Monday, December 31, 2012

Quiet Week Ahead, January Thaw Imminent

I don't have much time to get into the details, but it looks like this week will be slightly below normal (temperature-wise) with mostly dry conditions.  We may get a flurry or two tonight to ring in the new year, but other than that, don't expect much.  Then indications exist that show much of the country warming up.  The Great Plains will certainly turn much above normal, while we are left on the envelope of the warmth.  Maybe we can get a snow chance yet?

Have safe and happy new year's celebrations tonight!

Saturday, December 29, 2012

FINAL CALL: Saturday Snow

(12:00PM / 12-29-12) I updated the snowfall map from last night and really bumped up totals for eastern Massachusetts.  Inside of Route 495 will really get pounded tonight with 1-2"/hr. snows for a few hour period.  The coastal low is now taking over off the Delmarva and really looks impressive on satellite imagery.  Also, the computer models (all of them) strengthen the storm tremendously ("bombogenesis") and push that comma head of most intense snows and wind over eastern Mass.  This is why I had to increase totals to 6-10" in that heaviest band.  SE of it, there will likely be more precipitation (QPF), but it will be warmer and they will have to contend with precipitation type issues for the beginning of the storm.  NW of Plymouth, you should remain mostly if not all snow.  This is the biggest storm in eastern Mass in over 2 years, so please take it easy out there later tonight.  Our winter driving skills haven't been tested in a long time.  Take care.

(11:55PM / 12-28-12) Here is my last call for tomorrow's snow.  Computer models came in a little 'juicier' today, forcing me to increase totals across the board today.  I like interior SE MA, eastern CT, and northern RI for the jackpot area (4-8").  Most areas will likely come in on the lower end of these totals, but it would not shock me if a few towns finished on the higher end.  The one wildcard is the Cape.  If they somehow avoid mixing or starting as rain, then they could be off to the races and that 2-5" call would be extremely conservative.  However, it looks like they will be dealing with precipitation type issues throughout the storm until the very end.  Overall, the further N&W you go, the fluffier the snow.  The closer to the coast and SE MA you go, the more pasty the snow will be.

Start time is from 10AM to 2PM from SW to NE.  Expect it to end some time overnight Saturday or the wee hours of Sunday morning.  Clearing through the morning hours Sunday and a cold Pats game at 4PM at Gillette.  The real Arctic arrives later next week.  By next Friday, high temperatures could struggle to get out of the TEENS with lows BELOW ZERO in the suburbs.  Welcome to winter!  It's been missing in action for the past two years, but I think it's almost safe to say that it is back and with  a vengeance.  

Friday, December 28, 2012

Snow Potential Saturday

Here is a very crude map for the snow potential on Saturday afternoon and night.  I will be the first to tell you that this does not look all that impressive on the computer models and it probably never will.  However, some of the models are printing out a light to moderate event for much of SNE.  The last time I checked, Boston had not seen a 1"+ event in nearly ONE YEAR!  This means that a 2-4" event that would normally barely warrant a mention in a normal winter season now makes headlines.  Let me warn that this one is still many hours away and has the potential to fizzle out and leave us with little if any accumulation.  Some reliable computer models are doing just that, while others are holding serve for advisory snows for many south of Route 2 in Massachusetts.  Even the Cape should get in on the action with any rain quickly changing to all snow down there.  I wanted to wait until the 00z EURO run came out at 1AM, but I can't so I made this knowing that it could change with whatever the reliable EURO comes out with in one hour.  But I think this is a good first guess.  My next update will come tomorrow night late.

Thursday, December 27, 2012

Finally a SNE Snowstorm to the Coast En Route?

Possible....More on this later tonight, but pinpointing Saturday night into Sunday for potential significant snows to affect all of SNE including the Cape and islands.

Wednesday, December 26, 2012

FINAL CALL:  There are two camps with this system - (1) the warm/rainer camp and (2) the colder, snowier camp.  Of course the computer models that the TV weathermen use are showing any snow quickly changing to rain, while the much more reliable EURO computer model continues to show impressive snow just outside of Boston.  I'm taking the warmer route just because the NWS is so conservative with this one and likely for good reason.  I've pushed the heaviest snow amounts NW and dramatically cut any accumulations for the vast majority of SE NE.  I think the changeover line will only make it to about Manchester, NH - Orange, MA - Pittsfield, MA.  NW of there, the storm should be primarily snow.  SE of there, fair game for freezing rain, sleet, and plain rain.  

