Sunday, January 29, 2012

Don't call it a comeback--

The pattern change we have speculated on is coming-- no longer speculation. If the pattern change had NOT developed as speculated, winter would be about flat lined. Instead, it's like the OLD wrestling days of Hulk Hogan in a sleeper hold and as the ref would pick his hand up and drop it once, twice and just as the third drop would be the final blow, his hand would shoot up and he'd garner the strength to break the sleeper, big boot to the face and he's the winner (again)

I often throw out many "initials" and assume that if my readers want to know more the will use google. The Arctic Oscillation, AO which had been very positive is very low at this time -4 today, which is bodes well. The MJO-- which is moving from phase towards phase 7 is good as phases 7-3 tend to be cold and stormy in the east. The NAO is close to neutral which means it's not helping, but could be worse. The AO and NAO have about a .8 correlation or so, so the NAO may start to slide negative.

For the record, I was rather skeptical about this change and still skeptical that it does much for us here in the SW and Central VA region, with that--

Too much technical talk, Keith-- I want snow.

Storm 1 Feb 5-6.

We should have a decent chunk of low level cold air but the pattern isn't ideal. Low cuts to our west and we get maybe a brief period of Snow that goes to ice and maybe rain. Has some potential to be our first "winter storm warning" for the metro areas because the need is for over .25 of ice. Some model data now shows 2-3 inches of snow BEFORE the ice. As the low cuts west a secondary low pops off the coast to our east-- could be bigger event Northern VA west of the DC metro and into central PA.

My take-- In general, the models will look to ominous with snow early on, and as the event gets closer it becomes a mostly freezing rain event. If the the cold air is deep enough, sleet could be a larger part of the equation.

Here is a teaser map from the 12z ECMWF-- This is snowfall late Saturday night. Not saying this is accurate, just SHOWING what a model says. Storm would end as freezing rain in the later frames.

Possible event 2- Feb 9-13 ish.

Overall pattern looks pretty good- the lack of blocking in the NAO region could allow the "mean trough" to be a shade too far east meaning a storm slides off to our south and east and misses us or NOTHING comes from it. There will be some energy coming out of the So CALI region, but we need that energy to make it across the states. We live far enough south that depending on what is called a "miller B" to get snow is a bad idea. (Philly north is the Miller B favored spots)

After mid Feb-- some of the people I trust see it turning warmer. With the -AO at -4, I can see that being wrong, but I'm not sold either way. Something to watch-- the pattern has been so extreme warm, hard to see this being a permanent change.

Sunday, January 22, 2012

A little snow this AM, a little ice later on today--

Very rare snow this AM-- easterly fetch from from the Atlantic made a little low level snow to fall. I had no idea we could get something like this this far west, but that's exactly what it was. Since it came from lower tops, wasn't showing up on radar to well either. I have a friend up in Charlottesville who reported a half inch or so.

We've got a freezing rain advisory for everyone in our CWA except the counties along the NC border east of the Blue Ridge-- This won't be a huge event as a far as rain totals, but we've been colder the last 2-3 days and any thing that falls COULD cause a small mess. Temps are in the lower to mid 30's with the dewpoints around 30. If we get a steady rain, temps could fall as low as 30 with the dryer air a little higher up. A few pings of sleet are also possible, especially early. This rolls in after midnight as the winds shift to the south with a stronger storm to our west and low level cold air in place.

I'm glad the NWS put up the advisory-- my fear in events like this is one lives in a warm spot, sees no ice on their car and drives off to hit an ice patch. I've mentioned before in my blog, but there was a rough event like that back in December 07. Only .02 liquid fell, but the roads were horrible between the start and 11 am or so with some horrific wrecks near my home in Forest.

As always, I'll update as needed- via facebook at Keith D. Huffman, add me if you like the data or twitter Lynchburgwx

Long rang still looks uncertain. Reading some conversation between guys with a better skill level than I, wild guess is February comes in close to normal-- maybe 1 degree above normal. Better shot of some ice/snow compared to Dec and Jan, but nothing major. We are still lacking high latitude blocking.

