Thunderstorms/ squall line/ cold front/ downpours/ potential flash flooding:
- With a warm and humid day on Wednesday, a cold front will move through overnight bringing a potential squall line with thunderstorms and heavy downpours that have the potential to produce flash flooding, but this will be nothing like the flooding from the remnants of Ida.
- The image shown below is for 2 AM Thursday from the NAM model.
- The following is from the NWS NY, covering Long Island and the tri-state area: "The cold front will continues its approach Wednesday night and begins to move through the forecast area late Wednesday night into Thursday morning, as an amplifying upper level trough moves over the Great Lakes region into the day Thursday. Will have to monitor for the potential for flash flooding Wednesday night as PWAT (Precipitable Water) values increase to 1.5" to 2" across the area. Low level southwesterly winds will increase during this time frame, becoming nearly parallel to the cold front. Additionally, Conditions have been very wet lately and many rivers and streams remain at elevated levels, so flash flood guidance will be low and it won`t take much rain for additional flooding. Weak low pressure may form along the frontal boundary, adding more in the way of lift. Finally, The Weather Prediction Center has placed portions of NYC, northeast NJ, and southwest CT in a marginal risk for excessive rainfall. Cannot rule out flash flooding in any of these locations, and there is still uncertainty in where and how much rain will fall, but as of now, the best chances look to be north and west of NYC."