Tuesday, March 29, 2011

2 more threats of rain, with maybe a little snow.

We are in the middle of a crazy late season cold and stormy spell-- despite our system not really panning out as anticipated, the threat THIS late was rather interesting.

A system approaches our area tomorrow-- and again the higher elevations to our NW may get some accumulating snows. From Lexington north, up 81 East to the Blue Ridge may get a coating to maybe 3 inches at the highest elevations. 

Again, the parade of storms continues and storm approaches Thursday-- same set up, different day where the highest elevations have a shot to get some accumulations. 

Both tomorrow and Thursday have the chance to see some flakes flying in the Lynchburg/Roanoke region-- but I anticipate the best shot for more then flakes in the air will be at the highest elevations.

I won't be shocked if either tomorrow or Thursday has a heavy enough burst to coat the ground with snow for a short time in ROA/LGB. 

Sunday, March 27, 2011

Ya Blew it boy, you REALLY blew it (Krammer voice)

Last nights event was HORRIBLE-- Yeah, I stayed low but NOT low enough. Around 11 PM I figured we were toast-- hoped that band I mentioned via twitter would pull it through for an inch, but between the warm ground and the sleet mix it just wasn't in the cards. Models are guidance and nothing more. One key issue that modeling doesn't handle well is convection on the south end of storms. There were severe storms riding through AL and GA and in effect that robbed our moisture for our snow event. This is a well researched area and they can even gauge the impact based on the angle and trajectory of the storms, but it's hard to quantify the impact on total precipitation.

What killed us was a lack of total precipitation and nothing more. Most models ran between .40 and .75 or so consistently-- and at 10 PM the NAM which lead the way dropped us back to .20. We ended up with .16 total liquid.

There is another system dropping to our south late tonight. With our luck-- watch this one do BETTER compared to our system of failure last night. Galax to Danville has the best shot to see a coating to an inch.

If anything more important develops-- I'll update. Stormy and cool pattern for the next week or so with 2-3 shots of rain .

Saturday, March 26, 2011

Final thoughts before game time---

Fun late season event-- and basically harmless. There's not really going to be enough snow falling to cause any tree damage, the warm ground will melt this fast and despite me being certain it is going to snow, the total amount is a little uncertain.

I'm not wavering on my call of 1-3 for MOST areas. Blacksburg, Roanoke and Lynchburg along 460 will be in this zone. The southern line of an inch will be south of Gretna line, heading SW towards Max Meadows. The best accumulations will fall above 2k feet NORTH of Roanoke- Lexington, Stauton, Waynesboro, Hot Springs-- those locations. These places could see 4-6 inches.

In the lower elevations the inhibiting factor for 4-5 inches is a little mix and very wet snow the first couple hours.

The models have varied enough that there certainly is a chance we get a little more or less then anticipated-- and of course I will update as needed.

Late evening **Snow** Update *Sat am update*

Saturday AM update-- NWS out of Blacksburg side with me and upgrade our region to an advisory to 1-3 inches-- up to 4 in the Blue Ridge.

With the the time change--- weather model's are running a little later and the bottom line of that is I'm staying up another hour. VCU has 2 minutes to lock this up so I can sleep.

The NAM and GFS have run and the data hasn't changed much. The GFS hints that there could still be a sleet issue for a while and the NAM is still the outlier, putting down almost 3/4 of an inch of liquid from this system. I expect Roanoke and Lynchburg to end up with maybe .4 give or take .10 of total precipt falling during this event.

This is only a "big deal" because it's coming on the tails of some great weather and late March snows are rare around here. I can't 100% rule out over 3 inches in the 460 corridor but it's unlikely.

I like my original call-- 1-3 inches Blacksburg to Roanoke to Lynchburg with some sleet and snow grains likely mixed for a while Danville Martinsville MAY see some flakes and sleet with a coating. The BIG winners will remain the Blue Ridge areas just to our north with 2-5 inches, maybe a 6-7 inch total from Hot Springs or Afton Mt.

Friday, March 25, 2011

Rare late season snow becoming more likely--

March 30 2003-- a heavy rain switches to a driving heavy wet snow. Roanoke to Blacksburg had 4-8 inches. Lynchburg had 5+ inches fall, but only a 2 inch max depth. At my Forest home-- we had an inch, a lull which allowed it to melt and another 2 inches that accumulated.

This is the last latest snow in our region. In April 2007 we barely missed a late season snow that coating the ground from NE NC-- Mebane NC had a coating.

