Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
406 FXUS65 KTWC 141006 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 306 AM MST Fri Jun 14 2024 .SYNOPSIS...Virga showers stick around through this morning north and west of Tucson, then expect dry conditions into the middle of next week. Temperatures remain above normal through the weekend, with an Excessive Heat Warning in effect for portions of southeastern Arizona Saturday and Sunday. Then temperatures decrease to around normal or a couple degrees above normal into the middle of next week. && .DISCUSSION...Radar shows ongoing very weak virga showers over the eastern portion of the CWA. These virga showers progressed from west to east over the region Thursday as an upper level low moved through southern California helping to advect mid-level moisture into Arizona. This upper level low will continue moving east pushing the moisture and cloud cover/virga further east as it does. Virga will persist through mid-morning with the mid to the high level clouds clearing out by early afternoon. One lightning strike has already been observed, and can`t rule out one or two more through the early morning hours. The passage of the upper level low will also lead to breezy winds east of Tucson this afternoon. Gusts could reach up to 40 mph at some places as intense surface heating mixes stronger winds aloft down to the surface. Because of this and very low RH values (3-9 percent) a Red Flag Warning is still in effect. Temperatures today will be a few degrees above normal. Over the weekend high pressure builds in over the region centered over Baja California. This will bring temperatures back to similar levels seen this past Tuesday and Wednesday. Because of this have opted to upgrade the Excessive Heat Watch to a Warning Saturday and Sunday. Beginning late Sunday the high begins to get pushed south as a fairly strong upper level low moves into the Pacific Northwest. This will decrease 500mb heights over Arizona leading to temperatures around normal to a couple degrees above normal for the first half of the work week. This will also lead to breezy winds, especially Monday. However there is still some uncertainty in ensembles with how far south the core of the low will travel, which could affect high temperatures and the strength of the winds. By Thursday ensembles show a very broad area of high pressure dominating the eastern 2/3 of the U.S. with the desert Southwest on the western periphery. This could lead to another round of Excessive heat Thursday and Friday. However, this pattern would put Arizona in favorable easterly flow for mid to even lower level moisture advection. Right now the NBM has PoPs of 15-30 percent along the AZ/NM border next week Thursday and Friday. && .AVIATION...Valid through 15/12Z. BKN clouds around 13k-20k feet AGL this morning mainly east of KTUS and KOLS, clearing out by late morning. Virga/light sprinkles will persist in Graham/Greenlee Counties through mid- morning. SFC winds less than 10 kts through this morning. After 14/17Z winds become SWLY/WLY with speeds of 10-18 kts and gusts 20-30 kts. The strongest winds will be at KDUG and KSAD terminals. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Weak virga showers will persist through the morning with a lightning strike or two possible. Expect min RH values of 3-9 percent in the lower elevations and 7-15 percent in the mountains through this weekend, along with poor overnight recoveries between 20-35 percent in most locations. 20-foot winds will follow typical diurnal patterns, with afternoon/early evening gustiness due to strong surface heating. Winds will increase today especially in areas near the Arizona / New Mexico border, where a Red Flag Warning remains in effect. Another chance of increased winds may arrive on Monday. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning from 11 AM Saturday to 8 PM MST Sunday for AZZ504>506-509. Red Flag Warning from 11 AM this morning to 8 PM MST this evening for AZZ152. Excessive Heat Warning from 11 AM to 8 PM MST Saturday for AZZ501-502. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson