A pretty moist storm system is developing just to our south and will move up the coast. Because another system is to our west providing warming aloft, we won't see a major ice or snow out of this. However, with a colder air mass in place, the system will have some sleet and freezing rain overnight-and actually maybe a flurries late day and early evening. Temps will be very close to freezing and it should not be a big deal. However, if the temps are just a smidge colder, we could have more of a rush hour mess tomorrow morning.
Another cold front sweeps across the region Friday and a storm is forecast to form along this front as it passes our region. Exact time, track and amount of cold air are still in question. I'm not as "sold" as I was on this now compared to 2 days ago. As always, updates come as needed.
Monday, January 17, 2011
Saturday, January 15, 2011
The cold seems to bend, but just won't break..
As discussed in my early morning Friday blog, we were forced to accept the second half of the winter warm up predicted in my seasonal outlook won't pan out. And while the models have hedged at some warmer days compared to the minus -9 average from December the overall outlook was cold.
We have an event on tap for late Monday into Tuesday. Data is still not clear, but 2 systems approach our region-- one well to the north, and one down along the gulf. There is a MINOR amount of cold air remaining in our region from this cold stretch and depending on the amount of moisture that get into the area will determine the total impact.
Event 1.
Late Monday night, A mix of sleet and freezing rain will develop and eventually change over to rain. Tough forecast-- the models have shown anything from next to nothing all together, to 2-3 inches of snow and sleet to freezing rain, to just a good soaking rain. As of now, I think we get a little sleet to start, several hours of light freezing rain changing to rain near dawn on Tuesday. Southside may be spared most of the ice threat while the NRV could start as a little snow.
Event 2.
Another arctic air mass approaches late next week near the time a low pressure forms in the gulf. As of now, the cold air lags JUST behind the storm, so the air in front could be a little to warm, especially east of the Blue Ridge. This could end being an I-81 special where the elevated regions to our west get a decent snow and we get a messy mix or just rain. Cold air fills the region after this.
From here-- it seems the cold bends for a few days, never breaks and remain cooler then normal on average. Behind the system now COULD be some of the coldest air of the season.
We have an event on tap for late Monday into Tuesday. Data is still not clear, but 2 systems approach our region-- one well to the north, and one down along the gulf. There is a MINOR amount of cold air remaining in our region from this cold stretch and depending on the amount of moisture that get into the area will determine the total impact.
Event 1.
Late Monday night, A mix of sleet and freezing rain will develop and eventually change over to rain. Tough forecast-- the models have shown anything from next to nothing all together, to 2-3 inches of snow and sleet to freezing rain, to just a good soaking rain. As of now, I think we get a little sleet to start, several hours of light freezing rain changing to rain near dawn on Tuesday. Southside may be spared most of the ice threat while the NRV could start as a little snow.
Event 2.
Another arctic air mass approaches late next week near the time a low pressure forms in the gulf. As of now, the cold air lags JUST behind the storm, so the air in front could be a little to warm, especially east of the Blue Ridge. This could end being an I-81 special where the elevated regions to our west get a decent snow and we get a messy mix or just rain. Cold air fills the region after this.
From here-- it seems the cold bends for a few days, never breaks and remain cooler then normal on average. Behind the system now COULD be some of the coldest air of the season.
Friday, January 14, 2011
Mid Term Grades-- The Good, the Bad and the Ugly
Well, the half of winter is just now on the books--
First, quick updated about the earlier snow. My 1-3 inch call was a little too aggressive and we did have a longer period of freezing drizzle than first anticipated. My great intentions of updated the blog went under. If you read this and do not have me as a friend on Facebook, please add me as I will stream updates on there or add me on your twitter account.
Despite December coming in as record cold-- we are heading towards a pattern breakdown for a while. IF, the pattern would remain warm, my season outlook would be pretty good despite all things. (but it won't)
The good-- The cold pattern developed late in November as anticipated and lasted all month in December. Mid January the pattern has broken down,. As foretasted, it has been dry with no major snow events. The December 16th event has been our largest snowfall of the season. My snowfall outlooks have verified well, all within, even if just barely the range allotted. ( December 16 was a 3-6 inch call with 3 inches and 2.2 for a 2-4 for Christmas day.
