Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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840 FXUS65 KPSR 250003 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 503 PM MST Mon Jun 24 2024 .UPDATE...Updated 00Z Aviation Discussion. && .SYNOPSIS... Daily thunderstorm chances will persist through most of this week due to enhanced moisture levels lingering across the region. The greatest chance will be through Wednesday, before decreasing some late this week and into the upcoming weekend. Conditions will remain hot and humid, with temperatures remaining several degrees above normal. && .DISCUSSION... The early afternoon radar and satellite imagery showing the usual midday showers and thunderstorms forming over the high country north and east of Phoenix. The Phoenix valley into southwest AZ remaining more stable at the moment after early morning clouds dissipated. The latest SPC analysis showing lingering convective inhibition in these areas, but experiencing full insolation early this afternoon. Plenty of moisture ready to be acted on with Precipitable Waters close to 2 inches across the region. Our early Monsoon enhanced moisture levels will result in more shower and thunderstorm into this evening. The latest HRRR hinting on a bit more widespread northeast outflow driven convection spreading into the phoenix valley into this evening, even pushing further southwest toward Yuma County after midnight. This seems reasonable given more instability and daytime heating across SC AZ this afternoon with any outflows able to break through any lingering capping. Although, not a given, as many other high resolution models not as robust with this solution. Have included a 20 to 30 percent chance into the forecast. Strong outflow wind probabilities continue to run low as HREF probabilities of 35+ mph wind gusts remain around 10-30% across the higher terrain and lower elevations of southcentral Arizona, so appears mainly a heavy rainfall threat for storms that develop. Shower and storm potential does try to trend downward as upper level ridge retrogrades into AZ/NM region this week, which could tend to inhibit convection, especially for the lower deserts. However, given abundant moisture in place, the high country should still see additional storm formation. By Thursday and Friday, watching a stronger trough dig across the northern Rockies, which will break down the ridge over AZ, but also shunt deeper moisture to the south. This should further inhibit storm potential and confine it to mainly far SE and Eastern AZ into first half of the weekend. After this trough passes to the northeast, ridge builds again across the SE U.S. which will bring back the southerly flow and moisture that is poised to move back north into the region as early as Sunday. This will increase storm chances again into next week. CPC outlooks for 8-14 days (the first week of July) favors higher percentages for above normal precipitation. With all the moisture and associated clouds and precipitation, daytime high temperatures overall staying several degrees above normal through the period, but at least not near record levels. However, overnight lows will remain well above normal. This will all spell a consistent moderate HeatRisk across the region through the period for hot and humid conditions persisting. However, not to the levels of excessive heat at this time. && .AVIATION...Updated at 0000Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Westerly wind gusts of around 20 kt will continue into the early evening. There are two outflow boundaries out there currently that are moving into the Metro, one from the NW and one from the NE. The NE one might win out, mainly for KPHX and KIWA. But the winds could do some flip-flopping with the arrival of these outflows. We will also have to watch for any initiation of showers or storms as these outflows collide. Winds are expected to go light and variable late this evening and through the morning hours before a westerly component is developed. FEW-SCT mid and high level clouds will continue through the TAF period, and may occasionally become BKN. Southeast California/Southwest Arizona including KIPL and KBLH: Winds will follow their typical diurnal trends at both terminals, with occasional afternoon and evening gusts near 20 kts. FEW-SCT high clouds will continue to filter in through the TAF period. && .FIRE WEATHER... Monsoonal moisture will continue to result in daily chances for shower and thunderstorm activity, especially into midweek. The higher terrain areas will see the greatest potential with some locally heavy rainfall with any storms that develop. Chances for wetting rains will generally remain around 10-20% for the higher terrain areas and 5-10% for the lower deserts of south-central Arizona through the first half of the week. Shower and thunderstorm chances will gradually diminish throughout the week, as high pressure builds into the region. With the elevated moisture in place, MinRH values through early this week will range between 30-40% across the far eastern districts to between 15-25% across the western districts before slowly drying into the middle to latter half of next week. Winds will follow their typical daily tendencies, with gusty outflows from any thunderstorm activity anticipated over the next several days. Temperatures average several degrees above normal through the forecast period. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Frieders AVIATION...Berislavich FIRE WEATHER...Frieders