Crazy night on the models-- MONSTER low possible.

First issue-- I never updated this blog for the "snow threat" last night because I was never impressed with this storm. In a perfect world for snow lovers, we could have gotten a trace, but it never looked good. I'm always available via facebook if any questions do arise. (Keith D. Huffman, if your reading this via a friend)

We do have a legit storm to track-- and even if it ends up as rain the rain is WELL needed. This evening the models all showed a great consolidation of 500mb energy and create a MONSTER of a storm. However, the storm is just a SMIDGE west and for LYH east, its snow (couple inches) to heavy rain, ending as snow. (Maybe another couple inches)

Rain?? Yes--This storm could be an 1-81 special where all of 1-81 in VA gets SMOKED. Tonight's literal data showed about 18 inches or more along 81 and it drops off rapidly east of there due to mixing with and changing to rain.

Why- We have a great cold air mass in place, but it is leaving just as the storm approaches. This creates two issues. First, we are losing the cold air support and secondly, this is more conducive to a low that tracks JUST inland.

Looking at the above map-- If the H noted just east of Maine was sitting back 300 miles to the west, we'd have an all snow set up. As that H has been moving east, the cold air is also moving out. 

This is a VERY wet system. 

A region wide 1-2 inches of precipitation.



Note: Nothing is in stone yet and much can change as we watch this storm evolve.

So, this is something to track. 5 days away so plenty can and will change. The data takes the low from near Myrtle Beach to literally just on top of us.  Reality is that it could be 100 miles either side of that line and that the thermal profiles could be a few degrees off either way as well. So, the next couple days we work on track and exact temps. Lastly, if the energy aloft (500mb or 18k feet) doesn't phase or work together, we have a low but much weaker.

Teaser- Tonights ECMWF was all snow in Roanoke and 15+ inches. In LYH, it starts as snow and just about the time it gets really heavy it mixes with and changes to rain. 2-4 inches has already fallen. Rain is heavy and water is logging down the snow Almost an inch of rain falls during this time period. While the change to rain was a slower process, the switch to back to snow comes with rapid force and snows heavy. Temps are just above freezing and the snow struggles to accumulate at first. Another 2-4 inches falls on the back side. Temps slowly drop and as it ends in flurries, we are at 30 degrees and drop into the mid 20's Wednesday night. The slushy mess freezes into skating rink.

A little ice overnight-- Watching Friday for the next event.

A pretty moist storm system is developing just to our south and will move up the coast. Because another system is to our west providing warming aloft, we won't see a major ice or snow out of this. However, with a colder air mass in place, the system will have some sleet and freezing rain overnight-and actually maybe  a flurries late day and early evening. Temps will be very close to freezing and it should not be a big deal. However, if the temps are just a smidge colder, we could have more of a rush hour mess tomorrow morning.

Another cold front sweeps across the region Friday and a storm is forecast to form along this front as it passes our region. Exact time, track and amount of cold air are still in question. I'm not as "sold" as I was on this now compared to 2 days ago. As always, updates come as needed.

The cold seems to bend, but just won't break..

As discussed in my early morning Friday blog, we were forced to accept the second half of the winter warm up predicted in my seasonal outlook won't pan out. And while the models have hedged at some warmer days compared to the minus -9 average from December the overall outlook was cold.

We have an event on tap for late Monday into Tuesday. Data is still not clear, but 2 systems approach our region-- one well to the north, and one down along the gulf. There is a MINOR amount of cold air remaining in our region from this cold stretch and depending on the amount of moisture that get into the area will determine the total impact.

Event 1.

Late Monday night, A mix of sleet and freezing rain will develop and eventually change over to rain. Tough forecast-- the models have shown anything from next to nothing all together, to 2-3 inches of snow and sleet to freezing rain, to just a good soaking rain. As of now, I think we get a little sleet to start, several hours of light freezing rain changing to rain near dawn on Tuesday. Southside may be spared most of the ice threat while the NRV could start as a little snow.


