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Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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778 FXUS65 KPSR 080928 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 228 AM MST Mon Jul 8 2024 .SYNOPSIS... Extreme heat will continue across the region throughout this week as strong high pressure remains overhead. Lower deserts will continue to see afternoon high temperatures in the 112-122 degree range with little to no overnight relief with overnight low temperatures ranging from the low 80s to low 90s. Some moisture will start to move back into the region by the middle to end of this week, leading to an increase in thunderstorm chances for southeastern Arizona and the Arizona high terrain. && .DISCUSSION... Upon analysis of upper- and mid-level water vapor satellite imagery this morning, the strong high pressure system has not moved much and is currently centered over the south-central California and Nevada boarder. This high pressure system will slowly make its way eastward over the next week, with very minimal change in its strength. The 500 mb height fields will continue to be within the 594-597dm range. This will lead to the extreme heat continuing through the week. An Excessive Heat Warning remains in effect through Thursday with widespread Major HeatRisk with locally Extreme HeatRisk across the Arizona lower deserts and southeastern California. The lower deserts will continue to see afternoon high temperatures in the 112-122 range with overnight/early morning low temperatures ranging from the low 80s to low 90s through at least Thursday. It is crucial to stay proactive in protecting yourself from these extreme temperatures as they can become deadly! Remember to stay hydrated; wear light, loose fitting clothes; and try to limit your time outdoors, especially during the hottest part of the day. The center of the high pressure system will move into western Arizona by the middle of the week, which will promote some moisture advection into southern and eastern portions of Arizona. The increase in moisture will lead to daily isolated afternoon and early evening shower and storm chances across southeastern Arizona and higher terrain locations in eastern Arizona for the latter half of the work week. PWAT values will remain below 1" through Thursday and near 1" on Friday across the Arizona lower deserts. This continued dry air will keep the thunderstorm chances, across the AZ lower deserts, near zero through the work week. The high pressure system will continue its eastward trek, arriving in the Four Corners Region this weekend. Global ensembles continue to show PWAT values going above 1" across the Arizona lower deserts this weekend. The increase in moisture will cause a slight cool down in temperatures over the Arizona lower deserts, however the apparent temperature will remain largely unchanged. Due to this the Excessive Heat Warning may need to be extended into the weekend. The increased moisture will also promote increased shower and thunderstorm chances. This will lead to isolated showers and thunderstorms possible across portions of the south-central lower deserts and scattered showers and thunderstorms across the AZ higher terrain, mainly during the afternoon and early evening hours. && .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... 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 Thursday for AZZ530>555- 559. CA...Excessive Heat Warning until 8 PM PDT Thursday for CAZ560>570. && $$ DISCUSSION...Berislavich AVIATION...Whittock FIRE WEATHER...Berislavich CLIMATE...Berislavich/Kuhlman