Winter Storm Watch over our ENTIRE area... SIGNIFICANT snow likely now.

Certainly had a feeling that would be the right course of action after watching evening model runs.

First, in my "weather hobbyist" ever running chat-- I noted that I failed to mention the bitter cold this AM and snow showers yesterday. It wasn't a shock and played out as I expected. That was an exciting 20 minutes of snow.  I need to do a better job of conveying messages about cold and windchill. It's the big story today with temps at 7 or so this AM and windchills well below zero.

The wave 1- wave 2 issue has been resolved. For the last few days, resolving if wave 1 or wave 2 would be dominant was causing model chaos, which in turn lead to forecasting challenges. The traditional thinking was slow this down, let the jets phase as I mentioned and we'd get a bigger event.

1 is the polar Jet, 2 is the Subtropical Jet. 

Where this ended up was, the phase was NOT needed and Polar Jet is riding solo on this event. 

1. Time issues- When the thought that the phase was needed, it was almost a full 24 hours slower. As a result, our storm time is now Monday afternoon until Tuesday morning.

2. Mixing issues? Here goes my north trend talk. We are literally in the bullzeye at this point and 100% snow on most of the models. These things tend to nudge north with time. I'd put odds at 50/50 that some mixing occurs late in the storm up to the Blue Ridge including Danville, Lynchburg and Martinsville. 

3. Snow amounts.  I held to my thoughts of 2-4 and I'm glad I kept snow options on the table. Looks like DOUBLING that amount nice place to start most places. Even if we mix, 4 inches should occur most places. Very possible places exceed 8 inches and I've noted that in my map.

4. VERY cold during this event and even colder after. Reasonable shot many places get close to 0 Wednesday and Thursday AM. 

5. School closings-- Be ready for some serious closing issues. Tuesday is about a lock to be closed. 

Wednesday at best will be a delay, but with cold temps MAYBE slightly above freezing Tuesday afternoon I doubt the back roads are clear enough to have school Wednesday. Thursday AM will be COLDEST of the days with lows near 0, slightly below 0 possible. That screams 2 hour delay unless we get the 8-10 inch amounts possible. That gets us to Friday. (I heard some schools did not close for Presidents Day too-- which somewhat bothers me and I got an email from Abe Lincoln and he's really upset about it) So, as of now-- 1 day closed and 2 days delayed is about a lock.  2 days closed and 1 day delayed is likely. 3 days closed 1 day delayed is still an option and man, for you teachers out there-- would not rule out  the entire week being gone if your specific region gets 10 inches. 

6. Another storm on the map next weekend. Has the potential to be a decent event, good changes it's a mixed bag and another big cold shot behind that one. 

Region wide 4-8 is likely. ON the west side of the red, up to 10 inches possible.
These numbers may need to be massaged a little either way as we get closer
to the event. 

Not going to change anything...

I had hoped to gain a little more clarity yesterday for this event, and while we did get some my confidence level has not climbed a ton. Once we established that the low would not cut to our west, but move to our south I moved the region snow total to a general 2-4 inches. That isn't going to change at this time. 

Key Factor:

I've used the term phasing, which is when energy aloft from 2 jet streams work together. I used the term "bundled" energy and this is in that realm as well. The model runs that show a decent event 

have decent phasing and those who don't have a smaller or a NON event. If that energy from the Baha area ejects and phases (interacts) quick enough, we should have a decent, if not significant event. 

Best locations: 

At this point in time places along the VA/NC border are at higher risks to see more significant snowfalls. 

Model trends

If you want a snow storm-- Yesterday started as a great day and ended on the downslope. 

The trend yesterday was to slow down the system, keep the cold air in place and kept us on any models to an all snow event. Some of the mid day model runs had stripes of 9 to 15 inches across much of our regions. 

A late afternoon model run pulled the low more south and then ALL the late evening model runs went south and most kept the snow out of our region. However, the ensemble runs kept snowfall region. As a refresher, ensemble forecasting is taking a specific model (GFS, ECMWF, GEM- American, European and Canadian) and running a set amount of times with changes in run to weed out a bias of a model. 

IS IT GOING TO SNOW?

Great question and I'll do my best to answer. 

In general, this type event trends north as we get closer. So that's one in the in our favor. We have some subtropical jet interaction and those are famous for last day north adjustments even just in where the heaviest precipitation lines up. 

A concern is that the drastic trend on ALL the models could indicate something. 2 of those issues are:

1. The energy aloft is split, and as a result the storm is sheared out and weak, not throwing back moisture into the cold section. Just like bundling your TV and internet services, bundled energy is good for bigger storms. 

2. COLD air. The track has been adjusted in part because the cold air coming down is harder to forecast and the models adjusted in part because of the cold air in place AND the cold air coming in. 

