Wednesday, March 18, 2015

On & On We Go..A Classic Long New England Winter

Well, after a few days featuring a "Spring feel" around Southern New England (which I must admit, it did feel good !) we are back into a Winter type pattern, one that continues to feature below normal temperatures and the potential of snow/winter events. Many of us are living through a good ol fashion long New England winter that we heard of as kids and breaking many records along the way for many. One that will soon not be forgotten and one that seems to just not want to die. The bitter cold winds of today are reminding us of this harsh reality and still with a ton of cold, arctic air over Canada and an active northern branch of the jet stream, there is no clear signal of Spring- type weather arriving just yet. Every time we start to make progress, we go back the other way as a western US ridge pumps the heat to our west resulting in eastern troughiness and mostly normal to colder than avg temps around here. I do not see a clear end to it just yet.
Our next system comes in Friday and should persist into Saturday morning. Important to note right off the bat that this will not be a significant storm with significant impacts. It simply does not have the power to produce big numbers or any significant coastal effects to the region and is moving fairly quickly.
Light snow or even a light mix should break out across the region from southwest to northeast Friday late morning into the early afternoon hours. As precipitation becomes more steady later in the afternoon and early evening hours , most will be seeing snow falling. It could be a tricky afternoon commute. Snow will persist for most the evening hours into very early Saturday morning for most. Heaviest bands should be confined to the south of the Massachusetts Turnpike where the most moist air will be at low and mid levels and closer to the weak storm center. Due to a weak storm center and no upper level support, I do think we will be at least tracking a mix line close to the south coast of SNE later Fri eve and early Sat. Some mixing should make it in for a time at least up to the Cape Cod Canal, though this could depend highly on the intensity of the precip, so will have to watch that progression closely at that time. Either way, snow ratio's do not appear very high. It is a case of where there is the most moisture, there will be lower ratio's, so a trade off of sorts in that regards. Mix and or snow should wrap up by noon Saturday but we will have to keep an eye on the chance of additional snow showers/squalls with a fresh injection of cold air and northwest winds on the storms backside. Very cold Sunday with the likely potential of even a few more snow showers/squalls. No real warm up in sight that I see with even more winter type events potentially looming ahead.
Below is my best shot at snow totals Friday into Saturday. I will continue to evaluate model trends, satellite and even some analogs and see where we stand tomorrow. If anything I think some higher amounts could shift to the southwest. Thank you for reading !    ~Anthony S.

Saturday, February 28, 2015

Another Weekend Winter System

Sure felt nice out there on this last day of February 2015 didn't it? What an incredible recording breaking extreme month it was though. The numbers are staggering. One of the coldest on record for many and the snowiest month ever for many as well. I will have a comprehensive round up of the historical month in a few days , but for now there is some more wintry weather to talk about. It will be the 6th weekend in a row with a winter storm affecting the region !
The storm system we are watching is rather weak but has a decent precip field associated with it due to a nice interaction with the sub tropical jet and some Gulf and Atlantic moisture being drawn into it. The system is now dropping snow across the nation's heartland and will follow the jet stream right into Southern New England, arriving late Sunday morning or early afternoon spreading a swath of accumulating snow into the area. The precip will have to overcome a layer of dry air at the onset, so snow should start off fairly light. Once we saturate the lower and mid levels of the atmosphere , it should fall at a good clip Sunday late afternoon and eve for most areas. We will have to watch a mix line coming close to the south coast, especially for Cape Cod and the Islands. Due to that and the likelihood of lower snow to liquid ratio's down there, I have held amounts back a bit there. I do not foresee any coastal concerns with wind or flooding, but the winds will certainly increase behind the storm system on Monday with a fresh injection of arctic air taking over the region. The snow/mix should wrap up from west to east Monday morning. Below is a map of the snowfall amounts I am expecting. Areas near and south of the pink dotted line at least run a risk of some mixing.
 

Wednesday, February 25, 2015

More Cold & Snow Is In The Forecast Ahead

There is a big winter storm starting to affect portions of the southeast US this afternoon. It looks to bring heavy accumulations of snow and ice to Tennessee again, also into West Virginia, Virginia and even North Carolina. Lighter snows should clip southern Pennsylvania, Maryland, New Jersey , southern New York State and Southern New England later this eve through Thursday eve. 

The Jet stream looks to take this just far enough south to spare Southern New England from another significant snowfall, though it does not appear we will escape from seeing at least a few flakes and some light fluffy accumulations once again from this next storm system. The center of the storm will pass well southeast of Nantucket tomorrow eve. The air will be quite dry especially for areas near and north of the Massachusetts Turnpike, so not expecting much if any accums there but further to the south the northern fringe of the ocean storm snow shield should bring light snow into the region. Like this mornings system, mid levels are quite dry, but closer to the surface there will be more moist air and just enough to squeeze out some fluffy flakes to areas near the South Coast. Important to note the system still could tick north a bit, so I am watching that potential closely still today (see graphic below).
Click on Images for a larger view
One other factor here will be developing NNE winds which will lead to some ocean effect or ocean enhancement for parts of eastern Massachusetts, esp the South Shore and Cape Cod.

