FXUS65 KPSR 092030 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 130 PM MST Thu Jul 9 2026 .KEY MESSAGES... - Hot temperatures will continue this week resulting in areas of isolated major Heat Risk and lingering Extreme Heat Warnings. - The chance for showers and thunderstorms will mainly be confined to higher terrain areas of far eastern Arizona through Saturday. - Deeper moisture will move into the region early next week resulting in better chances for widespread showers and thunderstorms. && .SHORT TERM /Today through Friday/... Early afternoon WV imagery depicts the eastern edge of a subtropical anti-cyclone over Arizona with the core high pressure center along the southern California coast. Meanwhile, shortwave energy in the northern stream across the Great Basin was acting to dampen and partially erode this ridge aloft. While H5 heights have retreated somewhat to around 594dm, thermal profiles through the middle troposphere are steady or even warming as a result of midlevel subsidence warming south of a westerly jet streak across Utah. This evolution will yield a continuation of surface temperatures 5F-10F above normal today and patchy areas of major HeatRisk. On Friday, the high pressure center will move back into Arizona as the northern stream shortwave exits into the plains. Temperatures should cool very slightly in response to the loss of subsident warming, however localized areas in SE California continue with major HeatRisk and continuation of Extreme Heat warnings. Given increased subsidence, warming aloft, and a modest reduction in low level mixing ratios, deep convection will be reduced through Friday, though not completely eliminated across eastern Arizona high terrain. Conceivably, a weakening outflow could propagate into parts of the CWA this evening, however waning instability and greater inhibition should limit convective coverage and intensity. Even more sparse and weaker thunderstorms would be expected Friday under a similar hostile environment, and not even justifying POPs above 10%. A far more conducive environment will materialize over northern Sonora Friday evening with models hinting at an well organized, intense MCS. With mean flow turning SE by this time, this will set the stage for deep moisture advection into the forecast area Saturday with sfc-H7 mixing ratios 10-11 g/kg and total column PWATs over 1.50" surging through south-central Arizona. These moisture parameters along with the evolving synoptic pattern will become favorable for scattered storms, multiple strong outflow boundaries, and locally heavy rainfall into lower elevation communities into early next week. && .LONG TERM /Saturday through Tuesday/... As mentioned, the overall weather pattern heading into the weekend and next week will become more favorable for a more active monsoonal pattern to set up. The subtropical ridge will quickly migrate northeastward into the Rockies over the weekend and then set up over the Central Plains early next week while strengthening in the process. As this whole pattern evolution materializes, the mid-level flow will shift out of the east to southeast. This will introduce strong moisture transport into the Desert Southwest with the latest EPS and GEFS showing PWATs increasing to at least 1.4-1.5" starting as early as Sunday and remaining above 1.5" into next week. Moisture on Saturday will likely remain fairly limited across south- central AZ with low-level mixing ratios remaining between 9-10 g/kg, with the better moisture and thus the best convective potential remaining relegated to the higher terrain and southeastern AZ. There are strong indications from the latest guidance of a strong convective complex likely to develop over northern Sonora Saturday evening, which will likely send of pool of higher moisture into central AZ heading into Sunday with mixing ratios solidly above 10 g/kg. As a result, Sunday looks to be the first real potential for greater thunderstorm activity to materialize across the south- central AZ lower deserts with NBM PoPs solidly in the 30-50% range. With PWATs values remaining above 1.5" along with mixing ratios above 10 g/kg through the first half of next week, the potential for additional convective activity will remain in place and likely expand further west to include the western deserts as well with NBM PoPs ranging between 20-40% each day. We will also have to be on the lookout for any potential easterly waves that could enhance the convective activity, however, pinpointing the track and timing of these waves this far out is very difficult. Therefore, high uncertainty exists of which particular days next week have the potential to be more convectively active. With the increasing moisture and potential cloud cover, afternoon high temperatures this weekend into early next week will gradually retreat to near to slightly above normal levels with widespread moderate HeatRisk in place. && .AVIATION...Updated at 1730Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: The main aviation forecast uncertainty will be the potential for an outflow from distant convection moving through region early tonight. As of now, best timing looks to be between 05Z-08Z, though timing may need to be adjusted in later TAF updates. Due to the uncertainty of this feature, it only included in the TAFs as TEMPO group. No significant dust is expected if an outflow were to come to fruition, but some slight reductions in surface VIS cannot be ruled out, mainly at KIWA. Outside of this, diurnal trends will be observed through the period, with the timing of the nightly/early morning E'rly shift highly conditional the advancement of a possible outflow. Afternoon gusts around 20 kt can be expected. Besides some distant CU from high terrain thunderstorms, skies will be mostly clear in the vicinity of the terminals. Southeast California/Southwest Arizona including KIPL and KBLH: Multiple round of breezy to windy conditions, mainly at KBLH, will be the main aviation concern during the next 24 hours. Gust there will hover around 25 kt this afternoon before relaxing after sunset, though sustained speeds are expected to remain elevated. The next round of breeziness is anticipated overnight in a window between 08Z-12Z, this time with gusts that may approach 30 kt at times. Speeds should once again relax around sunrise. At KIPL, gusts will not be as strong, nor as prominent during the forecast window, but obs around 20 kt are likely to be seen this evening, and maybe again for a brief moment overnight. Clear skies will be common through Friday morning. && .FIRE WEATHER... Gusty and erratic thunderstorm winds with isolated lightning over the far eastern districts through Friday will be the main fire weather concern. Outside of any potential outflows, winds should favor diurnal trends with typical afternoon breeziness around 20 mph. Some stronger afternoon gusts between 20-30 mph will be common through Friday along the Lower Colorado River Valley. Afternoon RH values between 10-20% will be common across the region through Saturday. Overnight recoveries will generally range between 30-60% with the upper end of the range across the Imperial Valley and the eastern Districts. Temperatures are expected to run well above normal today, with the lowest elevations reaching between 110-115 degrees before a very gradual cool down takes place starting Friday. More widespread monsoonal activity is likely starting late this weekend and continuing into next week. Moisture levels and humidities should also improve considerably heading into next week, alleviating much of the fire weather concerns. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Extreme Heat Warning until 8 PM MST Friday for AZZ530-537-540- 542>544-546-548-550-551. Extreme Heat Warning until 8 PM MST this evening for AZZ531>534- 536-538-539-541-545-547-549-553>555-559-560-562. CA...Extreme Heat Warning until 8 PM PDT Friday for CAZ562-566-567- 569-570. Extreme Heat Warning until 8 PM PDT this evening for CAZ564-565- 568. && $$ SHORT TERM...18 LONG TERM...Lojero AVIATION...RW FIRE WEATHER...Lojero/Kuhlman