Stormier Pattern Expected...White Christmas?

We are through the first third of December and so far most of the United States has escaped the cold and snow.  A pattern change is on the way and at least one plow-able snow event is likely before Christmas.  The Pats-49ers game on Sunday may be played in snowy conditions. Until the weekend the weather will be mainly dry with seasonable temperatures.  Overall temperatures will be slightly above average.

combined snowfall from storm 1 and 2 through Dec 20

Wednesday-Saturday
Dry and calm weather for this period.  Today and tomorrow feature high temperatures in the upper 30's/low 40's for most of Southern New England.  Friday will be near 50 but this is short lived as temperatures drop to 40 by the beginning of the weekend.  Overnight lows will hover around freezing with the exception of tonight which will drop into the lower 20's.

Storm Number 1/Sunday-Monday

144 hour GFS accumulated snowfall forecast valid Monday 7 PM

This is the 00z GFS run for accumulated snowfall off Dr. Ryan Maue's Weatherbell site.  A piece of energy will break off a cut off trough in the west and makes its way across the country.  This system is not a Nor'Easter but will likely deepen once it begins to feel the effects of the Gulf Stream.  Here is the system off the NCEP charts at the 500 mb level and on the surface

While there isn't much to the system in terms of support, there is more than enough for a  plow able snow event

Notice the dip over the Great Lakes.  Here is what the model thinks the surface precipitation will look like

540 thickness cuts across MA/CT/RI border

Temperatures Sunday will support snow

EURO Temps Sunday 7 PM from Dr. Maue and Weatherbell

The weather will be completely different at Gillette Sunday when compared to Monday night.  It might effect the over/under if one is interested in that type of activity.  The EURO has the bulk of the action during the day Monday; the GFS has the heaviest snow during the day Sunday.  Here is the EURO for Monday 1 PM-7 PM precipitation totals

From Weatherbell

I suspect this system dives just south of the New England coast and everyone ends up with snow.  I expect somewhere to get close to 10 inches as these storms can explode offshore and drop a lot of snow in a short period of time.  There won't be much time to recover before

Snowstorm Number 2 Tuesday-Thursday

The timing is unsettled on storm 2 as well.  Storm 2 looks bigger and stronger than storm 1 by far so it is bound to get more attention from meteorologists.  However recent Decembers have featured snowstorm after snowstorm (2011-12 not withstanding).  There was a series of storms in December 2008 in which it snowed for 45/48 hours in the Blackstone Valley that in total dropped over 20 inches of snow. It was right around the 20th as well.  

EURO for 1 week precipitation

Temperatures are much more interesting with the second system as a classic rain/snow line will develop.  The EURO wants to back that line to 495

EURO temperatures.  West of 495/95 will be snow according to the EURO

The GFS has a very strong low pressure system offshore

Strong low pressure with intense precip

GFS is similar with rain along the coast but snow inland

Valid Wednesday 1 PM

What to take away from this- the pattern is changing.  It is not last year as there has been measurable snowfall three times since November 7.  The cold source regions are set to invade the United States for the end of December and January.

Warm Start, Cold Finish

EURO forecast for 7 am, right on track.  Image credit Dr. Ryan Maue/Weatherberll

Temperatures will be dropping quickly this afternoon after a cold front pushes across the Northeast.  Temperatures right now are running in the mid 50's. By tonight these will drop into the 20's and will only rebound into the mid 30's tomorrow.  There is another rain threat Friday after some showers this morning.

Surface Analysis reveals cold front diving into Northeast

There is a line of showers associated with the front pushing across the Pioneer Valley as of 518 AM

Radar Image Northeast 518 AM

Behind this front lies a cold winter air mass.  Here is the EURO forecast for tomorrow morning at 7 am

Image Credit Dr Ryan Maue/Weatherbell

Winds are a bit gusty today with the passage of the front but will die down for the rest of the week.  Temperatures rebound a bit Friday by reaching the mid 40's.  Over the weekend temperatures will again soar above normal but there will be a chance of rain overnight Friday into Saturday.  Have a good Wednesday

PS while we are warm in the United States check out Europe

EURO ensemble system

Well below average and it has been for a week or so now.  Here is the 8 day snowfall depth forecast by the GFS.  Each image credit Dr Ryan Maue and Weatherbell

GFS 8 day snowfall forecast

It was only a few years ago someone said the children of England would never know what snow is due to global warming.  This is the 4th straight December snow will have fallen in December.

