![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
712 FXUS65 KPSR 081930 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 1230 PM MST Mon Jul 8 2024 .SYNOPSIS... Extreme heat will continue to prevail across the region throughout the work week as high temperatures across the lower deserts are expected to range between 112-122 degrees. Some moisture will start to move back in starting on Tuesday, providing isolated t-storm chances for southeastern AZ and the Arizona high terrain. The chances for more widespread thunderstorm activity increases by next weekend. && .DISCUSSION... The latest water vapor satellite imagery shows very dry air encompassing most of the western third of CONUS as a result of an expansive ridge of high pressure that has been sitting near CA since late last week and will slowly shift eastward as the week progresses. The current positioning of this ridge continues to provide a northerly wind flow, which is keeping very dry air entrenched across the region with near zero storm activity. This will continue to be the case through today, where most of AZ is likely to be convection free once again. The main weather concern as a result of this high pressure continues to be the extreme heat as the mostly clear skies and the enhanced 500 mb height fields ranging between 594-597dm will continue to support high temperatures across most of the lower desert communities to top out between 112-122 degrees, with the highest readings across the western deserts. These temperatures will be high enough for multiple areas to either tie or break record highs. Widespread major to locally extreme HeatRisk will continue through the end of the work week and as a result the Excessive Heat Warning has now been extended through Friday. Therefore, if partaking in outdoor activities it is very crucial to take all the necessary heat precautions to avoid any heat-related illnesses. Heading through the middle and latter half of the week, the ridge of high pressure is expected to shift into northwest AZ. The flow pattern will be more favorable for some moisture intrusion into the region, enough to spark isolated thunderstorm activity across portions of southeastern AZ as well as across the AZ high terrain such as the White Mountains and Mogollon Rim. The overall isolated coverage will likely continue through the end of the week with the lower deserts expected to remain dry and thus any associated cloud cover/outflow boundaries emanating from the convective activity will likely not have any effect on the temperatures across the lower deserts. This is the reason why confidence continues to remain high enough for the extreme heat to continue right through the end of the work week. Heading into next weekend, the ensembles continue to remain in very good agreement that the high center will shift into the Four Corners Region. Thus, the flow pattern will shift more from the east to southeast, which will advect some deeper moisture into the region with ensemble mean PWATs rising to as high as 1.2-1.5". Therefore, conditions are going to become more favorable for more widespread thunderstorm activity to materialize, including for the lower deserts. Given the increasing moisture and convective coverage, temperatures luckily are expected to cool off as well below the excessive heat threshold. && .AVIATION...Updated at 1745Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation weather concerns will exist through the TAF period under clear skies. Satellite imagery does indicate some wildfire smoke aloft, however this smoke should remain diffuse enough to not cause any issues with slantwise visibility. Winds will follow typical diurnal trends with an hr or two of variability expected at KPHX before winds go westerly. Afternoon gusts up to around 20 kts will be common through sunset. Winds will shift back around to the E-SE by 08Z-09Z tonight. 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 southeasterly at KIPL through this afternoon before becoming WSW by sunset. There is a potential to see some gusts up to 20-25 kts at KIPL this evening, otherwise speeds will remain around 10 kts or less. Winds will continue out of the S-SW at KBLH with gusts increasing to around 18-20 kts this afternoon. && .FIRE WEATHER... Well above normal temperatures and dry conditions will continue through the majority of this week. Daily afternoon high temperatures will generally be in the 112-122 degree range across the lower deserts and in the 95-110 degree range across the higher terrain. MinRH values will range from 5-15% across the lower deserts and 10- 20% in the higher terrain, with overnight recoveries generally in the 30-50% range, through Friday. Winds will be fairly light and tend to follow their typical diurnal patterns, with some occasional afternoon gusts up around 20 mph. Limited moisture will start to creep back into the region for the latter half of the work week, leading to a slight chance for isolated thunderstorms in the higher terrain. The very hot and dry conditions will lead to an increased fire danger threat. && .CLIMATE... Record Highs Phoenix Yuma El Centro --------- ------- ----------- 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 Friday for AZZ530>555-559. CA...Excessive Heat Warning until 8 PM PDT Friday for CAZ560>570. && $$ DISCUSSION...Lojero AVIATION...Salerno FIRE WEATHER...Berislavich CLIMATE...Berislavich/Kuhlman