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Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
256 FXUS65 KTWC 211548 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 848 AM MST Fri Jun 21 2024 .SYNOPSIS...A strong increase in moisture will bring a chance of thunderstorms to the area into next week. Some storms will generate strong outflow winds with locally heavy rain possible. This will also knock several degrees off of the heat. We may see temperatures climb back up a bit as high pressure settles overhead next week. && .UPDATE...The 12Z KTWC sounding came in with 1.27" of PWAT and additional moisture continues to advect in from the east to southeast today. HREF/CAMs are showing a similar setup to yesterday with a north-south axis of showers and thunderstorms developing early this afternoon across central portions of the forecast area. Within this axis, SBCAPE values are as high as 1000-1500 J/KG, with the highest values in northern sections of our forecast area across eastern Pinal/western Graham Counties. DCAPE values are also around 1500-2000 J/KG which will result in gusty outflow winds. HREF isn`t as robust with winds today so while we did add areas of blowing dust into the forecast for susceptible areas of Pinal County, we`re not going to issue a longer lead Blowing Dust Advisory with this update. Otherwise, storm motions today will be to the north around 10 to 15 mph and given the deeper moisture profiles, the stronger storms have the potential to produce locally heavy rainfall in addition to the wind threat from the storms. No other changes/updates this morning. See previous discussion below for additional information. && .DISCUSSION...A broad and strong easterly wave across central Mexico has pushed much deeper moisture toward our area, with moisture continuing to increase over the next 24 hours. Initial precipitable waters in the 1.2 to 1.5 inch range will see additional moisture pushed up from the south as the wave pushes across the entrance to the Gulf of CA. We may flirt with near record PW for June. There isn`t much chance for that remnant wave to get organized as it pushes into much cooler water near and west of southern Baja, however a southerly surge should be no problem. With high pressure centered east of the area over the weekend, we suddenly see a deeper monsoon type forecast jump start the season for SE AZ. Atypically for June, locally heavy rain a concern along with SREF CAPE values supporting a few stronger storms. Deeper moisture probably not pushing into western areas until tomorrow night. Marginal risks from both SPC (for thunderstorm winds) and WPC (for excessive rainfall) look reasonable. Ensemble means spread the ridge further west with the high center reconsolidating overhead the first half of next week. Warmer mid levels and weaker moisture support should start to tamp storm coverage down a bit, but additional surface heating will counter that somewhat. The bottom line is we keep a chance of thunderstorms going well into next week, however we should start to rely more on recirculated boundary layer moisture with the overall trend down. It remains to be seen if we will keep enough moisture around to avoid more excessive heat headlines, but my guess is we will. There`s even a hint that we may see some moisture reinforcement from newly awakened Sinaloa and Sonora later next week. An unusual June as we typically see sputtering starts before deeper moisture sets up immediately upstream in July. && .AVIATION...Valid through 22/12Z. SCT-BKN clouds 10-14k ft AGL. SCT -TSRA will develop after 21/19Z, with TSRA and BKN CIGS around 6k ft AGL possible between 21/21Z and 22/03Z. East to southeast winds 10-20 mph, diminishing after 22/03Z. Stronger and erratic outflows possible with storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Gusty east to southeast winds this morning will diminish through the day. A strong increase in moisture will bring better RH values along with a chance of thunderstorms into at least early next week. Some storms will generate strong and erratic outflow winds. Moisture is expected to be deep enough for some storms to generate locally heavy rain. Temperatures may heat back up by mid week as high pressure builds nearly overhead, however we should keep some storm chances around. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson