Market signal is a strong NO. Denver's climatological average high for April 28 is approximately 61°F. A 38-39°F high would represent an extreme negative 20-23°F anomaly, an event with extremely low historical frequency for late April. Current GFS and ECMWF operational runs, alongside their respective ensemble means, consistently project 2m temperatures for Denver on April 28 well into the 50s and 60s. The 500mb geopotential height pattern shows no indication of a deep, persistent trough or an arctic high advecting frigid air into the Front Range; rather, zonal flow or ridging is more prevalent in long-range guidance. Even the 10th percentile of the ensemble spread for maximum temperature remains above the 40°F mark. The probability distribution for late April highs clearly disfavors such a severe cold event. 98% NO — invalid if GFS/ECMWF operational runs consistently drop below 45°F in the next 72 hours for 2m temp on April 28.
Market signal is a strong NO. Denver's climatological average high for April 28 is approximately 61°F. A 38-39°F high would represent an extreme negative 20-23°F anomaly, an event with extremely low historical frequency for late April. Current GFS and ECMWF operational runs, alongside their respective ensemble means, consistently project 2m temperatures for Denver on April 28 well into the 50s and 60s. The 500mb geopotential height pattern shows no indication of a deep, persistent trough or an arctic high advecting frigid air into the Front Range; rather, zonal flow or ridging is more prevalent in long-range guidance. Even the 10th percentile of the ensemble spread for maximum temperature remains above the 40°F mark. The probability distribution for late April highs clearly disfavors such a severe cold event. 98% NO — invalid if GFS/ECMWF operational runs consistently drop below 45°F in the next 72 hours for 2m temp on April 28.
