Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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133 FXUS65 KPSR 080527 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 1027 PM MST Sun Jul 7 2024 .UPDATE...Updated 06z Aviation Discussion. && .SYNOPSIS... Extreme heat will continue to prevail through the upcoming week as strong high pressure remains entrenched across the region. High temperatures across the lower deserts will range between 112-120 degrees. Some moisture will start to move over the region by the middle to latter half of the week, aiding in increasing thunderstorm chances across southeast AZ and the Arizona high terrain. && .DISCUSSION... Strong surface high pressure is currently situated along the central CA/NV border with a northerly wind flow prevailing across the region. This northerly flow is continuing to promote a very dry air mass with SPC mesoanalysis indicating PWATs ranging between 0.5-0.8" across the majority of the region. As a result, mostly clear skies along with near zero storm activity will continue. The surface high pressure is expected to very slowly drift eastward and be situated near the NV/AZ/UT border heading into middle to latter of the week. As a result, the 500 mb height fields will continue to remain steady state, in the 594-597dm range, through the majority of the upcoming week. The enhanced 500 mb heights in combination with the mostly clear skies will continue to result in extreme heat conditions through most of the upcoming week. High temperatures across the lower deserts will range between 112-120 degrees, with the highest readings across the western deserts. The magnitude of these temperatures will result in widespread major to locally extreme HeatRisk, with Excessive Heat Warnings in effect through Thursday. Therefore, if performing outdoor activities, it is crucial to take all the necessary heat precautions to protect yourself and others from these extreme temperatures as they can become life-threatening! As the center of the high pressure moves near the NV/AZ/UT border by mid-week, the flow pattern will become a bit more favorable to allow for some moisture intrusion into portions of southeastern and eastern AZ. This will lead to afternoon and early evening isolated storm chances starting as early as Tuesday across portions of southeastern and the higher terrain areas of eastern AZ. Unfortunately, given the isolated nature of the storms, any associated outflow boundaries or cloud debris will likely not be enough to have a significant effect on the overall temperatures, which is why confidence is high enough for the extreme heat conditions to continue through the latter half of the week. Heading into next weekend, the high pressure is expected to migrate towards the Four Corners Region. As it does so, it will promote better moisture advection with model ensembles showing PWATs rising to above 1" across the region. This will lead to increased storm chances, at least for the Arizona lower deserts, where NBM PoPs for next weekend range between 20-30%. With the increased moisture, temperatures will trend down below the excessive heat threshold. && .AVIATION...Updated at 0525Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation weather concerns will exist through the TAF period under mostly clear skies. Slantwise visibility reductions may become a concern midday tomorrow, with smoke moving southward over much of eastern Arizona. Confidence in visibility reductions to MVFR (as low as 5SM) at the surface is very low. Winds will exhibit diurnal tendencies, with directions becoming E`rly or VRB overnight before establishing back out of the west by late morning or early afternoon tomorrow. Afternoon gusts into the upper teens will be common late afternoon and early evening tomorrow. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns are expected through the next 24 hours under clear skies. Winds will favor SE overnight into early tomorrow morning at IPL before going VRB, whereas directions will favor SSW at BLH with extended periods of variability during the day tomorrow. Speeds will generally remain aob 12 kt sustained through the TAF period at both terminals. && .FIRE WEATHER... Hot and dry conditions continue through most of next week as high pressure remains overhead. Extreme temperatures continue with daily high temperatures generally between 110-120 degrees across the lower deserts and 95-110 degrees across the higher terrain. Daily MinRH values will range from 5-15% across the lower deserts and 10-20% across the Arizona higher terrain, with overnight recoveries generally in the 30-50% range. Winds will be fairly light and tend to follow their typical diurnal patterns, with some occasional gusts near 20 mph in the afternoons. This afternoon looks to be the breeziest this week, with afternoon wind gusts up around 20-30 mph, mainly across the eastern districts. The very hot and dry conditions will lead to an increased fire danger threat. && .CLIMATE... Record Highs Phoenix Yuma El Centro --------- ------- ----------- July 7 118 (2017) 118 (2017) 121 (2017) July 8 115 (1985) 118 (1958) 117 (1942) July 9 116 (1958) 119 (1958) 117 (1958) July 10 115 (1958) 118 (1959) 116 (2021) July 11 118 (1958) 118 (1958) 117 (1975) && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Warning until 8 PM MST Thursday for AZZ530>555- 559. CA...Excessive Heat Warning until 8 PM PDT Thursday for CAZ560>570. && $$ DISCUSSION...Lojero AVIATION...Whittock FIRE WEATHER...Berislavich CLIMATE...Berislavich/Kuhlman