Brief Cold. Mild Conditions Return

Discussion: Real quick, rain is departing to the E over the ocean and a cold front is moving in to drop temperatures for this afternoon through tomorrow night. By Sunday, the mild conditions will return and stick around until about Friday of next week. The snow lover’s nightmare of a winter continues. Since December, we haven’t been able to stay in a favorable snowstorm development pattern for more than a few days. And in those transient periods, nothing has come into fruition. It’s been the worst winter (snow-wise) since probably 2011-2012. We’re good for these kinds of winters about every 1-3 times per decade and this is one of them. The weak La Nina, raging Pacific jet, and lack of sustained blocking are the main reasons this happened. And even the few possible thread-the-needle events fell apart within 24-48 hours of go time. In summary, meteorological winter (Dec 1 – Feb 28) has been a dud snow wise. Now we turn to one last hope which is a Sudden Stratospheric Warming Event (SSWE) that began a few days ago. A SSWE is a process where the polar winds reverse from Rossby wave disruption. The stratospheric polar vortex then implodes inwards and downwards on itself creating warm high pressure in the stratosphere. This then squashes the troposphere beneath with the coldest polar air on the planet having nowhere to go but spill downwards into the lower latitudes. It looks like this is happening however we don’t know if the cold will spill into the E US. It takes up to a few weeks for the colder air to propagate downwards into the troposphere for NJ latitudes. Around the first week of March, the SE ridge is modeled to put up a good fight and possibly set up a very strong gradient pattern (flat W to E boundary with very cold air to the N and very mild air to the S). Snow storms can happen in this pattern but are entirely dependent on the latitude of the boundary. A quick peak at the tellies indicates NAO and AO going negative around that time frame. PNA has been negative and looks to head towards neutral around that time. It just means we won’t have a sharp ridge over the W US helping to support an E US trough…it jives with the suggested zonal gradient pattern. We’re going to have to get through the cold snap tonight-tomorrow then the milder Sunday-Friday before having a good handle on where, if any, the SSWE impacts will occur in the N hemisphere. I would say right now there is a non-zero chance of snow in the first few weeks of March. We know it’s going to get colder but we just don’t know if the pattern will be active enough. I know it feels easy to write this winter off but we do have to give it until at least the ides of March IMO given the suggested atmospheric dynamics.

Friday (Feb 17) high temperatures are maxing early near-60 for most areas. After a cloudy/rainy start, skies should improve by afternoon as temps drop and W/NW winds pick up a bit. You should really notice the temp drop through sunset hours. Overnight lows should drop into the 20s for most of NJ…closer to 30 along the immediate coast. Winds should howl through Saturday sunrise.

Saturday (Feb 18) high temperatures should reach the mid-40s for most areas. Skies should be mostly sunny. Winds should relax out of the W around sunrise or shortly after. Overnight lows should range from mid-20s to mid-30s from elevations to coasts.

Sunday (Feb 19) high temperatures should reach the low-to-mid 50s. Skies should be mixed with sun and clouds. Winds should be light out of the S for most areas…SNJ coasts a little breezier. Overnight lows should range from mid-30s to mid-40s.

An early look at next week indicates the milder conditions (Starting Sunday) lasting through about Friday…50s and 60s for most areas perhaps NWNJ elevations hang slightly cooler. A few rain chances throughout the week. Looks like a cold front Friday (Feb 24) to start a prolonged period of colder conditions. It doesn’t look like we’ll see anything much wintry for the rest of February. March can go a few ways depending on the influence of the stratospheric warming event currently occurring (see above discussion for more details). Stay warm tonight and tomorrow for the transient cold snap but remember we’ll warm right back up Saturday night into Sunday. Everyone please have a great weekend and be safe! JC

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