoon/evening and possibly into Sunday morning. The main threats remain damaging wind gusts (40–60 mph), small hail, and localized heavy downpours. Modest instability paired with favorable 0–1km/0–3km helicity and moderate to strong deep layer shear maintains a non-zero tornado threat (2% risk per SPC) primarily across western Pima County (including Ajo, Lukeville, and Why) from Saturday afternoon through early Sunday morning. Looking over some of the CAMs, the greatest severe threat would be later in the afternoon, the evening, and possibly overnight. There are solutions that bring one or two broken lines of convection through the western third of the CWA in the E/SE quadrant of Rachel as she makes landfall in northern Baja. Given the shear, supercells are possible, even as far east as of Tucson. However, any tornado threat should remain confined to far western Pima and perhaps into central Pima County.

As for the rain an possible flash flood risk, scattered to numerous showers and storms will pick up this afternoon into Sunday. Storm total rainfall averages 0.25" to 0.75" west of Tucson and 0.10" to 0.25" east of Tucson, with 1 to 2+ inches possible in mountain locations or under localized training cells. While widespread flooding is not expected, localized quick bursts of a half-inch to an inch could yield an isolated flash flood threat. Southerly flow ahead of the longwave trough keeps lingering rain/thunderstorm chances (20–50%) going Monday and Tuesday. Drier air returns by Wednesday, clearing out shower activity across the area. Expect an extended period of below- normal temperatures starting Sunday and persisting through mid- week.

While its fairly early, there is an increasing signal for another east wind event late week. Just something to keep on your radar as winds could be fairly strong in the usual easterly wind even prone areas.

AVIATION /10Z SATURDAY THROUGH 10Z SUNDAY/
SCT-BKN clouds 9-12k ft AGL this morning with VCSH and possibl VCTS. Renewed development of SCT SHRA/TSRA is expected for much of the area aft 10/19Z through end of valid pd. Brief MVFR possible under heavier showers/storms. Gusty winds to 45 kts possible around convection later this afternoon. SFC winds S/SW around 8-15 kts with gusts to 25kts this afternoon.
Aviation discussion not updated for TAF amendments.

FIRE WEATHER
The combination of a low pressure system and the remnants of Tropical Storm Rachel will bring breezy to windy southwest winds Sunday and Monday with wind gusts of 35 to 45+ mph on Sunday for much of southeast Arizona. Highest wind potential will be from central Pima County west. Breezy winds continue on Monday as well with winds 15 to 25 mph with gusts around 35 mph. This weather system will bring a 30-70 percent chance for rain Saturday and Sunday, lowering to 20 to 50 percent Monday and Tuesday. Minimum relative humidity values will remain 15-30 percent in lower elevations and above 40 percent in high elevation terrain through Saturday.

TWC WATCHES/WARNINGS/ADVISORIES
Wind Advisory from 2 AM to 11 PM MST Sunday for AZZ501-502-505.
Wind Advisory from 7 AM to 11 PM MST Sunday for AZZ503-504-506- 514-515.