ECMWF-ENS and JMA MSMs project a decisive high-geopotential height anomaly at 500 hPa over Honshu for April 28, a clear signal for sustained anticyclonic flow aloft. This structural setup drives subsidence, limits upper-air divergence, and ensures atmospheric stability, maximizing insolation potential. Surface analysis reveals a robust Pacific high-pressure ridge, delivering an unambiguous warm air advection (WAA) vector from the SW, confirmed by 850 hPa temperature anomalies hitting +4°C to +6°C above climatology across Kanto. Boundary layer thermodynamics, amplified by persistent clear-sky forecasts (<20% fractional cloudiness), guarantee maximum diurnal heating, propelling surface temperatures decisively past 19°C. Suppressed Convective Available Potential Energy (CAPE) removes any threat of convective inhibition to the warming trend. Sentiment: Local weather blogs are trending towards 'pleasant and mild.' 90% YES — invalid if a significant cold-core low develops or a robust cold frontal passage occurs within 24 hours of the resolution period.
ECMWF-ENS and JMA MSMs project a decisive high-geopotential height anomaly at 500 hPa over Honshu for April 28, a clear signal for sustained anticyclonic flow aloft. This structural setup drives subsidence, limits upper-air divergence, and ensures atmospheric stability, maximizing insolation potential. Surface analysis reveals a robust Pacific high-pressure ridge, delivering an unambiguous warm air advection (WAA) vector from the SW, confirmed by 850 hPa temperature anomalies hitting +4°C to +6°C above climatology across Kanto. Boundary layer thermodynamics, amplified by persistent clear-sky forecasts (<20% fractional cloudiness), guarantee maximum diurnal heating, propelling surface temperatures decisively past 19°C. Suppressed Convective Available Potential Energy (CAPE) removes any threat of convective inhibition to the warming trend. Sentiment: Local weather blogs are trending towards 'pleasant and mild.' 90% YES — invalid if a significant cold-core low develops or a robust cold frontal passage occurs within 24 hours of the resolution period.
