Weekend: Continued cold with less wind and sunshine. Some surprise snow flurries from Philly north and east on Saturday. Temps will be colder than NWS forecasts. Could this be the setup for the next storm? The analysis and summary for the weekend storm event is at the bottom of this post.
HISTORY SHOWS THAT IT OFTEN REPEATS ITSELF
It is important for powderhounds to understand the large-scale climatological factors which lead to big winter storms. Believe it or not, air pressure trends in the SOUTHERN hemisphere have a big impact on what happens way up here in the NORTHERN hemisphere. One such factor is called the "Southern Oscillation Index" and it is similar to the NAO.
December 2002 -2.4 / January 2003 -.6 / February 2003 -2.0 / March 2003 -1.6
This winter featured a kickoff snowstorm on December 5-6, a series of ice storms in January, the February Blizzard, and March roared in like a frozen lion with the coldest air of the season. I remember because I was in Vermont on that day, and even locals up there said it was very cold for March. The punchline...the SOI tanked in December, and again in February.
December 1992 -1.4 / January 1993 -2.0 / February 1993 -2.1 / March 1993 -1.8
I remember like yesterday the Dec 10, 1992 storm in State College, PA as I was riding my bike down a snow-covered road to the bus station, with 12-20 inches falling on that day. In Maryland, it was just rain. The rest of the winter was uneventful, until the famous Superstorm of March 11-13, secured in history as the "Storm of the Century."
December 1986 -3.0 / January 1987 -1.5 / February 1987 -3.1 / March 1987 -3.3
This was a classic winter of my younger days, as we had storm after storm from January to March. I remember it distinctly, especially March because I was on the spring track team at my high school and the brutal west winds of training blew in my face day after day.
December 1982 -4.6 / January 1983 -6.9 / February 1983 -7.6 / March 1983 -5.6
Another cold, stormy winter that led to a great big Northeast Blizzard on February 11, followed by a very cold March.
December 1977 -2.3 / January 1978 -.7 / February 1978 -5.7 / March 1978 -1.8
This is a memorable winter for New Englanders...highlighted by the all time snow record on February 6, 1978 in Boston. The tell-tale sign was there, a negative SOI in December, followed by another tanking in February...leading to a cold, stormy end to winter.
December 1965 0.0 / January 1966 -2.8 / February 1966 -1.1 / March 1966 -2.8
This winter was before my time, but I have done enough research into storms to know that the February 1996 Blizzard was a huge event for the Northeast. All I have to say to any of my parents, grandparents or "seasoned teachers" is say... "tell me about the February 66 Storm" and they go to town with the stories. Granted the SOI indicator was not as revealing, since it was flat neutral in December, and then more negative in January.
WHAT DOES IT ALL MEAN?
The Southern Oscillation Index can also be considered the fingerprints on the smoking gun. Either we are in for another March 1993 type megastorm, or this will be the first anomaly winter in 50 years of record-keeping which did not produce a giant storm with a strongly negative SOI and NAO.
NEXT, ANALYSIS OF WEEKEND STORM POTENTIAL
Compare January’s pattern to how February has shaped up thus far. January started with temps way above normal for much of the east, then around the 15th, trended much colder and the month ended overall below normal temperature-wise. The kickoff to all this was the big Jan 22 storm, but then the snow events which followed got weaker, more disappointing, until snow just gave up all together as we limped into February. Now that you are past Valentine’s Day, and the heartache of getting this far along in winter still desperate for snow, there are some signs that a heart needs a second chance.
When there are big pattern changes on the horizon, the GFS (the Global Forecast System run by NOAA’s supercomputers in Silver Spring, MD) has a hard time picking out the change. Once we are well into the pattern, it can and often does nail storms one after another. Notice how the forecasts for Wednesday are pretty much in line with what is happening? Unlike last week at this time, where everyone was all over the place, because the GFS, NAM and other models could not sniff out how the pattern change was affecting the storm evolution. Now that we are late in the current warm pattern about to end, the GFS is batting .500. When the pattern shifts starting today, then you will witness a return to the waffling NWS forecasts leading up to the next storm late in the weekend.
I believe powderhounds are going to get a second chance for snow by Monday. The storm that is being advertised by the European, the UKMET and a few other models has the look of the February 2003 Blizzard, but not the feel of it. The analysis of this situation is a one-two-three wind up:
ONE: Front sweeps to the east today, ushering in much colder air. Snow in northern PA, central NY, northern New England helps to replenish the snowpack. This is a key item needed for the next storm.
TWO: A big Arctic high moves in behind the front over the next 2 days, and dominates the weather for much of the eastern ½ of the country into the weekend. NWS has been trending their Friday temperatures downward all week in anticipation of the GFS not initializing in it’s data stream the affect of recent snowcover on surface temperatures. Thus Friday will be a crisp and cold day heading into the President’s holiday weekend.
THREE: A strong El Nino-enhanced system in California will head east, and travel along the southern fringes of a new high heading southeast from Canada thanks to the negative NAO and positive PNA which tends to create a northwesterly flow of air from northern Canada to the Northeast U.S. The Icelandic Low has moved west to near Hudson Bay (hence the negative trend), and the Azores High is poking into the Polar regions over Greenland. This setup is called mid-latitude blocking and it is crucial to get a snowstorm on the East Coast.