Again, this map has extreme bust potential either way.  If we can get the precipitation in here quick enough, we can get significant accumulations right inside 128.  If not, I think we will have a map that looks something like this.  On a side note, it now appears that the weekend threat will slide out to sea, maybe scraping the Cape with some light snow or flurries.  Plenty of time for that one to change.

Tuesday, December 25, 2012

A Messy Midweek Storm

FIRST CALL (12/27 3PM) - Merry Christmas everybody!  I hope everyone enjoyed the little bit of snow we got this morning.  There was a burst around 8-10AM that whitened the ground in eastern MA, but most of that has since melted this afternoon with temperatures getting slightly above freezing.  Don't fret, snow lovers though.  More snow is on the way and it should be here by overnight tomorrow night.  Posted to the right is my first call for snowfall accumulations from this storm.  Many will change to sleet, freezing rain, and plain rain, but not after several hours of moderate to heavy snow.  Even the city of Boston should get several hours of snow too.  Outside of 128 and especially 495 will see mostly frozen precipitation as the temperature will struggle to get over 32 out that way.  Inside 495, after many hours of wintery precipitation, temperatures will warm from the easterly fetch off the warm Atlantic into the middle to perhaps upper 30s and change anything that is falling to plain rain.  The Cape and islands will likely be too warm throughout the storm and temperatures could actually warm into the 40s when the storm makes its closest pass to Nantucket.

All snow will be confined to the northern mountains where over 12 inches of snow is highly possible.  But as you can see, heavy snowfall accumulations will reach all the way down into the NW half of Middlesex County and most of Worcester County through the Berkshires. (Where 6-12" of snow is possible).  Inside 495, the warm Atlantic will likely warm the surface more quickly, limiting accumulations to 3" to as much as 6" (best chance for higher amounts further inland, while somewhere like Boston right on the shore gets more like 1-2", maybe 3").

I will post my final accumulation map tomorrow morning and have more detailed information about start and changeover times.  Again, Merry Christmas to those who celebrate!  We may be able to muster up another storm by the end of this weekend too. More on that potential snow later.

Update on BIG Storm Later Today...

Merry Christmas! I will have an important update of the impressive storm that will be slamming our area beginning tomorrow night and last through Thursday.  SPOILER ALERT - the low now looks to be tracking south of SNE and across Nantucket before exiting off into the maritimes.  Good news for snow lovers! More later.

Sunday, December 23, 2012

Festive Christmas Snow

What looked like to be at least advisory snows about 48 hours ago, the Christmas event now looks much more mundane.  Even though we will not be getting crippling amounts of snow, I am sure most will welcome event the small amount as they open up their gifts on Christmas morning.  However, my thinking to the right is probably the 'worst case' scenario, or the snowiest.  Some models have trouble even spitting out anything over SNE.  Others bring a bit more, so I chose the highest impact scenario.  The start time for CT should be right before midnight on Christmas Eve and then into the wee hours Christmas Day for the rest of the region.  There is little risk of rain mixing in, but the South Coast, Cape and Islands should have trouble accumulating with milder temperatures in the middle 30s.  Further north, we should be able to at least accumulate on the grassy surfaces and perhaps the pavement, but rates will likely be so low that the snow will have a hard time accumulating on paved surfaces.

The storm for the 27th and 28th still looks like a big rainstorm and the models have been pretty consistent in showing that storm as such.  More details on that after we move past this low-impact event on Christmas Day.

Saturday, December 22, 2012

Christmas Day Snow - An Early Look

UPDATE (12/22 - 5PM) - What a horrible run of the models today for snow lovers.  After last night's overnight EURO run dropping high-end advisory to low-end warning snows along the Mass Pike right into Boston, today's EURO nearly dropped the system off the radar - pun intended.  Now the early evening model runs are also showing this system losing steam as it heads out of the OH Valley and through PA.  Because of the weaker life and lower rates, it will likely warm into the middle 30s during the daytime on Christmas Day too, which will also limit accumulations near the coast.  Perhaps the Worcester Hills could still be able to pick up an inch or two, but even that might be generous with the unfortunate trends today.  We are still about 60-72 hours away, so the models could turn back to the snowier/more amplified scenario later tonight or during tomorrow.  However, in my experience, once these start to trend weaker at the 'last minute', then we probably will not return to the solutions that were giving much of the region a few to several inches of snow overnight Christmas Eve and Christmas Day morning.