AND YOUR ANSWER IS?

Yesterday I went 2-4 east regions. (Meaning east of the Blue Ridge) and west 4-8. This was based on the idea that we'd have a mix at certain points. Remember that forecasting is FLUID and information changes. Not much data shows the storm cutting to our west-- so the mix idea has dropped greatly. 

I'm going to blend the ensembles and operational models and hold to an idea that a 2-4 inch snowfall is the most likely outcome at this time. Usually, I'd love a low that is 150 miles too far SE at this time based on the ever present north trend, but with the drastic change yesterday (AKA disturbance in the force) I'm not positive we have a really good grasp on this yet. 

Model runs today between 9 and 1:30-- I'll toss a few ideas from those on FB and Twitter. But, as of now-- the best guess is 2-4 inches region wide, maybe more SE regions. 

Presidents Day followed by a snow day (s)

Legit threat Unfolding for Tuesday of next week...followed by bitter cold

The big picture of the pattern still isn't GREAT, but like most winters if you get enough storms rolling by ONE has enough cold air to work with for at least a spell.

A storm passes to our north Saturday-Sunday with some very COLD air in place Sunday-Monday. This cold air will set the stage for what could/should be a legit winter storm for our region.

1. This won't be an all snow event.

With a departing high pressure off the east coast, at some point we mix and change to sleet, freezing rain and even rain for a while. Literally as the storm ends and more ridiculous cold air zooms in right on the tail.

2. School/work is at risk Tuesday if not longer.

Looks like the event should start between Midnight Monday night and Lunch time Tuesday, and should start as snow. The slow change to ice then rain will happen and may even end as snow (also could remain ice some regions the entire event)

Temperatures/rain won't warm up enough to melt whatever falls and then temps by Wednesday AM are below freezing and stay there for days. Taken literal, at best we are above freezing 12 hours late Afternoon Tuesday till early Wednesday and then temps plummet during the day Wednesday. Temps fall back below freezing between Midnight and 5 AM and tumble all day long. By 5 PM we are down in Teens. Thursday AM lows are 0-10 above.

If you get 4 inches of snow at your house, by the time the ice/rain ends-- it may be 1.5 inches of slush and then it's going to freeze ROCK hard.

3. Initial Guess??

I don't mind throwing out thought as long as you as the reader accept this is fluid and subject to quite a bit of revision.
Broad brush now-- Western regions 4-8, with a good bit of sleet and freezing rain on top.
Eastern Regions 2-4 with a good bit of sleet and freezing rain. Ice may be the big idea for a while, ending as rain.

The world will look like a glacier for a few days after with lows in the single digits after the storm.

Superbowl Sunday & Nor Easter Comments.

I wanted to comment first on the Nor'Easter from this past Monday-Tuesday. Tough storm but fun to attempt and forecast. There has been a lot of comments either way and my readers are usually kind towards me for many reasons, some being that they've known me their entire life. (Yeah, like you Shannon H) It was like a comedy of errors watching model runs (Most run 2x a day, some run 4x a day and some run every hour) The lack of trends and consistency was remarkable.
1. Models are just that-- MODELS. They are not sensible weather and literally once the data is uploaded it's already WRONG. Point being, we've made huge advances but models will be wrong. When a low has to reform and the difference is 75 miles between a foot and NOTHING, these things will happen.
2. Damage control can be mitigated by conveying uncertainty in the forecast. Outside of Eastern New England, this was a KNOWN possibility all along. Chatting with a friend and his wife along the CT coast, I promised them a foot and said 24-30 was possible. I knew that was a lock. They were on the western edge of where I KNEW a foot was possible. I would not have promised them 2 feet. They reported 20, but a met from the area reported 14.
3. Start small. Even in most of Massachusetts, I found the 2-3 feet NWS calls a bit much. It's always easier to start small and convey totals could go up based on strength and track. In NYC area, where they were on the far west of the 2-3 feet 'modeled" snow-- even more so a reason to go low.
4. The trick is in the wording-- there has to be some ambiguity in forecasting.  Convey a cushion to your audience allows you to back track when needed.
5. You, as an "receiver" of the forecast needs to educate yourself.  Be able to tell where you on a map, have a radar app on your phone. (Rainy Days for Android, My Radar for Iphone)
6. Media outlets need to be quicker in updating forecasts. When a storm is developing wrong, radio stations, etc often have the "old" tape running for a long while after a storm is clearly going to different.
7. Facebook could do the world a favor and make a special category for Weather services, even if it doesn't include my "folksy" page. For legit weather entities, OLD data coming up in the FB stream is brutal. For the average person, they could have been VERY confused. I'd see an update from NWS near NYC that had old maps, then the new maps underneath it based on their algorithm of who liked and posted. Rather than putting more pressure on these outlets to delete data, have something done where old data can be pushed back in time sensitive situations like this. Facebook and Zuckerburg have changed the world-- how about some efforts to save some lives and just make it easier. SO many people get information from  facebook about the weather. Make it a priority that people are getting CURRENT information, not 12 hour old data, which is ancient in weather terms.


