####018003793#### FXUS65 KTWC 152105 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 205 PM MST Thu May 15 2025 .SYNOPSIS...High temperatures through early next week will generally be near normal. Breezy to windy conditions returning over the upcoming weekend as a system passes through bringing elevated fire weather conditions. && .DISCUSSION...Nearly zonal flow over the Southeastern Arizona today based on the latest water vapor imagery. Temperatures will hover around near normal for next two days before another weather system drops by this weekend. Ensemble models show this weekend to be breezy to windy condition with a two step sequence. Saturday, a short wave trough will be passing over the eastern portion of region (Cochise, Graham, and Greenlee Counties) to bring strong breezes in the afternoon to early evening. Right behind the short wave will be longer trough or a low pressure center that will be located to our north. This second feature will bring widespread breezy conditions areawide and windy conditions for the eastern counties on Sunday. This weather system will be dry and will result in near critical to critical fire weather conditions this weekend. This will also raise dust concerns along the major thoroughfares of Southeast Arizona. The weather system will slow for the exit by Monday and will likely to continue to bring those strong winds again, especially in the southeastern portion of the county warning area. This system will delaying our anticipation for the approaching summer heat. Mondays temperatures will be 9-12 degrees below normal. Most of the deserts, including Tucson, will be in the mid 80s to mid 70s. With any brief cool down, we will have a rapid warm up. A ridge of high pressure will start to build and bringing Southeast Arizona into our heat season by the middle of next week and raising our HeatRisk. Even more to note when we are not fully acclimated this heat yet. Best to start preparing for the heat late next week and into the holiday weekend. && .AVIATION...Valid through 17/00Z. SKC for most of the forecast period with high clouds at or around 20k ft AGL moving from the south and over the terminals south and east of KTUS after 16/18Z till the rest of the period. This afternoon SFC wind WLY/NWLY at 8-13 kts with gusts up to 25 kts. By 16/03Z, terrain driven winds less than 10 kts through the overnight period. After 16/18Z, SFC wind SWLY/WLY at 12-18 kts with gusts up to 25-30 kts. Terminals east of KTUS will experience the stronger winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...High temperatures will be near normal this Friday and Saturday. Typical afternoon breezes today and Friday for much of southeast Arizona, with breezy conditions persisting across Cochise, Graham and Greenlee counties where 20-foot wind speeds will be around 15 mph and gusts up to 25-30 mph during the mid/late afternoon hours. Increasing southwest winds are expected over the upcoming weekend as another storm system moves to our north. Near critical to critical fire weather conditions are expected this weekend and into Monday. Sunday looking to be the windiest of the period. Monday's winds will lower in speeds and focused on the eastern areas, Cochise County to the Gila River Valley. Temperatures will be 2-4 degrees below normal Sunday, lowering to 9-12 degrees below normal next Monday, warming to well above normal levels by the middle of next week. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson ####018006657#### FXUS61 KPBZ 152107 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA Issued by National Weather Service Charleston WV 507 PM EDT Thu May 15 2025 .SYNOPSIS... There is the potential for strong to severe storms late tonight into early tomorrow morning with a warm front. Severe storms are also possible late Friday into Saturday ahead of passing cold front. Probability of drier and cooler conditions increases after Sunday. && .NEAR TERM /THROUGH TONIGHT/... KEY MESSAGES: - Mostly quiet conditions this afternoon/evening with a building ridge - A passing warm front will return thunderstorms to the area overnight, some of which could be severe ------------------------------------------------------------------- A few stray showers are noted northeast of Pittsburgh with a passing shortwave near Lake Erie. However, convection is below 10kft and only poses an isolated lightning threat through 4pm. To our west, a warm front is currently draped across southern Ohio and central Indiana. Temperatures have jumped into the upper-80s and mid-70s behind the warm front. A surge of moisture is expected to advance late this evening as low-level winds (950mb to 850mb) increase to 40kts. Showers and thunderstorms are expected to accompany a warm front after 10pm tonight, some of which could become strong to severe. All threats are on