Friday, January 20, 2012

Ice is forming on the tips of my wings--

A little Pink Floyd for some late night ice--

As I suspected, we've flipped to freezing rain in Lynchburg, yet rain in most other regions. Strong flow down the east side of the Blue Ridge brought down just enough cold air to bring us to freezing. I did a brief walk outside and there is no ice on the cars yet, but on some of the trees and bushes there was just enough to notice it if you felt it.

This won't be a huge ice storm, but I just cringe at the thought of ONE bad wreck due to lack of warning. The off hour runs all showed freezing rain in Lynchburg-- so, I'm not shocked, but as I stated, I could have easily seen this being a 33 and very cold rain.

Be safe-- only the favored spots in the shade could get an icy spot or two. There are some heavier bands of ran heading our way and that actually helps the ice to NOT freeze to marginal freezing temps. (Rain falling faster than it can freeze)

Be safe-- if you have friend or family who went to a late movie, grab some food- shoot them a text out of caution.

Some sleet now, freezing rain very possible later tonight--

I just pulled in from work and a little sleet is falling. Model data has been very slowly trending colder at the lower levels of the atmosphere. The first bouts of sleet will fall as there is a pretty dry layer. As the sleet gives way to more rain, the lower levels of the column will cool and some freezing rain is likely in Lynchburg proper between 9 PM into early tomorrow morning. I can see the temp parking at 32.5 and NO icing occurring, but can also be at 31 or so where icing occurs on elevated surfaces etc.

Because the cold air is north south based -- Roanoke should be sleet but mainly rain after that.

Be alert-- will update on Twitter and facebook as needed.

Wednesday, January 11, 2012

What happened to winter?

It's January 10th and we've maybe had 2-3 days that FELT like winter. WOW

Why? Literally everything in the global pattern has pointed towards warmth. What is everything-- Teleconnections. Teleconnections are indices that gauge pressure at various place on the globe that show the general short and medium term weather patterns. PNA, NAO, AO, EPO, and MJO all measure various factors and when they measure certain ways we know the pattern is more favorable for cold and snow. In winter, one of the biggest buzz words used is the Arctic Oscillation and the North Atlantic Oscillation. The Arctic Oscillation in simple terms measures pressures up near the north pole. When it is positive. it tends to keep the cold air bottled up near the north pole. The negative phase allows the cold air to spread away from the pole. 

The North Atlantic Oscillation while measured separate (a contrast between the Icelandic Low and Azores high-- or simply the pressures near near Greenland compared to the Azores ( The area east of Bermuda but west of Africa and Europe)  There is a .82 correlation between the AO and NAO-- meaning when the AO runs one way, the NAO usually follows suit. The AO has been positive all but a few days since November and the NAO has been all but positive. 

How does winter end?? Simply put-- I'm not convinced either way. Most winter outlooks took a more traditional La Nina of colder December, warmer in January and warmest in February. This have all been wrong. I did share one outlook from a forecaster named Keith Allen.   Here where he predicted the coldest weather in February. So, not everyone went a more climo Nina. 

With that, I'm not convinced we are heading there.  What I do expect--

1. More frequent shots of cold air--even if they only last 2-4 days. 
2. Increased shot of minor snow events- Maybe a Clipper over the late weekend (I'd favor it passing to our north and bringing an inch or two near DC up towards the Mason Dixon line.
3. Between days 10-15 the pattern slides warmer as the Pacific NW becomes a colder up into western Canada. 
4. After that-- maybe a push east again. 

In general, nothing TOO exciting. As far as winter storms, 2-3 weeks down the road I can see us finally getting something where the cold air bleeds a little further south and we get an overrunning event. That is pure conjecture on my part, nothing on the models or pattern. 

There may be reason to update more, but nothing threatening at this time.