Heat Update: Warning Upgraded, Extended Again

The good news is temperatures are beginning to fall, but the bad news is a variety of other factors are extending the "heat wave of 2010" past early predictions, prompting the National Weather Service to extend and upgrade its heat warning for a third time.

As of 3:20 p.m. on Wednesday, July 7, the National Weather Service upgraded the current Excessive Heat Warning set to expire at 8 p.m. Wednesday night to an Excessive Heat Watch, the highest warning level, reserved for periods of heat indices over 100 degrees for a time period greater than 48 hours.

Heat index values reached 102 degrees again today, with actual temperatures in the mid-90s. Falling humidity levels will result in a dry heat causing yet another National Weather Service warning, in this case for wildfire threats.

The weather service issued a Red Flag Warning for Wednesday until 10 p.m.

"A red flag warning means that critical fire weather conditions are either occurring now or will shortly," a National Weather Service alert said. "This afternoon and early evening will be very hot and fine fuels are extremely dry. Relative humidity levels likely will drop below 30 percent in at least some parts of southeastern Pennsylvania, New Jersey, Delaware and the northern Maryland eastern shore. Winds will likely not gust above 20 miles-per-hour, but under the current weather conditions the threat of wildfires is sufficiently high to warrant a red flag warning through early evening."

The alert also said that the combined effects will create "explosive fire growth potential."

Temperatures are expected to drop by Thursday morning – forecast by AccuWeather between 80 and 89 degrees between 9 a.m. to 3 p.m. – humidity levels in the morning and early afternoon are predicted to cause heat index levels up to 102 degrees again around 11 a.m.

"The excessive heat should continue to ease slightly on Friday, but lower humidity levels will not occur until a cold front moves through the area about Saturday," a National Weather Service alert said.

Fallout from the heat has included NJ Transit train delays and cancellations, and Jersey Central Power and Light (JCP&L) reported that Bernards has experienced 500 or fewer power outages in the last couple days.

Residents concerned about heat-related illnesses and safety should refer to the Red Cross guide posted in a previous Basking Ridge Patch article.