Boyce Park Snow Report

380 FXUS61 KPBZ 200646 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 246 AM EDT Mon Jul 20 2026 .WHAT HAS CHANGED... No major changes have been made to the severe weather outlook for tomorrow, Enhanced Risk remains in effect across the region. && .KEY MESSAGES... 1) Code Orange Air Quality Alerts issued for parts of western PA and northern WV today due to lingering Canadian wildfire smoke 2) Enhanced Risk for severe weather on Tuesday; Slight Risk for Excessive Rainfall && .DISCUSSION... KEY MESSAGE 1... Lingering wildfire smoke particles has prompted a Code Orange Air Quality Alert (issued by the Pennsylvania Dept. of Environmental Protection) across portions of western Pennsylvania today. Smoke will likely exit the region, from south to north, as a new disturbance tracks into the Great Lakes and shifts the upper-level wind profile. KEY MESSAGE 2... A strong low-pressure system will continue to track through the Great Lakes over the next 24 to 48 hours, bringing an increased risk of severe weather to the region on Tuesday. The combination of abundant instability (1500J/kg to 2500J/kg of CAPE) fueled by warm, humid air and strong wind shear (35kt to 45kts of effective shear) will create a favorable environment for organized severe thunderstorms. As a result, the Storm Prediction Center continues to hold the Enhanced Risk (Level 3 out of 5) for severe weather across our entire region. The likelihood of a Severe T-Storm or a Tornado Watch during the afternoon hours of Tuesday are considered very high. Residents should prepare for damaging wind gusts, though tornadoes and large hail are also possible with any discrete supercell storms that are able to develop. Severe weather analogs associated with similar synoptic patterns in the summer season strongly support damaging winds over our region to be the primary threat. Showers and isolated non-severe storms may track through the region early Tuesday morning in the wake of the outflow from a passing mesoscale convective system (MCS) to our west. However, the main event for strong to severe storms appears favorable between 12pm and 8pm Tuesday. Anomalously high moisture levels with PWATS reaching the 80th to 90th percentile raise the risk of flash flooding Tuesday evening. Training storms could potentially create localized swaths of 3-4 inches of rainfall in a short period of time. Locations that saw significant rainfall from this past weekend`s thunderstorm activity may be especially vulnerable to flash flooding due to already saturated soils and increased runoff. The Weather Prediction Center (WPC) has issued a Slight Risk for portions of region. High-resolution model guidance continues to increase the probability of rainfall exceeding flash flood guidance, with 30-50% probabilities within a 25 mile radius. As confidence grows, a Flood Watch will likely be issued in the next 24 to 36 hours. Current model guidance highlights the greatest potential for excessive rainfall south of Pittsburgh, where enhanced low-level convergence across eastern Ohio may promote back-building thunderstorms. Expect lingering showers and non-severe thunderstorms into early Wednesday before a cold front tracks through the region after sunrise. The potential for precipitation remain lows through at least Sunday under high pressure. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... River valley fog is currently develop across the region, noted on Nighttime Microphysics satellite. Amendments may be needed over the next 3 to 6 hours for brief periods of MVFR to IFR fog. Otherwise, VFR conditions will prevail with variable winds into the overnight time period. Restrictions will likely return tomorrow with a passing low pressure system. Showers and thunderstorms are expected pass over or in the vicinity of all terminals. Cig and vis restrictions will likely occur with the conditions of -TSRA. Damaging wind gusts, between 40kt to 60kts could occur within a 25 miles radius of all terminals Tuesday afternoon (between 18Z to 23Z). Outlook... Remnant showers and non-severe storms may track through the region early Wednesday morning before a cold track advances. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...Air Quality Alert until midnight EDT tonight for PAZ013-014- 020>022-029-031-073>078. OH...None. WV...None. && $$ DISCUSSION...Hefferan AVIATION...Hefferan