I shouldn’t be going gray over snowfall forecasts of less than 4″, but this tricky storm that is heading south of Southern New England is doing its best to have me searching the aisles for Just For Men® – not that I’m ever going to do that! Just to recap, on Wednesday midday the Right Weather forecast was for another accumulating snow for all of Southeastern New England. I felt good about the forecast with two of the American computer models in agreement on a light to moderate snowfall, with the highest totals on the Cape and islands. With plenty of cold air charging in, there needn’t be a lot of precipitation because the snow would be dry – allowing for a fluff factor. It would be 1-2″ you could sweep instead of shovel.
Almost immediately after issuing that forecast, I added a caveat that not all computer models were on board with accumulating snow. The current heavyweight champ ECMWF (European) model was consistently sliding the storm out to sea with a minimal impact for mainland Southern New England. So, the Right Weather forecast was at odds with the National Weather Service and many media outlets. Last night’s runs of the American models jumped on the ECMWF bandwagon and had the storm basically missing SNE, with a little light snow on the Cape/Islands. At that point, the Right Weather forecast changed to a mea culpa near-miss for RI and SE MA, with some light snow on the Cape/Islands. Heck, the system was only 30 hours away, and all reliable computer models had it barely grazing SNE. It would be borderline arrogant to stay with a 2-4″/3-6″ forecast.
In the dark of night last night, the ECMWF model rolled in and predicted accumulating snow for RI for the first time. It wasn’t a lot (1-2″), but it was an indication of the flip-flopping that drives meteorologists nuts. Now, the American models are off the light snow bandwagon, and the ECMWF is on it! Look, it’s not a big storm, but 1-2″ of snow, with the temperature near 20° can cause some issues on untreated roads during the Friday morning commute. It’s a minor cause for concern.
That brings us to the situation as it stands early Thursday afternoon. The morning runs of the American models print out 0.01″ of liquid in Providence. That’s basically a forecast of flurries. The ECMWF model is printing out 0.24″ of liquid in Providence. That’s nearly 3″ of light, dry, fluffy snow. The short range models are predicting anywhere from the low end of snow showers and flurries to a situation similar to what the ECMWF has. So, what is one to do?
First, let me explain my rationale for the snowy forecast issued yesterday. So far this week, SNE has seen two different weather systems bring precipitation. The first, was somewhat of a sneak attack Monday night. A brief period of sleet was followed by some steady light rain. Most computer models missed it, and it wasn’t until the short range models picked up on it that most of us added it to the forecast. The storm that brought up to 5″ of snow early Wednesday was also a bit under-forecasted – not so much on the snow totals, but the amount of liquid (QPF) that the models printed out. Based on those two events, I thought, and still think, that this third event had a decent chance of being closer to the coast than projected by the models – which weren’t have a stellar week handling the stalled boundary offshore.
With this storm, however, there is the added element of an Arctic cold front that was plunging south through Northern New England on Thursday. This front is likely to bring some very cold air (teens to low 20s) into Southern New England late tonight. It will also interact with the offshore storm, but to what degree we’re not sure. That is the bottom-line – we’re not sure. The next time you fly into Southern England take a look at our beautiful shoreline and also note all the atmosphere above it! We’re trying to model an atmosphere of enormous proportions and deliver a forecast for your backyard. Unfortunately, we only get a grainy snap shot of the atmosphere for the computer models to run their simulations, and the resulting forecast is sometimes not as accurate or detailed as we like. The storm we’re referring to is only 12-15 hours away, but it’s also centered near Birmingham, AL – where it’s bringing snow. The science has not evolved to the point where every forecast is a slam dunk. This one’s a turnaround three pointer with LeBron James in my face. I think because forecasting has improved so much in the past few decades that expectations (for some) have become too great. I have no problem saying I won’t be surprised if I wake up in Bristol, RI to 3″ of snow or nary a flake tomorrow morning. It’s just the way it is, and with that, let’s finally get to the forecast.
Clouds will thicken Tuesday evening. Some light snow or flurries should develop around midnight near the coast. The best chance of steady snow is late at night on the Cape and Islands. It will become windy on Nantucket and Cape Cod, and breezy in the rest of Southeastern New England. Cold air will be moving in from north to south, and the low temperature is likely to be in the teens in Central MA and Northern RI and CT. Elsewhere, the temperature will fall through the 20s overnight. Any snow should end by around dawn in RI and interior SE MA, and by 8-9 am on Nantucket and Cape Cod. It will be brisk, dry, and chilly tomorrow. The high temperature will not make it out of the 20s.
The best chance of seeing plowable snow is on the Cape/Islands. If the storm comes close enough 3-5″ of snow is possible in those areas. In RI and SE MA, there is the chance for 2-3″ on the high end (esp. near the coast), with 0-1″ if the snow shield from the storm doesn’t spread as far north.
The temperature will moderate a bit this weekend before tumbling early next week. I’ll have more on that in an update later today.