Sunday, November 24, 2013

Arks will be needed for Thanksgiving Week

Social media chatter has continued about the big storm and possible snow.

Looks like the rain will start early Tuesday for most of the Lynchburg and Roanoke areas and it will POUR.
2-4 inches of RAIN very likely region wide.
Red are is OVER 3 inches.

2 possible winter precipitation events in this...

1. As it starts, cooler dried air will be in place with temps near freezing. A quick burst of sleet could transition to some freezing rain for a couple hours Tuesday AM. 
2. As the low winds down, colder air is filtering in behind and depending on that speed plus the upper air low, some model data suggest it ends as snow. Some model data says just light snow and flurries while others drop a coating to an inch or more. (Few runs of Euro drop 3-4 inches in both Lynchburg and Roanoke)

My take-- these lows with trailing upper lows are tricky and fickle-- would not be shocking if NO flurries fell and would not be shocked if 1-2 inches of snow on the backside. Let's play conservative as of now and go with NO accumulations, but ending as snow. Mountain areas will do a little better. 

Friday, November 22, 2013

Thanksgiving Snow Threat...???!!!

For those in social media world, there's been quite a bit of chatter about a possible SNOW event just before Thanksgiving.

The Cold is Coming...

A series of cold shots will be heading back into our area, the first on late Saturday and Sunday will be FRIGID. Temps most areas will struggle to get above freezing Sunday.

The Cold is Leaving...

Because we have no blocking (-NAO) the cold slides out to our east quickly just as another shot approaches from the west. It won't be WARM, but not the bitter cold air we will have Sunday.

The Storm Approaches....

More cold air is zooming in from the west as an upper air low literally moves across the country. Timing is key to when the cold air gets here and how much interaction takes places between the two jetstreams.

Options include:
1. Out to sea with little rain.
2. Up the coast but little or no cold air. (big rains)
3. Cold air arrives a smidge late..(rain ending as snow)
4. Storm is a bit slower and snow threat increases.

My current take:

I'd lean somewhere between options 2-3 where we get a nice rainmaker before the cold that COULD end as a flurries or snow showers, with an outside shot of a coating to an inch. Areas to our west in the Mountains should have their first snow of the winter and ski season will get a nice early season boost with the snowfall and NICE chances to make snow.

Looking forward...

My winter outlook may be on the ropes early. I went extremely low on snow and there is a decent chance we put a dent in that total before December 10th or so. Some higher latitude blocking called EPO and WPO are forcing things colder than most had thought. Most people expected a rather warm November and we should end the month 3-5 degrees colder than normal. This trend will continue through the first 10 days or so in December with perhaps a shot or two of snow in that time frame. (read that as a SHOT or two, not a promise :))

Will also be a challenge to get my +2-3 in December with the first 10 days likely to have a decently low of maybe -3 to -5 for those days.


With the Holiday week coming up, I will update more frequently as this storm and cold unfolds. As of now, a decent rain event seems likely with .5 to maybe 1.25 inches of rain falling that could end as snow in the Lynchburg and Roanoke areas.

Thursday, November 7, 2013

I feel obligated to post...Snow threat?

It would be very fitting since I went a warm, dry winter that winter kicks off with an event that completely ruins my winter forecast before both the winter solstice AND meteorological winter. (December 1)

Many of you may have heard a little chatter from various outlets about a storm literally 7-8 days away. Speculation is good, if it's presented as speculation. However, what I fear is blogging has turned into Black Friday shopping where people get earlier and earlier alerts and the public can't gauge the difference between an actual threat a couple days out and just some fun chatter about crazy model outputs.

What are the models showing?

The models are showing some VERY unseasonably cold air moving in out of Canada. At the literally perfect time, a short wave digs in and creates a storm. Now, some model data shows a "Alberta Clipper" type event and other blow it up via "closing off" the upper air low and there is a HUGE event. Some of the data has "fringed" our area with the blow up and others have made it a huge event.

The obligatory snow map from the most extreme run..

6-12 inches in our area, with a lot more just north and east.
What do you think will happen??

This falls under the banner of-- just keep watching. What we know is this: 1. Some colder air is heading in our region for a visit and likely a short wave. My guess is that the cold air won't be as cold as progged and short wave will be much weaker and well north. Hence, the upslope areas well north and west of our area could get a decent upslope snow and some lower lying areas in WELL NORTH of our area could see their first flakes of the year. 