Superbowl Sunday-

Don't think it's out storm again. *Lynchburg and Roanoke area*



Just can't get a break this winter. Decent cold air in place, and a strong arctic front racing our way and it seems the cold air will be 12 hours too late. Storm tracking JUST a bit to close for all snow.

1. Departing HP slow to leaving-- this doesn't allow our storm to move or develop south.
2. Our actual Low, forced to move between
3. Arctic High bringing cold air.

Low should track NE Louisiana to Bristol TN to Norfolk.-- if not even a shade north.

Starts as snow, mixes with sleet and rain, ends as snow.

Forecasting ...

Means to predict or estimate.

Remember that when your weather guy gets one wrong. :)

True story last weekend while watching that Seahawks - Pack game that I put on facebook-- Famous last words, this feels over. Pack had dominated most of the game, Seahawks had no time and again could not move the ball. We know how that ended up for my call-- NOT TOO GOOD!

This storm has been up and down-- the best thing I said was when it was suppressed (Best snows over eastern NC per the models) is that I am more concerned it will be too warm than not wet enough.

This map shows where our LOW is tomorrow early evening and shows you where the is a LOW over CANADA where we need a high. That low is what costs us a decent snow event. Had it been a decent High that pushed JUST cold enough air, we'd be looking at a 12 inch snow fall.

Note the L near FL coast and the SECOND L in Canada. That is killing our cold air supply. 

Forecasting this has been tough. There are no exact flow charts to show you what should go where for temps and this is very marginal everywhere. 

1. Danville should be mainly rain. Maybe a quick burst of sleet and or snow start then a cold rain. 

2. Roanoke and Lynchburg won't see a ton of snow, but an inch or two of sleet and snow is possible, especially west of LYH towards Roanoke. 

3.  Lynchburg will start as a burst of snow and sleet and move to sleety rain and maybe a period of freezing rain. The data shows cold air JUST above the surface so literally SNOWFLEX could have ice forming while timberlake road is just wet. (It's happened before)

4. Roanoke Will start as sleet and snow, hang on to sleet longer and end as rain. 

5. Would be remiss to not mention Blue Ridge Weather has idea of a second wave of snow saturday AM. Would be rare, but possible 

6. Fast mover- best stuff should actually be gone by midnight or shortly there after. 

We do have some other chances for snow in the next 2 weeks. Superbowl weekend LATE has an interesting set up where there is a strong pulse on the Sub tropical Jet and some decent cold shots coming from the arctic regions. Both seem legit.

1. The SOI (Southern Oscillation Index) bottomed WAY out which means the get will be more amped with moisture and energy. 

2. The EPO is forecasted to go negative. That is what kept us cold most of last winter. 

This will be a now cast event-- I like a quick coating in LYH and some freezing rain. I like more sleet in Roanoke, ending as rain. The further up 81 you get, the more snow and sleet you get. Decent event Hagerstown, Lancaster..etc. 

Dusting off the blog..Friday- Monday

It's been a while since a blog and honestly, I'm leaning towards event one (Friday Night and Saturday)NOT being a big deal for us. It's the classic case of so close, yet so far away. I think we get from between .75 to 1.25 inches of rain/junk falling out the sky saturday and 50% it's mainly rain, 25% we get enough snow to cover the ground and WAY at the bottom, 10% chance of 4+ inches of snow. (Not the WPC 10% chance either, for my weather enthusiasts)

Without getting to technical, where we need a HP to supply cold air, we have a low pressure. parts of NW Virginia and MAYBE the Mts to our west could survive this, but for Roaonke, Lynchburg and Danville LIKELY means MOSTLY rain. We've got 3 days to play this out, but I often say-- when is the last time in a storm we ended up colder than progged. Answer is--..A LONG WHILE.

Will update as needed, but strongly in the mainly rain for the Roanoke, Lynchburg and Danville areas. Areas above 2k feet and well to the north and west like Harrisonburg, etc may do well.

Event 2- Clipper type system is going to dig VERY deep Monday time frame. (Dig- how far south it goes with the upper air energy) In general, I like to see the energy at least at the VA/NC state line, if not down to -40 in Carolina. This vortmax is possible heading into GEORGIA. Funny, because it's not far off from making a heck of a low and there is a way we miss the storm as it moves south and then north up the coast.  As of now, this may be our first chance to get decent snow of like 1-4 inches over much of the region.

Will update with some maps later for those who like more data.