Colder Week Expected

Discussion: We’re still kind of dealing with the low that occluded off the jet/front from last week. This low is currently stacking with an upper low over/just N of the Great Lakes. It’s going to meander around in this area for a good portion of this week keeping NJ under below-average geopotential heights…a deepening E US trough trapped behind a SE Canadian ridge block. The first and immediate result of this is another frontal system pushing through NJ this afternoon into evening (Monday). This should bring scattered downpours and possibly some convective thunderstorm action across NJ from W to E between about 2pm and 10pm tonight. The possible convection is a worthy thought given the colder air mass moving into the current milder air mass. It doesn’t have to be “summer hot” to get storms. You simply need enough of a delta between the colder air moving in and the existing warmer air. This is why thundersnow and rogue off-season thunderstorms happen from time to time. From early Tuesday AM through about Friday morning, we’re going to turn colder with daytime temps pushing just into the 50s and overnight lows down into the 30s (in some cases below freezing – NNJ elevations/SNJ Pine Barrens). Wednesday and Wednesday night looks like the coldest point of the week. So it looks like a week of frost and freeze warmings by the NWS by state region. By Friday morning the E US trough should begin breaking down giving way to a zonal weekend pattern (still dry but milder). Some ridging is then expected to build for next week but let’s not get too far ahead of ourselves. For this week, get the coats out. Tomorrow/tomorrow evening should force most heaters on…if not overnight tonight.

Monday (Oct 17) high temperatures should reach the mid-to-upper 60s. Skies should be mostly cloudy with isolated showers possible during the day. Scattered frontal rain, possibly thunderstorms, are possible between afternoon and evening hours. Winds should be light out of the S/SW ahead of the front and then breezy, possibly gusty, during any frontal storm action. The frontal action seems scattered-to-widespread, not purely widespread. So more hit-or-miss type stuff…but the cold is coming for all. Overnight lows should range from mid-30s to mid-40s from elevations to coasts as colder air moves in behind the front.

Tuesday (Oct 18) high temperatures should reach the mid-50s for most areas. Skies should be mostly sunny. Winds should be breezy, possibly gusty at times, out of the W/NW to start. Overnight lows should fall into the 30s for most with a good chance of some areas dipping below freezing (mainly elevations). Coastal areas might hang near-40. Winds should gradually subside between afternoon and overnight hours.

Wednesday (Oct 19) high temperatures should reach the low-to-mid 50s. You might see some higher elevations max in the upper-40s. Skies should be mixed with sun and clouds. Winds should still be a little breezy out of the W/SW but no longer gusty. Overnight lows should range from 30-45 from elevations to coasts with most of NJ falling into the 30s.

Thursday (Oct 20) high temperatures should range from mid-50s to lower-60s from elevations to coasts. Skies should be mostly sunny. Winds should be light-to-breezy out of the SW. Overnight lows should again fall into the 30s away from the ocean with coastal regions hanging in the 40s.

Friday (Oct 21) high temperatures should reach well into the 60s for most areas. Skies should be mostly sunny. Winds should be light out of the SW. Overnight lows should range from mid-30s to upper-40s from elevations to coasts.

An early look at the weekend indicates afternoon highs in the mid-to-upper 60s and overnight lows in the 40s. A slight moderation after the expected colder week. Saturday looks a little sunnier, Sunday a little cloudier, but both days dry. Let’s take another look in a few days. Everyone have a great week and be safe! JC

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Jonathan Carr

Jonathan Carr (JC) is the founder and sole operator of Weather NJ, New Jersey’s largest independent weather reporting agency. Since 2010, Jonathan has provided weather safety and forecasting services for New Jersey and immediate surrounding areas through the web, social media, and app spaces. Originally branded as Severe NJ Weather (before 2014), Weather NJ is proud to bring you accurate and responsible discussions ahead of high-stakes weather scenarios that impact the garden state. All Weather. All New Jersey.™