May 22, 2013: Stormy Wed-Fri, Cooler Weekend

Forecast Highlights:

The heat and humidity return again today, with widespread highs in the 80s likely but with a risk of scattered thunderstorms, especially north of NYC. A cold front will move through on Thursday and Friday, producing widespread thunderstorms which could be strong, with cooler temperatures returning for Friday and  Memorial Day Weekend but with increasing uncertainty regarding the precipitation outlook.

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Today - Thursday: Hot, Humid, Stormy

Short Term: (Updated 11 AM) Last night, a frontal boundary gradually dropped southwest as a back door cold front through central New England, producing widespread severe thunderstorms in that region. The front has progressed more southwest than thought, and has stalled over the area, with 9 AM conditions from NYC and north/east consisting of cloudy skies, light east wind, areas of fog and temperatures in the mid 50s-low 60s, which is nearly 10 degrees colder than the models showed for 9 AM.

(Updated) as of 11 AM, the front has still failed to progress northeast, with the majority of the area remaining cloudy with temperatures in the 60s. In some locations, temperatures are almost 15-20 degrees colder than modeled. With the boundary less likely to push back northeast in time for temperatures to significantly warm up, forecast highs have been lowered, and are expected to peak in the mid to upper 70s from NYC and further east and the upper 70s to mid 80s west of NYC. Scattered thunderstorms are still expected for the western parts of the area, but with central and eastern parts of the area remaining cloudy with isolated showers possible.

With the frontal boundary staying northeast of the area tonight, mostly cloudy skies are expected with mild temperatures, only falling into the low to mid 60s east of NYC and the mid to upper 60s from NYC and west. A cold front will gradually approach the region on Thursday, with cloudy skies and widespread thunderstorms expected mainly after 12-2 PM, some of them strong and capable of producing heavy rain. Due to the cloud cover and precipitation, temperatures will be cooler, generally peaking in the mid to upper 70s. These storms will continue through Thursday night as well.


Friday - Memorial Day Weekend: Cooler, Uncertainty Regarding Storm

The cold front will be slow to exit the region, with clouds and showers persisting through the first half of Friday. Temperatures will be fairly cooler compared to Thursday, likely peaking in the mid 60s to low 70s across the area, subject to minor revisions. Uncertainty then increases going into the weekend regarding the cold front, ranging from the NAM and CMC which are on the progressive side, bringing dry conditions in for Saturday through Monday with temperatures in the 60s, to the GFS and ECM which are considerably slower, showing a low pressure cutting off near the region, resulting in rain persisting through Sunday along with much cooler than average temperatures, only peaking in the 50s. The latter scenario is a relatively new one and lacks model support and consistency at this time; at this time, I sided closer to the NAM/CMC, keeping the weekend outlook dry while slightly increasing cloud cover through Saturday, although the outlook is subject to change. Regardless of the storm, Monday is more likely to be dry at this time. Stay tuned for more information on the outlook for next weekend.