Nov 17: Cold Temperatures Approaching

Jonathan Carr
By November 17, 2020 14:50

Nov 17: Cold Temperatures Approaching

Discussion: Sunday night’s cold front was on the front of the trough that we (and most of the Mid-Atlantic/Northeast US) are now underneath. This means low geopotential heights and a condensed cooler lower atmosphere. Today, an upper level disturbance moved through, on the S side of the trough/jet, and brought some additional moisture with it. Some areas of NNJ saw flurries while the rest of NJ saw some light scattered rain. The moisture from this disturbance was also assisted by flow over the Great Lakes. Some areas to the W and NW of NJ saw more concentrated lake-effect streamers.

Like all cyclonic disturbances that move away to our E, we will now see an additional boost of N/NW flow behind it. Couple that with a stronger and broad area of high pressure tracking to the SW of NJ, and we’re looking at a stiff period of cold northerly flow tonight through early Thursday morning. You should already be feeling and hearing the N/NW winds picking up.

This is setting the stage for a cold Wednesday and Wednesday overnight into Thursday morning. The cold front Sunday night put us in first gear Monday and Today re: cold intensity. This disturbance should now put us in second gear…conditions you might expect in January rather than November. Wednesday night is probably the first night that things like pipes should be considered. I think the NWNJ elevations are likely going down into the teens, possibly single digits for the highest elevations. The rest of NJ should have no problem falling well into the 20s with teens possible for areas like the Pine Barrens. Your automated point and click forecasts might suggest temperatures not as cold but they are likely not factoring in radiational cooling from clear skies and light winds.

Thursday morning should therefore be a cold start but after that we should moderate through the weekend and into next week. I’m not seeing anything considered very cold again until Thanksgiving weekend when another trough moves in.

In English: Tonight through early Thursday morning should feel like January. Wednesday night into Thursday AM will be the coldest hours of this period. It’s not a bad idea to disconnect any hoses or make sure your properties are ready for below-freezing temperatures likely statewide. Thursday (once the sun is up) through this weekend and Thanksgiving should return to average temperatures before the next cold shot likely arrives Thanksgiving weekend. Be safe! JC

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Jonathan Carr
By November 17, 2020 14:50