National Snowfall Outlook

Posted at Tornado Titans

Super Bowl Saturday forecast

We have woke up to a light snow this morning which is fitting for December 1st.  This is a light event and is being forced by a warm front lifting north.  A weak front will also cross Southern New England tomorrow and then another boundary on Wednesday.  The benefit will be temperatures more like late April or early October on Monday, Tuesday, and Wednesday.  The first part of December looks to be above average temperature wise but the the final 3 weeks of the month look cold with snow threats.

Super Bowl Saturday
Today many local teams are playing for championships including Northbridge and Valley Tech.  There will be a light snow falling for most of the morning and afternoon.  Everyone played in this Tuesday night but its colder tonight and more likely to stick to the field a little bit.  Here is the radar image from 720 AM

Snowfall moving east

Here is the surface chart from 530 AM

Weak low pressure in Mid Atlantic lifting north.  Low pressure in Dakota's to bring rain tomorrow

The EURO model temperature forecast for this afternoon

Valid 1 PM Saturday from Weatherbell and Dr. Ryan Maue

Temperatures will struggle to break the mid 30's this afternoon.  Given how brutal the sun can be in December, cloud cover and the light snow should make passing the football a little easier.  

Sunday-Monday

The front moves north and a low pressure system emerging from the Dakota' will drop rain on the region tomorrow.  Here is the EURO forecast for over night Sunday into Monday.  Some models are a little quicker with the onset of rain.  It wouldn't be a shock to see rain tomorrow afternoon.

Temperatures will jump into the 50's tomorrow and stay that way for a few days.

Monday 1 PM EURO forecast from Dr. Ryan Maue and Weatherbell

Most of the country will be above normal this week.  The models did a nice job picking up on this a few weeks back.  It breaks Wednesday but will detail the rest of the week tomorrow or Monday.  We've got a Super Bowl to win today! Go Beavers

Tuesday Snow Forecast

06/27 GFS accumulated snowfall- image credit Dr Ryan Maue and Weatherbell

There has been a subtle shift to the north with guidance overnight.  Its not unexpected, but will make tonight's commute a little slower.  Also watch for black ice if out tonight.  Highest snow totals for SNE look to be over the in Bristol and Plymouth counties.  Expecting about 1.5 inches in the Blackstone Valley.  Snow starts late morning/early afternoon and carries on until after midnight.  When the sun goes down road some snow may stick to the roads where it comes down the heaviest.

Pretty good slug of moisture to work with

HPC has upped snow probabilities into New England...now a wide swath has a 10% chance of 4 inches of snow

Day 1 snowfall probability forecast

All in all not a big deal, biggest issue will be with slick roads.  Moisture already streaming into SNE is evaporating before reaching the surface.  This will continue for awhile.  It will be cold tonight, bundle up.

Minimum temps between 1 PM and 7 PM today, EURO model- image Dr Ryan Maue and Weatherbell

Winds will remain light as this storm system is not very strong and there is not a tight pressure gradient.  The snow won't stick around too long although watching a clipper for Thursday night.  Warm up is expected next week.  More details on the extended range later...big playoff game tonight for the Beavers!

Tuesday Snow Event...How Much?

Temperatures will moderate slightly for Monday, but winds will still gust to 25 mph so another cool and brisk day is on tap to kick off the final week of November.  Things change Tuesday as a generally light snowstorm moves into the region.  Most model guidance is keeping snowfall totals less than 2 inches but it will be falling Tuesday afternoon into the evening.  This will means the high school football playoff games will be played in snow.  Great for the players...and coaches who get to sit in a heated press box but for everyone watching the game dress warm.  

HPC snowfall probability 

The chart above shows less than a 10 percent chance of snowfall exceeding 4 inches in WV and PA and no chance anywhere in Southern New England.  The model support for a big event has gone away.  

