February Looks Active As a Western Ridge Maintains In the Means

The last week or so has been dominated by chaotic modeling in the longer time frames and now they are starting to correct themselves.  Overall my long range synoptic pattern recognition was toward a rebuilding of the western ridge, linking with the Alaskan Block, and producing eventual cross polar flow and downstream below normal temps across most of the central and eastern US, and I still think that. So far though, there’s no strong signs of a hugely Amplified flow to deliver severe cold into the Southeast anytime soon–however, offsetting that may be eventually one or more of the active waves can attach to a lobe of the Polar Vortex, or a piece of it in mid February such that we do have  a severe cold attack, following a Winter storm.

I’ll bypass the minor event of tonight and Tuesday in the Apps and part of Virginia since I covered that in last update. On to the more important story that begins with the first of many, many, many diving waves in the eastern mean trough. The first will bring rain to snow in Kentucky to northern and eastern Tennessee Thursday night and across much of Virginia Friday, but this looks relatively weak and fast moving. I will do a snow map though in next update to outline impact areas-but this looks weaker each run. Probably at the expense of the buffet of waves waiting in the wings.

Which brings us to that, and how those waves are going to dominate February I think.  Its’ important NOT to focus on modeling of any specific wave, as that will certainly change and the models will bounce around with which one to amplify the most, leaving the next one or the preceding one to be more strung out. Could one be a major Winter storm in the MidSouth or even Deep South in February? Odds are one or more will.  We’ve seen this exact flow before.

Watch on the CFS as week 2 goes into week 3 and the ridge builds in the means, taller with time. The action actually begins before this time frame though, but we’ll keep on seeing storms and rumors of storms throughout February most likely. I’m not saying there can’t be a warm period of a few days in between storms though, since the PV or part of it may drag into eastern Canada, but it will quickly get cold again as the reservoir of cold air always comes across the North Pole and spins around in most of central Canada and the northern United States this month, as “spokes” of cold air rotate and wobble through the central and eastern US, particularly following storms.

A flow pattern with anomalies like above is shown on GFS and Euro as well (Euro has really been chaotic run to run and playing catch up I think, if you’re following modeliing) This flow would be overall colder than average in the central and especially eastern US with near average cold most of the time in the Deep South. There’s room for some waffling at times based on the large surface Arctic Highs that continuously get produced–and this is one of the more interesting parts of the month…..all those large surface highs pressing down to the tune of 1045, 1050, and even higher.Some Winters we may get one period with a 1045 mb high, if that. This Winter appears to be record breaking going from my memory of most Winters recently, perhaps the late 70s had an equal number or so. The flow is perfectly setup to deliver the big highs. And so far, in this upcoming setup, they aren’t expected to push bodily into the Southeast just yet thanks to an influx of so many southern waves that around poised to roll under the bowl shaped trough in the lower 48 states I’ve been speaking of. That may be a good thing if you’re hunting for a Winter storm, as you’ll recall how often is was cold, but dry in late December and first half of January, with suppressed highs.  We have more opportunities for precip makers in this kind of flow, unless and until that tall western ridge matures in mid February and begins to deliver a very cold pattern to the South. We’ll have to wait and see.

The flow is set to begin to deliver wave action rolling over the western ridge and diving into the Eastern or central trough as early as Sunday.  But once again , don’t focus on any particular wave just yet, since any of them can either dig or minor out for a plethora of reasons. Not all of them will make it into anything substantial and models at this time range will probably focus on the wrong ones, and the locations are bound to change–we simply can’t trust them yet. Only the mean ridges and troughs may be trusted more and more now.

Day 6:  Possible system in Mid South with snow and mixed to the north of the low pressure or overrunning. Where this is will have to wait. Right now, its only a possibility but is shown to some degree on most globals now and we’re within 7 days.

GFS carries this basic ridge/trough couplet through time and matures it, as this is a pretty stable pattern (and one we are familiar with this Winter and the Winter of 13/14 and 14/15)

Day 10:

Day 12:

 

Its hard to ignore that massive ridging in the means, but the models are certainly struggling with the depth of the trough downstream each run. Some runs of GFS are quite cold and cross polar, some are average cold. Some runs of Euro and GFS and GGEM also had the main cold rolling under the Alaskan block for  atime,but that seems unlikely now, and instead more likely will be the Alaskan block setting up basic Cross Polar Flow and sending spokes of cold to rotate through the mean trough in the lower 48. Just how cold, its uncertain. None really show the Arctic Blasts we had yet anytime soon. I think possibly because there are simply so many waves in the Pacific that are slated to under cut the bowl shaped trough and none of them are tremendous blockbusters yet on modeling, which means they dont phase or fully pull down massive cold advection following storms. That may be an error and of course we may see things change toward a much colder blast in mid February or late month (I’d be inclined to think one system likely can do that especially when the tall western ridge “tips” inland.  We’ll take it day by day and see.  It should be active though with minor to moderate systems rolling anywhere between the Central Rockies to Texas to Gulf States and MidAtlantic.  Already, GFS is showing the most Gulf Lows I’ve seen in a while, just a testament to how many waves there are in the flow–beating out most Nino Winters recently (when you’d expect Gulf lows).  Some of these waves may be closed upper lows–If So Watch out! We’re approaching that time of year for those upper lows to be more powerful, and we’ve already seen what moderate upper lows can do (recently in NC, VA) and early January (blizzard east Coast) and early December in the Deep South. Nina’s seem to deliver upper lows often, and this time we may have more cold air than most Winters available, so that’s one reason I’m confident of more Winter Storms to come to the Southeast and MidAtlantic in February.

Here are some waves according to the GFS going from this Thursday until mid February. About 5 or 6 of them are shown, each with a chance at some precip in the Southeast. Not all will be real I think, But with this many shown, it’s obvious we’re entering an active pattern and one that has to be watched. Nothing like last Winter at all.