Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
068 FXUS65 KTWC 020928 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 228 AM MST Sun Jun 2 2024 .SYNOPSIS... Temperatures will remain a bit above normal through early this coming week, with hotter temperatures likely by Thursday. Sunny skies and afternoon breeziness can be expected over the next few days. && .DISCUSSION... Weak and dry troughing will develop across Arizona today with shallow height falls while an associated modest speed max crosses northern Mexico. The main impact of this feature will be to bring an afternoon southwesterly breeze and a few high clouds to southern areas. High temperatures will remain above just above normal, though a couple degrees down from yesterday thanks to this passing trough. High temperatures through Tuesday will likely remain consistent under the persistent flow pattern aloft. From Wednesday through the remainder of the work week, a mid to upper level ridge is expected to set up across the western CONUS. Height anomalies will become particularly stronger on Thursday, setting up potentially the first excessive heat day of the season. Tagging along with the upper ridge is a closed low, forecast to sit under the ridge just off the western Baja coast by Wednesday before eventually merging with the mean flow by sometime this weekend. Ensemble 500mb solutions remain in good consistency in keeping this low south of the forecast area through Thursday, which leads to increased confidence in the Thursday excessive heat potential. As such, an Excessive Heat Watch has been issued for Thursday across the lower elevations of southeastern Arizona. High temperatures may also tease excessive heat criteria Wednesday and Friday, though with less certainty as first the ridge will still be building on Wednesday and then the potential for the closed low to meander northeast into southern Arizona on Friday. Speaking of this low`s progression into Arizona, 00Z and 18Z ensemble runs have brought a slightly deeper trend, which is in turn producing an uptick in model QPF. This is especially true from the GEFS-CMC ensemble precipitation probabilities Friday and Saturday afternoons. That said, it is not a very notable amount of precipitation as it only takes the forecast rain into the measurable tier and not much further. Additionally, the ECMWF remains on the drier side and with a closed low under a dry ridge, a drier solution seems more reasonable anyway. NBM precipitation probabilities have come up with slight to chance values east of Tucson-Nogales through the New Mexico border, but the likelihood of these areas seeing more than a few hundredths remains very low. The more likely scenario should be very dry sub-cloud layers under dry thunderstorms producing gusty winds and lightning Friday and Saturday afternoon- evenings. && .AVIATION... Winds will become southwesterly after 17Z and increase to 13 to 18 kts with gusts to 30 kts, before gradually diminishing after 01Z. Otherwise mostly SKC with a few high clouds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Dry conditions and high temperatures 2 to 5 degrees above normal will continue through next Wednesday, becoming 5 to 8 degrees above normal the second half of next week. Minimum relative humidity values of 5 to 10 percent in the lower elevations and 8 to 15 percent in the mountains through the middle of next week, along with poor overnight recoveries between 20 to 30 percent in most locations. Afternoon winds should be breezy, especially today and Monday with 15 to 20 mph winds and gusts to around 30 mph (more likely south to southeast of Tucson). Chances for dry thunderstorms with gusty outflow winds arrive Friday and Saturday, generally more likely in eastern areas. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Watch from Thursday morning through Thursday evening for AZZ501>509. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson