Unsettled Conditions

Jonathan Carr
By December 16, 2021 16:24

Unsettled Conditions

Discussion: Temperatures soared into the 60s today (Thursday) as expected in the warm sector (after yesterday’s warm front). A cold front will push through tonight, but it looks mostly dry. Also, we’re not talking any serious drops in temperatures just no more days like today. The cold front should then sag across the Mid-Atlantic US laterally Friday and allow for a tranquil day of W/NW winds. By Friday night, some overrunning precipitation should approach NJ from the W and linger all day Saturday, possibly into Saturday night. Areas N of I-78 and NW of I-287 could see some snow or ice (likely in the form of sleet) mix in at times. But only the highest elevations of NWNJ keep the surface at freezing or below. So very little wintry accumulation at elevations under 800ft are expected. For CNJ/SNJ this is likely an all-rain scenario. For NNJ, it’s more likely rain less likely snow/ice but it doesn’t take much to slick untreated roads up for the extreme NWNJ elevations that might hang on to at/below freezing surface temperatures. The next signal I was monitoring was early next week (Monday-Wednesday Dec 20-22). The N and S streams of energy are modeled too far apart with very little interaction. I’ll be watching this signal in case it comes back. We’ll be propagating through a phase 7 MJO at this time which correlated to the transitional period. But once those systems depart to the E (by next Thursday), they will pull much colder air southward out of Canada over NJ. Christmas Eve through the rest of the year then looks colder with several wintry storm signals showing. That’s when we’ll be propagating through a phase 8 MJO with a strong blocking signal. Not much ridging is expected in the W US (-PNA) but the setup would allow for overrunning snow events to travel laterally from W to E across the US towards NJ. Let’s get through this next week and then see how the signals look.

Friday (Dec 17) high temperatures should reach the mid-to-upper 50s for most areas. Skies should be mixed with sun and clouds during the day. Rain chances should increase after sundown. Winds should be light out of the W/NW. Overnight lows should range from upper-30s to mid-40s from elevations to coasts.

Saturday (Dec 18) high temperatures should range from near-40 to near-50 from N to S. Skies should be mostly cloudy with periods of rain likely. Areas N of I-78, especially N of I-80/NW of I-287, could see some wintry precipitation mix in but snow accumulations are unlikely. Ice in the form of sleet or freezing rain would be a more probable form of wintry precipitation in NNJ/NWNJ. Otherwise, it looks like a mostly/all-rain event with above-freezing surface temperatures, especially for NENJ/CNJ/SNJ. Overnight temperatures should range from just above-freezing to lower-40s from N to S.

Sunday (Dec 19) high temperatures should max out in the 30s/40s statewide. A return to back towards normalcy for December in NJ. Skies should transition from mixed to mostly sunny. Winds should pick up in the morning and become breezy, even gusty at times, out of the NW. Overnight lows should fall into the 20s for most areas.

An early look at next week indicates slightly above average temperatures hanging on through about Thursday but not mild like today/this week was. Highs in the 40s lows in the 20s/30s type stuff (cold enough to support snow overnight). The early-mid week signal (just before Christmas) is still there but would need to improve more. Next Friday (Christmas Eve) and beyond then looks even colder (highs in the 30s lows in the teens/20s)…cold enough to support snow 24/7. Have a great weekend and please be safe! JC

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Jonathan Carr
By December 16, 2021 16:24