Tuesday Night and Wednesday Snowstorm ideas.

First- Always remember if I saw or show what a model does, it doesn't mean it will happen. It also doesn't mean that is my forecast.  Maybe I was careless with my words about the Euro run Friday and it seemed some people may have ran with this as my forecast. I don't run with one model, I blend some model runs with added knowledge about our local climate and past events. When I make a forecast, it will be clearly marked. I share model data to raise awareness of future events.

This event: As stated, Friday looked like a nice step towards a decent event, we had a backing off  late Friday into Saturday and then last night a step back towards a decent event.

The floor of this event seems to be a coating to an inch for most places.

The ceiling seems to be a 3 to 6 inch snowfall.

Right now,  the best bet is a 1 to 3 inch snowfall for most of my readers (Blacksburg, Danville, Roanoke and Lynchburg. 

Somewhere, right now it seems to be favored east could end up more in that 3 to 6 range.

The basic set up. 

There is a clipper system that has a cold front attached to it. The front slows down and a wave develops on it, enhanced by a strong jet aloft. So, there isn't really a "strong low: or really even any low at this point. If we do get a low developing faster, like the Euro showed on Friday we could end up with a decent event again.

The Euro last night was a little more bullish on the wave..


3 AM

6 AM

9AM

12pm

This is the total precipitation from the last run of the euro. The best enhancement is just east of Lynchburg, but about .25 falls in Lynchburg.  This could move  either way before Wednesday.

That is the progression of the snow as it moves through. It strengthens over our area due to a strong jet over head. Basically, when the air aloft is moving that fast, our air rises to replace what is moving away. Lift = wrings out our moisture into cold arctic air.

Not in this mapthe strong winds from the Jet stream (Lets say from 15k to 30k feet, flow is out of the southwest.

Summary:

At this point, Most areas are on target to see a 1-3 inch snow fall.
Some places, as show on that map, could see a bit more like 3 to 6. As of now, best locations may be east of Lynchburg but that will likely change a bit as get closer.

I will tweet out updates throughout the day and likley have a blog updated in the morning. Share this write up with your friends..

Christmas week cold and storm threats! 2 or more "shots" at hand, yes I am serious, Clark.

If we could "flip" Christmas and New Years!

First, Merry Christmas to all!  Hope your holiday season is filled with love, joy and peace. My 9 year old is almost sure that Santa isn't real, but I just caught him red handed in my house..

I was snapping a pic of my tree..

Had a second pic that looked like "this".. 

So, the cold is a little later getting here or we could be talking about a little threat tonight. With that, Grandma's cabin up at 3k feet may see a litle snow up in West Virginia. 

We remain cold Christmas week. Model data has been insistent that we see some snow in the next 10-15 days but it can't figure out when/how much.  Breaking down the details. The ensemble numbers have been impressive with near double digit totals for the 15 day period.  

1. We will have plent of cold/air in place and a "pattern" that supports snow/ice.

2. 2 maybe 3 shots at hand.

3. Details are sketchy, The models have gone from a focus on the Friday event, to a focus on the New Years eve/day event. There is some hints at another event Jan 5/6 which could be the "breaking the cold" storm. 

4. Details are are hard with a faster jet, finding the right short wave to amplify is a challenge. Legit shot we get next to nothing and legit shot we score some snow on maybe all 3 events. This is more of an awareness post :)

Friday's event- At this point looks to be a southern slilder, with somewhat of a lack of moistuer. As modeled, if we "max" the potential a 2-4 incher is possible, and a total miss to our south is possible. Worth tracking- moving a storm 100 miles NW on the models in 5 days is not hard at all, but this is less than ideal and  very werid set up with cold in place but a second low in the Great lakes and at one point 4 areas of low pressure. 

New Years Eve-Day is on some models. The Euro model last run had the cold overwhelm the pattern. Some hints it could be a classic coastal low, (Nor Easter, Maybe  a Miller A)  Not a lock, but worth watching. 

Jan 5-6- Just looking at patterns and longer term ensemble members display a threat. No specifics. Often, as cold leaves and the pattern breaks down you get a  See ya! Storm. 

Will updated as needed. This evenings GFS/GGEM (American and Canadian) displayed a close call with Friday and more significant event Sunday.

Will blog when more details are needed. Look for updates on Facebook/Twitter and share with your family and friends. If you're bored.. click an ad :)

Full Snowstorm update 5 am , Friday Dec 8th.

I get that no one else is calling for a major storm yet. No model, NONE doens't give our area a big snow.  NWS has issues a Winter Weather Advisory for the NC/VA border states for 1-3 inches of snow. Our forecast is for a 50% chance of snow.

Last nights call:
1-3 West of 81.
2-4 LYH to ROA
3-6 Southside.

I'm going to hold those I see the noon data. If noon data shows the same information, I will double thouse totals (approx). We just need to train a little more.. :)

3-6  along 81  including Roanoke/Blackburg
4 to 8 Lynchburg to Danville Back west to Galax.

Crazy in that some areas may have some rain or snow falling by then.

