Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 11/17/20

Area Forecast Discussion
National Weather Service Phoenix AZ
455 PM MST Mon Nov 16 2020 .UPDATE...Updated 00Z Aviation Discussion. && .SYNOPSIS... Dry conditions will continue into at least the middle of the week as temperatures steadily warm back above normal. Readings will likely be nearing record territory today through the middle part of the week with afternoon highs pushing close to 90 degrees in lower elevation communities. Some cooling is possible during the late portion of the week as an area of low pressure aloft starts to approach from the west. && .DISCUSSION... Water vapor imagery shows a dry air mass over Arizona while a strong shortwave off the West Coast funnels deeper moisture into the Pacific Northwest. A strengthening area of high pressure, centered over Colorado, will keep that shortwave out of the Southwest and preserve our immediate sunny and warm conditions. The most recent aircraft soundings show a significantly warmer air mass from the surface through the H7 layer than recent days which has translated into surface temperatures 5-10 degrees warmer now compared to this time yesterday. As of this moment, Phoenix has just reached 90 degrees with a few more hours of daytime heating left. This date is now the latest 90 degree day recorded in Phoenix besting the previous record by one day (Nov 15, 1999). The next few days will be similar to today as we sit underneath that ridge. H5 heights are rising and likely to peak between 584-587 dm today and tomorrow before the aforementioned Pacific shortwave is able to dampen the ridge somewhat as it moves through the PNW. Ensemble guidance shows a much weaker secondary wave cutting across Arizona late this week, finally displacing the ridge entirely, and resulting in a cooling trend towards more seasonable temperatures by next weekend. The latest NBM guidance median shows high temps cooling into the mid to upper 70s by Saturday. Do not expect much in the way of precipitation with this wave as the overwhelming majority of guidance indicators keep any significant moisture away from the forecast area. Instead, we will likely be looking at some clouds to pair with the cooler temperatures. && .AVIATION...Updated at 2353Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation weather concerns. There has been a weak attempt at a southwesterly wind shift at KPHX late this afternoon, but speeds are generally less than 5 kts. Otherwise, easterly winds are favored through most of the TAF period. There is a better chance at a late westerly switch Tuesday afternoon, around 23-00Z. A brief uptick in wind speed to 10 kts is possible Tuesday morning, but speeds should generally remain less than 8 kts through the period. Mostly clear skies are expected with FEW passing mid and high clouds Tuesday. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns expected through the TAF period. At Winds at KIPL will generally be light and variable for the majority of the period, but favor a light west wind overnight and southeast wind Tuesday afternoon. At KBLH, winds will continue to favor the north and gradually shift westerly overnight before becoming variable. A southerly wind should then kick in in the afternoon at KBLH. Speeds will be light at both terminals and skies will be mostly clear aside from passing mid and high clouds. && .FIRE WEATHER... Thursday through Monday: No significant changes to the forecast...Unusually warm and near record breaking temperatures will continue through Friday across the entire region. Dry weather will also persist with afternoon humidity levels generally falling into a 10-25% range, while overnight recoveries only rebound towards a 25-50% range. A modest cooling trend is likely Friday into Sunday with temperature readings returning closer to seasonal normals. Winds will generally remain light through much of the workweek, before some increase in breeziness is expected over the weekend in southeast California and the lower Colorado River Valley. && .CLIMATE... Record highs next week: Date Phoenix Yuma El Centro ---- ------- ---- --------- Nov 16 89 in 1999 91 in 1990 89 in 2017 Nov 17 87 in 2008 89 in 2019 88 in 2019 Nov 18 88 in 2008 88 in 2008 90 in 1936 Nov 19 88 in 2007 88 in 2008 90 in 2008 && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...AD AVIATION...Benedict FIRE WEATHER...Smith/Rogers CLIMATE...MO