Aggressively fading the 50-51°F range for Denver's May 5th high. Climatological normals for early May average near 65°F. Current GFS and ECMWF operational runs, along with their respective ensemble means (GEFS, EPS), show consistently warmer profiles. 850mb temperatures for May 5th are projected firmly in the +6°C to +8°C range across the Front Range. This thermal advection profile is fundamentally incompatible with a 50-51°F surface high unless extreme, persistent upslope with heavy, duration-limited precipitation were forecasted, which is not the case. The upper-level pattern indicates a progressive, not anomalously deep, trough, allowing for quicker warm-up post-frontal passage. Surface pressure fields are not setting up for prolonged, intense cold air damming. Ensemble plume agreement above 52°F is exceptionally high, with less than 5% of members registering a high below 52°F. Sentiment: Local NWS discussions emphasize a return to more seasonable conditions after any early May transient systems. 95% NO — invalid if 850mb temps drop below +2°C with persistent 700mb upslope over 12 hours.
GFS and ECMWF ensemble means indicate persistent upper-air troughing driving cold-air advection over Denver through May 5th. 850mb temps are pegged at 0-2°C. Even with moderate diurnal heating and anticipated post-frontal clearing, max surface temps will struggle to push beyond this range. Probabilistic output clusters tightly around 50-51°F. This specific band represents the most probable outcome given suppressed conditions. 90% YES — invalid if 850mb temps exceed 4°C by 12Z on May 5th.
Aggressively fading the 50-51°F range for Denver's May 5th high. Climatological normals for early May average near 65°F. Current GFS and ECMWF operational runs, along with their respective ensemble means (GEFS, EPS), show consistently warmer profiles. 850mb temperatures for May 5th are projected firmly in the +6°C to +8°C range across the Front Range. This thermal advection profile is fundamentally incompatible with a 50-51°F surface high unless extreme, persistent upslope with heavy, duration-limited precipitation were forecasted, which is not the case. The upper-level pattern indicates a progressive, not anomalously deep, trough, allowing for quicker warm-up post-frontal passage. Surface pressure fields are not setting up for prolonged, intense cold air damming. Ensemble plume agreement above 52°F is exceptionally high, with less than 5% of members registering a high below 52°F. Sentiment: Local NWS discussions emphasize a return to more seasonable conditions after any early May transient systems. 95% NO — invalid if 850mb temps drop below +2°C with persistent 700mb upslope over 12 hours.
GFS and ECMWF ensemble means indicate persistent upper-air troughing driving cold-air advection over Denver through May 5th. 850mb temps are pegged at 0-2°C. Even with moderate diurnal heating and anticipated post-frontal clearing, max surface temps will struggle to push beyond this range. Probabilistic output clusters tightly around 50-51°F. This specific band represents the most probable outcome given suppressed conditions. 90% YES — invalid if 850mb temps exceed 4°C by 12Z on May 5th.
