Hot Start Cool Finish (Sept 25-29)

Discussion: Jose is gone, even the system’s upper-level energy. We’re left with the decaying stubborn ridge over NE US/SE Canada that will take time to break down completely. Therefore, the current warm and muggy temperatures should gradually step down through Thursday. Heights will still be raised for Monday and Tuesday which should cap out the environment regarding possible convection. Wednesday and Thursday should have lower heights with the ridge breaking down and therefore the expected warmer surface could lead towards a destabilized convective environment (pop-up showers and thunderstorms). Maria will be nearby along with the frontal boundary. Therefore we have to allow for isolated-to-scattered precipitation chances from all the region-wide lifting. By Friday night there should be a noticeable difference in temperatures and humidity. A few shortwaves coming off the polar and pacific jets will phase into an upper level low over Canada. This will force the jet stream southward into the Mid-Atlantic US for the weekend. This upper-level W to E flow is what will ultimately transport Maria to the east by Thursday. But after the jet drop pushes in the Canadian air, I’m seeing highs struggling to escape the 60s with lows down into the 40s and 50s, all with noticeably lower dew points. It should feel cool and crisp this weekend, under a dome of approaching high pressure. This should jumpstart the pumpkin-spiced everything. The jury is still out on how long the fall air mass hangs around after this weekend.

Monday (Sept 25) high temperatures should reach well into the 80s for most. 90 is not off the table for the usual interior hot spots in CNJ/SNJ. Immediate coastal regions could max out in the upper-70s. Skies should be partly-to-mostly sunny with a humid feel. Winds should be light out of the E/NE. Overnight lows should fall into the 60s statewide.

Tuesday (Sept 26) high temperatures should reach well into the 80s for most. Immediate coastal regions could again max out in the upper-70s. Skies should be partly-to-mostly sunny with a humid feel. Winds should remain light out of the E/NE. Overnight lows should fall into the 60s statewide.

Wednesday (Sept 27) high temperatures should reach into the 80s for most. Immediate coastal regions could again max out in the upper-70s. Skies should be partly sunny with a humid feel. A small chance for showers or even a pop-up thunderstorm is possible. Winds should be light-to-breezy out of the NE (breezier along the coast) . Overnight lows should fall into the 60s statewide.

Thursday (Sept 28) high temperatures should reach the lower-80s for most. NNJ elevations and coastal areas might hang in the mid-to-upper 70s. Skies should be partly cloudy (more clouds in SENJ than NWNJ). Humidity should be noticeably decreased. Winds should be light-to-breezy out of the N/NE (breezier along the coast). Overnight lows should fall into 40s for NNJ elevations and 50s for everyone else in NJ.

Friday (Sept 29) high temperatures should reach the low-to-mid 70s statewide. NNJ elevations might not make it out of the 60s. Skies should be mostly sunny with a comfortable feel. Winds should be light out of the NE. Overnight lows should fall into the 40s for most. I could see NNJ elevations and interior pine barrens dipping into the 30s while immediate coastal areas hang in the lower-50s.

An early look at the weekend indicates a firm first slap of fall to the face. Afternoon high temperatures on Saturday and Sunday could fail to escape the 60s. Overnight lows should be similar to Friday night. A few models are spitting a precipitation signature out for Saturday which is probably showing up as possible rain on your point and click/app forecast apps. I’m not really buying that right now. A dome of high pressure should approach on Saturday and be overhead on Sunday. That tells me the air will be pretty dry since the northerly jet’s source will be from Canada.  Therefore I’m currently leaning towards a cool, crisp, partly sunny and dry weekend. Let’s re-visit the idea in a few days.

Coastal Statement: The biggest threat for New Jersey this week from Maria are swimming conditions along beaches. Dangerous rip currents and increased wave heights are expected between now and when Maria is heading away Friday morning. Peak coastal effects should happen in the Tuesday PM-Thursday AM period. Please use caution as many beaches have concluded their life guard duty for the year. High tides between Tuesday PM and Thursday AM could feature minor coastal flooding for the usual suspects (barrier islands and immediate coast). Minor beach erosion is also likely.

Have a great week and please be safe! JC

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 discussion and forecasting services for New Jersey and surrounding areas through the web and social media. Originally branded as Severe NJ Weather (before 2014), Weather NJ is proud to bring you accurate and responsible forecast discussion ahead of high-stakes weather scenarios that impact this great garden state of ours. All Weather. All New Jersey.™ Be safe! JC