August 13: Widespread Rain Returns Monday

Thursday ended up being a very chilly day, with high temperatures only in the 70s to lower 80s, with the western and central parts of the area seeing some light rain. The heaviest rain fell in northern New Jersey, where as much as 3/4 inch of rain fell. Today was also chilly, with similar high temperatures, but conditions were dry with more sunshine than yesterday.

Yesterday’s rain was the first measurable rain for parts of the area since July, ending a 13-day stretch of dry weather. Parts of Long Island though have yet to see rain this month, with the last widespread rain event there being on July 29. The next rainfall there is expected on Monday, which would make this a 17-day stretch of dry weather.

Tomorrow’s Outlook:

Tomorrow will be mostly sunny across the area with a SE wind expected. Due to this and a chilly air mass over the area, high temperatures will reach the lower 80s inland, lower to mid 80s for the immediate NYC area, and upper 70s to lower 80s for Long Island and S CT.

Dry conditions are expected again tomorrow, however these dry conditions won’t last for long. Showers and thunderstorms will already approach the western parts of Pennsylvania and West Virginia, and will reach the area by Sunday night.

Sunday – Tuesday: Locally Heavy Rain

Sunday will continue with the SE onshore wind, however temperatures will become warmer, with high temperatures expected to reach the lower to mid 80s inland, mid 80s for the immediate NYC area, and the upper 70s to lower 80s for Long Island and S CT. Scattered showers and thunderstorms, locally heavy, are expected for the western parts of the area starting in the afternoon, spreading eastward through the overnight hours.

These storms are expected to affect the area between Monday and Tuesday. With a humid air mass and precipitable water values over 2 inches, locally heavy rainfall is expected. Most models have trended considerably drier for this time period, with the GFS model only showing 3/4 inch at most, however the GFS is not very reliable, as it has been too variable with this event over the last few days, and I am leaning towards the NAM, as it has performed better than the GFS for the last few events, and it also shows the possibility of locally heavy rainfall. At this time, I am expecting a general 1/4 to 3/4 inch for the area, with amounts locally as high as 1 to 2 inches of rain. Drier conditions are expected by Tuesday night. This will not be enough to end the drought, but it will prevent the drought from becoming worse for the short term.

For Wednesday, there is a lot of uncertainty as the models have significant differences with the rain, cold front location and the air mass. For now, I leaned towards a solution where an isolated shower or thunderstorm is possible with highs generally in the lower to mid 80s, though this is likely to change as details become clearer. More on the longer range will come tomorrow.

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