NOW HERE’S THE PITCH: The timing of a few key elements on Sunday-Monday will make the difference in DC, Baltimore and Philly between 3-6” of snow and then a changeover to rain OR 6-12” of snow because the changeover never happened. If you want me to make an early call on accumulations in the I-95 big cities and their suburbs, the best I can tell you right now is 3 to 12 inches, which is ridiculous. Reminds me of last week when George in New England asked if he should prepare for anything from 3” to 36” Instead of telling him 36, I should have said 3. The pitch for a qualifying snowstorm worthy of our attention will come if I see these elements coming together:
A. The Arctic High on Sunday-Monday begins to show staying power and ends up taking a “banana like” orientation. This means the eastern portion of the high extends out into the Atlantic, the central portion is over upstate New York, and the western portion angles toward the Great Lakes. The end result is a High shaped like a Banana in a sense. This slows forward motion of the approaching Low, and the fresh cold air causes the storm to squeeze out a lot more moisture than originally anticipated due to higher liquid to snow ratios.
B. The storm coming out of California and heading towards the Northeast is going to go on what we call at Cub Scout camp a “Wild Cheese Moose Hunt” While hunting for the wild cheese moose, our fearless hunter encounters a series of large obstacles, such as a big lake, mountain, forest or other natural feature. Each time the hunter reaches the obstacle… we say, “BIIGGGG Lake, WIDE lake. Can’t go UNDER lake, can’t go AROUND lake… GO THROUGH LAKE!” And then all the cubbies simulate sloshing through the lake.
It is the same deal with our Cali-Plains-Northeast storm. With a giant Arctic high in the way, the storm can’t go AROUND the high, can’t go OVER the high… so it must GO THROUGH HIGH!” This of course is ludicrous, because storm’s can’t cut through highs.
The compromise will be one of two possibilities… the storm takes an amazingly sharp left turn, cuts up through the lakes (in the face of a negative NAO and the polar vortex sitting over Hudson Bay), and then goes somewhere up there. Yeah, okay. Believe that if you will and you’ve just read the idea put out by the GFS. The other and more likely outcome is the storm begins encountering the BIG HIGH by the time it reaches the Ohio Valley. This will undoubtedly sap the storm of strength, and taking the path of least pressure resistance, like a student trying to finagle their way out of homework, the storm takes a more southerly track and a secondary Low develops near the Virginia or Del-Mar-Va Coast. This is similar to what happened with the Feb 2003 Blizzard, but this storm does not have the same feel as that one.
SO WHAT’S THE BOTTOM LINE WITH THIS STORM?
When I see those two elements coming together, or not, then I can make a definitive call on this storm. When will I know this? Probably not until Saturday, once we see from observations how strong the second high is and the rate of it’s movement. I am not waiting for the models to give me signs, I want to see what the actual observations will be.
SUNDAY: I expect the Laws of Physics to rule the day, and cause the Western system to not only slow down and take a more southerly track from the Rockies to the southern plains. I also think the High will not retreat as quickly, preventing the storm from cutting up to the Lakes.
MONDAY: In response to the high and the intensely negative NAO by that time (which I will be watching like a hawk) , a secondary will develop around Virginia, and slowly move out to sea. The first phase of snow from the primary storm will toss out a couple inches over the Mid-Atlantic Monday morning, and then the secondary gets going, and throws back a few more inches. The NAO is forecasted to be almost 4 deviations negative from baseline. That is about as low as you can go... which means something wicked this way comes.
IS THIS THE BIG KAHUNA # 2 ? Most likely not. This is the corrective action the atmosphere has to go through to get the physics in place for a bigger storm. We need extensive snowcover in the Northeast to keep the atmosphere chilled so that when a new High arrives, it will be enhanced and strengthened by this.
WILL THERE BE A K2 OR ARE YOU JUST BLUFFING? Yes, I believe winter’s last stand will be in the 10-25 day period from February 25 to March 15. There are some rumblings of another storm in the Feb 25-27 time frame. But it will be in this 15-20 day period when I think the Northeast and Mid-Atlantic finally get their much overdue storm. Given the trends of the SOI, it could be a very significant event. Those of you with snowblowers, you will have had all winter to get that puppy ready in the event this final round goes out with a real bang. Looking ahead to the transition period from winter into spring, I also believe that whatever snow occurs in the next 2 storms will be it for the winter my fellow powderhounds. An increasing sun angle, already above normal water temps in the Gulf of Mexico, and a probable early ignition of the Bermuda High engine due to the expansive below normal water off Florida’s east coast means that winter will be unsuccessful in striking back with snow anytime after March 15.
WHAT DOES THIS MEAN FOR SPRING? The problem I see is that the normal climatological cold budget may end up underspent as spring begins. What that means is a real battle will be shaping up for the mid-March to early May period as instead of a nice easy slide into warmer weather, we get these competing air masses which are more extreme than usual. Just when you are ready to start gardening, it turns cold again, threatening the new plants. Then all of a sudden it gets hot, and seems like spring was overlooked, that old winter to summer situation we’ve seen before. This is the price we will pay for an abnormally warm December and two other warm spells.
I am preparing to return the comments in the next couple days, hopefully by the weekend, so you all have the opportunity to participate in the discussion about winter's last stand.