Monday, February 17, 2014

More Snow Tuesday, possible wintry mix Wednesday, then changes !

Here we go again Southern New England ! Yes there is a brief and much needed warm-up approaching us Thursday through Sunday but before then we must grind through another period of accumulating snow for much of the region on Tuesday and likely a bit more later on Wednesday. It has been relentless this season.
  WARNINGS & ADVISORIES:  In advance of the storm system all of Connecticut (except the extreme SE part of the state) , central and northern Rhode Island and much of Massachusetts  (away from areas S&E of RT 24)  are under a Winter Weather Advisory for much of Tuesday. Winter Storm Warnings are up for parts of Worcester County north and east into Southern New Hampshire away from the Seacoast.            
  THE SETUP: The System we are watching has brought some heavy snowfall rates to the Chicago area today and reports of thundersnow. This is all associated with a energetic northern stream pool of upper level energy. This energy will be over the eastern Great Lakes by early Tuesday and will form a new low just off the Southern New England coastlines into the Gulf of Maine Tuesday evening and bring us our snowfall. Enough mild air will flow in to make for a mix with rain over southeast portions and likely be mostly rain over Cape Cod and the Islands, so not much if any snowfall is expected 
  TIMING: Snow appears to break out over southwest Connecticut between 7-10am and progress off to the northeast thereafter reaching far northeastern Massachusetts between 11am-2pm give or take. With impressive indications of vertical upward velocity at 700 mb (10,000 ft above) there is the potential for brief snowfall rates to reach or exceed 1" per hour with even the possibility of thunder. This will have impacts on the afternoon and evening commute east of Worcester, Ma up and down Southern New England. Below I have put together a animated simulated radar loop giving a general idea of how precipitation should develop and progress through the day on Tuesday.

   SNOWFALL: Away from the immediate shores and parts of southeast CT, RI & Ma we are looking at a general 2-5" snowfall with this. There will be a couple areas that have a chance to exceed 5" of snowfall though and this will be northern Worcester county into northeast Mass into SE New Hampshire. The reason for less snowfall near the coast this go around is mainly due to low pressure tucked close to our coastlines Tuesday and the projections of a south/southeast onshore wind direction during heaviest period of precipitation.
   OTHER IMPACTS: This is not a typical 'snowstorm' or coastal storm so I am not expected too many other  impacts of significance though we could see some sustained SE winds between 20-30 mph developing over coastal Massachusetts and especially Cape Cod and the Islands as these locations will be nearest to developing and likely  intensifying low pressure off the coast.  Much of Southern New England will see some gusts at times 25-35 mph with  perhaps a few near/over 40mph on the Cape & the Islands Tuesday afternoon and evening.
   WHATS AHEAD ?: Milder weather !  Before we get there though we have a transition day shaping up for wednesday with another potential event with weak low pressure trying to form off of the New Jersey coast Wednesday afternoon which looks to bring  a mix of wet snow and rain to portions of the area. It currently favors central and east the most. I will surely have more details on that potential after Tuesday's event passes and I can get a quick glance at exactly how the upper level pattern appears at that point.  Beyond Wednesday  a south/southwest flow develops along with warming at the mid levels which will bring surface temperatures into the upper 30's to low 40's for much of the area Thursday with a few rain showers possibly brief icing transitioning to rain at night into much of Friday with a storm well off to our northwest and trailing cold front passage slated. Highs on Friday look to soar into the 40's and 50's to near 60 for some ! It looks a bit cooler but mild again Saturday and early Sunday with colder air arriving late with a few rain or snow showers possible.  All indications continue to bring us into a  much colder and potentially stormy pattern once again thereafter.  Thank you for reading.   ~Anthony 

