Wednesday, January 6, 2016

Wednesday Morning Weather Discussion: Enough Data to Make an Initial Call

Good morning and thanks for checking in. Over the last 24 hrs the signals have been loud and clear regarding the storm system late this weekend and early next week. Things have not trended in a winter direction and my call is that we have a storm that tracks inland. This is against the initial hunch I had where I thought the Polar Vortex would press more  causing things do develop more south. 

Lets take a quick look..



The image above is a projection of upper air energy from last nights GFS model. You can see three clear energy centers on this image. The first circled piece is an initial low pressure system that will tack into the Great Lakes this weekend. This storm causes the Jet Stream to kink upstream (behind it) which helps guide the second piece of energy over Texas more to the west. Now the key always was the third component, the polar vortex, which you can see on the top of the image edging its way into North Dakota. If this was positioned more to the Southeast then all the energy pieces under it would have been forced more south and east as well. This would have caused our second bigger storm system early next week to form more towards the coast along with pressing the first system more to the east.

Below shows the difference between an older run left images and the new run right images..




Notice on the old images to the left the circled vortex feature is pressing more southeast you can see how on the surface projections this causes the low pressure to form more south due to the cold air press. On the new image the vortex does not press as much and the storm develops more north and west.  

So there you go, I expected the press to trend and it did not. 

So now that we are 4-5 days out here is my  preliminary prediction..

A low pressure center forms in the western Gulf of Mexico and tracks right to west of the App Mountains through central or western PA on Sunday into Monday. Western PA and Western NY State may see some snow on the back end. Otherwise we got an old fashion rain storm on our hands here. I will tweak this forecast if necessary over the next few days. 

Oh course the bitter cold arctic air arrives after the storm as you can see below. The good news is this keeps us in the game for other snow opportunities. 



So as you guys can see getting a big storm is not easy but the good news is the pattern should be able to support more storm opportunities as we get through next week. Once this next round of cold air gets established we will monitor any disturbances that might interact with it. That includes middle to end of next week by the way. I know every snow lover wants to give up right now but I am telling you it is not time to do so. Remember we have 8 more solid weeks of winter ahead and a pattern that is not like we had back in December. Patience is key. When it is all said and done if nothing ends up happening my comments section is open for your commentary.

More later. 

4 comments:

  1. The Northeastern United States has been moderately dry since the summer, the only exception being around the holidays during which rain was recorded on each day. This is somewhat surprising for an El Nino winter, however, some speculate that the "cold blob" in the Atlantic may be responsible indirectly. I'm not sure how far-fetched this is or if there is any hard evidence for it. If there were more storms coming through, some would probably arrive during a cold outbreak and there would be a greater chance for more significant snow. However, we have been spoiled with cold and snowy winters over the last few years. That being said, there is still a ways to go before winter is over and nobody knows if we'll be surprised before it's all over.

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  2. Willie, I was just looking at the Atlantic SSTA chart -- so as the other commentator sez, there is a whole lot of cold water in the Atlantic between Greenland and Europe. But there's also quite a bit of (relatively) warm water off the northeastern coast, from Carolina on up. I was also looking at some 2-week model runs before, and the ground level temp charts show some incredible thermoclines between the coast and the inland mountains, including over NJ. By all rights, we should already be in a true winter pattern here, with the PNA, EPO, AO, NAO and MJO all favoring a deep cold trough over the coastline, all set for some El Nino moisture to be slammed into it via the Southern jet (although, there haven't been any strong "sudden strat. warming" events to really squish all of that unbound Arctic air southward -- perhaps because of reduced solar flux activity this winter?). So this relatively warm water hugging the Atlantic seaboard seems to keep the first 40 or 50 miles inland from getting too terribly frigid for more than a day or so. Is it also keeping the moisture flow out at sea . . . I mean, where are the Noreasters? I myself say don't trust any model runs past 120 hours, especially during winter. I will stipulate that forecasts change really quickly at this time of year. But for now, the models at best see maybe 2 or 3 inches on the ground by the 17th. Where the heck did all that warm-ish Atlantic water come from, why is it accumulating along our coast? El Nino was supposed to be the big driver, but it's starting to look like this local pool (wouldn't call it a "blob", it's mostly strung out along the coast) could play a big role in the weather for everywhere east of 287, or maybe even out to 94. Will it have staying power, like last year's blob in the NE Pacific? Most interesting, this whole weather thing. You never know when some new unanticipated pattern is gonna unfold and change everything. So yes, I agree, winter is still very much in play; even though things seem relatively calm for now, we are in a highly dynamic winter set-up, given how we are caught between a loose Arctic air mass above and a peaking but still strong El Nino below. Thus a whole new unanticipated pattern can come out of nowhere, and suddenly we're looking at 15 inches on the ground over the next 12 hours. Don't let your guard down, for sure! Jim G

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  3. All great commentary guys. This winter really will be a great case study. We have a strong el nino but bc of other ocean patterns like you mentioned, we are getting some unique responses. The warm water off atlantic coast will only help in developing the land sea temp contrast due to rising air in ocean and arctic air rushing in to fill the void. This has big implications for coastal storms. However notice I did have mixing issues for coastal areas in my winter outlook snowmap bc of this factor. The cold blog is good bc it helps drive the negative NAO which we are seeing unfold impressively right now. As this season gets to peak maturity I am very optimistic that we will get our snow. Then again, a great pattern doesn't guarantee that but it def increases our chances

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  4. My guess is that a zonal-flowing disturbance could bomb out right over us as it hits the big coastal thermocline. But a counter-clockwise Noreaster is going to be pushing ocean air over us, so you may then have to drive pretty far up Route 80 or 78 to see some real accumulation. Jim G

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