August 3: Heat And Humidity Return, Persist

Blog Updates: The 5-Day Forecast page has been updated. The Severe Weather/Tropics page was not updated tonight, as these forecasts have been discussed below.


Today was slightly warmer than yesterday, with high temperatures generally in the mid to upper 80s across the area, with mostly cloudy skies, though it was slightly more humid, with dew points back into the mid to upper 60s. During the last two days and the weekend, we had a break from the hot and humid pattern that has been persistent most of this summer, however this pattern is going to return again tomorrow, and is going to bring above average temperatures over the next week to the area.

Tomorrow’s Outlook:

Tomorrow is likely to be warmer than today, with mostly cloudy skies and a SSW wind expected. High temperatures should be in the mid to upper 80s inland, upper 80s to lower 90s for the immediate NYC area, and the lower to mid 80s for Long Island and S CT. There is the potential of rain tomorrow, which could cause slightly lower high temperatures. Dew points will be even warmer, in the lower to mid 70s, which will lead to the heat index reaching the mid 90s in places that do not see rain.

As previously mentioned, there is the potential of scattered showers and thunderstorms tomorrow. Severe weather parameters are unfavorable, with only a 5% risk of severe weather expected, however with the moisture around and precipitable water values over 2 inches, tomorrow’s storms will be capable of producing heavy rainfall.

Hot, Humid And Stormy Thursday; Hot And Less Humid Friday

A slow moving cold front will affect the area on Thursday, bringing a risk of severe thunderstorms. While some thunderstorms are possible in the morning, the highest risk of thunderstorms, potentially strong to severe, will be in the late afternoon and evening hours, when the best parameters for severe weather are expected, along with CAPE between 1500-2500, LI between -4 and -6, shear up to 35-40 knots, and lapse rates up to 6.5. The GFS is showing a relatively fast solution, however with the other models being slower, and with the GFS having a history of being too fast with cold fronts, the slower solution was favored for today’s forecast.

High temperatures are expected to reach the upper 80s inland, lower to mid 90s for the immediate NYC area, and the upper 80s for Long Island and S CT. Parts of western Long Island may reach the upper 90s. With dew points in the 70s, it will feel much hotter, with the potential for the heat index to reach 100 degrees for the immediate NYC area. This potential continues to be mentioned in the 5-Day Forecast. For precipitation, I expect scattered showers and thunderstorms, mainly after noon, which should continue into the overnight hours. With precipitable water values again over 2 inches, thunderstorms will be capable of producing heavy rainfall, as well as the potential for strong wind gusts and small hail. A 15% risk of severe weather is expected for this day.

Friday’s Forecast: Friday will be less humid across the area as the cold front moves offshore, though hot temperatures will continue, with high temperatures in the mid to upper 80s across most of the area and upper 80s to lower 90s for the immediate NYC area. Partly cloudy conditions are expected for Friday.

Saturday And Longer Range: Heat Wave Potential Returns

Several days ago, I mentioned the potential of a heat wave that some models have been showing instead of a very chilly air mass that others were showing. Yesterday, I went with a slightly cooler forecast, expecting highs in the upper 70s and 80s, though most of today’s models have significantly backed away from this cool down. As a result, Saturday’s high temperatures are expected to be in the mid 80s inland and in Long Island/S CT, and in the mid to upper 80s for the immediate NYC area. Sunday will be warmer, with mid to upper 80s inland, and upper 80s to lower 90s for the immediate NYC area. Humidity will slowly increase during this time period.

For Monday, several models are showing very hot temperatures as a cold front approaches. There is uncertainty with the timing, some showing it moving through on Monday and others on Tuesday, however high temperatures in the 90s are likely to start next week. More details will come on this once there is less uncertainty.

Latest On The Tropics

Tropical Storm Colin: Now An Open Wave, But A Long Range Threat

Yesterday’s discussion on Tropical Depression 4 expected an upgrade to a tropical storm during the overnight to morning hours, which is what happened, as TD4 was named Colin. One of the possibilities that was mentioned yesterday mentioned Colin peaking as a weak TS, then becoming an open wave due to its fast forward speed, and while it was unlikely, it ended up becoming reality, as the NHC issued their last advisory on Tropical Storm Colin at 5 PM.

This morning, Colin started speeding up while becoming more disorganized, which is when the 5% risk for that possibility I posted yesterday would have gone up to at least a 30% or 40% risk. By the afternoon, there was no closed circulation, and Colin becane an open wave. Its forward motion became even faster, moving at 35 mph, unusually fast for tropical cyclones this far south.

For its longer range, Colin’s remnants should move WNW, reaching the Bahamas by Friday or Saturday, however by that time, a regeneration of Colin may be possible, with some models suggesting a favorable environment. More details will be posted about that potential over the next few days.

Invest 92L: A new invest formed this evening in the Caribbean, which was named 92L. This invest is likely to track towards the Yucatan Peninsula, and may threaten parts of the Gulf of Mexico. More details will come on this invest tomorrow.

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