Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
894 FXUS65 KTWC 271625 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 925 AM MST Thu Jun 27 2024 .SYNOPSIS...Southeast Arizona will continue to see enough moisture for a daily chance of thunderstorms. A few degrees hotter today before storm chances increase over the weekend and early next week. Some storms will generate strong winds and locally heavy rain. && .UPDATE...A storm develop north of Graham County and moving into Greenlee County this early morning. The upslope flow aid in the development of this storm. The storm will continue to move eastwardly for the rest of the morning. 20% chance for another shower and thunderstorm to develop along the White Mountains this morning. Otherwise, the rest of Southeast Arizona is still on track for thunderstorms to develop early this afternoon mainly in Cochise and Santa Cruz Counties. 12Z HREF still shows the best areas for thunderstorms in those counties with the 70% chances for thunderstorm gusts of 35 mph or greater along the international border. Essentially, nearly the same story as yesterday but a little more umph...or favorable atmospheric dynamics. && .PREV DISCUSSION... /issued 130 AM MST Thu Jun 27 2024/ Surface dewpoints are a few degrees with a few locations dropping into the 50s as our deeper source for moisture wanes for a few days and we rely on recycling boundary layer moisture and modest outflows from complexes in northwest Sonora. Precipitable water values remain above climo for late June, generally ranging from 1.3 to 1.6 inches. Another day or two where we see the bulk of our thunderstorm chances east and south of Tucson. The ridge will shift eastward over the weekend as a trough develops near the west coast. As the high center reconsolidates east of our area, it will bring the solid easterly to southerly flow back and re-engage a fetch of deeper moisture to reinforce what we`re working through now. Once feature in particular is the potential of multiple easterly waves across northern Mexico with the first shifting from Chihuahua to Sonora late in the weekend, and another on a more southerly track across north central Mexico early next week. After that, ensemble means are suggesting strong positive height anomalies in a blocking position across western portions of the desert southwest the following weekend. Something like that would push some of the moisture back south of the area. Not at all unexpected as the monsoon comes in like a tide, with individual waves that recede at times even as the overall trend is gradually (usually) higher. && .AVIATION...Valid through 28/18Z. SCT 100-140 kft SCT-BKN 180-220 kft AGL thru the forecast period. Isolated- scattered -TSRA 27/19Z thru 28/03Z with brief MFR conditions possible near storms. SFC winds generally remain below 10 kts through the forecast period, except for gusty outflow winds from storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Relatively deep moisture will keep RH values on the higher side into next week, along with daily chances for thunderstorms. Moisture is expected to be deep enough for some storms to generate locally heavy rain. Winds should generally remain below 15 mph each afternoon, though occasional gusts to 20 mph are possible. Stronger erratic outflows with some thunderstorms. && && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson