When will these quiet conditions end?

 I’ve been talking a lot about the polar vortex, currently the PV is relatively strong. Keeping the cold air and conditions trapped near the North Pole. But as I’ve been saying there are signs that a early season sudden stratospheric warming (SSW) event, will lead to a PV disruption; that would weaken the jet stream, sending Arctic air plunging into the lower latitudes, possibly into parts of North America. The stratospheric sudden warming can sometimes cause the jet stream to become kinked, and this tends to create a large area of blocking high pressure, which could lead to same very cold air for someone. The reasons for this are outlined in the winter outlook.

The northern Pacific jet has been very active, with a seemingly endless parade of storms slamming into Alaska. Currently Temperatures in Alaska Are fairly mild for this point in the season Running in the 20s and 30s. But temperatures over Siberia and Eurasia But temperatures over Siberia and Eurasia Are running very cold With temperatures running 15-25 ° below 0. That cold pack in Eurasia is going to continue to build; and at some point it's going to spill over into Alaska and then down into Canada and the US.

Over the next few weeks, we’re going to see the storm track move south allowing these storms to start impacting the western CONUS. Part of the reason for the shift south is the seasonal switch to winter, but the El Nino is also playing a big part in what we’re seeing. As I’ve been saying for several weeks, the sub-tropical- jet is starting to ramp up, as the El Nino conditions and atmospheric interaction continue to become more and more coupled; there will be a lot of changes in tropical heating which can strengthen and then shift the Pacific jet stream. So, the sub-tropical jet is going to become increasingly active. The influence of El Nino and the QBO and PDO is going to adjust the jet stream which will determine temperature and precipitation patterns over the CONUS and alters the track of winter storms. Over the next several weeks, the northern Jet is going to send troughs into the Plains, leading to more storms tracking over California and the southern United States. This is the type of pattern that we expect to see during a strong El Nino.

El Nino is strengthening rapidly, the latest weekly SST departures in the equatorial Pacific are: Nino 4-0.0ºC, Nino 3.4-2.5ºC, Nino 3-3.6ºC and Nino 1+2-4.4ºC

All of this is connected.

A low-pressure system will move out of Mexico and will move northeast into the Plains tomorrow into Saturday. Then this will move into the Southeast on Sunday. This is the first low that is enhanced by El Nino, as the waters of the Pacific are warmer, which causes more evaporation over the ocean giving storms more moisture.  This first storm is the opening act. On Sunday while this storm impacts the Southeast a second much bigger storm is going to move out of the Southern Rockies this will move into the Plains on Monday and then will be approaching the Upper Great Lakes on Tuesday. The storm is going to be pulling tropical moisture and Gulf air northward.  Behind this bigger storm, colder air will be pulled southward into the Rockies and Plains.

The Northeast

For the last couple of weeks, the weather not only in the Northeast but the entire eastern seaboard has been incredibly tranquil. Those tranquil continue are going to continue at least for the next few days, with high pressure in control. Today is going to become milder but will stay generally dry. We will have that low pressure system I talked about above in the Upper Great Lakes as it pushes into Canada, the leading warm front will be moving through the region on Thursday, allowing tomorrow to become much warmer than today. Tomorrow during the day will stay dry. Then a trailing cold front will drop in and move through Thursday evening into Friday. 

Those of Y’all who what to see rain, don’t hold your breath. The rain that comes from this will be sporadic and very hit and miss. Rain amounts will end up barely measurable if that! And not all of us will see any rain at all.  Those with the best chance of seeing limited rain will be across the northern parts of the region, with things generally falling apart as it drops farther south and east. Generally, any rain should be over by late morning early afternoon on Friday. High pressure builds back in with sunshine and dry conditions.  We will cool off a little be for the weekend, but it won’t be all that chilly.

For Halloween Saturday the Little ghosts, witches, ghouls and whatever, should have very calm and dry conditions for trick-or-treating.  The slight cool down won’t last. Remember we return to Standard Time on Sunday, so set your clocks back one hour Saturday night. Sunday will be more of the same with dry conditions and seasonal temperatures.  Monday will see high pressure move off the Coast.  We will be watching a slow-moving cold front approaching from the west.  Ahead of this we will become very mild for Tuesday.  Tuesday night into Wednesday morning the cold front will start to move into the region but then stall over New York State and northern New England.  Those northern parts of the region could see some rain, but the farther south and east you are the greater your chance to stay dry.  Generally next week is looking to stay fairly mild for this time of year, with another possible cool down for next weekend!

Back to the polar vortex 

OK what about the polar vortex? I’ve been talking about the PV weakening for several days. There is a chance a sudden stratospheric warming     could even reverse the flow of the PV, which would be the earliest SSW on record going back to the 50’s, which would split the vortex and maybe send down some of that locked up cold into Southeast Canada. Typically, it takes 10 to 14 days or so for the cold air to start to work its way down into our region (the split could impact Europe or Asia) so for now it’s a wait and see.  But the PV is currently bulging with part of that bulge pointed at eastern North America, so the odds do favor we get a piece of it if it splits. My feel of the pattern is telling me, the last part of November into early December is going to get cold with a good chance for winter snow to be falling over parts of our region.   

With the subtropical jet becoming supercharged and becoming very active, the entire Atlantic seaboard will likely get heavier precipitation this winter.