We still have the late week system too though? Sorry to be the bearer of bad news, but all computer models are focusing on that system to amplify rather quickly once it is in the TN Valley.  Consequently, there is not much of a handoff to the secondary that 'was' developing off the Mid Atlantic coast in previous days' runs. Also, the high pressure system to the north of us is weaker and further west (north-northwest) too, which also allows this thing to push up the spine of the Apps.  A secondary low pressure surface reflection tries to show later in the game near NYC, but even that gets pulled WNW on  most of the computer models, flooding much of SNE with warm maritime air that changes any brief period of snow at the onset to heavy rain with strong southeasterly winds.  Even ski country might have a hard time dodging the rain drops with this one if it verified as depicted on the models today.  This one is still about 4.5 to 5 days out, so we still have time to work on the details, but the trend is definitely not our friend (if you're a snow lover anyway).

Last minute shopper?  Tomorrow should be a fine day (weather-wise at least) to get to the malls.

00z GFS - 12-22-2012
I am updating the blog from last night's optimism regarding the potential snow for Christmas Day.  Well, it now appears more likely after tonight's late hour model runs.  Last night's EURO run and this afternoon's EURO run gave much of SNE several inches of snow, away from the Cape and Islands.  Now the American model (GFS) is coming on board with a snowier solution too as depicted above.  

The GFS still keeps this as mostly a Pike-south event, but the EURO (admittedly a more reliable model) gets at least a few inches up across the MA/NH border.  Right now I would have to go in the middle of the two, but tend to favor the EURO solution.  The newest EURO solution comes out at 1:15AM, so we will have to wait and see if it keeps the Christmas Day snow hope alive.  The trends are encouraging for snow lovers this evening though across all fronts.  The snowier models are giving this low pressure system time to develop and amplify off the NJ/LI coasts, so this will only contribute to a widening snow band that reaches across much of SNE.  

Thursday, December 20, 2012

Christmas Miracle?

Not a lot of time to post today, but there are subtle indications that a weak area of low pressure could develop off the South Coast of SNE later Christmas Eve night into the wee hours of Christmas Day.  Right now most models keep most, if any, of the light snow south of the Mass Pike, but a few ensemble members of the American GFS model bring advisory (2-4" type) snows for much of the region.

I would bet against much of anything during this time frame and expect a brown Christmas for most outside of the northern Whites, Greens, and mountains of Maine.  That midweek storm (along about Thursday of next week) is still on the models and was a monster on the latest midday run of the GFS.  The European model (EURO) is coming out right now and we will have to see what it does with both the Christmas event and midweek system.  The overnight EURO run had this trekking along the Apps, bringing most of SNE rain.  It's still a week out, so we will continue to see change after change leading up to that event.

Next update most likely on Saturday. 

Wednesday, December 19, 2012

This Winter will be NO '11-'12 Repeat!

First update in nearly 3 years!  I figure after last winter's 'non-winter', why not give it a shot.  Here we are deep into December without much cold or snow since early November.  Fear not, snow lovers.  We are not nearly in the same horrible pattern of last year with a dominating polar vortex rotating south of Alaska, dropping feet and feet of snow up there, while we were in shorts in January.  I repeat, that will not be the theme of this winter.

When do we start seeing a more wintery pattern?  It's coming, but it may take time.  There are indications that a storm the day after Christmas Day could move far enough east of us to drop some snow across (esp. interior) SNE.  However, there is almost an equally likely chance that this will cut well west of us again to deliver more rain and southerly gales.  However, with a negative NAO index, coupled with the fact that the gradient is moving south, with a high pressure nosing in from southern Canada, this thing could trend into a colder solution for SNE.  I would feel better for snow if I was reading this from CNE or NNE. If you're reading this from Sugarloaf, more snow is coming for you by Friday, while the rest of us rain all the way up into the Mount Washington Valley towns.

By New Year's that gradient will start to sag south (coupled with colder climo), which leads me to believe that I will actually be able to post some snowfall accumulation maps by then with imminent storm(s).  Who knows?  Maybe we will be able to muster up something by the middle of next week.