485 FXUS65 KPSR 072200 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 300 PM MST Mon Jul 7 2025 .UPDATE...Updated Short Term Discussion. && .KEY MESSAGES... - Dry conditions and above normal temperatures are expected this week with highs forecast to reach and exceed 115 degrees across many of the lower desert communities Wednesday - The heat will result in widespread Major Heat Risk with Extreme Heat Warnings in effect for much of the region Tuesday through Thursday - Temperatures are forecast to lower a few degrees by the end of the week through this weekend, but will remain above normal - Thunderstorm activity will remain subdued due to strong high pressure and lower moisture, and confined mostly to the Arizona high terrain and Southeast Arizona && .SHORT TERM /TODAY THROUGH TUESDAY/... Strong high pressure remains centered near the AZ/NM border this afternoon, with H5 heights around 594dam, and WV satellite shows a cutoff low pressure circulation just off the CA coast. Aircraft soundings out of Phoenix show minimal changes to the boundary layer thermal profile over the last 24 hours. Thus, afternoon temperatures today are expected to be similar to yesterday, with lower desert highs forecast around 106-111 degrees. Through Tuesday, modeling consistently shows the coastal low circulation weakening while the high strengthens and shifts more into AZ. H5 heights are forecast to increase up to 597-598dam by the end of the day Tuesday, which is right around record level for this time of year. As a result, surface temperatures will further heat up. Highs Tuesday are forecast to be 2-4 degrees warmer than today, with lower desert highs more around 109-114 degrees. The highs tomorrow, with warm morning lows, will push more areas into Major HeatRisk, especially across the eastern half of the CWA. An Extreme Heat Warning begins tomorrow for the lower deserts of Maricopa and Pinal Counties, and the San Carlos area of Gila County. Aside from the heat, breezy to locally windy conditions are ongoing along the lower Colorado River Valley this afternoon. Winds are a little stronger than originally forecast, with southerly wind gusts reaching up to 25-40 mph. This is leading to some widespread hazy conditions from lofted dust and sand and even may be creating some localized surface visibility reductions from shallow dust channels. Winds in this area are forecast to gradually weaken late this afternoon and evening. Thunderstorm activity the next couple afternoons will remain confined to the High Country and parts of Southeast AZ, as meager moisture profiles and increasing subsidence from the strengthening high will hinder any potential for more widespread convection. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Wednesday is expected to be peak of the extreme heat episode as the subtropical high becomes more expansive across the Desert Southwest and strengthens slightly. This will translate to widespread high temperatures of 115+ degrees across the lower deserts with the latest NBM showing a greater than 80% of occurrence. Temperatures of this magnitude will result in widespread Major HeatRisk across the majority of the region with Extreme Heat Warnings in effect across virtually the entire CWA with exception of the elevations above 4000 feet east of Phoenix where Heat Advisories are effect. Both Phoenix and El Centro have a 70% chance of at least tying a daily record high. The subtropical high is expected to weaken slightly heading into Thursday as what is leftover from the aforementioned cutoff low moves eastward through the Great Basin and Intermountain West Regions, resulting in a suppression of the high. Temperatures are expected to cooldown slightly but still hot enough for areas of Major HeatRisk to remain in place with Extreme Heat Warnings in effect for all of the lower deserts. Heading into the end of the week and next weekend, the high will continue to slowly migrate westward towards the southern CA coastline and as a result heights aloft will continue to decrease slightly. This will translate to slightly cooler temperatures, enough to drop readings below extreme heat thresholds but still remain above normal as afternoon highs will hover around 110 degrees across the lower deserts. With the subtropical high stationed over the region and the flow pattern not favorable for deeper moisture advection into the region, conditions are expected to remain mostly dry for the next several days across the majority of the region with any storm potential to be confined across the White Mountains through the southeastern third of AZ. In fact, virtually all of the EPS and GEFS ensemble members do not indicate any measurable rain potential for the lower deserts until at the earliest the middle of next week when potentially the subtropical high migrates into the Four Corners Region, resulting in a more favorable flow pattern for deeper moisture advection and thus more widespread storm chances. && .AVIATION...Updated at 1720Z. South Central Arizona including KPHX, KIWA, KSDL, KDVT: No major weather issues will exist through Tuesday morning under FEW/SCT mid/high cloud decks that will be primarily relegated to the mountains east of the terminals this afternoon. West winds will dominate the TAF period. Confidence is moderate to good that the typical nocturnal switch to east winds will not take place at KPHX tonight. The typical shift to east/southeast is only expected at KIWA overnight tonight. Southeast California/Southwest Arizona including KIPL and KBLH: No major weather issues will exist through the next 24 hours under clear skies. Winds will mostly favor SE to S at both terminals, with a relatively short period of SW winds during the evening for KIPL.Slightly stronger winds (10-15 kts sustained with gusts up near 20 kt) anticipated at KBLH this afternoon. && .FIRE WEATHER... Above normal temperatures will persist throughout the week as lower deserts highs reach and exceed 110 degrees each day. MinRH values will generally be in the teens each day, while MaxRH values will be lowest Tuesday and Wednesday night at 20-40% and then increase up to 30-50% the rest of the week for most of the area. The exception will be across Imperial and southern Yuma Counties where periodic gulf surges will result in MaxRH values in excess of 50%. The overall wind pattern will follow the familiar diurnal trends, with some afternoon/early evening breeziness. A slight uptick in the winds is expected Wednesday and Thursday afternoon, which may lead to locally elevated fire weather conditions in the afternoon. Very minimal rain chances will exist throughout the week with CWR <10% through at least next weekend. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Extreme Heat Warning from 10 AM Wednesday to 8 PM MST Thursday for AZZ530>533-535-536. Extreme Heat Warning from 10 AM Tuesday to 8 PM MST Thursday for AZZ534-537>540-542>544-546-548-550-551-553>555-559-560. Heat Advisory from 10 AM to 8 PM MST Wednesday for AZZ557-558- 563. Extreme Heat Warning from 10 AM to 8 PM MST Wednesday for AZZ541- 545-547-549-552-556-561-562. CA...Extreme Heat Warning from 10 AM Wednesday to 8 PM PDT Thursday for CAZ560>570. && $$ SHORT TERM...Benedict LONG TERM...Lojero AVIATION...Berislavich/Whittock FIRE WEATHER...Lojero/Benedict