Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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776 FXUS65 KPSR 281716 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 1016 AM MST Tue May 28 2024 .UPDATE...Updated Aviation Discussion. && .SYNOPSIS... Hot and dry weather will continue for the foreseeable future with lower desert highs reaching 100-105 degrees each afternoon. A weak disturbance will pass north of the region mid-week, but will result in almost no sensible change in conditions outside of a slight increase in winds. Above normal temperatures will carry into this weekend with dry conditions prevailing. && .DISCUSSION... We will begin today with an upper level ridge becoming more amplified over the Intermountain West. This ridge will continue to bring dry and tranquil conditions to AZ and southeast CA. 500 mb hghts are expected to rise slightly this afternoon to around 584-586 mb, resulting in highs peaking a couple degrees warmer than yesterday. Expect highs across the lower deserts to reach the upper 90s to around 105 degrees or around 5 degrees above average. HeatRisk levels will increase to moderate in some areas including the Phoenix Metro area, Colorado River Valley, and Imperial Valley this afternoon, so make sure to take proper heat precautions if working outdoors. Besides localized gusty winds in the Imperial Valley this evening, another tranquil night is anticipated across the region with lows settling into the mid 60s to lower 70s. On Wednesday, a trough of low pressure will move into the Pac NW and displace the upper ridge ewd into the Central Plains. Despite a slight decline in hghts aloft, there will be little to no discernible difference in temperatures across our region with widespread 100 degree highs still expected. A tightening pressure gradient between the troughing feature to our north and high pressure in N Mexico will result in slightly breezier conditions Wednesday afternoon with gusts reaching 15-20 mph across the lower deserts and 20-25 mph in the AZ high terrain. Higher gusts up to 35 mph will also be possible in far western Imperial County. Once the trough axis passes through the region, high pressure will again build across the Desert Southwest through the rest of this week. Temperatures will rise a degree or two each day, peaking on Friday which looks to be the hottest day of the forecast period with highs approaching 105-106 in the Phoenix Metro. Therefore, we can expect a greater coverage in Moderate HeatRisk by Friday afternoon. Heading into this weekend, 500 mb cluster analysis continues to indicating positive hght anomalies overspreading the region despite overall broad troughing across the western CONUS. Temperatures will therefore remain around 5 degrees above average Saturday and Sunday with highs mainly ranging from 100-105 degrees across the lower deserts. Clusters analysis and global ensembles are still showing the potential for a further amplification of ridging aloft by the middle of next week, which may result in the first 110 degree highs in some desert communities. The 75th percentile of the NBM has temperatures in Phoenix reaching close to that mark by next Wednesday, and this will certainly be something to keep an eye on in the coming days. && .AVIATION...Updated at 1715Z. South-Central Arizona including KPHX, KIWA, KSDL, KDVT: No aviation weather concerns are expected through the TAF period under FEW-SCT high clouds this evening and overnight. Winds will continue to exhibit diurnal tendencies with speeds generally aob 10 kt sustained, although some periodic gusts in the mid to upper teens will be common this afternoon once again. There will likely be extended periods of very light speeds and variable directions as well. Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation weather concerns are expected through the TAF period under FEW-SCT high clouds by this afternoon. At KIPL, winds will mostly be out of the west, with light and variable winds favored through the rest of this morning and into the afternoon. At KBLH, winds will mostly be out of the south to southwest. Gusts are expected to increase to around 20 kts this afternoon at KBLH and this evening at KIPL. && .FIRE WEATHER... Hot and dry conditions will persist through this weekend with highs topping out around 5 degrees above normal each afternoon. MinRH values will remain at or below 10% across the central and western deserts and overnight recoveries will continue to range from poor to fair at around 25-40%. Winds are generally expected to remain below 15 mph, but an uptick in breeziness could result in pockets of elevated fire weather concerns by the middle of this week (peaking on Wednesday). && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Salerno AVIATION...Smith/Whittock FIRE WEATHER...Salerno