Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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930 FXUS65 KPSR 032337 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 437 PM MST Mon Jun 3 2024 .UPDATE...Updated 00Z Aviation Discussion. && .SYNOPSIS... Quiet conditions will prevail through the work week with temperatures hovering near to slightly above normal through Tuesday. An Excessive Heat Waring is in effect Wednesday through Friday as the hottest temperatures of the year are expected over the Desert Southwest. A weak disturbance will move through the region during the weekend, providing some relief from the excessive heat. && .DISCUSSION... Current analysis reveals quasi-zonal flow currently stretched out across the Desert Southwest, while a relatively potent upper-low advances toward the Pacific Northwest. This rather benign pattern over our forecast area will continue to promote dry and tranquil conditions, with temperatures hovering near to slightly above climatological normals. Forecasted highs across the lower deserts this afternoon will generally range between 100-105 degrees, with similar temperatures anticipated again on Tuesday, yielding Minor to locally Moderate HeatRisk for the next few days. As mentioned in previous discussions, an anomalously strong ridge is expected to build over much of the western CONUS during the middle of this week, pushing temperatures to easily their hottest levels since last September. Mid-level heights by Wednesday will rise to between 591-594 dam across the Desert Southwest, allowing for day-to-day temperatures to rise 5 degrees or so, with forecasted daytime highs ranging between 105-110 degrees across lower elevation communities. These enhanced heights aloft will then persist through the remainder of the week, promoting further warming and the development of widespread Major HeatRisk through the end of the week has highs exceed 110 degrees for many areas. In response to the increasing heat levels, Excessive Heat Warnings have been posted for much of our forecast area for Wednesday- Friday. Record highs may also be challenged during this period, with the current Thursday forecasted high for Phoenix (113F) set to break the daily record high (111F set in 2016). Global model guidance depicts a weak shortwave trough approaching the Desert Southwest this weekend which may offer at least some relief from the aforementioned unseasonably hot temperatures as it helps to erode positive height anomalies across the region. Given the forecasted evolution and orientation of this system, increased moisture flux is anticipated over the region, with PWAT values rising to 175-200% of normal for this time of year across much of Arizona. However, forecast soundings show much of this moisture suspended aloft with a dry sub-cloud layer. This setup would inhibit rainfall chances for much of our area, with the NBM squeezing out max PoPs of only 10-15% for far southern and eastern Gila County. However, if sufficient moisture becomes available like the models expect, it would not be surprising to see a few showers and perhaps a thunderstorm over high terrain areas. As of now, the most lower elevation areas would see in terms of rainfall would be virga and maybe a shower or two, but PoPs over these areas remain <10%. At a minimum, the increased moisture should blanket the region in considerable cloud cover, which will also help keep temperatures cooler compared to the days prior. Heading into the start of next week, model clusters become more separated with their forecasts, with some projecting the ridging pattern returning, while other develop another trough/cut-off low just west of the Baja Peninsula. The former would suggest the return of well-above normal temperatures, with the latter solution favoring the continuation of more seasonal temperatures. Plenty of spread remains, so how the pattern evolves will be something to keep an eye on over the next several days. && .AVIATION...Updated at 2335Z. South-Central Arizona including KPHX, KIWA, KSDL, KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH: Across the Phoenix Metro, winds will follow their typical diurnal tendencies with speeds generally aob 10 kt. The one exception is occasional westerly gusts of 15-20 kt through sunset tonight and then again tomorrow during the late afternoon/early evening. Similar to today there will likely be a brief period of southerly winds, aob 5 kt, before the typical westerly shift in the afternoon. At KIPL, winds will generally be out of the SE, with a brief period of SSW`rly winds between 02-07Z this evening. AT KBLH, southerly winds will prevail. SCT-BKN high cirrus clouds will move through the region throughout the TAF period. && .FIRE WEATHER... Little to no change in the weather pattern will keep seasonably dry and hot conditions in place through Tuesday. Expect lower desert highs between 100 and 105 degrees, or 3-5 degrees above average each day. MinRH values will continue to run between 5-10% across the majority of the area each day, while overnight recoveries will continue to range from poor to fair at around 25-40% over the eastern districts to 35-50% over the western districts. Winds will remain fairly light following diurnal tendencies with periodic afternoon gusts of 15-20 mph. The latter half of the week will see even hotter temperatures with potential for highs around 110 degrees Wednesday through Friday over portions of the lower deserts. There will also eventually be a slight improvement in humidities by next weekend along with a low end chance (10-15%) of some isolated thunderstorms over the Arizona higher terrain. && .CLIMATE... Record high temperatures: Date Phoenix Yuma El Centro ---- ------- ---- --------- June 5 113 in 2016 115 in 1957 114 in 2016 June 6 111 in 2016 114 in 1928 113 in 2002 June 7 115 in 1985 116 in 1985 113 in 1985 && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Warning from 10 AM Wednesday to 8 PM MST Friday for AZZ530>556-559>562. CA...Excessive Heat Warning from 10 AM Wednesday to 8 PM PDT Friday for CAZ561-563-566-567-569-570. && $$ DISCUSSION...RW AVIATION...Berislavich FIRE WEATHER...Young/Kuhlman CLIMATE...18