the table, with noted dry air above (DCAPE over 1000J/kg) and sufficient mid-level lapse rates (+7.0C/km) to prompt strong downdrafts and large hail. Effective low- level shear near 30kts and curved hodographs may also promote rotating updrafts for tornadoes. There is a noted low- level stable layer on model soundings. However, with ongoing energy from an upstream mesoscale convection system (MCS), severe storms will easily plow through that environment. As for flooding, storm motion should be fast enough to avoid a widespread flood threat, though heavy downpours will still be likely, given PWATs near 1.50 inches. Any vulnerable locations could still experience localized flooding issues (e.g., urban and low-lying areas, and any locations that experienced flooding from recent rains). && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... KEY MESSAGES: - Storms likely ongoing early Friday with the passage of a warm front - A break in severe storms expected between 10am and 5pm Friday; isolated thunderstorms can't be ruled out - Severe storm potential increases with an approaching mesoscale convection system after 6pm Friday ---------------------------------------------------------------- Between midnight and 9am Friday, strong to severe storms are expected to be passing through the region from west to east with the remnants of convection initiated off the warm front (see near term discussion). By late Friday morning the environment will likely need some time to recover, rebuild instability, to initiate organized storms once again. However, a isolated storm can't be ruled out from lingering outflow boundaries. High resolution model guidance has been consistent that by late evening (between 6pm to 8pm) a mesoscale convection disturbance will initiate to our west, just ahead of a cold front. The disturbance will potentially track east into the Ohio River Valley. Machine learning and sounding analogs support damaging wind gusts, hail, and tornadoes with this new round of severe weather Friday night into early Saturday. Over the last 12 hours, the Storm Prediction Centers has expanded the threat east to support high resolution model trends. A large portion of the region is now under a Slight Risk (2/5 on the severity scale index). Probability of severe weather appears promising between 9pm and 2am Saturday morning. && .LONG TERM /SATURDAY THROUGH THURSDAY/... KEY MESSAGES: - Cooler and drier pattern returns Sunday through Tuesday. - Precipitation chances return Tuesday into Wednesday with a new low - Potential for heavy rain mid-week ------------------------------------------------------------------- Increasing mid-level subsidence and decreasing dew points in the wake of the cold front Saturday afternoon will likely decrease the potential for thunderstorms. Models have been consistent that troughing over the Great Lakes and northwest flow will keep temperatures seasonable Sunday into Monday. Probability of precipitation increases late Tuesday into Wednesday with a new low ejecting out of the Rockies and tracking east. A few model scenarios note a stationary boundary straddling south of Pittsburgh with this passing low. If this scenario plays out, heavy rain could pose a threat for portions of the region. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... Expect VFR conditions this afternoon despite the increased cu development. A few instances of showers and a couple thunderstorms will develop this afternoon and will most likely move around the terminals but an isolated occurrence is possible. Winds will mainly be light across the area out of the south. A shortwave trough is expected to track across the Upper Ohio Valley region tonight. A line of showers and thunderstorms is expected to develop as the trough crosses the region. Included TEMPO lines in the taf for the most likely time of occurrence of these storms. Enough instability is expected to support these storms well into the overnight hours, though intensity is in question, especially east of a FKL-PIT-MGW line. Still, severe storms are possible with this line. Some restrictions are likely behind the MCS expected tonight, mainly due to fog and low cigs. However, this will clear out and will expect VFR conditions by 15Z. Outlook... Showers/storms should exit the region early Friday morning, though some patchy MVFR fog/stratus is possible early. VFR is then expected until an approaching cold front returns a thunderstorm and restriction potential late Friday into Friday night. Some of these storms could also be severe. Patchy MVFR is possible in scattered showers Saturday into early Sunday with a subsequent upper trough. VFR returns Monday under high pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Hefferan NEAR TERM...Hefferan SHORT TERM...Hefferan LONG TERM...Hefferan AVIATION...Shallenberger