Forecast Discussion
000 FXUS65 KTWC 280940 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 240 AM MST Thu Mar 28 2024 .SYNOPSIS... Expect warmer temperatures today into Saturday before a weather system brings colder temperatures and widespread precipitation chances early Sunday into early next week. Rain and accumulating mountain snow is likely. Winds will increase ahead of this system on Friday, with windy conditions lasting through the weekend. && .DISCUSSION... As an upper level ridge crosses the region, temperatures today through Saturday will be well above what they were just a couple days ago. Forecast highs today and Friday are in the 70s to lower 80s across the lower elevations, and a tick lower on Saturday. By Saturday, a deeply anomalous trough (500mb heights near climatological minimum on NAEFS guidance for this time of year) will be over the California coastline, while strong southwest flow will be present over southeastern Arizona. The increased unidirectional flow aloft will drive breezy to windy conditions at the surface starting Friday, and lasting through the weekend as an associated jet streak crosses aloft. Precipitation will arrive initially along a mid-level frontal push crossing the state early Sunday through early Monday. This will combine with strong divergence aloft to drive periods of heavier rain and mountain snowfall rates along and near the frontal boundary. Additional precipitation is likely Monday as cold air aloft will bring diurnal instability and convective activity. The seasonally impressive upper level support and southwesterly moisture draw will bring chances for precipitation to all of southeastern Arizona, with Sunday potentially exceeding the normal monthly precipitation total for April in under a day as described in the previous discussion. Accumulating mountain snow above 7000 feet may need headlines, most likely in the Whites but potentially the Catalina, Rincon, and Pinaleno mountains as well. Sunday and especially Monday, high temperatures will be well below normal. The ECWMF extreme forecast index highlights the highly anomalous temperature forecast for Monday with values near bottoming out in southern Arizona, as forecast highs range from 15 to 20 degrees below normal. Low temperatures Tuesday morning will depend on the exiting moisture, but still have likely probabilities of near to below freezing morning lows in historically cooler valleys of Cochise and Graham counties. Temperatures should moderate going into the middle of next week as the trough exits. It`s worth noting that long range models are in good agreement with lower height anomalies returning by the end of next week, which is leading to CPC`s 8-14 day outlook leaning below normal for temperatures and above normal for precipitation for that period. && .AVIATION...Valid through 29/12Z. Gradually increasing cloud cover today at 20k feet and above. Winds may increase to around 10 kts out of the west in some exposed areas this afternoon, but generally remain light and terrain driven. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Warmer today through Saturday as a ridge builds. Winds will increase on Friday to around 15 to 25 mph ahead of an approaching storm system, which may overlap relative humidities of 10 to 15 percent in the lower elevations. Winds should become a bit higher on Saturday, though moisture will be on the rise. Good chances for widespread precipitation arrive with a cold front by early Sunday, lasting through Monday and potentially Tuesday. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
NWS TWC Office Area Forecast Discussion