The Bad-- While getting the general idea for a cold December right makes me happy, the pattern was much more amplified than I first anticipated. Much more is code for record setting amplified. My thoughts of a HISTORIC cold outlook from 10 days ago looks really bad. Yes, its been colder than normal but nothing historic.
The Ugly-- Nothing remotely close to a pattern that resembles ice threats, much more intense blocking. Also, while the pattern is shifting, I doubt the cold is mostly gone for the winter.
From this point forward-
We have a rain threat Monday with MAYBE a little sleet or freezing rain in the front side.*Nothing major* Something called the PNA spikes (PNA is a ridge over the west coast). This brings a colder pattern to the east, but NOTHING to lock in cold air or slow down a storm.
Something called a "Sudden Stratospheric Warming" is linked to a -AO -- and one of those could be in the works (I'm no expert in the this process, just know the impact, here is a wiki link of you want to read more http://en.wikipedia.org/wiki/Sudden_stratospheric_warming ). What this COULD mean is a return to the stronger blocking we had in December. I've not noted the updated information from this, but this usually takes a few sides of 10 days to re establish the colder pattern. The bottom line is it weakens the polar vortex. When the polar vortex is weaker or in several smaller pieces it allows for blocking to dominate.
Moving forward, My guess is that the first half of my winter outlook is going to be MUCH better than the remainder. It does seem like this will be a more intense winter cold wise and the snow card has basically 8 viable weeks to play out somehow seems bleak to verify with a 5-10 inch allowance I predicted.. La Nina winters are NOT known for historic events, and yet we've had 2 on the east coast--- the Boxing day event and this past Sunday to Wednesday event that just slide past our region with a minor dusting. We've officially clocked 7.4 inches this winter in Lynchburg and I expect this to increase. Putting aside the dry nature of this winter, the overall pattern has been NOTHING like a La Nina and there are not many signs that this will end anytime soon, just breaks.
One of the points of my outlook was that seasonal pattern changes often weaken and mute the impact of La Nina's. If we get a Sudden Stratospheric Warming-- the impact would likely be the first 2 weeks of February. At that point, the long wave pattern is starting to make the seasonal change to spring and the impact of La Nina is drastically dropped. So, I'm hedging colder overall for the remainder of the winter, just not as cold as December. Snowfall hasn't been hard to come by--but hasn't been anything significant. My guess is that we could move the seasonal total is more like 10-15 inches this winter rather than the 5-10 forecast.
First, quick updated about the earlier snow. My 1-3 inch call was a little too aggressive and we did have a longer period of freezing drizzle than first anticipated. My great intentions of updated the blog went under. If you read this and do not have me as a friend on Facebook, please add me as I will stream updates on there or add me on your twitter account.
Despite December coming in as record cold-- we are heading towards a pattern breakdown for a while. IF, the pattern would remain warm, my season outlook would be pretty good despite all things. (but it won't)
The good-- The cold pattern developed late in November as anticipated and lasted all month in December. Mid January the pattern has broken down,. As foretasted, it has been dry with no major snow events. The December 16th event has been our largest snowfall of the season. My snowfall outlooks have verified well, all within, even if just barely the range allotted. ( December 16 was a 3-6 inch call with 3 inches and 2.2 for a 2-4 for Christmas day.
The Bad-- While getting the general idea for a cold December right makes me happy, the pattern was much more amplified than I first anticipated. Much more is code for record setting amplified. My thoughts of a HISTORIC cold outlook from 10 days ago looks really bad. Yes, its been colder than normal but nothing historic.
The Ugly-- Nothing remotely close to a pattern that resembles ice threats, much more intense blocking. Also, while the pattern is shifting, I doubt the cold is mostly gone for the winter.
