Area Forecast Discussion
Issued by NWS Phoenix, AZ

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904 FXUS65 KPSR 241047 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 347 AM MST Fri May 24 2024 .SYNOPSIS...
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A weak disturbance will pass over the region this weekend leading to breezy to locally windy conditions and cooler Saturday high temperatures. The strongest winds are expected this evening over portions of Southeastern California, and widespread breeziness can be expected on Saturday. By Memorial Day, highs will have heated back up to around the century mark and remain near to slightly above normal through the work week.
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&& .DISCUSSION...
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Current mid level wv imagery and streamline analysis shows a positively tilted shortwave trough moving onshore along the Pacific Coast. Ahead of this feature, mostly zonal flow remains over the Desert Southwest this morning. Heights will not begin to fall until late today, so high temperatures this afternoon will reach similar values to those observed yesterday in the mid to upper 90s across the lower deserts. As the shortwave trough traverses the Great Basin on Saturday, highs will be notably cooler at between 5-10 degrees below normal for this time of year in the upper 80s to low 90s. Widespread breezy to locally windy conditions will accompany the aforementioned shortwave as it traverses the Great Basin this weekend. This evening, winds will pick up primarily over portions of Southeastern California such as JTNP and Southwestern Imperial County including the Imperial Valley. Gusts are expected to peak between 35-45 mph in these areas, with gusts up to 55 mph in the far Southwestern corner of Imperial County along high terrain. Wind Advisories have been issued for portions of Imperial County for late this afternoon through this evening. Confidence in winds reaching Advisory criteria in JTNP and locations further east in Imperial County is low at this time, though HREF mean gusts are upwards of 35 mph in some of these areas this evening. Elsewhere across the lower deserts, gusts will peak in the 20-30 mph range today. On Saturday, afternoon breeziness will be widespread and South-Central AZ high terrain will see peak gusts around 30 mph as the trough axis passes overhead and quickly ejects east northeastward. In the wake of the shortwave disturbance, heights will begin to rise on Sunday and a ridging pattern will set up over the western CONUS by Memorial Day. Global ensembles are in good agreement that this ridging pattern will persist through much of next week, with some slight discrepancies in strength/position of the ridge apparent in the WPC cluster analysis. Temperatures into the middle 90s can be expected by Sunday, rising further into the upper 90s to around 100 degrees for some areas by Monday. Day-to-day temperatures will continue to increase through the middle of next week as the ridge continues to dominate our forecast area. Afternoon highs by Tuesday across the lower deserts are forecasted to range between 100-105 degrees, with similar conditions expected again on Wednesday. This pattern will also promote tranquil and very dry conditions, with no rain chances anticipated potentially through the end of May.
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&& .AVIATION...Updated at 0536Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation weather concerns are expected through the TAF period. Winds will continue to favor diurnal tendencies, with a period of southerly winds expected mid/late morning Friday before veering toward a westerly component during the early afternoon. Breezy conditions will return once again Friday afternoon as gusts climb to around 20 kts. Otherwise, FEW-SCT high clouds will pass over the region throughout the period. Southeast California/Southwest Arizona including KIPL and KBLH: West winds will continue through most of the TAF period at KIPL while winds remain southerly at KBLH. Wind gusts at the terminals will climb to around 25-30 kts going into tomorrow afternoon before further increasing to around 35 kts at KIPL at times by late afternoon into the evening. Strong winds may generate areas of blowing dust, which could lead to some slantwise and surface visibility reductions. Otherwise, FEW-SCT passing high clouds will move over the region throughout the period. && .FIRE WEATHER...
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Elevated fire weather conditions will exist today and Saturday over parts of the western districts and high terrain of the eastern districts as a weak system helps to generate breezy to locally windy conditions. Strongest winds (35-45 mph peak gusts) will be focused over the western districts and enhanced terrain areas, with 20-30 mph gusts expected elsewhere. MinRH values during this timeframe will increase slightly from 10-15% today, to 10-20% Saturday. Overnight recoveries will be fair tonight and Saturday night at around 30-50% and locally higher in high terrain locations. Hot and dry conditions will persist beyond Saturday, with generally lighter winds speeds and typical afternoon breeziness each day. Daily highs will reach the century mark in many lower desert locations by Monday and values generally top out between 100-105 through the middle of next week.
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&& .PSR WATCHES/WARNINGS/ADVISORIES...
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AZ...None. CA...Wind Advisory from 4 PM this afternoon to 9 AM PDT Saturday for CAZ562. Wind Advisory from 4 PM this afternoon to 11 PM PDT this evening for CAZ563-566-567.
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&& $$ DISCUSSION...Whittock AVIATION...Smith FIRE WEATHER...Whittock/RW