Same set up as before-- The cold has been trending a smidge colder, but the models do want to punch a warm later through between 7 and 10k feet. This is a tremendously cold air mass so even when this happens, the snow would partially melt and fall as snow grains rather than pure sleet. When I examine the layers of the atmosphere and see that in theory Roanoke and Lynchburg are supposed to change to sleet before Richmond-- usually this indicates this warm air push is not only very likely, but often will occur sooner than modeled.

Brutally cold day Sunday for LATE March-  temps may struggle to reach freezing once the snow starts, even with a strong late day March sun.

My best guess now is start time between 10 PM far west to 2 AM far east overnight Saturday into Sunday.

Martinsville to Danville-- rain, mixing with sleet. Sleet could coat the ground.

Blacksburg, Roanoke, Lynchburg-- could have a little rain to start, but snow-- changing to snow grains and sleet ending as flurries.  (Snow grains look like rice) 1-3 inches.

Jackpot-- Lexington to Hot Springs to Harrisonburg to Waynesboro into Charlottesville-- 2-5 inches, best accumulations at the highest elevations. Would not be shocked to hear a 6-7 inch total from Afton Mt or some other elevated location.

We are about 48 hours out from this event-- so it has some wiggle room to change. I'm always leery of the "north trend" the models often display. In terns of wiggle room-- we don't have much because Danville starts as rain and changes to sleet as modeled now well into the event. 60 miles isn't much of a jog in 48 hours. Having said that-- there has been remarkable consistency in the models for days now. Still, I've seen the north trend OVER and OVER in years past-- sometimes the models never even show it, but it takes place anyways.

As a result, I'm in full storm mode-- blog updated 2x a day until this event passes by.

Thursday, March 24, 2011

Sharply colder weather on tap-- with a side of white ??

Crazy to think that we've had some great weather the past couple weeks and in the blink of an eye we MAY be looking at a late season snow/sleet event. But, alas-- spring time.

Reality, we've been playing with fire a while because there's been plenty of cold air on our side of the globe, just no blocking to force it south. Enter the block and we've got a legit shot at something over the weekend and MAYBE again next week.

This is a quick heads up, but I will elaborate later. Cold front drops through or region and stalls to our south as a storm forms along it. If the cold air settles as far south as the NAM/ EC we'd have a good shot at some snow/sleet and rain--  Timing looks to be Saturday night into Sunday. This could be a wet system-- but with the warm ground and sun  angle -- a slushly inch or two is likely the best we can do. Some data also has hinted as sleet being the predominant precipitation type. We've got about 60 hours until game time.

Friday, March 11, 2011

So, you're telling me there's a chance??

If something does come of this-- it will be a million to one.

The model data has been all over the place. ( Putting aside that guidance showed between 2-3 inches of rain in Lynchburg with the storm Wednesday and Thursday and we got a meager .65 inches or so)-- there has been SOME event hinted at on the data for a week or so.

Some days, there has been NO storm, some days-- Models made a MAJOR storm.

Slowly, it seems there will be a storm.

Could it be SNOW??
Well, I don't usually blog that much over rain, so YES-- but I highly doubt it. Since this blog is often used to speculate I don't mind throwing this out there.

Basically,  HP is sliding to an ideal spot for our location and a short wave consolidates at the about best time and fires up a decent event. The forcing is supplied from the closing off upper air low and a sinking cold front. If you've been reading me a while-- lift= precipitation.

Temps are very marginal and its still 3 days out.

My gut says we get a storm but its about 100 miles north of shown-- and temps are warmer. Waynesboro, Harrisonburg and those places may see a decent late season snow.

For the record-- some data I just checked out showed between .5 and  1.25 inches of liquid over our region with a decent path of 1-5 inches of snow in that. Temps are horrible the last 2k feet or so-- hence the lack of snow from all that precipitation. Ironically, the storm putters so slow because there isn't much of a jet stream speed wise as of now-- that it actually warms up aloft as the storm unfolds. So, if some places do see snow, it may end as rain.

As of now, anywhere below 2k feet-- expect rain. Those higher elevation places COULD get a get something-- rain switching to snow. We've got plenty of time to watch this event--

Tuesday, March 8, 2011

Flood Watches Hoisted again--

Another late winter storm will impact our region starting Wednesday. The rain will begin Wednesday afternoon and will be rather heavy overnight into early Thursday morning. Region wide totals-- 2-3 inches, with maybe a few spots ending up with more.

With the good rain over the weekend, rivers still running high from the rain on Sunday, and likely more rain falling this time a more potent flood event could unfold. Again, the highest prone regions will be along the rivers and the low lying areas.

Wednesday night will be a pretty raw, nasty night with temps in the low to mid 40's and a breeze out of the NE.

The great issue is that we certainly need the rain. As we predicted in our winter outlook, this was a rather dry winter and any rain is needed.