Event 2.
Another arctic air mass approaches late next week near the time a low pressure forms in the gulf. As of now, the cold air lags JUST behind the storm, so the air in front could be a little to warm, especially east of the Blue Ridge. This could end being an I-81 special where the elevated regions to our west get a decent snow and we get a messy mix or just rain. Cold air fills the region after this. 

From here-- it seems the cold bends for a few days, never breaks and remain cooler then normal on average. Behind the system now COULD be some of the coldest air of the season. 

Mid Term Grades-- The Good, the Bad and the Ugly

Well, the half of winter is just now on the books--

First, quick updated about the earlier snow. My 1-3 inch call was a little too aggressive and we did have a longer period of freezing drizzle than first anticipated. My great intentions of updated the blog went under. If you read this and do not have me as a friend on Facebook, please add me as I will stream updates on there or add me on your twitter account.

Despite December coming in as record cold-- we are heading towards a pattern breakdown for a while. IF, the pattern would remain warm, my season outlook would be pretty good despite all things. (but it won't)

The good-- The cold pattern developed late in November as anticipated and lasted all month in December. Mid January the pattern has broken down,. As foretasted, it has been dry with no major snow events. The December 16th event has been our largest snowfall of the season. My snowfall outlooks have verified well, all within, even if just barely the range allotted. ( December 16 was a 3-6 inch call with 3 inches and 2.2 for a 2-4 for Christmas day.

The Bad-- While getting the general idea for a cold December right makes me happy, the pattern was much more amplified than I first anticipated. Much more is code for record setting amplified.  My thoughts of a HISTORIC cold outlook from 10 days ago looks really bad. Yes, its been colder than normal but nothing historic.

The Ugly-- Nothing remotely close to a pattern that resembles ice threats, much more intense blocking. Also, while the pattern is shifting, I doubt the cold is mostly gone for the winter.

From this point forward-

We have a rain threat Monday with MAYBE a little sleet or freezing rain in the front side.*Nothing major* Something called the PNA spikes (PNA is a ridge over the west coast). This brings a colder pattern to the east, but NOTHING to lock in cold air or slow down a storm.

Something called a "Sudden Stratospheric Warming" is linked to a -AO -- and one of those could be in the works (I'm no expert in the this process, just know the impact, here is a wiki link of you want to read more http://en.wikipedia.org/wiki/Sudden_stratospheric_warming  ). What this COULD mean is a return to the stronger blocking we had in December. I've not noted the updated information from this, but this usually takes a few sides of 10 days to  re establish the colder pattern. The bottom line is it weakens the polar vortex. When the polar vortex is weaker or in several smaller pieces it allows for blocking to dominate.

Moving forward, My guess is that the first half of my winter outlook is going to be MUCH better than the remainder. It does seem like this will be a more intense winter cold wise and the snow card has basically 8 viable weeks to play out somehow seems bleak to verify with a 5-10 inch allowance I predicted.. La Nina winters are NOT known for historic events, and yet we've had 2 on the east coast--- the Boxing day event and this past Sunday to Wednesday event that just slide past our region with a minor dusting. We've officially clocked 7.4 inches this winter in Lynchburg and I expect this to increase. Putting aside the dry nature of this winter, the overall pattern has been NOTHING like a La Nina and there are not many signs that this will end anytime soon, just breaks.

One of the points of my outlook was that seasonal pattern changes often weaken and mute the impact of La Nina's. If we get a Sudden Stratospheric Warming-- the impact would likely be the first 2 weeks of February. At that point, the long wave pattern  is starting to make the seasonal change to spring and the impact of La Nina is drastically dropped.  So, I'm hedging colder overall for the remainder of the winter, just not as cold as December. Snowfall hasn't been hard to come by--but hasn't been anything significant. My guess is that we could move the seasonal total is more like 10-15 inches this winter rather than the 5-10 forecast.

Big Snows South, Big Snow north-- with a little in the Middle--

And, we live in the middle.

