Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
572 FXUS65 KTWC 210914 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 214 AM MST Sat Sep 21 2024 .SYNOPSIS...Dry conditions with temperatures near seasonal normal to below normal today. Temperatures will warm to above normal on Sunday and into the new week with areas from Tucson westward possibly seeing 100 degree highs. && .DISCUSSION...Water vapor imagery shows a closed low in west central Arizona with a few cloud build ups in Pinal County. There is enough divergence and moisture to help with the cloud build ups. Radar shows some returns, albeit on the low end of reflectivity, which may be enough to produce virga this early morning in eastern Pinal County and into western Graham County. Rest of Southeastern Arizona has mainly partly cloudy skies that will clear out by mid morning. The low pressure center will move eastward to bring westerly to northwesterly winds with a strong breeze east of Tucson and much cooler temperatures. These temperatures will be a few degrees below normal. Ensemble models show a ridge of high pressure building across the western states starting tomorrow. Temperatures will start to warm up to a few degrees above normal by Monday. This warming will keep going through rest of the week as the center axis of the ridge moves over the region by Wednesday and slowly move east by the end of the week. Yet, there is fuzziness in the ensembles on the exact position and strength of the ridge by midweek to the weekend. Individual ensemble models paint a different picture on the ridge axis orientation due to a longwave trough downstream over the midwest and another forming in the Pacific Ocean, depending on the ensemble model. These troughs will help shape and dictate how the ridge will play out for Southeast Arizona. Plus, on the position of the high may result in flow over the eastern part of the state to produce isolated thunderstorms on Wednesday. Forecaster confidence is extremely low on this occuring over the White Mountains and along the New Mexico border, yet it is still a non- zero chance of occuring-less than 20% chance. However, it is still over 5 days out and the main story will be warm and above normal temperatures because of the better signals from all of the model guidance. With that, most of the region will be in the 90s, except for higher locations being in the 60s-70s, with areas Tucson west being in the upper 90s and flirting around the 100 degree mark for the new week. If the ridge strengthens and or holds, Tucson and several locations could be near record temperatures. With this forecast package, Tucson will be within 3-4 degrees of its records on Thursday and into the weekend. This weekend is a good time to remember and practice heat safety tips. Hydrate, cool off in shade or inside with AC, and wear proper sun protective clothing such as hats. And take breaks! && .AVIATION...valid through 22/12z. SCT-BKN clouds at or around 08-12K ft AGL this morning and by 21/16Z becoming SKC through rest of the forecast period. SFC winds will be light and variable this morning and again after 22/04z for the overnight period. During the day, starting by 21/18z, westerly to northwesterly winds of 10-15 mph with the occasional gust to around 20 kts. Terminals east of KTUS can experience the stronger winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Dry conditions with temperatures a few degrees below normal Saturday. 20-foot winds will generally be 10 to 15 mph with occasional afternoon gust, especially east of Tucson. Min RHs will generally be 14 to 20 percent in the lower locations and 20 to 30 percent in the higher locations. Starting Sunday, high pressure ridge will bring above normal temperatures and lighter and terrain driven winds through next week. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Strongman Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson