Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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332 FXUS65 KPSR 130515 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 1015 PM MST Mon Aug 12 2024 .Update...06Z Aviation Discussion && .SYNOPSIS... Showers and storms will be again be possible this afternoon and evening, but activity will mainly favor the higher terrain locations. Drier air will work it`s way into the region for the middle of the week causing a significant downtrend in monsoon activity. Moisture looks to rebound slightly by the end of the workweek and heading into the weekend leading to storm chances returning to the region, mainly for the higher terrain locations. Temperatures will remain largely unchanged through the week and run slightly above normal. && .DISCUSSION... An overall pattern change expected this week as the Monsoon pattern gets displaced with a drier westerly flow. Best chance for storms this week will be into this evening as moisture and instability remains in place for one more day. Environment continues to support convection with MUCAPES 1000-1500 and weakening inhibition. Latest Hi-Res, continues the focus on the higher terrain and into SE AZ with initiation. Depending on the magnitude of the convection in SE AZ, that could play a role in an outflow heading northwest across the valley and be a trigger for isolated storms, but coverage will be 10-20 percent. Otherwise, current troughing across the Pacific Northwest moving into the northern Rockies will begin to flatten upper heights in our region, making that transition from a moist southerly flow to a dry west/northwest flow by the middle of the week. Some lingering storms in the eastern 3rd of AZ for Tuesday, but dry conditions look to settle in for Wed/Thu as ridge axis shifts to the south of the area cutting off moisture. Precipitable waters of 0.8-1.2" in most areas, unfavorable for storm development. By Friday and into the weekend, the upper flow becomes more amplified with deeper trough digging off the west coast and strengthening High to our east across NM/TX. This will return a south/southeast flow, moisture and our daily storm chances, especially for those favored higher elevation locations. Temperatures this coming week are forecasted to remain largely unchanged. For the lower desert communities, afternoon high temperatures are forecasted to be in the 100-110 degree range through the week. For the higher terrain areas, afternoon high temperatures are forecasted to be in the 90-100 degree range. With temperatures being near to slightly above normal, HeatRisk will be in the Minor to Moderate range across the region. && .AVIATION...Updated at 0515Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation concerns are expected during the next TAF period. Winds will follow typical diurnal trends, with occasional gusts during the afternoon hours near 15-20 kts. Shower and thunderstorm activity will once again initiate over the usual areas tomorrow afternoon but chances of in the vicinity of the terminals during that timeframe is less than 5%. Chances of distant outflows impacting the terminals are also minimal (~10%). SCT mid and high level clouds will diminish in coverage overnight, with just a FEW low-level clouds prevailing through the remainder of the period. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation concerns are expected during the TAF period. Winds will follow familiar diurnal trends, with occasional gusts near 20 kts during the afternoon and evening hours. Mostly clear skies will prevail during the next 24 hours. && .FIRE WEATHER... Shower and thunderstorms chances will continue today, with the best chances confined to the higher terrain locations. Shower and thunderstorm chances tomorrow will be limited to just the higher terrain locations. With any thunderstorm activity, there will be strong winds along with the potential for gusty outflows to travel long distances and cause sudden wind shifts. Thunderstorms will also contain localized heavy downpours and frequent lightning. Drier air will move into the region for Wednesday and Thursday with little to no thunderstorm activity expected. Aside from thunderstorm winds, the overall general winds will tend to follow their typical diurnal tendencies with some afternoon upslope breeziness. MinRH values today will be in the 20-30% range with a downward trend for the middle of the week with MinRH values in the 10-25% range. Overnight recoveries will be in the 30-50% range. Temperatures though the week will remain largely unchanged and run near to slightly above normal. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Frieders AVIATION...RW FIRE WEATHER...Berislavich/Frieders