How appropriate that Meteorological Winter (3-mo period of coldest average temps) starts tomorrow and we are talking our FIRST Winter storm? Looks like we are coming out of the gate ready to go for the rest of the season! This just so happens to go right in line with my thinking for Winter 2020... and I can't wait. I KNOW there are MANY of you who hate snow and I totally understand. For me it's like I'm 5 years old again and the magic that got me into this field is reignited. Of course, I'm aware that safety trumps personal feelings so it's important to forecast based on FACTS, not feelings. My job is to have you as prepared as possible in any situation.
With that said, let's get into it. This thing is going to bring an impact for EVERYONE... but those impacts are going to vary greatly, based solely on WHERE you are. MAJOR snow for our friends in North Jersey, SOME snow for Central and mainly rain for us down here in South Jersey. First the quick info for the soccer moms with 5 kids running around with a half-drunk iced latte...
Who: ALL of New Jersey.
What: Moderate to Heavy snow north of New Brunswick, wintry mix to rain for MOST of South Jersey.
When: Wintry mix moves in late tonight into early tomorrow morning. This could make travel difficult around the Philly Metro area and North Jersey. Not really sure why the brine is on the roads SE of Hammonton though...
Why: Area of low pressure advances northeast from Dixie. Cold air is in place at the surface by the time the precip starts. This will allow the warmth to override the cold and create wintry precip early Sunday. As the warm air wins out, we will see a flip to plain old rain for most of South Jersey. As the COASTAL low forms, colder air will move in and a period of snow is possible on Monday... again, mainly for NORTH JERSEY, but some minor accumulations are possible NW of Hammonton.
Coastal Impact: Not too concerned with this one. We are coming off the new moon and don't have a storm that's going to create a large push of water towards the coast for 2 days leading up to its arrival... so that's all good. Looks like MOST tide levels will remain shy of minor flood stage but if there was a last minute change, there could be SOME very minor ponding in the low laying areas... those culprit zones. Certainly nothing moderate or severe.
Rain Totals: I think we are good for 3/4" to 1 1/2" of rain. There could be some areas of moderate to heavy rain on Sunday morning and afternoon.
Snow Totals: This one is going to vary GREATLY. I'd say at MAX 1-3"for anyone west of Hammonton, I'm leaning lower than that but let's leave the door open for over-performance... why not? Southeast of Hammonton? If there's a band that comes through on Monday afternoon and evening there could be enough for a coating or so. That's supposing the moisture doesn't all dry up beforehand. Tricky forecast for sure and will likely be revised again before the actual snow so stay tuned!
The Full Report...
What we are looking at here is my LEAST favorite type of storm to forecast, a true Miller B type storm. In a classic nor'easter setup, you've got one deep area of low pressure (storm) that comes out of the Gulf and up the coast. You generally know exactly what to expect and there isn't a whole lot of grey area. In a Miller B, the ENTIRE FORECAST is literally based on the transfer of energy from the parent low to a coastal storm. We are forecasting things before the storm even forms! How crazy does that sound? I've been burned a couple times in my career by these setups. There's no way to sugar coat it - they are THE most difficult types of storms to nail down and are highly temperamental. Below is an illustration explaining how these form.
The thing with Miller B storms is that they are oftentimes slow moving because the full transfer of energy doesn't happen in the blink of an eye... it's a process. You can get some BIG snow out of them too, but we need moisture on the backend of them as the cold is flowing in. You dry up that moisture, which is often the case, and you end up with much less. So yes. Tricky.
My number one concern with this storm is, and has always been, the potential for ICE/SLEET on Sunday morning. Here's a look at what things look like as you wake up tomorrow:
Notice the pink and purple? That's frozen precipitation. Best chance of seeing that is on the other side of the Delaware river but EVERYONE should be prepared for slow travel in the morning before the flip to rain. The concerning part is this... temperatures at 5k feet above our heads in the 850mb layer of the atmosphere are cold enough to support the wintry precip. JUST below freezing:
Usually the 850mb layer determines what type of precip we will see... now for SURFACE temps? Marginal. Around freezing. It won't take a lot to get some ice in this setup so THAT is why the brine is down... less concerning for the coast as I'm expecting mostly rain. Perhaps some ice pellets mixed in.
The warm air will win out for the afternoon and by midday we see our temps shoot up into the upper 40s. Clearly no snow or ice will fall in those conditions. North Jersey? That may be a different story. This is happening because out ahead of the storm as the warm front comes through, winds are out of the southeast which warms things up.
It's not until the secondary low forms and the cold air gets manufactured, that we start talking about the prospect of snow... at least for us down here in South Jersey. Winds shift out of the northwest and temps come way down again. The HIGH for Monday will occur at midnight but most of the day will be in the mid 30s. Any leftover precip by Monday afternoon is likely snow. If we can get some showers or even better, a band, to come through, then yes, minor accumulations are possible for several areas in South Jersey too.
Winter Storm Watches are posted throughout North Jersey... a season first. There will be plowable snow in those areas. I wouldn't be 100% shocked if a Winter Weather Advisory was extended to include the immediate Philly Metro area. So stay tuned on that!
There is only a 20% chance of seeing anything over 2" South of say Trenton. That's right now. Waiting on the updated guidance, but my thoughts from yesterday haven't really changed.
With that said, here's my first-call snow map for New Jersey... I will re-visit this tonight. Stay safe and don't hesitate to ask questions!
PS, don't forget to download my FREE weather app by searching NorEasterNick in your app store and SUBSCRIBING to my website right here to get alerted when severe weather strikes!