Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/25/21

Area Forecast Discussion
National Weather Service Phoenix AZ
503 PM MST Mon May 24 2021 .UPDATE...Updated 00Z Aviation Discussion. && .SYNOPSIS... Temperatures have rebounded back near normal today, and will hover at or slightly above average throughout the rest of the week. The weather pattern this week will ensure very dry conditions with only a few passing high clouds. && .DISCUSSION... The upper level low that brought cooler air into the region over the weekend continues to exit to the northeast and is now in southern Canada, with any lingering cool air rapidly moderating. ACARS soundings show about a 2-4 C warming throughout the lower atmosphere compared to yesterday at this same time. Upper level heights are steadily climbing and are now near normal for the date. This should lead to surface temperatures climbing into the mid 90s today and near 100 degrees on Tuesday. As we head into Tuesday and Wednesday, a very weak open wave embedded in the southern periphery of the ridge will move into southern California and dissipate over Arizona. There will only be a minor increase in low level moisture and no instability to speak of. Accordingly, no rain is expected. However, the increase in high clouds and plateauing of upper level heights should keep temperatures from getting much above about 100 F or so. For the second half of the week ridging will increase in amplitude and intensity, but not significantly, with 500 hPa heights peaking around 585 dm by Thursday or Friday. Surface temperatures will increase into the low 100s for this period. Friday and Saturday look to be the warmest days. NBM temperature probabilities show a 10-20% chance of reaching 105 F on each of these days. There is some signal that by next weekend another dry open wave may approach from the west. WPC cluster analysis shows relatively high confidence in this outcome. The main uncertainties for this period relate to the amplitude of the trough as well as the magnitude of the ridging to its north. The ECMWF ensemble is slightly deeper with the trough signal, but overall all of the global ensembles paint a similar picture. The main impacts of this trough would be another plateauing of highs in the low 100s, a slight increase in high cloudiness, and somewhat gustier winds. With generally diffuse pressure and temperature gradients, most likely this system will be of little consequence in the end. && .AVIATION...Updated at 0002Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Diurnal wind tendencies will prevail through Tuesday with increasing high clouds from the west during the day. Wind speeds should generally remain aob 8 kts with periods of variability in the morning and during diurnal shifts. Southeast California/Southwest Arizona including KIPL and KBLH: Winds will favor the west through tonight at KIPL and west to southwest at KBLH. Both terminals will see a shift to the south by late Tuesday morning. Speeds will increase up to 10-14 kts through the afternoon and be strongest in the evening with gusts up to 20 kts. High clouds will spread across the area tonight, becoming BKN Tuesday morning. && .FIRE WEATHER... Thursday through Monday: With temperatures oscillating near to slightly above the seasonal normal, extremely dry conditions will persist over all districts. Occasional breeziness will be possible each afternoon, yielding a slightly elevated fire danger on most days, with Sunday likely being the windiest day. Afternoon minimum humidity levels will regularly fall into the single digits with the driest locations as low as 5%. Overnight recovery will only be poor to fair in a 15-35% range. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Hodges AVIATION...Benedict FIRE WEATHER...Hodges/Kuhlman