Wednesday, December 17, 2014

582 & Florida..

Looks like the American model, the GFS will win a round of the model wars.  Maybe??

The Euro was gung ho on a strong low, with plenty of wintery precipitation this weekend before Christmas.

The GFS never really bought in and ALL the data is trending towards a very minor event, or maybe just some clouds and drizzle.

With all the reading I do on weather, I recall once reading the 582 height line needs to be in south Florida, or even off shore towards Cuba. I commented in my " chats" with my weather people/meteorologist that it was north of Orlando. To me, it's not a forecasting tool, but like an easy cheat that may give you some insight.

With that, the low will be much weaker and drier and the with that the temps end up warmer for many reasons. Some light snow, sleet and rain still possible but not a big deal.

I've attached a picture of what I mean.. DT from Wxrisk showed what was wrong with the BIG pattern, and I just circled my little clue over Florida. When the 582 height line is that far north, the flow aloft can be hostile for storm development.  DT made this map, but note where I circled Florida.. the orange is the 582 line. When the storm looks good, its just about SE of Miami and when sheared out, it's almost north of Orlando.

Monday, December 15, 2014

Quick update..

If forecasting was easy-- anyone could do it. I mean, what job lets you get it wrong HALF the time and still have a job?

:) Of course, .350 is a great baseball average and .500 is a good shooting percentage for the NBA. I'm a big fan of Will Ferrell and I'd say like a third of his movies are actually good.

Where we stand--

Models are not in agreement but we know this:

1. Cold air works in Friday..
2. Low forms in Gulf of Mexico

What we don't know:

1. Does cold air get locked in? I've mentioned a feature called a 50/50 low-- it sits at 50 latitude, 50 longitude. (New Foundland area) This feature keeps the cold air locked in by keeping the high pressure from scooting out to sea. Times like this I need to make video blogs. :)

2. Where does the low pressure go? Some data has kept it WELL south where we get fringed with light stuff, some take a pretty aggressive track up to Wilmington, NC and then up the coast and others take the first low into Kentucky and then reform it in NC.

A. WELL south is a fringe job-- it may be mainly snow, but not a ton.. like 2-4 inches at best.

B. The aggressive southern route brings us more moisture, but with moisture comes warmth. This would allow some mixing, especially along and east of the Blue Ridge. I could see this being a 6-12 inch event along 81, with more of a 2-4, 1-3 event east of there.

C. Primary low goes into Kentucky and reforms somewhere. This would be mix to maybe even plain rain many areas, ending as some mix or snow. Mts areas may get 2-5 inches while the sleet and snow MAY cover the ground east of the blue ridge. This has variables because there is a big difference between the low reforming of the South Carolina Coast vs lets say 50 miles east of Raleigh.

Any guesses?

Model data didn't really clarify much today. For everyone that looks like it moves towards the Euro, the Euro moved away from it's last 2-3 days of runs and it's ensembles moved towards the solution from last night.

Best guess as now:

NRV and MT Empire-- 2-5 inches of snow and sleet.
Roanoke Valley- `2-3 inches of snow and sleet, with some glazing of freezing rain.
 Bedford, Lynchburg down to Altavista- Coating to 2 inches of sleet, decent amount of freezing rain.
Martinsville to Danville- Sleety rain, ends as some snow maybe a coating and slight glaze of ice.

This is NOT locked in stone and still very fluid. I tend to warm up the models based on what usually happens on southern stream events in the mid levels, cool the surface at this point out.

Best snows at this point still look to be on 81, north of Exit 220-- Stuanton area north into PA on 81..

Saturday, December 13, 2014

Dub stepping to Christmas..

Storms and rumors of storms will abound.

We are in a slow change pattern time and as we move towards Christmas week we will have SOME cold air around and some storms. 

What does this mean? 

Those of you who are on social media have likely already noted some posts discussing possible storms on Dec 20-21 and a follow up December 25 or so. 

Dec 20-21

The Euro has been consistent with showing an event that stays to our south, times just enough cold air and holds it JUST barely and we get a pretty nice pre Christmas storm. Now, if the euro is exactly right we'd have a NICE mix to snow event with accumulations north of 460 north of 6 inches, with 2-3 inches down to the NC state line. If the Euro is exactly right.

The biggest thing that always happens is UNLESS the confluence (Air moving quickly behind a low that parks near 50/50) there will be a north trend. Models always tend to start too far south and trend north) Outside of a couple events.. FEb 2012 and Jan 2013, the north adjustment is real. If I had to target an area that is in the highest risk, I'd take the 81 corridor NORTH of Staunton as the highest risk, but extend the risk down the NC state line all the way east to the piedmont. 

We are stepping slowly towards a colder pattern, but the real cold is still 3-4 weeks away. Just cold enough works in a perfect set up, but I'd not be too excited at this point. Everything would have to go swimmingly for us to see a nice storm. 

Follow up possible Dec 25 or so-- 

The signs are there for a colder pattern early January but I'm always nervous at this point. DT from Wxrisk-- and many of you follow him has a good eye for these type events and he's updating a lot. He's a great follow for big ideas and patterns but when events get close, always stay with your local guys. Sean Sublette from WSET is fantastic. I say this often, but we are blessed with a skilled met who takes his job very seriously. For my people in Roanoke, Kevin Myatt is as good of an "semi professional" as I am (if not better) and if you know people in the NRV down to the Mt Empire, Zach from Blue Ridge Weather is a great resource. What skills that Kevin, Zach and I have are just great feels for the local climate and how storms would impact our specific region. I'd trust Kevin in about any event if I was unable to access model data. As we move forward,, Kevin from the Roanoke Times, Zach from Blue Ridge weather and let me throw in WxSouth with Robert Gamble are great resources for 411. Of course, stay with me for your local and precise winter weather updates.  Even if the 21st and Christmas Day event don't pan out, things look to be picking up.