Even if the STRONGER colder air and upper air low cuts of, it is well favored that any extreme event (which  I've stated is unlikely) would happen WELL to our north.

Friday, November 1, 2013

Winter Outlook 2013-2014

I could give you the blah blah of why I don't update, but let's be honest-- I'm a winter weather guy. Yes, I talk Hurricanes and Severe on FB when it happens but my intense forecasting is about winter.

So, if you are NOT a winter fan, you will like my update.

Roanoke, Danville, Lynchburg

5 inches or under of snowfall. Mountain areas see more, but still well below normal.

December temps 1-2 above normal
January 2-3 above normal
February 1-2 above normal.

Not much data I see supports lasting cold or great storm patterns. I like to see how Eurasian snow cover trends in October as the final piece and that did NOT look good.

My point of going so low is to point out that this will be a boring, mild and likely dry winter. I could of hedged at 8-12 inches and hoped for ONE bigger event to save the day. These are ALWAYS possible (not 12+, but a fluke 4-8 inch event)

Why?

I think the Arctic Oscillation runs Neutral to positive most of the winter. ( Cold is bottled up on other side of globe, tighter wound Polar vortex that keeps cold air away)

Negative PDO - leads to trough on West Coast and Ridging in the east.

Storm track well to our west, and when the pattern "relaxes" more east is still into the Ohio Valley reforming off the Delmarva.

If I'm wrong-- there are ways to get stronger discharges of cold air into the east (-EPO) at times. I'm hedging it won't be.

Also, you CAN get a fluke snow storm-- but I'm hedging against that too.

That's all I got to say about that.
























Monday, March 25, 2013

Biggest Spring snow in 42 years--

And, a winter review--

Wow, if that storm didn't meet or exceed your expectations you can't place things in proper context.  And, it will be all melted by noon tomorrow.

March 25-26 1971 was the last time Lynchburg had a spring storm of that size. The official total of 6.5 inches  is a little under the 7.3 from 1971, but when we beat a record that is older than ME (turning 40 soon) you need to be impressed.

Such a difficult forecast where I tried to say that if everything went right,we could see 6 inches. How many times has something gone RIGHT this winter for snow? Each event had small challenges and issues that derailed the event--

1. Jan 17 deformation zone forms a bit south compared to modeled and much of Amherst, Bedford and a small sliver of Lynchburg got next to nothing. Sean Sublette in Midtown had 2 inches while Timberlake road had a good 3.5 to 4.5 inches. I put that down as 3.5 but could justify a 4 or even 4.5 honestly.

2. Mid Feb event-- inverted trough that dumps up to 8 inches over parts of Campbell, Appomattox, Charlotte, Buckingham and even into Nelson County. Tricky, tricky event. I drove down Timberlake and it was Covered  with snow from the 460 back entrance near 7/11 and snow free past Lowes. I believe Sean Sublette reported .8 from his house in that neck of the woods.

3. March 5-6- marginal warm temps, early change to snow-- not much backlash. 3-3.5 inches. Didn't feel like that much.

So, this event-- with a bad track record, going more than 1-3 seemed unwise. If you follow me on twitter and FB, I did say 3-5 early afternoon. The overnight went as I expected with 1.5 or so at my place.

Fun event and you may not see this type event, this late in the season for a LONG LONG time.

With that--

My winter outlook--

HERE--
http://lynchburgweather.blogspot.com/2012/11/winter-forecast-12-13.html

I should have included March as I would have went cold (Not this cold, but cold)

Seasonal outlooks are rough because it's part skills, part luck and part luck?? So, I'd say it wasn't my finest outlook (09-10 has that honor) but wasn't bad.

Horrible on December, I'd grade it an F.
I said colder, it was +5.5

Better in January- I said +2 and it was +4.3. January was also very went between 2-3 bigger storms.

Feb-- I just missed a decimal, calling for a -3 and it -.3 :)

No March to grade.

Snowfall-- Climo is 18, range of 13-18 and we have that.

2-4 months were drier than normal- I touched on that.

Temps were warmer than I thought, especially early in the winter. I had banked on colder air and it never showed up-- until march.