 The air will be plenty cold enough at all levels to support snow. No issues with any mixing. Light snow could break out as early as 10am- noontime along the south coast of Connecticut and Rhode Island and more towards 1-2pm for areas of eastern MA, Cape Cod and the Islands. Most locations are done by dark , except for the Cape and the Islands where some ocean effect light snow could continue through the eve. 

High temperatures on Thursday throughout Southern New England will range from about 16° to the far NW to about  25-30° on Nantucket. Again, a fairly low impact event though the timing could cause some issues near the shores during Thursdays afternoon/eve commute with reduced visibility and slick spots on any untreated surfaces. 

The cold is not in any rush to go anywhere across New England as we approach March, but the jet stream will lift north this weekend into next week creating a boundary for more precipitation and storminess to form. We should be on the cold side of that again ! Below are my thoughts for accumulations tomorrow  Stay tuned and thank you for reading     ~Anthony  

2014-2015 Seasonal Snowfall Totals (updated 2/25)


Friday, January 16, 2015

*New Weather Blog* Updated 5pm 1/16/15

An arctic front is crossing the region this evening. It brought with it some snow squalls and gusty winds. Now we will watch the temperatures drop rapidly this evening as a large, but brief dome of high pressure begins to settle in over Southern New England bringing much colder air and very low windchill's. High pressure moves off the coast allowing for our next system to approach for Sunday into very early on Monday. More arctic air engulfs the area next week with a couple chances of snowfall as the northern branch of the jet stream remains active with some sub tropical jet stream interactions.  

A rather robust Alberta clipper is forming near the US/Canada border near Montana and the Dakota's, meanwhile high pressure situated over the Gulf States is sliding away allowing for an increase in moisture along the sub tropical jet stream. These 2 pieces meet up right over Southern New England on Sunday. The track of low pressure looks to be just a bit too far to the west along with a negative tilt to the jet stream to allow for a flow off the relatively mild ocean waters to the south of Southern New England into the region spelling out a mostly rain event for the area.  
                                                                    CLICK ON IMAGES FOR A LARGER VIEW


Further Storm Details : Light, scattered rain looks to break out across the region from south/southwest to north/northeast during the mid to late morning hours on Sunday and becoming heavier during the afternoon into the early evening with a few downpours and very gusty winds. It is a thin line of precipitation and is likely offshore near/after midnight Monday. There will be a very tight rain/snow line out back in western SNE, where some snow is possible. I am not sure much accumulates due to a rush of colder and more importantly, drier air is ushered in on the west side of the storm system. High temperatures will vary on Sunday but look to be in the upper 30's to the northwest (falling through the day) to to near 50° on Cape Cod & the Islands. Winds will be an issue for a time as well gusting between 30-35 mph in Foxboro for the game to as high as a few gusts near 50 mph over southeast areas into early Monday.
Areas most likely to see some snow out of this system appears to be west of the Connecticut River Valley. Just some back end flakes though as it looks. Perhaps some accumulation over southern Vermont and NW Massachusetts 

Into Next week: A drying, cold west/northwest wind comes into the area on Monday and most of Tuesday before we start to see some more action approach.
The northern branch of the Jet stream will remain active as a clipper approaches mid week, that could become enhanced near the shores with some interaction with the moist sub tropical jet. This has the potential to drop some accumulation snow across the region. 
Overall it still is a rather progressive pattern. It is the reason we can see such cold temperatures followed quickly by a storm that brings rain. It is not the first time this year! Too much movement and motion of high pressure and low pressure centers will do it every time. There are and have been indications of developing high latitude blocking near Greenland from time to time in the weeks ahead and more of an influence from that sub tropical jet. The blocking signals never really hold strong though (yet). It then becomes a situation and pattern of timing all these pieces together in order to get a decent snowstorm in here. Unless all the pieces gel, we are left with weaker "systems" like we have seen throughout the entire season to this point. I believe conditions ahead favor an increase chance at this occurring form here out out right through February. Whether it will please all the die hard snow lovers, I am not sure but the potential is there for some white stuff. Not much more to ask for at this point. 
I wish I could go further into details about the pattern and specifics with it ahead but can not do so at this time. I can say with a great deal of confidence that winter is not over. 
Thank you for taking the time to read. Go Pats !  ~Anthony
                               
                                     



Thursday, December 18, 2014

Where We Have Been and Where We Are Going

     So, lets cut right to the chase shall we. The question that is on many minds, where is the snow? Well, its in Maine, head north !  Before I can get into that lets discuss how we have gotten to where we are now this season. First there was a drought, but we have certainly have taken care of that for the most part during the past 60 days or so with well above normal precipitation observed for most locations in Southern New England. In the temperature department , November featured below average temperatures for most the area, now into December we are seeing slightly above avg temps. I thought it would be a bit cooler, but it has not. The Climate Prediction Center has been right on though for the most part. We will see how the rest of the month shapes up, but I can tell you there are very good signals of cooler air heading into January. It has been a fairly "normal" period of weather in recent months, no real extremes occurred other than some daily precipitation records. The map below shows the daily high and low temps for Hartford CT since October. Nothing really jumps out in either direction and only one extreme was reached, and that was a record high of 67° on November 12. 

