Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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782 FXUS65 KPSR 080921 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 221 AM MST Sat Jun 8 2024 .SYNOPSIS... Cooler temperatures are expected through the weekend as a weak disturbance moves across region. Temperatures then heat up once again heading into the middle of next week as high pressure builds over the region. Seasonably dry conditions will prevail through the next 7 days. && .DISCUSSION... The latest water vapor satellite imagery depicts a weak circulation over the central Baja Peninsula associated with a very weak upper- level low that has been spinning over this general region during the past couple of days. This weak low will gradually move northward across AZ through the weekend helping to slightly lower the 500 mb heights to 585-588dm. As a result, temperatures will cool slightly from what they were the past couple of days. High temperatures today will generally range between 105-110 degrees and cool even further Sunday-Monday into the low to mid 100s across the lower deserts. The overall HeatRisk will remain moderate across most of the region through the weekend and as a result, if planning outdoor activities, the necessary heat precaution measures should still be performed. Along with the cooler temperatures, the weak upper- level low will also help enhance somewhat the afternoon and early evening breeziness across the area, with the potential for some gusts exceeding 30 mph at times across portions of western Imperial County due to mountain rotors. Heading into next week, the model guidance continues to remain in pretty good agreement in the overall synoptic pattern as another upper-level low is set to cutoff off the coast of southern CA/northern Baja by Monday with a ridge strengthening across the southwestern CONUS. There still continues to be some discrepancies examining the ensemble cluster analysis in the overall positioning/strength of the cutoff low, which will dictate the positioning of the ridge downstream. Latest trend indicates a pretty robust ridge building across NM/AZ by midweek with 500 mb height fields rising above 590dm across most of the region with values as high as 594-597dm across the eastern half of AZ through NM. Therefore, an uptick in temperatures can be expected heading into the Tuesday-Thursday timeframe with another round of excessive heat conditions becoming more likely, especially across the south- central AZ lower deserts, as highs will likely once again reach 110+ degrees and potentially necessitating the issuance of new excessive heat products. The ensembles show the cutoff low eventually making its way through the region by the end of the week, bringing slightly cooler temperatures. Heading into next weekend, a more potent large- scale trough will approach the Pacific Northwest and traverse the western CONUS. However, there is a large degree of spread amongst the ensembles on the overall depth of the trough, which will dictate whether or not the Desert Southwest sees some sort of impacts in the form increased winds and further cooling. && .AVIATION...Updated at 0500Z. South-Central Arizona including KPHX, KIWA, KSDL, KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH: No aviation concerns are anticipated through the TAF period. Winds will follow typical diurnal tendencies with speeds generally aob 10 kts outside of occasional gusts up to 20-25 kts, mainly at the southeast California terminals tomorrow afternoon. Winds should shift out of the ESE at KPHX and KIWA by 08Z-09Z tonight and slowly veer back out of the WSW by 21Z-22Z tomorrow afternoon. High clouds will remain FEW overnight before becoming SCT at 25 kft over the region early tomorrow morning. && .FIRE WEATHER... Hot and seasonably dry conditions will continue to support a high fire danger across the area during the next several days. Slightly cooler temperatures, although still remaining above normal, can be expected through the weekend before heating up once again heading into the middle of next week. Winds will continue to generally favor diurnal tendencies with occasional afternoon breeziness of 20-25 mph expected across most of the region. MinRHs ranging between 5-15% with poor to fair overnight recoveries of between 20-40% will be common. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Lojero AVIATION...Salerno FIRE WEATHER...Lojero