A Runner, A Gunner and the GFS folds-- No Stunner

My son is napping so a quick update---

Mid day model update--

GGEM (and the NAM extracted) go negative tilt to early and chung the the low as an inland runner. 
This would be a driving rain storm with maybe a little snow to start and maybe a little snow to end.

Inland Runner-- 

Note on the top image that low pressure is in WESTERN NC-- That's not a good snow track for us. Once the low passes to our east the upper air support COULD support some snow, but those don't always work out as modeled. 

The 12Z ECMWF slide a little east and is basically just concentrates all the precipitation on the coast. The precip maps are the least reliable feature, but it does bring caution at this point. The inch line of precipt is from near Raleigh, NC to RIC to DOVER DE-- Well to our east. Guns those areas with a little spill over to our region. Taken literal, about a quarter inch of liquid that falls as snow.  

In what is NO STUNNER, the GFS moves away from the Miller B ( Storm forms off the coast rather then rides out of the Gulf of Mexico) It is now a Miller A that rides the coast from the Gulf of Mexico, but matches the EC with not much moisture in our area. Actually, much less and once it reaches near Cape Hatteras it goes out to sea. 

Miller A -- grazes our area. This run looked great until about hour 90.

I am concerned about the low level warmth displayed on the models, even the ones that offer some snow. Usually, its safe to assume that the models are too warm a the lowest levels, but most of our grandparents had a nice catchy phrase about ASSumptions. 

My plan is to view the evening data and have some type of update tomorrow AM-- things SHOULD become a little clearer at that time.

Happy 24th Birthday to the Twin Big snows of 87-- Could we celebrate with repeat?

January 87 was on of the "analog" winters I cited last year for my winter forecast(Winter 09-10) and it actually worked well. Most of the snow that winter was centered around the time period of Jan 22 until Feb 22 for our region. Jan 22 and Jan 25-26 had back to back snows of close to a foot over most of central and southwest Virginia.

I'm not sure how the event was forecast down here because at the time I was living in Delaware. Up there, they played catch up all day. Initially, we had a Winter Storm watch-- but the forecast called for 1-2 inches with a change to rain. By my bedtime, we had been upgraded to WARNING with 4 inches expected and then a change to sleet and rain. The next morning, the ante was upped right before the storm started to 6-8 inches with a possible mix and once the storm started that was upped to 8-10 inches. About the time we hit the 8 inch mark, they upped us to  foot. Schools were not cancelled and snow begin to fall shortly before my bus arrived. We basically sat in first period while they decided what to do with us and by 10 am we were on the bus home. Took us a couple hours to get home ( I lived 3 miles from my school and had the LAST stop of the day) In Delaware we had a couple sleet pellets late, but nothing to hold down accumulations.  Both Lynchburg and New Castle, DE had about 12.5 inches from this event.

Lynchburg had 3 hours of VERY heavy snow where 5 inches fell in that time frame--- Here is the total snowfall map AND the hour obs for the day here locally. Most places had between 12-15 inches because it was a fast mover. Click the second map to increase size--I've highlighted the hours where snow was heaviest and 5 inches fell in three hours.

About Next Week--

I'm still tracking an event for the the 25 and 26 of next week (To celebrate our second of the Twin Storms of 87??) There are three major models that extend that far, one is the GFS-- an american model, The second is the GGEM, from Canada and third is the ECMWF, from Europe. 

The Breakdown-

Both the GGEM and the ECMWF dive some energy from the PAC NW of Canada, dump a little over the SW and bring it all out to create a storm in the Gulf of Mexico. Same issues sit as yesterday where the cold high is retreating but the low chugs JUST far enough east in todays data to provide a mainly snow episode compared to yesterdays snow to rain and back to snow scenario. 

The GFS doesn't dig that energy as far SW befor ejecting it and we get a Miller B system ( Miller A- Storm out of the Gulf of Mexico, Miller B has a secondary development of the East coast. Historically, most of big snows are Miller A's. We get the all snow, maybe 2-3 inches in the GFS scenario. While this is an option I'm not willing to pull off the table, I don't see as the most likely outcome. Even the short term model called the NAM that goes out to 84 hours shows a much different synoptic set up compared to the GFS. In the end, someone's going to be wrong, and at this time I believe it will be the GFS. The GFS ensembles ( The model run multiple times to weed out bias issues) also "hedge" that this is not the most likely set up. 

What's Next

Once we establish the general track, we begin to focus on the fine details of the temperatures and exact track to see if and when what area's turn to ice/rain. Because the existing cold air mass is rather strong, ice is a much bigger threat than normal. While I much prefer to have a forecast nailed down, this could come down to "nowcasting"-- checking radar and obs. In preparation, add me as a friend on Facebook (Ketih D. Huffman) or make a twitter account Lynchburgwx. 

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)