Good evening to you from Southern Connecticut Weather!
It’s been a week with little sunshine in Connecticut, and while there is a light at the end of the tunnel, we’ve got one more storm system to get through first that will bring rain and close to record warmth to the state on Christmas Eve/Day. After that, however, we begin a slide that will last for several days into a more wintry like regime, possibly culminating with the first widespread accumulating snowfall of the season! Let’s break down the forecast.
Tomorrow and Wednesday will maximize the gloomy pattern that we’ve seen the last several days as a storm system cuts to our west and brings warmth and rain to the state. Rain will be in the cards for most of the day tomorrow right through Christmas morning, and along with that will come close to record highs, with temps making it into the mid to upper 50s tomorrow evening into Christmas morning before temps fall Thursday afternoon as the storm departs. As shown on the departures map below, this is ten to twenty degrees above normal for this time of year! As the storm pulls away, we’ll see temps drop back down to more seasonable, yet still above normal levels as colder air comes in from the west. Here’s images of the forecast MSLP at 7 PM tomorrow night, the warmest expected temps, the total QPF, and the forecast departures from normal all from the 18z GFS model. Model consensus is excellent for this close in event as far as our area goes so just took a blend of all models.
It’s been a week with little sunshine in Connecticut, and while there is a light at the end of the tunnel, we’ve got one more storm system to get through first that will bring rain and close to record warmth to the state on Christmas Eve/Day. After that, however, we begin a slide that will last for several days into a more wintry like regime, possibly culminating with the first widespread accumulating snowfall of the season! Let’s break down the forecast.
Tomorrow and Wednesday will maximize the gloomy pattern that we’ve seen the last several days as a storm system cuts to our west and brings warmth and rain to the state. Rain will be in the cards for most of the day tomorrow right through Christmas morning, and along with that will come close to record highs, with temps making it into the mid to upper 50s tomorrow evening into Christmas morning before temps fall Thursday afternoon as the storm departs. As shown on the departures map below, this is ten to twenty degrees above normal for this time of year! As the storm pulls away, we’ll see temps drop back down to more seasonable, yet still above normal levels as colder air comes in from the west. Here’s images of the forecast MSLP at 7 PM tomorrow night, the warmest expected temps, the total QPF, and the forecast departures from normal all from the 18z GFS model. Model consensus is excellent for this close in event as far as our area goes so just took a blend of all models.
In general, expecting between one and two inches of rain across the state, although as always, locally higher amounts possible in heavy cells. A slight chance of thunderstorms is in the cards for Wednesday night into Thursday morning, and while not expected to be at damaging levels, windy temps are expected, with wind gusts in the 30-40 MPH range, especially on Thursday as the low departs. Highs Wednesday and Thursday both in the mid to upper 50s, although Wednesday will see temps rising through most of the day and Thursday will see them falling. Chance of precipitation is 100%.
Behind the storm, we finally say goodbye to the clouds, as Thursday afternoon we will see clearing skies and then by Friday, close full sunshine! Friday and Saturday look like incredible days to get outside and enjoy the sunshine, with highs in the upper 40s to lower 50s expected. Don’t expect it to last though, so enjoy it while you can as clouds build again by Sunday in preparation for our next possible system.
Modeling is in relatively good agreement on a system moving north from the gulf Sunday into Monday, but how it tracks and a result it’s sensible impacts for our region are still very much in question. The 18z GFS has an anafrontal signature to it, bringing a broad wave of moderate precipitation across much of the east coast. Given the cold air in place from the EPO ridge pressing down from the north, this would result in an overrunning snow event for the area, similar in nature perhaps to some of the events we saw last winter with the thermal boundary being set up to the south of our area and the axis of the heaviest precipitation riding up along that boundary. The GFS would be an all snow event for our area, with accumulations for all right down to the shoreline. Here’s an image of the MSLP and precipitation type from the GFS at hour 144, that being 1 PM Monday afternoon.
Behind the storm, we finally say goodbye to the clouds, as Thursday afternoon we will see clearing skies and then by Friday, close full sunshine! Friday and Saturday look like incredible days to get outside and enjoy the sunshine, with highs in the upper 40s to lower 50s expected. Don’t expect it to last though, so enjoy it while you can as clouds build again by Sunday in preparation for our next possible system.
Modeling is in relatively good agreement on a system moving north from the gulf Sunday into Monday, but how it tracks and a result it’s sensible impacts for our region are still very much in question. The 18z GFS has an anafrontal signature to it, bringing a broad wave of moderate precipitation across much of the east coast. Given the cold air in place from the EPO ridge pressing down from the north, this would result in an overrunning snow event for the area, similar in nature perhaps to some of the events we saw last winter with the thermal boundary being set up to the south of our area and the axis of the heaviest precipitation riding up along that boundary. The GFS would be an all snow event for our area, with accumulations for all right down to the shoreline. Here’s an image of the MSLP and precipitation type from the GFS at hour 144, that being 1 PM Monday afternoon.
The 12z EURO, however, paints a different picture. The EURO has this first wave of overrunning much further north and weaker than the GFS, bringing nothing but some light rain showers for the area. It then forms another low in the gulf and brings it west of the area before it runs into the block of cold air and slides east, redeveloping into a coastal low just south of Long Island. Given that the storm tracks further north, more warm air is allowed to intrude, and the end result is a snow to sleet to rain scenario, with little to no accumulation along the coastline and perhaps a slushy few inches inland before a changeover to sleet and finally rain. Here’s an image of the MSLP from the 12z EURO for 7 AM Monday morning, showing the storm tracking up to our west and warmer temperatures as a result.
The GEFS and EURO ensembles support their respective operationals to a degree, although the EUROens are a little south of the op, suggesting a blended compromise between the two operationals might be an optimal forecast for the time being. However, the 12z Canadian and 18z Parallel GFS have no stronger storm at all for the period and only a weak wave of overrunning, which would result in light rain showers for the region. Given the uncertainty and the seasonal trend we’ve seen this year to deamplify storms, I’m giving more weight to these solutions than I would ordinarily(considering their relatively poor verification scores overall), and as a result, will keep precipitation chances relatively low for now. Therefore, all factors considered, will forecast a 40% chance of rain and snow for Sunday and a 50% chance of rain and snow for Monday to represent the uncertainties in precipitation type between the EURO and the GFS. As it’s 5-6 days out, won’t go into too much detail re. timing and impacts, but the potential for a moderate event is there. Remember, it’s 5 days out, and considering the shifts we have seen in guidance inside that window so far this season, I wouldn’t expect to see this locked down until later in the week.
Much colder weather is expected throughout the period, with highs generally in the low to mid 40s Sunday and in the low to mid 30s Monday, although this will vary due to the storm track that ends up verifying. Even colder temps come in behind the storm, with temps perhaps not getting out of the 20s next Tuesday.
We’ll update as needed tomorrow and Christmas day, with a full discussion (along with any needed storm disco) on Friday. Until then, Merry Christmas, Happy Holidays, and thanks for reading Southern Connecticut Weather!
-SA
Much colder weather is expected throughout the period, with highs generally in the low to mid 40s Sunday and in the low to mid 30s Monday, although this will vary due to the storm track that ends up verifying. Even colder temps come in behind the storm, with temps perhaps not getting out of the 20s next Tuesday.
We’ll update as needed tomorrow and Christmas day, with a full discussion (along with any needed storm disco) on Friday. Until then, Merry Christmas, Happy Holidays, and thanks for reading Southern Connecticut Weather!
-SA
