Serious ice or serious sleet? Big event on the way region wide.

 Winter Storm watches are out for everyone in our region for a little snow, some sleet then ice. 

The basic set up is we have a piece of the polar vortex moving across New England pushing cold air into our region at the same time the "south east ridge" ridge means warmth in weather terms. This battle between the warm and cold will make for very moisture laden system with precipitation amounts of 1 to maybe 1.5 inches. 

I'm somewhat optimistic at this point that it will be a serious winter storm in the NRV to ROA to LYH with some icing concerns but we may just see enough sleet to mitigate HUGE issues with our power grid. (May, not a lock yet) This could keep freezing rain total UNDER a catastrophic level. Southside is another issue where they will get mostly freezing rain. As bad as the Farmville to Charlotte to Halifax area saw, this could be worse and more wide spread with more precipitation and colder tempatures. 

1. It may be a smidge colder, especially early on. You may be shocked to know that ice builds up more at 29 degrees than 31 or 32. 

2. It may rain harder, which is actually a good thing with freezing rain because it can't freeze fast enough but the duration will likely offset this. 

Basic Details:

Snow sleet and freezing rain develop overnight Wednesday into Thursday. Midnight to 4 am)

Southside: Quick burst of sleet to freezing rain. This will have a huge impact on the power grid. An inch or more of freezing rain will fall and build up on trees, power lines etc. I expect serious issues in this region with long term power outages.  Ice build up will be greater than a half inch most areas. It may take days to restore power. 

North of an Amherst to Daleville line, precipitation may start as an inch or two of snow, then sleet. 

** Caveat** The GFS blast a quick burst of snow from the NRV to Charlottesville that is in the 4-8 inch range before ice. I don't think it's going to happen but wanted to throw it out there. This gives Lynchburg an inch or two at the same time before any sleet falls. 

NRV to Roanoke to Lynchburg- 

A quick burst of snow will flip to sleet. We should see a good bit of sleet before freezing rain because the "warm layer" sits pretty high, above 5000k feet and from that point to the ground is a solid 3--6 degrees below freezing. That's a classic sleet signal. We could see between 1-4 inches of  quick burst of snow then mainly sleet. This should eventually mix with then become freezing rain and we will get a quarter inch of freezing rain build up. Most places had that in this past event, so I think we can mostly survive without HUGE power issues. With that, this is a Fragile forecast because if we change to freezing rain sooner, the Ice build up and power outages will be greater. 

For this region, I mostly see 1-4 inches of sleet, then freezing rain of about .25 build up. This is close to a crucial breaking point but hopefully we stat at this level. 

Temperatures may creep above freezing later Thursday but the damage will be done. We have better antecedent cold air, so there is a shot we remain at 31-32 until Friday AM. 

I'll pop some images on the bottom of this post but here are two- the top is predicted sleet  and ice accumulation from the RGEM model.  Note the sleet is total in inches and that in general 1 inch of rain is 3 inches of sleet. (meaning that most those in that area see an inch of precipitation fall as sleet.  Also note that the freezing rain map counts all that has fallen but it all won't freeze because when it is HEAVY freezing rain much runs off before it freezes. With that, those totals over 1.5 inches will be catastrophic. (At this point, those in Southside and Northern NC)

Wintery 10 days coming up- can we do better than mostly ice?

 We have a fun, fascinating pattern setting up where a piece of the polar vortex will position itself over the upper Midwest. (Great for Cold)

We also have a Southeast ridge based on other issues in the pattern ( Leads to warmth for the southeast) We sit in the Northern part of the south, tucked in near the Blue Ridge and quite honestly, the next 10 days will be chaotic. 2-4 chances of winter precipitation(and rain) We could see 2-3 inches of liquid in that time frame and trying to separate what falls when and where will be a challenge. 

Event 1 2-11/12. Cold air sinks in from the North, rain changes to freezing rain then sleet and perhaps snow. In general the further north you go the more sleet and snow you see. This likely won't be a big snow maker but 15 miles may be the difference between 3inches  of a sleet snow mix and a half inch of freezing rain. 

* I think the kids are out of school regardless most places Friday and maybe even Thursday*

Event 2 possible as early as 2/13 or Saturday as another weaker wave drops some light freezing rain during the day Saturday. 

Event 3 has the potential to be the worst of the three. This would be on or about February 16th.  The cold air REALLY builds in at the surface and some data suggests an ice storm that starts while temps are below 20. This would be Monday into Tuesday time Frame.  This is just one plausible outcome, but isn't the forecasted outcome at this time.  Liquid amounts of over an inch with temps in the teens rising towards freezing has BIG TICKET written all over it. 

This is a map of the heights anomalies. In simple terms, heights are calculated by the average temperature below that level. Those area blue and purple along the Canadian border and much lower than normal heights, meaning COLDER than normal temperatures. (Actually a piece of the polar vortex is there) The red over the Southeast USA is higher heights, or what should be warmer than normal temperatures.  

This gradient between higher heights and lower heights is creating all these storms. Cold air likes to push south in this pattern but is being pushed back by the Southeast Ridge. If that ridge wasn't there, we'd be cold and dry and that meaning very cold.  If that colder anomaly was not there, we'd be rather warm. What makes our situation unique is the Blue Ridge Mountains where the cold air, which is heavy and dense gets trapped and can't be moved out. (Remember, cold heavy- warm, lighter)  Some of the data for our storm Tuesday has surface temps in the teens but 5000 feet above temps are in the 40's. For those who remember the ice storms of 1994, this pattern is not far off looking 6-7 days out. 

The first of three chances is on Sunday- Monday.

 The long story short is we should have 3 distinct chances at some wintry precipitation starting Sunday. We can get all 3, we could get 2-3, (Which by Meatloaf standards isn't bad) We could only strike on one event and we could miss all 3 (And with three strikes you're out)

Setting up Sunday is a storm cutting to our west Friday that cause some rain then drag a cold front through.  A second piece of energy will then trail up that cold front. Where this gets dicey is- some model data doesn't push the cold through enough and primary low goes into the Ohio Valley then a secondary low forms. This set up ALWAYS changes us over or event starts as ice or rain OR the boundary could push too far south and is oriented in a way that allows it to escape harmlessly out to sea.  

I'm leaning towards Ohio Valley transfer at this time- but have plenty of time to adjust. This favors more snow in western regions, mix/rain set up East of Blue Ridge and Mainly Rain southside. 

Event two will be about Feb 11 second change at a winter event. (It's also the 38 year anniversary of the Megalopolitan storm of 1983 that dumped 15-20 inches region wide in our area of Virginia. I was 9 years old and we had true blizzard conditions at my home in New Castle, Delaware. 

We should have better cold air in place for this event and if there is any threat, it would be suppressed (To our south) or sheared (Upper energy weakens) and the storm falls apart. 

Looking past Valentines day, the 14-16 range may hold the best potential of the year as the blocking maxes out and just starts to relax. Often, in those relaxation stages a big storm pops. This is 2 full weeks out but this image shows strong cold air in place via upper air energy (starting the 50/50 lat/lon) with pieces of the a weakened polar vortex across the upper mid west. Energy near Cali indicates either ONE big storm potential or several smaller events if only pieces of the that upper energy comes out. 

The red stretching from Maine to Minnesota is a fragment on the weakened polar vortex while that red over the northern Baja is upper energy from the sub tropical jet.  

 

Again, this is about potential, not actual events. Things will change and adjust as we get closer. If you love snow, get your favorite lucky mug and if you are a snow hater, well- we went 700 days without accumulating snow. We know what they say about paybacks!