Marine Weather and Tide Forecast for Casas Adobes, AZ

DISCUSSION
Partly cloudy skies across southeast Arizona this afternoon with a few cloud build-ups especially across the higher terrain south and east of Tucson. Just a few showers so far on radar for these locales and these should diminish after sunset. A fairly similar forecast for Friday but with a slick uptick in mid level moisture we'll see a few more cloud build-ups with a slight chance (10% to 20%) of showers and thunderstorms once again mainly from Tucson area south and eastward. Rain amounts will be mainly less than 0.10" so not really impactful though can't rule out a few stronger wind gusts of 30 to 40 mph near any showers.

For this weekend, all eyes will be focused on the trough of low pressure to the west along with Tropical Storm Rachel which will recurve towards northern Baja Mexico. The latest forecast from the National Hurricane Center shows Rachel moving onshore as a 50 kt Tropical Storm across northern Baja late Saturday night and then becoming post-tropical as it moves into southwest Arizona Sunday morning. The track has shifted a bit to the east over the past 24 hour which does put some potential for higher wind gusts from Tucson westward. The ECMWF and its ensembles are particularly strong for wind gusts, depicting a widespread area in excess of 50 mph over the T.O. Nation and western Pima County on Sunday with 35-50 mph elsewhere. The GFS/GEFS and official forecast are a bit more muted for winds but certainly the potential is there for an upward adjustment in our official wind forecast which has wind gusts of 35- 50 mph. Later shifts will likely need to hoist wind headlines for Sunday. It is not unprecedented that tropical origin systems can result in gusty winds across the desert southwest. While not exactly the same setup, an example of this was Hurricane Nora in 1997 that came into north central Baja as a hurricane and resulted in sustained tropical storm winds in Yuma as it raced north.

Outside the wind threat on Sunday, the other main impact from this system will be rainfall. Moisture will be on the increase on Saturday ahead of Rachel and given enough solar insolation, we expect scattered to numerous showers and thunderstorms to develop Saturday afternoon and continuing into Saturday evening. A few of these thunderstorms may be strong with gusty winds in excess of 40 mph and locally heavy rain with localized rain amounts 0.50" to 1 inch in the strongest storms. Otherwise, for Saturday, precipitation amounts will generally range from about 0.05" to 0.35" for those locales that see rain.

On Sunday, rain will hinge on 2 factors...the remnants of Rachel and precipitation along its immediate track and outside of that, how much atmospheric destabilization we see for shower and thunderstorms activity especially from Tucson eastward. This part of the forecast still has quite a bit of uncertainty with is but any thunderstorms that do develop have the potential to be strong to severe given the strong wind-shear that will be present.

For Monday and Tuesday, the main factor for our weather will be the trough axis to our west. There will still be another area of forcing and lift as a cold front moves through the region from late Monday into Tuesday and that is likely to bring us more shower activity and potentially a few thunderstorms as well. Winds will remain gusty on Monday but certainly not nearly as strong as Sunday. Drier air will then move in Wednesday with any lingering precipitation chances Wednesday to the east of Tucson.

Storm total precipitation amounts of 0.25" to 1 inch still looks reasonable for most valley locations with 1 to 2 inches in the mountains. The lower end of these amounts will tend to be over Cochise County with the highest amounts north to west of Tucson.
Most of the precipitation is expected Saturday and Sunday and while isolated flash flooding may occur with any stronger thunderstorms this weekend, we're not expecting widespread flash flooding concerns.

Above normal temperatures through Friday will give way to near normal temperatures on Saturday, then an extended period of below normal temperatures will occur Sunday through the middle of next week.

AVIATION
Valid thru 10/00Z.
FEW-SCT clouds 8k-12k ft AGL through the forecast period with BKN cigs into this evening from KSAD northeastward and along the international border. Isolated -SHRA/-TSRA will be possible from KTUS south and eastward into this evening and again Friday with the likelihood of any terminals being affected by TSRA low. SFC winds E/SE 6-12 kts through the period. Aviation discussion not updated for TAF amendments.

FIRE WEATHER
Easterly winds continue through Friday with wind gusts 20-25 mph in the normally susceptible locations for east winds. Minimum relative humidity values will remain 15-30 percent in lower elevations and above 40 percent in high elevation terrain through Saturday. A few storms are possible mainly south and east of Tucson this afternoon and from Tucson south and east Friday afternoon. A weather system will move through this weekend into next week bringing a 30-70 percent chance for rain Saturday through early next week. This system will also bring breezy to windy southwest winds Sunday and Monday with wind gusts of 35 to 45 mph on Sunday for much of southeast Arizona.

TWC WATCHES/WARNINGS/ADVISORIES
None.