The prognostic charts for May 5 show a dominant synoptic pattern favoring robust warm advection over the NYC metro. Both GFS and ECMWF long-range runs consistently depict a significant 500mb ridging pattern building across the Eastern Seaboard, driving a persistent southerly flow at the surface. The GEFS ensemble mean low for KNYC is currently 59.8°F, with the ECENS slightly higher at 61.2°F, indicating high consensus within the ensemble spread for an elevated minimum. A warm front is projected to lift poleward by late May 4, placing the city firmly in the warm sector overnight. This will be characterized by elevated boundary layer moisture with dew points forecast in the upper 50s to low 60s, critically inhibiting radiational cooling. Overnight cloud cover, roughly 70-80% according to FV3-GFS high-res, will further cap temperatures. This confluence of strong warm advection, substantial moisture content, and cloud deck guarantees a suppressed cooling environment. A 60-61°F low is a high-probability outcome within this tight thermal gradient. 90% YES — invalid if the 500mb ridge axis shifts west by >2 degrees longitude.
The prognostic charts for May 5 show a dominant synoptic pattern favoring robust warm advection over the NYC metro. Both GFS and ECMWF long-range runs consistently depict a significant 500mb ridging pattern building across the Eastern Seaboard, driving a persistent southerly flow at the surface. The GEFS ensemble mean low for KNYC is currently 59.8°F, with the ECENS slightly higher at 61.2°F, indicating high consensus within the ensemble spread for an elevated minimum. A warm front is projected to lift poleward by late May 4, placing the city firmly in the warm sector overnight. This will be characterized by elevated boundary layer moisture with dew points forecast in the upper 50s to low 60s, critically inhibiting radiational cooling. Overnight cloud cover, roughly 70-80% according to FV3-GFS high-res, will further cap temperatures. This confluence of strong warm advection, substantial moisture content, and cloud deck guarantees a suppressed cooling environment. A 60-61°F low is a high-probability outcome within this tight thermal gradient. 90% YES — invalid if the 500mb ridge axis shifts west by >2 degrees longitude.
