Heat and Humidity on the Rise; Storms Possible From Wednesday to Friday

While the mid-section of the United States has been dealing with historic rains, the weather in South Plainfield and the rest of New Jersey has been quite dry.  Both are the result of a stagnant weather pattern that has basically flip-flopped the rainfall situation in the Northeast and Great Plains.  Prior to the start of May 2015, Texas as well as other parts of the Southwest have been dealing with a serious drought while the Northeast was just starting to run below normal in terms of rainfall.

New Jersey has started to dry up.  During the month of April, there had only been 1.63 inches of rain at GWC and then just 0.90 inches during the course of May as of today.  Most of that rain came in a downpour  of 0.83 inches on May 16th.  View the video of a drive into that downpour.  A bit further north in New York City, there had been no rain for 22 days prior to May 16th.  Since it has been dry here in the Garden State and the rest of the Tri-State area, humidity levels have been mostly low, which has enhanced the fire risk.  Before the holiday weekend, the maximum high temperature for the month at GWC was 85 degrees, which occurred several times.

Memorial Day Weekend started modestly. Temperatures were in the mid 40s at GWC in South Plainfield on Saturday morning, and only got into the upper 60s during the afternoon. Sunday was a bit warmer with a high of 81. Over the past couple days though, the temperatures and humidity levels have been on the increase.  Although dew points have not been as high as they were prior to the rains of May 16th, they have climbed up into the mid to upper 60s. On Memorial Day, the high reached 87 degrees at GWC, which was the highest temperature so far this year before Tuesday.  Then, the mercury surpassed that mark with a high of 89 on Tuesday afternoon.  The heat combined with a peak dew point of 67 to produce a top heat index of 93. 

High pressure offshore is responsible for the increase in heat and humidity.  It is more like a Bermuda High pattern typical for mid-summer.  The clockwise flow of air around the high has brought up warm and humid air from the south, where there has been record rains in Louisiana, Arkansas, Oklahoma, and Texas this month.   With the increase of heat and humidity, there is also a rise in instability.  A slow moving cold front is also approaching the area, which means that there will be a higher likelihood of showers and storms for the rest of the week.   Already there have been some isolated storms in Northern Pennsylvania, South Central New York, and a stray storm over Northwestern New Jersey during the day on Tuesday.

These showers and storms will become more numerous on Wednesday and Thursday, but still won’t be widespread.  However, those areas that end up getting these showers and storms could get heavy downpours as the cold front  drags its way slowly eastward.  The threat of wet weather could linger into Friday.  Probability of showers and storms is between 40 to 50 percent.  Severe Weather is more likely to occur further north and west from Northeastern Pennsylvania through New York, and into parts of New England.