Forecasters say cold temperatures Wednesday morning could end the 2016 growing season.
UPDATE: The freeze watch that was previously issued across most of New Jersey has been upgraded to a freeze warning. It's effective from midnight through 9 a.m. Wednesday, when temperatures are expected to drop into the upper 20s to low 30s. A frost advisory is in effect for Mercer County and Cape May County, from midnight to 9 a.m. Wednesday.
If you want your mums and pansies to survive for Halloween, you might want to cover them up or bring them indoors before you go to sleep Tuesday night.
A surge of cold air is expected to push temperatures down near the 30-degree mark early Wednesday morning across more than half of New Jersey, prompting the National Weather Service to issue a freeze watch in 13 counties.
The watch is in effect from 2 a.m. to 9 a.m. Wednesday for Atlantic, Burlington, Cumberland, Hunterdon, Middlesex, Monmouth, Morris, Ocean, Passaic, Somerset and Union counties, along with western sections of Bergen and Essex counties.
Chance of snow or sleet in northwestern N.J.
"Frost or freezing temperatures are forecast within the watch area," the weather service said in its freeze watch advisory, issued Monday afternoon. "The coldest temperatures should occur between 6 a.m. and 7:30 a.m. Wednesday, with frost or freezing temperatures possibly beginning as early as midnight in the normally colder, sheltered valleys."
The morning cold blast "will probably end the growing season in parts of this area, especially near and north of Interstate 78, inclusive of the Lehigh Valley," the advisory says.
The freeze watch comes amid a chilly week, particularly in the northwestern corner of New Jersey, where there's a possibility of light snow changing to a wintry mix of rain and sleet on Thursday morning. No accumulation is expected, but the weather service said driving conditions could be slick in high elevation areas of Sussex and Warren counties.
Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com. Follow him on Twitter @LensReality or like him on Facebook. Find NJ.com on Facebook.