The big issue is we have our low in the gulf, and it gets renergize by energy from the clipper energy aloft. This won't happen until late evening and overnight. I imagine our heaviest snows will be pre dawn tomorrow into late morning.  Restated - Our best snows fall towards Morning tomorrow and the bulk of the morning tomorrow. There could be some rain mixed in or even straight rain falling today. **If this pans out, our accumulating snow falls late tonight and tomorrow am**

Still a high risk bust event. Waiting on a storm to fire up overhead is RISKY! Things can go wrong.

Some maps!

This map is the short term Canadian. This is 10 am tomorrow morning. Heavy snow extends back to the blue ridge.

These two are from the latest run of the GFS. So the snow map could be a little overdone with some snow from today melts or falls as rain. But, shows the moisture. 

In summary, HOLDING with our calls but will double if the models hold..(Not doubling southside exactly) The short term models (Higher resolution) start around 9 am and the Euro at 1pm. Will tweet/post updates in run. 

When it's snowing heavy tomorrow morning and you hear a yell, It may be this guy!

6pm fast update 12/7/17- What is going on..Snow expected

 Model data has trended to a more snowy look.

Why?

1.Low in the Gulf was progged to head NE to a spot off the NC coast but be weak. A Clipper system and it's upper air energy didn't look to interact much. The model runs that showed snow had some level of interaction

2. Last night ALL data trended away from a low being close enough for snow.

3. Noon data showed more interaction or phasing between the clipper system over The Great Lakes and our storm in the Gulf. The result is a slower system that is stronger ( Maybe sub 1000 mb east of Hattaras)

4, Snow may be in southside mid morning, up to 460 by mid afternoon, but that's just the teaser.

5. The bulk of our accumulating snows will come overnight into Saturday. There may even be a lull the bulk of Friday evening.

Best guess
East of 81 Roanoke to Lynchburg 2-4
Southside  3-6. (Martinsville, Danville
West of 8 1 1-3

If the trends continue, we could up those especially in the Roanoke and Lynchburg area.. and at some point mixing could be an issue in Southside areas.

Please share this with family and friends.


Rapidly changing data.. expect a ton of data tonight. 

It gets cold, then what??

Most of my friends and followers for my weather stuff likely follow other weather resources ( Yes, I consider that cheating :))  Haha, I should make a list of good people to follow (Kevin Myatt, Blue Ridge Weather, Wxrisk) and those to avoid (DooleyCaster)

So, this means that most knew the pattern change to cold was coming.  However, what it means in your backyard is much different.  Here are a few thoughts.

1. It will be cold by December 7th. Well below normal for a few days here and there and seasonable cold many other days.  Normal to above will be limited, but still happen.
2. The pattern looks more cold than not through December 20th, then make sink back colder after a lull or small break. Most data supports cold through the end of December and maybe even into the first 2 weeks of January. (The further out we get, the more risk is involved with that statement)
3. Most people care mostly about snow chances. Now, I do love a cold brisk day.. but reality is cold without snow kinda sucks. So, what do we know about snow changes.
A. No specific threats to really track. The models have flashed a couple of things starting December 7th, but nothing at all to "track".
B. It's not out of the relm that we don't see a decent snow, even though it will be cold.
C. With that, It's been snowless in December since 2010, and I think odds are greater than 50% that we break that streak.

Types of storms that impact our area (Central and Southwest VA, including Lynchburg, Danville, Roanoke and Blacksburg) that bring ice/snow to the region. 

1. Nor Easter, Coastal lows(Also called Miller A )- These are the classic big storms. They originate in the Gulf and head up the coast. These have the most potential for big events.

Risk of mix- high, especially east of the blue ridge.
These storms often deepen quickly, which creates for stronger winds.

2. West of the Mountains (Miller B)
These storms form in the south/west and end up west of the mountains. At some point, the jump to the coast, 99%of the time too far north to impact our area.

These often start as snow, change to ice and eventually rain. Snow amounts can be small to at times significant (each set up is different, and is dependent on the strength and depth of the cold air in place

3. Clipper systems (Alberta, not Los Angelos)
These systems originate over the Alberta Region of Canada and head south east. Most often, the pass to our north, but in times of strong blocking, will dip over our region. These systems are usually in the 1-3/2-4 inch amounts with the occasional amounts hitting the 3-6 inch range.

4. Overrunning-
No realy defined low pressure, but cold air in place and the flow aloft turns to the south and southwest pushing warm air our direction). These systems vary from ice events to decent snow events. Bigger overunning events can be in the 6-12 inch area, but more often are a few inches that changes to ice ( Think this way, if there is cold air in place and warm air pushes in, it would eventually change to ice/rain unless more cold pushes in

5. Souther slider- A coastal low like a nor easter that heads out to sea near the NC coast rather than up the coas.t

Less likely to mix, can be a big or biggest event

Now, these are labels we put on storms and not every storm falls into a box like I've described.  Once  we have a few storms to track, this is a handy glossery to use when I start talking about storm tracks.

A winter outlook so to speak..

In the past I have done a more in depth write up and conveyed more "personal"ideas about what may happen in the upcoming winter. In General, long range at some levels is more of a "good guess" area rather than skill. Often I read many outlooks then do some local research and put out a forecast. This year,  I have some ideas

This year we have two schools of thought.