From this point forward-
We have a rain threat Monday with MAYBE a little sleet or freezing rain in the front side.*Nothing major* Something called the PNA spikes (PNA is a ridge over the west coast). This brings a colder pattern to the east, but NOTHING to lock in cold air or slow down a storm.
Something called a "Sudden Stratospheric Warming" is linked to a -AO -- and one of those could be in the works (I'm no expert in the this process, just know the impact, here is a wiki link of you want to read more http://en.wikipedia.org/wiki/Sudden_stratospheric_warming ). What this COULD mean is a return to the stronger blocking we had in December. I've not noted the updated information from this, but this usually takes a few sides of 10 days to re establish the colder pattern. The bottom line is it weakens the polar vortex. When the polar vortex is weaker or in several smaller pieces it allows for blocking to dominate.
Moving forward, My guess is that the first half of my winter outlook is going to be MUCH better than the remainder. It does seem like this will be a more intense winter cold wise and the snow card has basically 8 viable weeks to play out somehow seems bleak to verify with a 5-10 inch allowance I predicted.. La Nina winters are NOT known for historic events, and yet we've had 2 on the east coast--- the Boxing day event and this past Sunday to Wednesday event that just slide past our region with a minor dusting. We've officially clocked 7.4 inches this winter in Lynchburg and I expect this to increase. Putting aside the dry nature of this winter, the overall pattern has been NOTHING like a La Nina and there are not many signs that this will end anytime soon, just breaks.
One of the points of my outlook was that seasonal pattern changes often weaken and mute the impact of La Nina's. If we get a Sudden Stratospheric Warming-- the impact would likely be the first 2 weeks of February. At that point, the long wave pattern is starting to make the seasonal change to spring and the impact of La Nina is drastically dropped. So, I'm hedging colder overall for the remainder of the winter, just not as cold as December. Snowfall hasn't been hard to come by--but hasn't been anything significant. My guess is that we could move the seasonal total is more like 10-15 inches this winter rather than the 5-10 forecast.
Sunday, January 9, 2011
Big Snows South, Big Snow north-- with a little in the Middle--
And, we live in the middle.
The storm appears to be developing as I expected--with big snow totals over much of the deep south. My college city of Chattanooga, TN COULD get 10 inches.
This storm weakens and drys out as it approaches our region. Among the reasons, DRY DRY air-- temps between 5k and 10k feet are at -10 c with dewpoints BELOW -30. So, we could have snow aloft (Virga) for 12 hours or so-- plus the systems upper air support is dying out-- the moisture transport from the Gulf of Mexico is gone.
Next-- Energy diving in from the Pacific NW tracks just to NW and invigorates our storm JUST north of our region. My home base growing up of the New Castle, DE and Chadds Ford, PA region look to get maybe 6-10 inches while NYC to Boston look to get a foot.
Region precipitation map- note how it swings around most of the VA region.
Our region--
NRV and Southside- 2-4 inches. Southside may get a little freezing drizzle for a period as well.
ROA to LYH-- 1-3 inches.
My guess as of now-- 2.2 inches for Lynchburg.
We are going to monitor trends, sometimes when you have extreme dry air in place and the best moisture intersects the best lift-- no more moisture falls, but the flakes are well constructed (Dendrites) and you can get better snow ratios. our Jan 30th 12 inch event-- this happened last year up near DC. This could mean an extra inch tapped on this storm. (DCA has 6.2 inches of snow reported from 1.3 of liquid. I imagine the liquid is under done, but the it was a 25-1 ratio-- I checked Wilmington, DE and they had 4.3 inches from .20 liquid)
The storm appears to be developing as I expected--with big snow totals over much of the deep south. My college city of Chattanooga, TN COULD get 10 inches.
This storm weakens and drys out as it approaches our region. Among the reasons, DRY DRY air-- temps between 5k and 10k feet are at -10 c with dewpoints BELOW -30. So, we could have snow aloft (Virga) for 12 hours or so-- plus the systems upper air support is dying out-- the moisture transport from the Gulf of Mexico is gone.