EURO temperature forecast- from Dr. Ryan Maue and Weatherbell

This is Tuesday night at 7 PM.  Temperatures will be running in the upper 20's/lower 30's for most.

EURO precip forecast- from Dr. Ryan Maue and Weatherbell

A track slightly north of what is currently being forecast would bring those heavier precipitation bands into Southern New England.  As a meteorologist I find these type of snowstorms very difficult to forecast.  I've seen these little low pressure systems explode when the hit the gulf stream and the 1-3 inches of snow quickly becomes 8-12 (December 13, 2007 for example).  The jet stream will remain split so we don't need to worry about a major nor'easter.  

NAM wind forecast- From Dr Ryan Maue and Weatherbell

Not a heavy wind maker but will be a cold north wind.  So in summary we are looking at 1-3 inches of snow, but the potential for a 3-6 inch storm remains on the table.  Temperatures will be cold enough for snow and winds remain light.  More on the this tomorrow.

Saturday Morning Weather Discussion

For the second time this November snow is in the forecast.  The 50 degree weather has went away for now.  For those of you who hate snow this isn't welcome, but the 50's may return in the long range.  We are going to have to deal with snow Tuesday evening into Wednesday morning.  Until then we are due for a stretch of below normal temperatures.

Weekend
There could be a snow flurry today; other wise partly to mostly cloudy with temperatures in the low 40's.    Tonight is mostly clear allowing the heat to escape the surface; the result is lows in the lower 20's.  The coldest valleys where this cold air sinks will drop into the upper teens.  Sunday is more of the same although it will be harder to break 40 tomorrow.  If we could gamble on weather the line would be 38.5 degrees.  Clouds will be on the increase Sunday afternoon so Sunday night will not be as cold.  Temps in the mid to upper 20's.

Valid last night at 7 PM.  850 mb temperature anomaly from Dr. Ryan Maue and Weatherbell

The divide in temperatures clearly shows the cold front.  Here it is on the surface charts 

Valid 7 am this morning.  Cold front has pushed through

Current temperature observations in New England

9 am temperature observations

It will be hard for the temps to get much higher.  Winds will also be an issue today.  Very windy weather with the frontal passage.  Winds will be gusting over 30 mph this afternoon.  Its going to feel a lot colder than it actually is.  Here is the temperature anomaly (departure from average) for tonight at 7 PM (EURO thinking anyway)

7 PM EURO 11/24 00z 24 hr forecast. Notice wind arrows are longer, indicating stronger winds 

Tuesday-Wednesday

Some of you know, others may not that I coach HS football and we have a game Tuesday night.  For awhile I have seen support for some type of event on Tuesday.  After jumping the gun on a possible Thanksgiving week storm I held off for this one but there is agreement that at least several inches of snow will fall.  The event looks to start Tuesday night in time for the commute and the playoff games.  This is not set in stone; it could hold off until overnight Tuesday though I am leaning toward a Tuesday evening start.  

The EURO model is further offshore but it still produces 1-3 inches of snow for most of SNE.  The American GFS model is closer and has a heavier snow event.  Here is the predicted snowfall map from this mornings GFS run

This is valid Thursday morning.  System will be gone Wednesday  night

Too soon for specifics, but leaning towards accumulating snowfall for most.  For people of ski country do take the GFS with a grain of salt.  The EURO has very little precip for the mountains.  It will be interesting to see which solution ultimately verifies.  As usual its probably something in the middle.  

Extended Range

Analog forecast upper air pattern for 6-10 days

December is right around the corner.  What I find amazing is all of the analog dates occurred within a Cold PDO (2006 can be debated; even if we call 2006 a warm PDO its still 9/10 cold PDO).   I suggest searching the PDO and AMO if you want some information on naturally occurring climate patterns.  Anyway this set up screams blocking by Greenland and a trough in the east.  The 2010's and 1960's have shown consistency in producing big east coast snows.  White Christmas odds are high for 2012.

That said everything I have seen on the guidance is that in the 10-14 day range we see a warm up.  I think we see one last warm up in early December before winter kicks in.  Have a good weekend everyone, thanks for reading.