The storm appears to be developing as I expected--with big snow totals over much of the deep south. My college city of Chattanooga, TN COULD get 10 inches.

This storm weakens and drys out as it approaches our region. Among the reasons, DRY DRY air-- temps between 5k and 10k feet are at -10 c with dewpoints BELOW -30. So, we could have snow aloft (Virga) for 12 hours or so-- plus the systems upper air support is dying out-- the moisture transport from the Gulf of Mexico is gone.

Next-- Energy diving in from the Pacific NW tracks just to NW and invigorates our storm JUST north of our region. My home base growing up of the New Castle, DE and Chadds Ford, PA region look to get maybe 6-10 inches while NYC to Boston look to get a foot.

Region precipitation map- note how it swings around most of the VA region.

Our region--

NRV and Southside- 2-4 inches. Southside may get a little freezing drizzle for a period as well.

ROA to LYH-- 1-3 inches.

My guess as of now-- 2.2 inches for Lynchburg.

We are going to monitor trends, sometimes when you have extreme dry air in place and the best moisture intersects the best lift-- no more moisture falls, but the flakes are well constructed (Dendrites) and you can get better snow ratios. our Jan 30th 12 inch event-- this happened last year up near DC. This could mean an extra inch tapped on this storm. (DCA has 6.2 inches of snow reported from 1.3 of liquid. I imagine the liquid is under done, but the it was a 25-1 ratio-- I checked Wilmington, DE and they had 4.3 inches from .20 liquid)

Storm on track-- Cold more cool, not bitter. **Edit to add photo**

I must say that I just hate this storm coming our way-- so many good things about it that simply can't deliver for many reasons.

A strong southern short wave spins a storm up in Texas and it heads east, However, the block causes this energy to dampen out and the storm loses its punch at our doorstep. A second piece of energy swoopes down from the Pacific Northwest and regenerates the storm-- but its just a little too late for our region.

As of now, I'd predict 1-3 inches from late Monday into early Tuesday.

We are very cold for a couple days after that, and then get a brief warm up before another arctic surge.

Map from the HPC--- precipitation outlook. Note the minimum over most of our region. The Southern low dies our, it meanders off shore, to be energized JUST to our north. The ridge out west isn't large enough to cause any digging of the second piece of energy to drive it more south. Looks like a DECENT event in Philly and a LARGE event for NYC to Boston.

Next update Sunday afternoon.

Complicated snow event possible-- Cold still coming

The cold is still on tap as discussed in my last blog. As usual, the extreme version won't be as likely-- much much colder then normal, but some of the cold trickles into the pacific northwest and the core of the cold sits in NW Canada sending pieces down towards our region. Doubt we get below zero unless we get a quite the snowfall but lows and highs both average 6-12 degrees below normal for the next 10 days. The warm days will reach 40 at best and the cold days will struggle to reach freezing. For a reference point-- the average high for this time of year is about 44 and the average low is 25.

Snow wise--

As an arctic front drops through today-- a piece of vorticity swings to our south and and could bring some flurries or even a dusting of snow. Places along i40 in NC could see a couple inches from this event.

The Big Show is far from decided.

Set up- Cold air settles over the region and a strong shortwave heads east from the south Cali coast. Low pressure forms over the deep south and heads east. Because of the strong block over the NE--this original short wave gets sheared out and our low doesn't deepen and loses the moisture transport from the Gulf of Mexico. As a result, what was putting down over an inch of liquid over the TX to GA areas is suddenly very dry.

A second short wave races east from the Pacific northwest and at some point re-energizes the storm.The quicker this happens, the bigger of a storm we get.

How much snow is possible?
If its a smidge late-- we get a 1-2 inch snowfall.
If its a tad faster- 2-5 inch snowfall.

I'm not willing to commit either way at this time. Both pieces of energy are just coming ashore on the west coast and as they get close with better sampling data for the computer models, we should have a better handle on this.