Quick thoughts before the evening models

Just wanted to post a quick map before the evening data. Each model run brings us closer to a REAL solution. A big event is happening as the main shortwave is getting closer and closer and should be sampled better.

Most of the data was good if like big snows. However, the 18z GFS took the more north track and was a TON of rain ending as some snow.  More like 2-6 inches rather than the BIG event I want.

I tried fooling with GIMP software and it was not cooperating with me. :)

So, this was done ghetto style on one note.

1. I drew two red lines-- One goes down into SC and NE towards Hampton Roads.
the second line goes across Kentucky, along the VA NC line and near Hampton roads.

These are the two presented tracks for the upper air low. For Lynchburg and Roanoke to get a big snow, we REALLY need the southern track. If it touches down in South Carolina, we are golden. If it takes that more northern track we will mix with rain for a while and it gets more complicated.


2. I drew those blue lines up east of Maine, near Nova Scotia, That is tied into point 1. The stronger, more west that it, the better chance we have of driving that energy down into South Carolina. When the 18z GFS had the more north solution, that blocking was weaker.(There is an upper low tied to that blocking as well called a 50/50 low)


While I liked the 12z runs and think it's plausible, as stated-- the north trend ALWAYS scares me.

Help, I'm stepping into the twighlight zone...

Well, most of the evening model data was promising if you are a snow lover. I tried to stay awake for the ECMWF or Euro and nodded off around 60 hours. Waking up and seeing it was UNREAL.

The Euro was a madhouse-- with literally 15-25 inches of snow from Roanoke to Lynchburg with maybe close to 30 inches in places NW of Richmond.

Don't take this literal-- at all, yet. Potential has certainly grown and we could be staring down a potentially historic weather event. We've moved away from a full phase event where two vort maxes merge near our region and more towards just a strong closed upper air low being pushed south of our region and slowing down due to the stronger blocking. The low gets vertically stacked which means the surface low and upper air low are on top of each other and it's a beautiful event.

Here's a link to an article about the Ash Wednesday storm. This guy was up towards Massanutten, but it conveys how intense that storm was. This storm, 51 years later, would fall on Ash Wednesday. Lynchburg had almost 18 inches of snow from this event that stalled off the VA coast for day and was one of the costliest storms ever in terms of coastal beach erosion.

http://www.glenallenweather.com/links/digest/greatestsnow.htm



What could go wrong??

We are still 100 hours away. There will be changes in the final solutions.. Here's a quick guide to ways to sabotage our winter event.

1. Temp profiles are not horrible, but March with sun and no cold air advecting. In our region of the state, with a late afternoon Tuesday start, it may start as rain. Models are tad warm at the surface and this is always a concern. Taken literal, the EURO has rain in Danville for HOURS after it's snow in Lynchburg and Roanoke. Models TEND to be a bit cold at this time frame in general. So, we could get the BIG event, but too much rain that limits it.

Further, if we don't get quite as heavy stuff--we could get what many refer to as "white rain" where it snows for hours but doesn't lay. The

Once we get under the "deformation zone" we should get plenty cold-- but deformation = banding. I've mentioned before how banding can be hit or miss. This could start and end as rain-- once the storm occludes, it quits making cold air.

2. The upper air low doesn't dig as much. This would cause both temperature issues AND less precipitation. From my experience, you want the upper air low to travel about along 1-40 in North Carolina to max things out here. This is a very strong low and moves from North Central South Carolina NE towards let's say Kill Devils Hill on the Outer Banks. That's an incredible track. Until we hit the 72 hour mark, I'm not sure this willing to bet on a track like that. If it slides NORTH,we are warmer and a less hours under the "heavy" bands. This issue comes in if it DOESN'T dig down into South Carolina- what if it's only North East Tennessee. This can't be ruled out yet.

3. It doesn't slow as much-- Very possible. Spring is notorious for slow moving upper air lows-- and I'd love to see it but this looks extreme on the EC. A faster solution could yield a nice event, let's say 6-12 inches, but not historic.