I want to give myself a B-, but objectively it's more like a C/C- Getting a snow total close due to a late season 7 inch is more luck than skill.


Saturday, March 23, 2013

Reluctant Blog, reluctant forecast--

I believe this event was mentioned on my last blog March 17th. Great pattern, strong short wave-- end of March??

As I stated, had this been a January pattern and not the end of March, it of been one for the record books.  March 5-6 is a 10-20 inch event, a couple smaller ones and this one on the horizon. If it were January 24th, I'd be deciding between forecast 3-6 and maybe 8-12.

But, we are stuck. I've considering blogging but being honest-- the models have STUNK this year and it's made it hard. They keep upgrading these things and before you can work out the kinks for your specific region in interpretation, (especially winter with the temp issues of snow vs rain vs sleet) and just a LACK of events has made it a challenge.

So, model data is all over the place. Some models have been showing pretty snowy solutions and others have been showing SOME snow, but daylight, lighter precipt etc makes me infer it won't accumulate.

I'm still a snow lover at heart and part of my NON blogs was just not wanting to invest in ANOTHER event that will disappoint me. I mean, Jan 25th clipper with an inch was fun, but I expected an inch. Jan 17th rain to snow was fun-- 3-5 inches of heavy stuff and 2 hours of the biggest flakes I've seen in LYH was awesome. Everything else has been a let down.

From a snow lovers point of view--

If everything goes right--

We can see 6 inches.

If everything goes wrong, we get a burst of sleet and snow that doesn't lay-- and then occasional flurries and snow showers that don't accumulate.

As a forecaster-- I feel obligated to share both sides and then make an official call.


As of now-- Roanoke and Lynchburg 1-3, with a little sleet likely as the events start. The biggest part is over by 8 PM tomorrow if not sooner and we just have lingering flurries and snow showers.

NRV into the Highlands 2-5-- mostly snow. Better snow in the favored up slope areas.


Will hit Facebook and twitter harder from this point. Everything else will be really now casting. . The LATEST Euro and NAM have a pretty decent burst of snow tomorrow mid day through dinner time.
*GGEM* as well-- canadian model. If your  a snow walk or like taking snow pictures, would be an excellent time.

BTW, no complaining over late March snows. They literally melt the same day. Literally, I would expect most to melt overnight Sunday, event if we get 3-4 inches.

Sunday, March 17, 2013

A touch of winter--lingering.

This is the winter that didn't really want to get started, and now really doesn't want to end. 

It's not usually fair to say "What if this were"-- but we've had some pretty strong blocking most of March. Had this taken place 2 months ago-- we'd of had a heck of a winter. The March 5-6 storm likely would have been all snow, and 10-as much as 20 inches region wide. Even with the warm March sun pushing Tuesday March 5 up to 50, it started as sleet in Roanoke with dry and and even the rain here, the first 10 minutes or so had some "slush" in the drops as the dry air didn't allow for total melting. 

With that, another minor event possible-- I should of blogged this yesterday, but the kids got me busy playing Mario on the Wii U :)

Cold front has passed and colder air is filtering in--

This is a 100% timing event-- as warm air is being pushed back over the top and causing more precip to fall. If the timing is off, we could get a little more or less than anticipated. Either way, not a huge event. There are winter storm warnings for the same areas that got BEAT DOWN on the March 5-6 storm The warnings are for 4-8 inches. Timing is good, with much falling as night, but as we've gotten closer, the warm air aloft is coming in a tad faster. So, sleet may be a bigger issue on some areas of 81 as well cutting down on the large 8 inch amounts. (Especially east of the Blue Ridge like Charlottesville)

Southside is mainly safe-- rain. 

NRV would likely see less than LYH and ROA.

Some freezing drizzle is possible after the main batch moves out and we have some linger moisture in the early and mid morning. 

ROA and LYH-- up to a slushy inch of sleet and a little snow. Not a big deal, and certainly likely a school delay NOT needed but I'm sure they will. :)

March isn't over-- and neither is our shots at snow, yet. Data has been hinting around March 25 another "big" coastal low. I know March 5-6 failed due to the lack of fresh cold air-- this storm "may" have it. That's a LONG ways away and subject to much change.