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 

Monday, April 14, 2014

Winds of Change

The winds of change are upon us ! They brought many 70's the past couple days and will bring other changes over the next couple of days but you may not like them this time.
A powerful early Spring cold front will be approaching the region Tuesday bringing with it scattered early downpours which will become more widespread as Tuesday wears on. Overall the entire region is prone to about an 1-1.5" of rain with a few isolated higher amounts possible, especially over Connecticut.  For this reason there is a  * Areal Flood Watch* is up.  And If you think the winds were strong today, wait till tomorrow and tomorrow eve.
They will scream from the south with gusts between 40-55 mph. A few isolated higher gusts are certainly possible over the hills and over Cape Cod & the Islands. I would expect at least widespread Wind Advisories to be issued for tomorrow shortly. For now though, Gale Warnings are up for the waters just off our coastlines from 2pm Tuesday through 6am Wednesday.  Gusts of this magnitude are certainly capable of isolated damage and power outages. As the strong cold front passes the region late Tuesday into Wednesday wind will shift to the west/northwest and still be gusty especially early on Wednesday as they usher in much colder air. Its during this time (late Tues night-early Weds) that some cold air aloft will creep in and marginal surface temperatures snow for may will bring the potential for heavy rain to turn to some wet snow flakes over the higher elevations and western Southern New England. Believe it or not the potential is there for a slushy inch or two ! Some wet flakes could even make it all the way to to the coast. Wednesday we are left with morning lows near freezing and high temperatures that will struggle to get of the upper 40's and low 50's with developing sunshine during the afternoon. A frost is likely Thursday am and again highs struggling to get out of the upper 40's and low 50's even with quite a bit of mid April sunshine. Quite impressive!   Cool weather looks to rule right into the coming weekend.    ~Anthony