4. Snow ratio's are horrible. On the January 17th event this year. Near my place on Timberlake rd, we had close to 4 inches from about .7 liquid. So, it was close to a 5-1 ration. Normal ratio is 10-1 or so. Between warmer temps, slower spells that could mix with rain, even if we get the 2.5 liquid as modeled. Ratio's could be as low as 6-1. That would be 14-15 inches of the heaviest concrete snow you'd ever seen in your life.


Vegas odds-

1. Over 2 inches of snow 75%
2. Over 6 inches of snow 50%
3. Over 12 inches of snow 25%
4. Over 18 inches of snow 5%.

I'd love to show the vorticity  maps I get from a vendor, but I'm not willing to risk that. However, here is a qpf map from another site I found on FB. It shows one of the 6 hour snap shots of how much precipitation falls in 6 hours. MOST of VA has at least .5, places in the east exceed an inch. The model has 2 time frames like this plus another not far off.

The March 6 hype--

Social Media has made weather forecasting next to impossible. Just about everyone has an idea some of the data shows a potential big snow next week. Someone posts a map, people take it as gospel and chaos ensues.

Here is the skinny..

1. Pattern is ripe for a big storm, but has some flaws and issues.
2. We have decently cold air aloft, but the lack of High Pressure to our north to push in LOW LEVEL cold is an issue.
3. Model data spread is from suppressed in South Carolina to blowing up late and missing our region, but bringing a good event from DC north.
4. Timing is everything-- the exact strength of the blocking to our northeast and timing of the shortwaves will determine this event.

My guess at this point-


33% chance we see an accumulating snow. From that, 10% shot it's over 6 inches and 3% shot it's over a foot.

Key issue is how hard it snows. If we get 12-18 hours of light to moderate snow, we could get ..50 of liquid that only accumulates a slushy inch and is basically melted before the last flurry ends.

Trends last night-

If there were any trends last night, it was for a later phase which leaves us drier as the storm is disorganized before this point.

The key shortwave will be coming ashore later tonight over Western Canada-- that will help. I think by mid day tomorrow we should have a general idea of if this is a legit threat.

FWIW--


The HPC HAD an area of liquid in our region of between .5 and .75. After the model data last night they shifted that east and we are in a .25 to .5 for the period. Not that this is gospel, but it was a step back for our region and a step forward for places to our north and east.

Another interesting smaller event--

This winter-- UGG.

Larger events can be a challenge, but there is a sense of ease because you know what you have it's just the finer details of rain/snow and amounts. This year, we've had so many smaller events-- per example last Saturday's events where some of the model data hinted of a stronger band and sure enough it happened. (smaller then modeled, but that's expected because of model resolution)

Here, we've got a storm dying over the Midwest and some moisture pushing on the east side of this low SMACK DAB into very dry air. Dry air, that often just dries this stuff up. Next, we have second wave coming through late Friday into Saturday and cold air, just cold enough lingering around.

1. Don't fret temps-- this air is colder and drier than Monday's fiasco. Temps are near 40, but they will drop a degree or two and before precip starts and then tumble quickly down to near freezing, bottoming out in the upper 20's.

2. I'm still not sure where this is going.

Short term models have the heavier stuff going to our south-- closer to the NC/VA border with even maybe a quick 2-3 inches before it changes.

The GFS/ECMWF (Euro) are much drier and maybe give us .15  or so before noon tomorrow that starts as snow and ends as freezing drizzle.

The NAM which is ALWAYS too wet-- has almost 2 inches of snow in our region.

Meh--

I think that snow and sleet breaks out after midnight west and between 2-4 east. It may mix with sleet at first, kick to all snow and then transition back to sleet and then eventually freezing rain.

Amounts-- Coating to 2 inches snow and sleet. Best snow amounts NORTH of 460. (Closer to two inches)

Most schools and stuff cancelled tomorrow.

