August 14: Severe Thunderstorm Possible Monday

Today was another comfortable day, as high temperatures were generally in the upper 70s to mid 80s. Over the next few days, however, conditions will become more uncomfortable with increasing humidity and rain returning, with a recent trend in the models now introducing a severe weather outbreak possibility for Monday.

Tomorrow’s Outlook:

Tomorrow will be partly cloudy, with increasing cloud cover throughout the day. Despite an onshore SE wind expected again, high temperatures will be slightly warmer, in the lower to mid 80s inland, mid 80s for the immediate NYC area, and in the upper 70s to lower 80s for Long Island and S CT.

While most of the area will stay dry tomorrow, moderate to heavy thunderstorms are expected for most of PA and NY, with some storms reaching strong to severe levels. Some of these storms should reach the western parts of the area late tomorrow afternoon or evening, spreading into the rest of the area tomorrow night into Monday morning. Any storm that reaches the area will not be severe, but with precipitable water values near or over 2 inches, these storms could produce locally heavy rainfall.

Monday: Severe Storms Possible?

Up until now, the models were not supportive of any severe weather, with a lack of supportive parameters, along with cloudy skies, chilly temperatures and a SE wind. The latest model runs, however, took a significant trend that introduces a severe weather potential for Monday evening. The cold front will approach the area during Monday, with showers and thunderstorms, locally heavy, likely for the morning hours. Should the latest models verify, the sky will then clear for the afternoon, with temperatures rising into the upper 80s to lower 90s with hot and humid conditions, and thunderstorms will form in NY and PA, potentially reaching strong to severe levels while moving towards the area.

The parameters are supportive, with CAPE over 2000, LI up to -6, lapse rates between 6.0 and 6.5, and bulk shear between 30 to as much as 45 knots. Some factors that may limit severe weather chances are cloud cover and the relative humidity. Should the severe weather potential verify, a 30% severe weather risk may be possible, with damaging wind gusts the main threat, with heavy rainfall also possible due to high precipitable water values.

This is only a recent trend, and the models may not have finished trending yet, meaning that this solution can still change. More details will come on this potential tomorrow afternoon.

Longer Range: Uncertainty Continues

For the longer range, there is still a lot of uncertainty as the models are showing different solutions, however it is likely that Tuesday and Wednesday will be drier, despite a chance of a shower or storm, as the cold front moves to the east away from the area. Temperatures are likely to stay in the 80s during this time frame, and while the GFS shows more rain through next week, it is considered an outlier at this time as it has had several cases similar to this one where it showed widespread light rain in the longer range and backed away from the scenario towards the shorter range. The models do, however, agree on a chance of rain for Friday. More information will come on that once details become clearer.

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