1. Normal "La nina" winters which would favor milder tems and less snow/dry. 

2. Other impacted "La Nina "winters which would feature more snow/maybe more snow. 

- Other impacts are the QBO, Hurricane season and global SST's. 

Analog years are harder in the context of weather or not you are a "believer" in some type of climate change, the globe is very warm and this does impact our sensible weather.  You could go above normal temps in an season at this point and be correct maybe 80% of the time. 

For our area (Lynchburg, Roanoke, Danville, Blacksburg) I'm to hedge colder, with below normal snow, but due to ice/mix and dryness. 

Temps- All Areas Normal to -1. I do think we see a couple of significant artic outbreaks. Let's be honest, if our lows are in the single digits with wind chills, kids are getting snow/Cold  days  from school. 

Snowfall- 

Danville 2-12 inches

Lynchburg 5 to 15 inches

Roanoke 7 to 17 inches

Blacksburg 11-21 inches. 

Upslope regions will be above normal (those places that just snow when it's cold)

Why the weird snowfall range?

La Nina winters tend to lack  the sub tropical Jet.  With that you tend to have system that are a smidge to north for our region. Storm track may feature systems going into eastern Kentucky then jump to the coast north of our region. Those are classic snow to mix or just mix events here. The risk for increase blocking could push those to our south under the block and increase our snowfall.

Snowfall is a guess at best, so take that for a grain of salt. I'd expect a little drier than normal winter. IF we over achieve on blocking (Blocking up north pushes cold air south) during an active storm pattern, we could easily over achieve on snowfall.

Be ready for frequent twitter, facebook and blog updates when pattern changes arive. We should remain seasonable chilly for the rest of the month. Good bet that we remain snow/ice free through mid December. 

The impact of Irma on Roanoke, Lynchburg , Danville and Blacksburg

So, the blog has been dusted off for Irma. I'm a shameless winter guy but this is a big deal event in some areas and worth sharing ideas about. If you are reading this blog, again this is a discussion for Lynchburg, Danville, Roanoke and Blacksburg region.

Key phrase for our region:
Know the difference between disruptive and catastrophic.

Harvey was catastrophic in 2 ways.

1. The landfall region was horrible. Stormchaser iCyclone was in that region noted Click here for Harvey Landfall
2. The flooding was caused by the lack of movement and 30-50 inches of rainfall over a large region including Houston Metro.

Irma has been and will be catastrophic in a large area. Most have already viewed the footage from St. Martin and Barbados which are humanly horrific and hard to watch.

The track that is possible of destroying the more islands, avoiding Hispaniolia and Cuba as it gets a little stronger over the warmer water, landfall near Miami, then head due north just off shore (note the slight curve of the coast that could allow a due north track to get just off shore). This allows the eyewall scrape almost the distance of the eastern Florida coastline, a short timeover water before a final landfall in South Carolina region. Adding, a large storm like this has an expansive wind field and a larger storm surge. Most of that region will experience a catastrophic event.

Meanwhile, we don't really know what  the impact will here because the track has yet to be determined this far north.

Worse Case scenario: Irma Tracks from Landfall in SC to a Point near Martinsville/Galax area. most of the region sees 2-6 inches of rain and wind gust could reach 70mph, especially nearest the storm and the highest elevations.

In that case, we see some flooding, a good amount of power outages and life is disruptive a few days to maybe a week. It may be a challenge to get a hot meal, some power outages, local flooding in flood proned areas, but nothing remotely close to what we have noted in the islands so far  or what will happen over the those who get the direct impact of a Cat 4 or 5 system. In our region, Tropical Storm conditions are a worst case scenario.

Current trends have been a secondary landfall in South Carolina and a westward movement that keeps the worst away from us. We'd see winds up to maybe 30mph and under 2 inches of rain.

We could also have a mid track that meets those conditions in the middle, with up to 4 inches of rain and wind gusts up to 50 mph.

 Point being, it's always smart to check flash lights , candles and batteries. It is always smart to have some non-perishables and keep some water bottles handy in our region of Western Virginia.  Even if this event isn't a big deal, you are protected agains a future ice storm, derecho and even zombie outbreak. However, there is little or no chance of a catastrophic event here. In a worst case scenario, we have up to a week of smaller disruptions in smaller areas.

Supporting my point that we wont have a catastrophic event here..here are the local observations from Fran in 1996. Our highest winds were gusts to 36 and 6 inches of rain total. Rain and winds at 30mph is a lot more intense then one would recall and I lived in a second story apartment with cheap windows and the wind pushed the rain over the top of the window and leaked in that way. But, by 2 pm the sun was out and I went to the J Crew sidewalk sale in Forest.

Summary: Those in the Bahamas, Turks and Caicos, Florida will have a horrific and life changing event.  Failure to head warning will have significant consaquences including loss of life. 

In our region, in a worse case scenario we have a disruptive event. At this point, we don't have enough information for a "exact" forecast at this point. 

I'll throw another update or two out there in the next few days.