Snow through mid morning and sleet through 1 PM or so-- sooner the more South and West you go.

BTW, Blacksburg is on Facebook and here is their snow map.. I think their map is a bit cluttered, but conveys the general idea. You should follow them.

http://www.erh.noaa.gov/er/rnk/emer/emer.php

The Parade of Minor Storms continues...

Another storm system will pass WELL to our west and with it bring a chance of sleet and freezing rain late tomorrow night and Friday AM.

This is a limited moisture event and should only provide a minor glaze if it all materializes. Most of model data does bring in the moisture but a few are VERY light in the order of a couple tenths of an inch. In most cases their will be an initial burst of sleet that is quickly over to light freezing rain.

Temps look to get near Freezing by mid morning Friday. The temps will hoover just above freezing all day and may dip below freezing for a time as another slug of moisture comes through late Friday night into Saturday morning. IF this is just a tad cooler than anticipated, it could be a more substantial ice event. I'm thinking we JUST miss it but some areas to the north and west of Lynchburg and Roanoke, above 2000 ft may get a good glaze out of this.

We are in a stormier, wetter pattern through the first 10 days of March. Early next week, we may be looking at another event that starts as snow and or ice and ends as rain and then the first 10 days of March may have a shot at a Nor Easter or two-- with some colder temps CLOSE.

Another minor event

A storm is passing WELL to our west in the upper Great Plains. With that, a warmer push of air is going to create some precipitation in our region and we should get a burst of snow and sleet towards daybreak. 

NWS has an advisory for west of the Blue Ridge-- lower regions expect 1-2 inches of snow and sleet and higher 1-3 with both places at risk for a glaze of ice. 

Lynchburg is not under an advisory yet, but the forecast map created in Blacksburg has us getting a coating to an inch...

http://www.erh.noaa.gov/er/rnk/emer/emer.php

Southside may avoid most of the snow and ice. 

Expect school delays in the AM>...

Saturday Storm wrap up--

Pretty intense local event-- the NAM was on to something with a stronger band, but it was more NORTH SOUTH vs SE to NW. Also, because of the limited scope of a model-- it was a more defined pause of either IN our OUT of the band.. no real tapering. Places in Appomattox had up to 8 inches. A friend reported close to 4 inches in Eastern Campbell county but said a 5 minute drive towards LYH went to NO snow. On the way home from the moster truck show there was NO snow until I got off on 460 BUSINESS west-- by the 7/11 and then the ground was covered. Once I passed Lowes on Timberlake, there was NO snow again. 

Strong storm-- just the upper air energy had not consolidated before it passed our region. It has become a MAJOR storm over the Northern Atlantic Ocean. 

Could be a snowy day in parts of our area??

Part one of the storm has come and gone with LITTLE rain. I know LYH airport officialy had a Trace of rain. At some point in the evening I had some drizzle, but it never amounted to much. Further, a friend shot me an overnight text and reported some light snow in the 2-3 AM time frame. (Yeah, people do those nice things for me because of this hobby)

Round two is getting fired up. 

Model review-

NAM- Has a strong band that pushes up from the SE to the NW somewhere between lets say Altavista and Amherst. In that band, a few inches fall. Outside of it, coating to an inch. The NAM is a short term model-- may have an edge here. 

GFS- has a general 1-2 inch snowfall from lets say LYH and DAN east. 

Super short term models RAP and HRRR. These update hourly.

RAP- really over emphasizes that big band and dumps up to 5 inches for those under it. Outside it, coating to an inch.Shows it much closer to LYH in the same general area. 

HRRR- Has a heavier area, but it's further east-- does NOT really get the greater LYH area. 

My thoughts-- I think Further east has the best shot of anything over an inch. LYH may see a coating. Roanoke maybe flurries. South Boston to Just west of Richmond may see 1-3

Will use Twitter and FB to update from here but I'm taking my boys to the Monster Truck show this afternoon, so I'll be cut off for a while. :) If it starts to snow good, flip on radar-- that may be your best bet.