ECMWF and GFS operational runs, corroborated by their respective ensemble means, are converging on a significant thermal anomaly for May 5. The latest 00z and 12z model cycles consistently show robust upper-level ridging building over SE England, pushing 850mb temps into the +8 to +10°C range. This setup facilitates strong positive thermal advection from the continent, enhanced by a developing surface high pressure system centered over the North Sea, ensuring minimal cloud cover and maximum insolation potential. Boundary layer mixing under these conditions makes exceeding 16°C a near certainty, with several deterministic members pushing towards 18-20°C in Greater London. The ensemble spread tightens significantly, placing the 75th percentile for max temp well above 17°C. Sentiment: Local Met Office reports also indicate increasing confidence in a mild day. 92% YES — invalid if a persistent stratocumulus deck develops post-06z on May 5.
ECMWF and GFS operational runs, corroborated by their respective ensemble means, are converging on a significant thermal anomaly for May 5. The latest 00z and 12z model cycles consistently show robust upper-level ridging building over SE England, pushing 850mb temps into the +8 to +10°C range. This setup facilitates strong positive thermal advection from the continent, enhanced by a developing surface high pressure system centered over the North Sea, ensuring minimal cloud cover and maximum insolation potential. Boundary layer mixing under these conditions makes exceeding 16°C a near certainty, with several deterministic members pushing towards 18-20°C in Greater London. The ensemble spread tightens significantly, placing the 75th percentile for max temp well above 17°C. Sentiment: Local Met Office reports also indicate increasing confidence in a mild day. 92% YES — invalid if a persistent stratocumulus deck develops post-06z on May 5.