Next-- Energy diving in from the Pacific NW tracks just to NW and invigorates our storm JUST north of our region. My home base growing up of the New Castle, DE and Chadds Ford, PA region look to get maybe 6-10 inches while NYC to Boston look to get a foot.
Region precipitation map- note how it swings around most of the VA region.
Our region--
NRV and Southside- 2-4 inches. Southside may get a little freezing drizzle for a period as well.
ROA to LYH-- 1-3 inches.
My guess as of now-- 2.2 inches for Lynchburg.
We are going to monitor trends, sometimes when you have extreme dry air in place and the best moisture intersects the best lift-- no more moisture falls, but the flakes are well constructed (Dendrites) and you can get better snow ratios. our Jan 30th 12 inch event-- this happened last year up near DC. This could mean an extra inch tapped on this storm. (DCA has 6.2 inches of snow reported from 1.3 of liquid. I imagine the liquid is under done, but the it was a 25-1 ratio-- I checked Wilmington, DE and they had 4.3 inches from .20 liquid)
Saturday, January 8, 2011
Storm on track-- Cold more cool, not bitter. **Edit to add photo**
I must say that I just hate this storm coming our way-- so many good things about it that simply can't deliver for many reasons.
A strong southern short wave spins a storm up in Texas and it heads east, However, the block causes this energy to dampen out and the storm loses its punch at our doorstep. A second piece of energy swoopes down from the Pacific Northwest and regenerates the storm-- but its just a little too late for our region.
As of now, I'd predict 1-3 inches from late Monday into early Tuesday.
We are very cold for a couple days after that, and then get a brief warm up before another arctic surge.
Map from the HPC--- precipitation outlook. Note the minimum over most of our region. The Southern low dies our, it meanders off shore, to be energized JUST to our north. The ridge out west isn't large enough to cause any digging of the second piece of energy to drive it more south. Looks like a DECENT event in Philly and a LARGE event for NYC to Boston.
Next update Sunday afternoon.
A strong southern short wave spins a storm up in Texas and it heads east, However, the block causes this energy to dampen out and the storm loses its punch at our doorstep. A second piece of energy swoopes down from the Pacific Northwest and regenerates the storm-- but its just a little too late for our region.
As of now, I'd predict 1-3 inches from late Monday into early Tuesday.
We are very cold for a couple days after that, and then get a brief warm up before another arctic surge.
Map from the HPC--- precipitation outlook. Note the minimum over most of our region. The Southern low dies our, it meanders off shore, to be energized JUST to our north. The ridge out west isn't large enough to cause any digging of the second piece of energy to drive it more south. Looks like a DECENT event in Philly and a LARGE event for NYC to Boston.
Next update Sunday afternoon.
Friday, January 7, 2011
Complicated snow event possible-- Cold still coming
The cold is still on tap as discussed in my last blog. As usual, the extreme version won't be as likely-- much much colder then normal, but some of the cold trickles into the pacific northwest and the core of the cold sits in NW Canada sending pieces down towards our region. Doubt we get below zero unless we get a quite the snowfall but lows and highs both average 6-12 degrees below normal for the next 10 days. The warm days will reach 40 at best and the cold days will struggle to reach freezing. For a reference point-- the average high for this time of year is about 44 and the average low is 25.
Snow wise--
As an arctic front drops through today-- a piece of vorticity swings to our south and and could bring some flurries or even a dusting of snow. Places along i40 in NC could see a couple inches from this event.
The Big Show is far from decided.
Set up- Cold air settles over the region and a strong shortwave heads east from the south Cali coast. Low pressure forms over the deep south and heads east. Because of the strong block over the NE--this original short wave gets sheared out and our low doesn't deepen and loses the moisture transport from the Gulf of Mexico. As a result, what was putting down over an inch of liquid over the TX to GA areas is suddenly very dry.
A second short wave races east from the Pacific northwest and at some point re-energizes the storm.The quicker this happens, the bigger of a storm we get.
