Marine Weather and Tide Forecast for Catalina Foothills, AZ

DISCUSSION
Radar shows a few weak echoes east of Tucson with a couple lightning strike along the AZ/NM border. Marginal mid- level moisture is in place with PWAT values around 0.70 inches from central Pima County eastward. Aloft a longwave trough extends from the Pacific Northwest down to the west coast of Baja. To the east an omega block is in place over the Midwest with broad high pressure to the south extending from the west Atlantic into Texas. The trough is likely lending some synoptic scale support to the weak storms along with surface heating. Hi- res guidance like the HRRR shows a few weak storms late this afternoon into the overnight hours east of Tucson. Its possible this activity continues through tonight, although rainfall will likely be negligible with the main threat being gusty outflow winds. NBM PoPs were adjusted up for this afternoon and evening to account for the current storms and possible overnight activity.

Over the next couple days the upper air pattern will slowly change as the broad area of high pressure moves westward and the trough flattens out over the desert Southwest. Winds will be breezy each afternoon this week and into the weekend. Today the strongest winds will be likely be west of Tucson switching to east of Tucson the rest of the week. Winds will be strong enough to combine with low RH to create elevated fire weather conditions through Thursday. With the ridge moving further west temperatures increase above normal Tuesday and Wednesday, then back to around normal Thursday and Friday as a trough moves through Wyoming and Colorado and briefly nudges the ridge away.
Temps then warm back 3-7 degrees above normal this weekend.

At the same time ensembles show PWAT values steadily increasing starting Thursday with mean PWAT values around an inch by the weekend, but still a large spread around the mean. NBM has increased PoPs slightly compared to 24 hours ago with slight chances along the international border Thursday and Friday. This weekend PoPs are 15-35 percent along the international border and the White Mountains. Storms likely won't be big rainers, but will be capable of strong outflow winds and lightning.

AVIATION
Valid through 10/00Z.
SCT-BKN cumulus clouds 10k-14k ft AGL from Tucson eastward through most of the period. Weak isolated -TSRA will be possible over Graham, Greenlee, and Cochise Counties this afternoon through the overnight hours. Chances that an airport will be impacted are low. Surface winds will be southwesterly 10-15 kts with gusts to 20 kts through 09/02Z then light and terrain driven overnight. Winds increase again Tuesday afternoon with similar speeds to today. Aviation discussion not updated for TAF amendments.

FIRE WEATHER
Winds through the middle of the coming week will be southwesterly (becoming west/northwest Wednesday) 12-18 mph each afternoon with gusts to 25-30 mph. Minimum relative humidity values should remain fairly consistently 8-15 percent across desert locations and 12-18 percent in the mountains, with the potential for increasing relative humidity Friday into next weekend. Elevated fire weather conditions will be possible each afternoon through Thursday, especially through the valleys of Graham county where winds should be a bit stronger.

TWC WATCHES/WARNINGS/ADVISORIES
None.