Location is key with weather pattern this summer

The position of upper level features this summer will be key in determining the week to week impacts of the weather pattern this summer.  

The difference between a hot and humid week in Freehold or a dry and pleasant week basically comes down to the position of the upper level ridge axis.  First, a ridge is an area of higher heights at the upper levels or higher pressure which produces a clockwise flow in the wind patterns over the northern Hemisphere.  Upper level ridges become more dominant and expansive over North America in the summer months as the Polar jet stream lifts north, so typically the summer weather pattern is strongly influenced on the exact position of the ridge axis over the United States.  This summer the weather pattern is expected to feature a trough in the West and a ridge over the East, which means that the potential for periods of hot and humid conditions is enhanced.

 When the center of the ridge is to the east of New Jersey, the upper, mid, and lower level winds are from the southwest.  This southwesterly wind can transport a very hot and humid air mass from the Gulf of Mexico leading to record high temperatures and uncomfortable weather conditions as seen this past Monday and Tuesday this week.  In patterns where the ridge axis is to the east of New Jersey, the potential for thunderstorms increases as disturbances from the Tennessee River Valley are able to race from the southwest into the northern Mid Atlantic.  With plenty of warm, moist, unstable air ahead of these thunderstorms, the thunderstorms are able to become intense and at time severe.  Also, when the ridge axis is to the east of New Jersey, Tropical low pressure systems or tropical storms and hurricanes, are able to impact the weather pattern over New Jersey as well which brings an increase potential for precipitation.  Overall, when a ridge axis sets up to the east of New Jersey, expect hot, humid, and stormy weather conditions.

However, when the ridge axis is centered to the west of New Jersey, especially over the Great Lakes like this weekend, more often than not this weather pattern leads to very pleasant weather conditions.  One fact to keep an eye on is the potential for a strong upper low over the Canadian Maritimes that could drive a back door cold front (a cold front that approaches from the northeast rather than the west) through the New Jersey coast leading to overcast, cool, and wet conditions.  However, overall this pattern leads to a northwesterly wind pattern at the mid and upper levels which transports a Canadian Polar air mass into New Jersey.  The weather pattern features very dry air, clear skies, and temperatures near normal for this time of year.  With winds down sloping off the Appalachian mountains, surface temperatures typically end up in the 80's over central and western Monmouth County and in the mid to upper 70's over eastern Monmouth County.  Overall this weather pattern, which will be in place this weekend, produces the best weather conditions of the summer.

The position of the upper level ridge is typically influenced by the developments in the Pacific Ocean and where convection develops along the equator.  A key factor in the ridge placement is where the trough in the West sets up and how broad the trough is over the West.  In general, the further west the trough is along the West coast, the more likely the ridge axis will be west of New Jersey.  

For more details on weather impacts throughout New Jersey and the northern Mid Atlantic, visit NY NJ PA Weather!