Marine Weather and Tide Forecast for Naco, AZ

DISCUSSION
In the short term, the latest GOES blended total precipitable water imagery indicated a slug of deeper moisture with PWAT values between 0.5-0.75 inches situated across Pinal and eastern Pima county this morning. A weak shortwave observed on GOES-19 water vapor imagery across the backside of a weak trough moving NE through southwest Arizona this morning will interact with this moisture as it tracks into the east central mountains of Arizona this afternoon. The lower-levels are still rather dry, but there should be enough lift and instability to produce a chance (30-40%) of mainly dry storms/thunderstorms over the White Mountains this afternoon with gusty and erratic winds accompanying the downdrafts.

Otherwise, the upper pattern is defined by a strong upper-low off the coast of the Pacific Northwest/northern California this morning. There is strong agreement with the ensemble members of both the GEFS and ECMWF with tracking this upper low into NRN CA by 22/00Z Tuesday afternoon and through the NRN Great Basin Wednesday. As this occurs, a high-amplitude ridge of high pressure building off the coast of British Columbia Canada will force the development of a weak low to its south, creating a mean open trough with an axis extending from just off the central CA coast into the NRN Rockies Friday. This orientation is conducive for progressive shortwaves to zip by to our north in the nearly zonal upper flow. The low itself weakens and then moves through southern California/northern Arizona early this weekend. What does this all mean? Well, we will stay warm with afternoon breeziness the second half of this week into next weekend. The strongest winds will likely occur Friday and Saturday, and is supported by the 20/04Z NBM probability between 30-40% for wind gusts in excess of 25+ mph at the Tucson International Airport (KTUS).

The main weather impact this week will be fire weather related given the combination of low RHs and the breezy WLY winds. The 04/18Z NBM 5.0 probability for reaching critical fire weather conditions (RH<=15% and 20-foot wind speed=>20 mph) across portions of Fire Weather Zone 152 Wednesday through Friday is 50-70 percent. Given the uncertainty in the strength and timing of the stronger winds, we will just message elevated to near critical fire weather conditions for now.

AVIATION
Valid through 21/12Z. SCT 10-15k ft AGL decreasing through 20/18Z, with a development of 8-12k ft AGL clouds to the NE of KTUS (including the terminal at KSAD) in the afternoon through 21/02Z. After 21/02Z, increasing high clouds AOA 20k ft AGL from the southwest through the rest of the valid period.
Valid through 21/12Z. SFC winds light (less than 10 kts) and terrain driven through 20/20Z, then SWLY/WLY 10-14 kts with occasional gusts to 20 kts into the early evening. Aviation discussion not updated for TAF amendments.

FIRE WEATHER
There is a modest increase in mid-level moisture near the White mounatins will result in a chance (30-40%) for mainly dry storms/thunderstorms this afternoon with gusty and erratic outflow winds possible near the downdrafts. Minimum RHs will generally be 10-15 percent in the valleys and 15-25 percent in mountains today, decreasing to the single digits to mid teens areawide by mid-week. Otherwise, passing systems to the north this week will keep Southeast Arizona dry, but breezy the second half of the week into next weekend. There is a 50-70 percent probability that portions of Fire Weather Zone 152 will reach elevated to near critical fire weather conditions Wednesday through Friday.

TWC WATCHES/WARNINGS/ADVISORIES
None.