Click on images for larger views




November did feature a few snow "events" though. Four for some communities ! That is quite rare, and actually many folks across SNE saw more snow in November than what they have received thus far in December. Thankfully no snow was observed in October this season which is a good thing as many of you know I have a strong belief that seeing snow during October is a  curse for snowfall ahead. So as we sit here today on December 18, just a week away from Christmas and most SNE locations are right around either side of avg snowfall to date thus far, though I feel we need to get a decent storm in here before the month comes to a close if you really want that "big" winter. Why? A look back in time to past seasons shows that this month is critical towards the big one. Using Boston for December, the years between 1996 and 2003 there was not one December that featured more than a total of 10" for the month. Only ONE of those seasons finished above normal. 1981-1992, same thing , not one December even hit 10" of snow and only 2 of those seasons even finished above avg which is around 42" . History says we really need to get one before December wraps up. 

    
So that's a little write up on where we have been and now to touch on where we may be heading. We know for the past two months it has been quite active but we have lacked cold high pressure along the Canada/New England border that is necessary to lock in cold air as storms approach. You see, when coastal storms approach, they come with mild air from the tropics or sub tropics and from the moist Atlantic Ocean, its what feeds storms into cyclogenesis and when you lack a dome of *established* cold air, it is very hard to get a true SNE Snowstorm in the month of December. There is another wildcard this season so far too and that is well above avg SST's (sea surface temperatures) off the Mid-Atlantic coast right up into the Gulf of Maine. What this means is any onshore wind flow (which usually occurs as a storm is approaching and during it for a time till winds shift) brings milder air into coastal locations. Inland areas are less effected but still to an extent depending on the intensity of the winds and direction. We really need to get these ocean temps down before we can get too excited along the coast for "snowstorms" .
Here is a map showing those current SST anomalies. You can clearly see they are running well above avg.

The Pattern ahead looks to remain very active, but as discussed previously , its been mild for December for many so far, how do we change that and where do forecasters look for that big "pattern change" ? Well, there are a few places, 1st off models, but most of all teleconnections and more specifically The Arctic Oscillation (AO) and the North American Oscillation (NAO) . What you look for in a big pattern change is sharp changes in these phases, the graphs below show that we are heading in that direction and in a favorable direction with AO projected to head down as well as the NAO which will provide for some much needed Greenland Blocking . 

There is the hope for the snowlovers right there as we move into January, so lets see how this pans outs. Models are suggesting a huge dip in the jet stream in the days ahead but they are not in total agreement as to where the eastern edge of the dip/trough sets up and its eventual tilt which is very important along the East Coast. The Image below is a projection from the GFS model showing the 500mb height anomalies for Christmas Eve time frame. Notice the big ridging off to the northeast producing a high block, keeping storminess over the Northeast US. It's tilt is not quite ideal but could do the trick. Think of the red, yellow & orange (& green here) as a brick wall. We just have to watch trends, it already has shifted a bit in recent days. 

There are the signals that should bring us into a more conducive Winter pattern. Very anomalous. Often anomalous projections lead to anomalous results ! 
The forecast ahead is difficult past some ocean effect moisture on Sat & Sunday but we will likely track a wave of low pressure up the coast Saturday into Tuesday that looks to bring some rain and snow/mix for favored locations to some areas most likely Tuesday before the potential of a very large storm system that likely will move off to our west keeping us in the warm sector and mostly rain and wind on Christmas Eve into early Christmas morning as Santa is making his deliveries which the big fella will have a hard time doing over the Northeast, but something tells me he will get er done. Is there a chance the storm trends colder? Outside shot, yes. We would need to redevelop a new coastal low for that to occur, while that may happen, the negative tilt to the jet would still bring in marine air in regardless. This storm does bring BIG changes in its wake though and don't be surprised to see a few festive snow flakes flying around on Christmas Day ! Now that would be nice. Maps below are for Christmas Eve. Someone is going to have to get Santa a windbreaker for his flight into the Northeast   

A reminder: The first official full day of Winter occurs on Monday December 22 and will end on Thursday March 19th. The Southern New England Weather forecast remains calling for below normal temperatures and snowfall near either side of average. Thank you for reading.   ~Anthony