Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
933 FXUS65 KTWC 160930 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 230 AM MST Sun Jun 16 2024 .SYNOPSIS...Hot today with an Excessive Heat warning in effect for portions of southeast Arizona. Temperatures decrease a bit early in the week before likely heating up again by Thursday. Moisture may begin to increase late next week which would bring the potential for high-based thunderstorms. && .DISCUSSION...The sky was clear this morning across the desert southwest. Hot day with highs similar or slightly hotter than Saturday. Excessive Heat Warning remains in effect today for parts of Pima, Pinal and Graham counties. Monday: Slightly cooler with afternoon breezes as a trough moves thru WA/OR into ID/NV. Elevated fire weather concerns in the afternoon, mainly east of Tucson which is addressed in the Fire Weather section below. Tuesday: Coolest day of the week with highs at or up to 5 degrees cooler than mid-June normals with wrn Pima county seeing the biggest difference from climo. Wednesday: Hotter as upper high builds in from the east. Thursday and Friday: Hottest days of the upcoming week with increasing heat risk. However, latest NBM guidance is not as hot as previous runs and thats due to increasing moisture from the east which initially moves into the eastern zones Thursday, with surface dewpoints into the lower 50s thanks to thunderstorm outflows in New Mexico pushing low-level moisture west. Another low-level push of moisture again on Friday, possibly as far west as Tucson. What is not certain is how far west the potential for high-based thunderstorms will be on Friday. NBM may be a bit aggressive in the western extent of thunderstorms chances Friday especially when looking at the individual GEFS/EPS members. Saturday: At this time NBM has the chance of showers and thunderstorms ranging from a 10% chance western areas to 50% chance eastern areas. What happens Thu/Fri will determine Sat. Confidence low. && .AVIATION...Valid through 17/12Z. SKC. SFC winds less than 10 kts and vrbl in direction until 16/18z and then again after 17/04z. Btwn 16/18z and 17/04z, SFC winds SWLY/WLY at 11-16 kts with gusts of 18-25 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Hot and dry conditions will today with a few degrees of cooling early Monday and Tuesday. High temperatures will then heat back up late in the week, with the hottest temperatures of 2024 possible on Friday. Through the middle of this week, expect min RH values of 4-9 percent in the lower elevations and 8-15 percent in the mountains, along with overnight recoveries between 25-40 percent in most locations. RH values then increase 5-10 percent the latter half of the week. Sustained 20-foot wind speeds today will be 15 mph or less. Winds then increase on Monday, with southwest winds of 15-20 mph and gusts to 30-35 mph. A few areas will be near critical fire weather thresholds Monday, especially to the east/southeast of Tucson, but at this time we not expecting it to be widespread enough for a watch or warning. Elevated afternoon/early evening winds of 15-20 mph then continue for much of this week. By the end of this week, models show an increase in mid-level moisture, resulting in a slight chance mainly dry thunderstorms to the east of Tucson Thursday and and as far west as Tucson Friday and Saturday. && .CLIMATE...The average daily dewpoints will be increasing across southeast Arizona later this week. Below is the forecast daily averages for Tucson from Tuesday through Saturday. Tuesday: 34F Wednesday: 38F Thursday: 43F Friday: 52F Saturday: 53F && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM MST this evening for AZZ504>506-509. && #2709 $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson