Stormy End to Hot and Muggy Weather in New Jersey on Saturday

Three Rounds of Storms Usher in Cooler and Drier Air

Prior to mid-Saturday afternoon, the month of September had been off to a blistering start by relative standards. After a month of August that had seen only two days of 90 degree temperatures including one on August 31st, the first week of September brought in as many 90 degree days. The average temperature and heat index for the week were warmer than the three previous months, and Saturday’s high was the second highest temperature at GWC in South Plainfield since June 1st. The high reached 92 degrees in South Plainfield. Combine that with a stifling dew point of 78, and you had a peak heat index of 106, the hottest and muggiest day in Northwest Middlesex County since July 2nd.

The heat and humidity on Saturday was then put to an abrupt end when the first of several rounds of thunderstorms rolled through the Garden State. The first wave hit around 4:00 PM. Followed by another one around 6:00 PM, and then a final one around 11:00 PM. The first round of storms was probably the most severe. Over in the Raritan Center section of Edison, New Jersey, the powerful storms brought a combination of loud thunder, vivid lightning, gusty winds, and heavy rains. The combination helped flicker the lights inside some of the office buildings there. However, they only brought a trickle of rain to South Plainfield. The thrust of the next round of storms hit Southern Middlesex County, Mercer County, and Monmouth County very hard prompting a Severe Thunderstorm Warning from the National Weather Service office in Mount Holly.

There would be a lull in the action for a few hours around Middlesex County. While skies remained somewhat cloudy with large cumulonimbus clouds to the west of the area, no rain or storms would start to come through until about 10:30 PM. These storms came with some fanfare originally in Eastern Pennsylvania, and then crossed the border into Western New Jersey during the 9:00 PM hour. The storms were accompanied by some hail, winds estimated at 60 miles per hour, vivid lightning and heavy rain. After coming through Sussex, Warren, Hunterdon, Morris, and Somerset counties, the band of storms began pushing through Northwestern Middlesex, and put on a fairly good lightning display. Winds became a bit gusty with some thunder before rain began falling.

The first round of storms in the late afternoon actually provided some benefit in Northern Middlesex County by stabilizing the atmosphere just enough to prevent more severe weather from occurring.  When it was all said and done though, the three rounds of storms only produced a total of 0.22 inches of rain at Greg’s Weather Center in South Plainfield. Rainfall has been a bit scarce over the past 30 to 45 days. The month of August 2014 was the driest at GWC in the past four years with only 1.87 inches of rain. Yesterday was the first significant rainfall of the month of September here in South Plainfield, and on average Septembers are usually dry in New Jersey. So far this year, there has been 30.60 inches of rain at GWC in South Plainfield, and 14.07 inches of that has fallen since June 1st. This summer has so far been the coolest in the past four years with an average temperature of 73 degrees and an average peak temperature of 92 degrees. The peak heat index was only 110, and that was in July.

The forecast for this week calls for temperatures to cool down into the low 80s on Sunday, and then into the mid to upper 70s on Monday and Tuesday with showers before temperatures moderate into the low 80s again by Thursday and Friday. Models are indicating though that a significant cool down is expected starting next weekend with below normal temperatures across much of the eastern half of the United States starting next weekend.