Area Forecast Discussion
Issued by NWS Flagstaff, AZ
Issued by NWS Flagstaff, AZ
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359 FXUS65 KFGZ 121735 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 1035 AM MST Mon Aug 12 2024 .SYNOPSIS...Daily chances for showers and thunderstorms continue through Tuesday, before drier conditions set in for the middle of the week. Monsoonal moisture then looks to gradually return by the end of the week. Temperatures will be near-normal, along with generally light winds. && .UPDATE...The morning sounding showed some drying since yesterday morning (0.94 vs 0.79 inches Pwat). Storm motion today will be from the southeast to northwest at 10 to 15 kts...and may become more southwest to northeast later in the day especially over western Yavapai and Coconino counties. Another active day is in store. && .PREV DISCUSSION /402 AM MST/...Today and Tonight...Another round of showers and thunderstorms is expected later this morning and into this afternoon, with ample monsoonal moisture in place. Storms look to initially develop over the higher terrain later this morning and early this afternoon, then gradually pushing northward off the terrain into the lower elevations through the early evening hours. 00Z HREF guidance forecasts around 1000 J/Kg from northwest AZ and eastward along the Mogollon Rim, thus we`ll likely see the greatest coverage over these areas. With ample moisture in place (PWATs around 0.90-1.10 inches) and slow moving storms (~5-10 kts), flash flooding will continue to be the main threats with any storms that develop today. A couple strong to severe storms can`t be ruled out, but any organized severe weather seems unlikely given a weakly sheared environment with 0-6 km bulk shear < 20 kts. Latest hi-res and U of A WRF guidance do show a complex of storms moving northward from the Lower Deserts later this evening, which may continue showers and storms into the overnight across central AZ. Confidence isn`t all that high given that this will be highly dependent upon the progression of today`s storms, but we`ll maintain a slight chance through the early part of the overnight. Additionally, some guidance suggests the resulting outflow from this complex may make it further north into northeastern AZ by the early morning hours on Tuesday. Tuesday...Showers and thunderstorms look to return on Tuesday, although coverage may be a bit less and mainly focused to areas along and north of the Mogollon Rim. Flash flooding will continue to be the main threat with any storm. Wednesday through Sunday...Global ensembles continue to get into better agreement with a decrease in monsoonal moisture by mid-week as the upper-level jet becomes wavier and high pressure weakens. As flow shifts more northerly, drier air is advected into northern AZ. Thus, any preciptation chances mainly look to be near the White Mountains each afternoon. Slightly warmer, near-normal temperatures return for Wednesday and Thursday as well. This downward trend however looks to be short-lived. Most of the guidance is in agreement with moisture gradually retuning to the High Country as the high shifts into a more typical position, and subsequently a better flow regime. Thus, cooler than normal temperatures and daily chances for showers and thunderstorms look to gradually return by the end of the week. && .AVIATION...Monday 12/18Z through Tuesday 13/18Z...Mostly VFR conditions are expected with SW winds 10-15 kts this afternoon. Scattered TSRA will develop and move northward throughout the day. Brief MVFR to IFR in +RA and strong outflow winds in excess of 40 kts possible with the stronger storm cells. OUTLOOK...Tuesday 13/18Z through Thursday 15/18Z...MVFR conditions possible in SHRA/TSRA on Tuesday 19Z-03Z. VFR conditions are otherwise expected with mostly dry conditions prevailing on Wednesday. Daytime winds W/SW around 10 kts. && .FIRE WEATHER...Today and Tuesday...Scattered to widespread showers and thunderstorms each afternoon and evening. Heavy rainfall and gusty, erratic winds will be the main threats each day. Otherwise, expected west/southwest winds around 10 mph along with slightly below-normal temperatures. Wednesday through Friday...Mainly dry conditions, outside of a few isolated showers in the White Mountains. West/southwest winds 10-15 mph each afternoon and near-normal temperatures. && .FGZ WATCHES/WARNINGS/ADVISORIES...None. && $$ PUBLIC...MAS/Humphreys AVIATION...MCT FIRE WEATHER...Humphreys For Northern Arizona weather information visit weather.gov/flagstaff