The high temperature forecast for Tues. July 15, 2014 - cooler than normal for July (Source: Weather Prediction Center)
Is the polar vortex, which often brought frigid air to New Jersey this winter, planning a mid-July invasion?
Nope, said David A. Robinson, the New Jersey state climatologist at Rutgers University.
“This polar vortex (talk) is like out of control," Robinson said.
But the summer jet stream will be a little wavier than usual, dipping a little farther south than normal in the Midwest area, he said. "Along the Atlantic coast, not such a big deal."
Temperatures are expected to be about 5 degrees below normal in New Jersey, said Robinson, who was in Stevenson, Washington, at a meeting of the American Association of State Climatologists.
For example, the National Weather Service forecast calls for a high near 79 in Neptune on Wednesday and Thursday.
“The good news is if you don’t like summer heat, you’re not going to be hit with (extreme) summer heat for the next week, but it’s not going to be much below average,” Robinson said.
“It’s not like we’re falling into the ice box,” he said.
According to a Weather Prediction Center discussion that covers July 14 to 18, a "highly amplified pattern" that is expected across North America will lead to well above normal temperatures in the West and Northwest and well below normal temperatures in the Plains and Great Lakes area, where daily low temperature records for July will be tested.
A cool, dry Canadian surface high pressure system will settle over the Midwest, the discussion says.
According to the American Meteorological Society, the polar vortex is "a planetary-scale mid- to high-latitude circumpolar cyclonic circulation, extending from the middle troposphere to the stratosphere."
Robinson said the polar vortex is the area north of the polar jet stream. In the summer, it tends to contract and it weakens, he said.
The polar vortex brought cold air into New Jersey on and off from January through March, he said.
“It was just uncanny how it just kept recurring,” he said. “We don’t know really exactly why.”
"After last winter and the over-hyping of the polar vortex, it stands to reason that (for) first cool spell during the summer, someone would try to reignite that term. There’s nothing horribly wrong about it, but it’s just rather amusing.”
The Arctic has not been exceptionally cold, snow cover in the Arctic melted earlier than usual and sea ice in the Arctic is again below average for this date, Robinson said.
Temperature outlook from July 16 to July 20 (Source: Climate Prediction Center)
High temperature forecast for Wednesday July 16 (Source: Weather Prediction Center)
Low temperature forecast for Thurs. July 17 (Source: Weather Prediction Center)