Saturday, February 8, 2014

Light Snow Approaching. Watching Potential Storm Mid Next Week

Clouds are increasing this evening ahead of a northern branch disturbance (shortwave) moving east over the lower Great Lakes. It has produced a general Coating-4" to our west. There will be no big storm as I once thought was possible as that has now sped up and is missing off to our south and east this eve but there is enough energy with this shortwave to produce periods of light snow Sunday into Monday across Southern New England. Snow showers and periods of light snow will move in from west to east during Sunday. Before its arrival there could be some ocean effect snow showers as winds shift from west to northwest and to north that may affect parts of Cape Ann and Provincetown. Overall this is a minor event and looks to drop a coating to 2" with just a small chance at this time of a few locations seeing over 2"
This favors the south and east coasts. The storm simply is moving too quickly to produce more with no real moisture source and it being under a fast moving zonal jet stream. It will be all snow though and a bit of a fluff factor too so thats where we see a high end potential. It appears we remain cold for the foreseeable future and need to watch for another storm during the middle of next week. This would include the southern moist jet so the potential is there for a coastal storm but in the wake of the Sunday into Monday disturbance a large, cold dome of high pressure settles in and exactly how quick it releases or how long it decides to hold will make all the difference in the forecast for a potential snowstorm, a mix storm or even a suppressed storm missing out to sea. It is simply where we are at this point with that one and until we figure out how and where the upper levels will steer this thing there will be more questions than answers. I will surely be monitoring its every move and will keep you up to date on that.

Saturday, February 1, 2014

January Ends On A Quiet Note. February Starts Active

   January has come to an end with monthly temperatures averaging near or slightly below normal for much of Southern New England while many saw snowfall well above avg. Now its onto February, by far my favorite month to forecast in SNE and with signals of a very active pattern in the first week at least there are plenty opportunities to do such. February is know for some monster storms in this region (a few of which need no introduction) and actually 6 out of 10 of Boston’s top 10 snowfalls have occurred in the month of February and with the signals of an active pattern and a few snow chances for many in the near future, I think its safe to say that winter is far from over regardless of what that little rodent says on Sunday.
   The first system we are watching and quickly approaching is slated for Monday. Right now the energy for that is diving south/southeast from the Pacific Northwest towards Texas. It picks up some Gulf of Mexico moisture and heads off the northeast late tomorrow and early Monday. It’s a quick mover due to lack of blocking to our north but it packs a bit of a punch especially to our south once again.  Low Pressure forms over Mississippi/Alabama Late Sun eve, early Mon and cuts through the southern Appalachians before curving off the coast of the Mid-Atlantic northeast of the Outer banks of North Carolina Monday afternoon. This points to areas of Virginia to New Jersey in the meat of the precipitation through Monday afternoon, though SNE will be on the northern edge of this storm. With a 1028MB high off to the west pushing this and 1024MB high influence along the Ma & VT/NH borders, once again the precipitation favors areas to the south of the Mass Pike. Light snow should break out Monday morning along the south coast of SNE and slowly creep northeast to the Mass Pike by midday before coming to a halt and slipping off to the east by the evening. 

   As far as precip type goes, it is mostly snow as temperatures aloft support such but surface temps will be marginal for many so it does not appear to be a “fluff factor; event to which we have become quite accustomed to this year. It will be a wetter type snow and even a few raindrops mixing in for SE Mass. and Cape Cod & the Islands. As far as amounts go it looks like a general slushy coating-2” with a few locations seeing near or over 3” of snow favoring near the extreme south coast. Not much if any wind expected with this so impacts are minor with this event.

   We get a brief break in the action Tuesday , but then all eyes turn off to our southwest again with building Gulf of Mexico moisture being driven by a very energetic upper level disturbance which will steer all that moisture northeast towards SNE Late Tuesday night and Wednesday. A surface low will work up to the Ohio River Valley , begin to transfer its energy to a secondary low near the Delmarva Peninsula. With this secondary low offshore, it keeps SNE on the cold side of this storm for the most part and with anonymously cold ocean temperatures makes any wind flow off the ocean help retain cold to keep this mostly a snow storm and quite potentially a sizable one (over 6").  The air above will be marginal though, so periods of freezing rain also possible for some. There will be a mix line for a time and that should become much more clear hopefully by later Sunday as the main energy for that storm enters the West coast and more data gets fed into guidance. There is no doubt of the storm occurring though. Another storm looks likely next weekend too ! Busy Pattern. Thank you for reading  ~Anthony