How much snow is possible?
If its a smidge late-- we get a 1-2 inch snowfall.
If its a tad faster- 2-5 inch snowfall.
I'm not willing to commit either way at this time. Both pieces of energy are just coming ashore on the west coast and as they get close with better sampling data for the computer models, we should have a better handle on this.
Snow wise--
As an arctic front drops through today-- a piece of vorticity swings to our south and and could bring some flurries or even a dusting of snow. Places along i40 in NC could see a couple inches from this event.
The Big Show is far from decided.
Set up- Cold air settles over the region and a strong shortwave heads east from the south Cali coast. Low pressure forms over the deep south and heads east. Because of the strong block over the NE--this original short wave gets sheared out and our low doesn't deepen and loses the moisture transport from the Gulf of Mexico. As a result, what was putting down over an inch of liquid over the TX to GA areas is suddenly very dry.
A second short wave races east from the Pacific northwest and at some point re-energizes the storm.The quicker this happens, the bigger of a storm we get.
How much snow is possible?
If its a smidge late-- we get a 1-2 inch snowfall.
If its a tad faster- 2-5 inch snowfall.
I'm not willing to commit either way at this time. Both pieces of energy are just coming ashore on the west coast and as they get close with better sampling data for the computer models, we should have a better handle on this.
Wednesday, January 5, 2011
Pattern developing will be EXTREME-- this time it's More Than Words
The long range forecast reads like this--
Cold, Colder and Coldest--
My winter outlook called for colder than normal December ( OK, kinda whiffed on the 5th coldest December)
COOLER in the first half of January leading into moderation. Someone Que the Price is Right lose music, because I'm going to be wrong. Very wrong.
We are about to have an arctic invasion, perhaps one not experienced in 25 years. (Jan 1985) The next two days COULD get to near normal before the bottom drops out.
Why? The perfect global set up to drive cold air over much of the United States. The first wave of cold air begins to filter in later this week with even a chance for a few flurries and snow showers. It will be cold, but not anything historic.
Cold, Colder and Coldest--
My winter outlook called for colder than normal December ( OK, kinda whiffed on the 5th coldest December)
COOLER in the first half of January leading into moderation. Someone Que the Price is Right lose music, because I'm going to be wrong. Very wrong.
We are about to have an arctic invasion, perhaps one not experienced in 25 years. (Jan 1985) The next two days COULD get to near normal before the bottom drops out.
Why? The perfect global set up to drive cold air over much of the United States. The first wave of cold air begins to filter in later this week with even a chance for a few flurries and snow showers. It will be cold, but not anything historic.
This map is valid for the 13th at 7PM--that's a cold look.(Temps reflected are at 5k feet) Would translate into highs in the 20's to maybe low 30's and lows as low as 10.
Preceding this cold COULD be a possible snowstorm. Timing is huge to when the cold air works in VS the energy coming from the current California Storm- if the cold is a little to quick it shears out the energy and we get nothing. Also, some of the data has wanted to have a SMALL window where the low works up to our west . Hard to see that as a possible outcome, as the most likely way we miss this event would be sheared out and to our south.
This model called the GGEM shows a possible solution to how we could get some snow. The next frame moves it out to sea, so its not a HUGE event, but would be a 2-4 inch type snowfall. After this event, we have a couple frigid days (Map reflected above) There could be a BRIEF warm up and then the "Motherload" of cold air is about to move into the US.
That BIG L over Wisconsin is along the leading edge of BRUTAL cold air--and it would reach the East coast about 36 hours after that. This could be the coldest air mass in 25 years. (Thanks to something called the -EPO) Map valid 1/15/11 temps reflected again, at 5k feet. Note the -30 reading up in Canada.
Snow threats--Maybe a few flurries or snow showers Friday, but the first threat is Monday/Tuesday Next week-- next, with an arctic blast like that I would guess we could get a quick coating and then we sit in the cold (Day 11). Maybe around the 20th as the pattern starts to relax something is on the table.
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