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Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
263 FXUS65 KTWC 011624 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 924 AM MST Mon Jul 1 2024 .SYNOPSIS...Daily chances of showers and thunderstorms during the first half of this week will gradually diminish during the second half of the week. Some storms will generate strong winds and locally heavy rainfall. && .UPDATE...Visible satellite shows a debris cloud field eroding aways over the central part of the region and into the upper Arizona state. A few cumulus clouds have popped up on some of the Sky Islands due to the weak upslope forcing. The 12Z sounding has PWATs of 1.75 inches with a little shear of 21 knots and MUCAPE of 986 J/kg. These values are better than yesterday`s morning, but there is a little subsidence inversion. This likely will erode aways as the cloud field clears for better insolation and allowing the low and mid level lapse rates above 7.5 and possibly close to 10 degrees. There is very small area of diffluence aloft that can aid in the storm development, but the lower levels will need to the heavy lifting (i.e. better CAPE, steep lapse rates, etc.) The latest 12Z HREF run highlights the best areas for scattered thunderstorms will generally be the ling along the I-19 corridor to the east. Mountains will be the first areas to get storms due to the upslope winds. Theses multicelluar storms can rise and fall quickly this afternoon to produce gusty erratic winds and brief localized heavy rainfall. A few storms may be Severe Storm worthy in the late afternoon if the CAPE values are high, better inflow, shear, and cooler air in the midlevels (breaking the subsidence inversion). If the cumulus clouds start to form around 12-1pm, it will be a good sign that the atmosphere is in better shape for thunderstorm development. Otherwise, it can be delayed in the late afternoon and the coverage will be confined a little more. Keep an eye on the cumulus clouds for the rest of the morning. && .PREV DISCUSSION... /issued 239 AM MST Mon Jul 1 2024/ Plenty of debris cloud cover over the area this morning with water vapor showing a weak disturbance moving west across the area. At 2 am, radar was showing isolated showers developing west- northwest of Tucson. For today through Wednesday expect scattered showers and thunderstorms each day with a few storms being strong and producing locally heavy rain. The second half of the week, which includes the 4th of July holiday, will see a reduction of storm coverage as drier air moves in from the north as high pressure builds in from the northwest. High temperatures near or slightly above normal first half of week then heating up to close out the week. Next weekend could see an uptick in storms, especially east of Tucson. && .AVIATION...Valid through 02/12Z. SCT-BKN clouds at 9-12k ft AGL thru the fcst pd. Isold -SHRA/-TSRA this morning becoming SCTD after 01/18z. Expect brief MVFR conds nr storms. SFC winds 10 kts or less with the occasional afternoon gusts, except stronger due to gusty outflows from storms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Relatively deep moisture will stick around through the forecast period with daily chances of afternoon and evening showers and thunderstorms. Strong and erratic gusty winds of 40 mph or higher can be expected with any storm development, along with locally brief heavy rainfall. Outside of thunderstorm winds, 20-foot winds will generally be 15 mph or less each afternoon with the occasional gust of 20 mph. Min RHs will generally be around 20% in the valleys and 30s in the mountains with good overnight recoveries. && .CLIMATE...June 2024 goes into the record books as the 4th hottest and 10th wettest on record for Tucson. && && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...Strongman Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson