Forecast Discussion
953 FXUS65 KTWC 030900 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 200 AM MST Fri May 3 2024 .SYNOPSIS...Sunny, warm, and dry to end the week with breezy afternoons on most days. A dry weather system will bring stronger breezes to windy conditions with possible blowing dust on Sunday. && .DISCUSSION...Zonal westerly flow will prevail today with temperatures keeping the same trend of being slightly above normal with afternoon breezes. Satellite imagery this morning showed the next weather system that will impact the region. A low pressure center is just off the shore of Washington that is mainly dry based on the latest Total Precipitable Water imagery. The ensemble models are in sync with each other, with a few minor variations, on the progression of the weather system. The low pressure center is projected to move into Nevada by Sunday. The Extreme Forecast Index has highlighted the strong potential (60% of members agree on this), and same with the NAEFS, for strong winds across Southeast Arizona. This is due to the pressure gradient increasing by early Sunday morning as the low deepens towards Arizona. Several of the deterministic models forecast the 50-55 knots at the 500mb level which it translates down to the surface of speeds 20-30mph with gusts up to 45 mph. Blowing dust is possible given how the area has been drying out since the last rains. Another concern will be increase risk for fire weather as the relative humidities will be near the single digits with fuels already cured or curring. Headlines will likely to come forth soon to highlight the wind and fire weather concerns. By Monday, the trough will move out and morph into an elongated trough axis across the Desert Southwest. This will tap down temperatures a few degrees on Monday. The upper pattern will slowly shift back into westerly flow, but it keep breezy conditions and warm temperatures for the most of the week. && .AVIATION...Valid through 04/12Z. SKC through the majority of the forecast period with thin cirrus above 20 kft MSL moving in after 03/21Z from southwest to northeast. SFC winds this morning light and variable less the 10 knots and again after 04/05Z. In between, starting at 3/17Z, westerly winds up to 10 to 15 knots with occasional gusts to 20 kts in the late afternoon. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...High temperatures will remain above normal through Sunday. 20-ft winds will generally remain less than 15 mph today and increasing up to 20 mph on Saturday. Min RHs continue to be in the single digits to the lower teens for the valleys and the teens to lower twenties for the mountains through the rest of the weekend. A dry weather system will be passing on Sunday to bring windy conditions in the already low relative humidity environment. There is increasing confidence on of gusts getting up to 45 mph, especially in more expose areas. The combination of dry, windy, and warm conditions will put most of the fire weather zones at critical to near critical fire weather conditions Sunday afternoon. After Sunday, winds will return to the typical afternoon breeziness of 15 to 20 mph for the first half of the new week. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
NWS TWC Office Area Forecast Discussion