Friday, January 13, 2017

Friday Morning Pattern Discussion: Warming Up...For Now

Good morning everyone. Today we will talk about the next 10 days and beyond and what the weather might bring. There are certainty changes going on right now that will shift us to an overall milder pattern over at least the next 10 days (exception of this weekend). There then is building evidence that things start to turn back to winter again as we approach the last week of January into February. Lets take a look...

Summary:


  • Temperatures fall today and stay cold for the weekend.
    • Highs in the 30's for many spots
  • There is the chance for some light snow tomorrow with light accumulations <1"
  • As we head into next week things start to warm up by Tuesday.
  • This milder pattern should hold till at least the end of the following week
    • Expect temperatures in the 40's and 50's for this time period with chances at rain
  • As we enter the end of January signals from the models, stratosphere and pacific suggest winter makes a return to the east
    • The magnitude of this remains to be seen
Cold air moves in and light snow spreads across the region tomorrow...


The cold air holds until Tuesday when a warm front crosses our area. This marks the start of the milder pattern I am talking about. You can see this pattern is characterized by a trough of low pressure to the west and a ridge of high pressure in the east. Notice the low pressures over Alaska. This prevents arctic air from surging into the country..


As we then get towards the 10 day + period, evidence is building that we see this pattern start to shift back to cold and stormy for the east. That ridge of high pressure over the east could migrate to the west allowing storminess to form under it as seen by long range models below...


Remember this is a long range model which can be very volatile but putting a trough south of the Aleutian islands of Ak really helps pump up a ridge in the west and trough in the east which supports a stormy pattern. The model is hinting at this. 

We also are getting support from the stratosphere which has about a 2 to 3 week lag in effecting what happens at the lower levels of the atmosphere. You can see below that way up in the stratosphere there are projections that things can really warm up. This puts stress on the polar vortex and can lead to increased chances at cold. Notice how the vortex is getting stretched out and weakened. This is called a wave 1 response.  If it were to split, well then that would be even more impressive. We need to monitor this.

Generally what you see above can make its way into the lower atmosphere eventually.  Just looking at this alone is pretty impressive. This is a very strong signal for our upcoming mild pattern to erode as we head into the heart of winter (February into 1st week of March). 

Also, we have a pattern in the tropical pacific called the MJO that is projected to move into a favorable position towards the end of January. The MJO is an area of tropical convection that migrates into different areas of the tropical pacific. Based on where it goes influences the jet stream and in response our weather.  Models are projecting it can move into a phase that supports this pattern..


Remember this is similar what long range model showed seen again below..



So we never know exactly what the weather will do but we can build a case as to where we think it can go. Based on the factors I outlined above I would not be calling winter off due to this upcoming mild spell. In fact we might just be getting started as we enter Feb. Of course I do have a bias because I love cold and snow but I have some major atmospheric factors along with model support on my side. Now we just have to see how this plays out. If things do not turn well then that's just how the weather is sometimes.

4 comments:

  1. Thanks for all the time you put into this, your passion and knowledge of meteorology really shows. I really appreciate your explanations and feel like I learn a little
    more about the factors that go into your forcasts each time I check in-which is pretty much a daily occurrence during the winter as I am in the snow services business.

    Thanks,

    John from South Jersey

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    1. Thanks John! I appreciate the kind words.

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  2. Thanks Willy. Hard to believe we'll be pulling into February without a major snowstorm. This winter has certainly been wet enough, but it's been so warm for most of it. We'll see what Feb & March bring - or even April - I remember we got about 7" here in central NJ about 10 years ago on April 7th or so. I'd hate to go into spring without at least on or two more snow events (at least more than 2-3"). Thanks for putting the time in.

    Craig in Piscataway

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    1. Craig- I agree, so far it has not been impressive. Very wet with a periods of cold but nothing that locked in. Winter certainty can be back end loaded and I always like to think of the 2nd week of March as the cutoff. Of course there are exceptions like late March or April snows as you mentioned but its hard to bank on that. If we can hit the ground in the 1st week of February running then we might have the shot at a nice storm or at least a few moderate events. That would still give us a shot to hit average or above average snowfall. I love what I see on the models but again its also what mother nature wants to do. Models are just projections so we need to just wait and see. Im keeping my fingers crossed. Thanks for reading.

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