Marine Weather and Tide Forecast for Sierra Vista, AZ

DISCUSSION
The upper pattern impacting Southeast Arizona early this afternoon is defined by a 500-mb upper-low moving into Southern California and a subsequent 700-mb trough axis aligned along the Northern Baja. The latest Advected Layer Precipitable Water (ALPW) imagery indicated modest mid-level SSE winds along the eastern periphery of the mid-level trough axis is advecting a deeper plume of mid-level moisture currently residing in northern Sonora Mexico up into south-central Arizona today. The combination of this mid-level moisture and the upper-level diffluent flow with the advancing upper trough will provide enough support for the development of weak showers and thunderstorms across our neck of the woods this afternoon into this evening. This is supported by the latest 24/17Z HRRR which indicates storms developing across Santa Cruz and far SE Pima between 1-3 pm MST then expanding across SW Cochsie/ERN Pima and SE Pinal counties late this afternoon into the evening.

Surface dewpoints across the area range from the mid to upper 40s from Tucson west to the upper 30s east of Tucson. Dry, but not super dry. In any event, we will likely see strong evaporation occur within downdrafts today resulting in the possibility of wetting rains (albeit light) along with some frisky outflow wind gusts to 40+ mph. The 24/12Z HRRR indicated a neighborhood (within 25 miles) probability of 50 percent for wind gusts in excess of 30+ kts near thunderstorm between 4-8 pm today. I did modify inherited NBM forecast wind grids to include some gusts/outflow boundaries as well as include the mention of patchy blowing dust. I don't anticipate any major organized dust boundaries to develop, but I do expect localized reduced visibility near the stronger storms that develop.

Chances of storms will be limited to the eastern forecast zones near the Arizona/New Mexico state line Monday with the best lift out ahead of the upper-low moving into New Mexico. The upper feature itself ejects NE into the Four Corners Monday night as a stronger upper-low dives SSE along the Pacific Northwest coastline. Expect dry but breezy/windy conditions across Southeast Arizona Wednesday and Thursday of next week as this upper low expands across the Great Basin. This pattern setup may result in some fire weather concerns for us. In fact, the SPC indicated a 40 percent probability of critical fire weather conditions both Wednesday and Thursday of next week.

AVIATION
Valid through 26/00Z. SCT clouds at 10k-13k ft AGL with locally BKN 8k-10k ft AGL with a 10-30% chance of -SHRA/-TSRA mainly KTUS and east through the forecast period. The storm motion of the -SHRA/-TSRA will be from the south to the north.
There is a 30-50% chance for erratic and gusty outflows of 30 kts or greater from storms wilt localized VSBY 1-3SM in BLDU.
SFC wind SLY-SWLY 10-14 kts through 15/03Z, then light terrain driven wind less than 10 kts overnight becoming SWLY 10-14 kts Monday after 25/18Z. Aviation discussion not updated for TAF amendments.

FIRE WEATHER
A weak weather system will bring a 10-30% for thunderstorms and light rain showers from Tucson south, and then chances shifting and expanding east and northeast of Tucson this evening into tomorrow with lingering chances along the New Mexico state line into early Tuesday. Most of this activity will be a light shower to virga, although there will be the potential for isolated 'dry' thunderstorms and the threat of gusty outflow winds and lightning. Rainfall amounts will be light, generally only trace amounts to less than a tenth, with the highest precipitation totals forecasted in the White Mountains at 0.10"-0.30".

High temperatures will be within a couple of degrees of normal through all of next week. Min RH values will be in the 7-18 percent range in the valleys and in the 14-20 percent range in the mountains through next week, except on Monday in the eastern mountains when RH values will be in the 20-40 percent range.
20-foot winds will be 15 mph or less today, with some afternoon/early evening gusts to around 25 mph. Elevated 20-foot southwest winds of 15-20 mph and gusts around 30 mph are expected Monday and Tuesday across eastern Santa Cruz, Cochise, Graham and Greenlee counties. Breezy to windy southwest to west winds then spread across much of southeast Arizona on Wednesday and Thursday.

TWC WATCHES/WARNINGS/ADVISORIES
None.