As the last discussion noted, just as everyone thought winter was over, old man winter wants to make a comeback! The first indications of this will be over the next couple days, as colder air filters into the region. Then a potential significant or even major late-season winter storm in the Sunday-Monday timeframe- more on that a little later.
First, for tonight, temperatures should be fairly uniform. There will be varying amounts of clouds through the night, so radiational cooling will vary depending on who stays clear the longest. In addition, it appears the usually cool spots will probably have the most clouds, so this will negate their potential to be significantly colder. Therefore, expect low temperatures to be within a few degrees of 40 all locations.
For tomorrow, once again, there will be more clouds than sun. However, the potential for any precipitation is very low, despite the fact that a strong cold front (which will set up a cold air mass for the following storm), will be moving through. It just doesn’t have much moisture to work with. There is a small chance of a sprinkle. In the far north, a sleet pellet or snow flake could mix in with any sprinkles late in the day. But the chance is very low, so I have elected to leave it out of the forecast. High temperatures should be in the 50-55 degree range.
For tomorrow night and Saturday, cold air will begin to rush in tomorrow night, and the air will feel much more like winter! With the setting sun and strong cold air advection, temperatures will plummet and overnight lows should get into the 25-30 degree range. A few of the normally colder spots may make it even lower than that! Temperatures on Saturday will be about fifteen degrees colder than those of Friday- only in the low 40s. A few of the colder Northern locations may not even get out of the 30s!
The next portion of the discussion will be dedicated to the potential upcoming winter storm. So let’s start with a model rundown. The models are generally in two camps this evening, and it’s really an American vs. foreign model scenario right now. The GFS and NAM focus more energy on the first wave, although the NAM gets us a bit more snow than the GFS, since the follow-up coastal is a bit closer than on the GFS. However, the American models only really have a light to moderate snowfall.
Then there are the foreign models. The ECMWF and UKMET are VERY similar. It’s hard to tell exactly how similar, because access to the UKMET model is limited and we don’t have access to the “in-between” times. Unfortunately for forecasters, the most important time is the “in-between” time. The GGEM (Canadian) model is similar in terms of evolution to the ECMWF and UKMET, but winds up 50-100 miles west with the coastal low. The ECMWF and UKMET would result in a major snowstorm for all of CT, with over a foot of snow for the entire state if taken literally. The GGEM, being further west, warms the south coast and changes them to rain, after a moderate snowfall. Meanwhile interior portions still receive a major snowfall.
Summing this all up, it is too early to make a snowfall map. For one thing, there is still a lot of uncertainty regarding the track of the upcoming storm and the resultant impacts and snow amounts on the area. Secondly, the storm is still too far out to be able to pin down snow amounts. Even timing is uncertain. The foreign models downplay the initial Northern stream energy and give most of the energy to the costal. Thus, the snow takes longer to develop and doesn’t really get going until Sunday night. The American models emphasize the earlier, Northern stream energy more. Thus, going by those solutions, it is more of a Sunday morning and afternoon event. Therefore, with all this uncertainty still present, it is too early to issue a snow map. However, it is not too early to say that I have high confidence that the entire state will see some type of accumulating snowfall into the Sunday and Monday timeframe. Whether the state gets just light to moderate snowfall or a major winter storm remains to be seen. A snow map will be issued tomorrow, as the data (hopefully) converges on one solution and the storm evolution becomes more clear.
I didn’t focus too much energy on anything beyond this storm. However, what I did see was that a moderating trend should be expected. In fact, we could see a few very warm days a few days after the storm. There is also a signal for another blast from the Arctic toward the end of the month, and maybe, just maybe, another winter storm threat!
Now, here a few maps to visualize the pattern better.
First, for tonight, temperatures should be fairly uniform. There will be varying amounts of clouds through the night, so radiational cooling will vary depending on who stays clear the longest. In addition, it appears the usually cool spots will probably have the most clouds, so this will negate their potential to be significantly colder. Therefore, expect low temperatures to be within a few degrees of 40 all locations.
For tomorrow, once again, there will be more clouds than sun. However, the potential for any precipitation is very low, despite the fact that a strong cold front (which will set up a cold air mass for the following storm), will be moving through. It just doesn’t have much moisture to work with. There is a small chance of a sprinkle. In the far north, a sleet pellet or snow flake could mix in with any sprinkles late in the day. But the chance is very low, so I have elected to leave it out of the forecast. High temperatures should be in the 50-55 degree range.
For tomorrow night and Saturday, cold air will begin to rush in tomorrow night, and the air will feel much more like winter! With the setting sun and strong cold air advection, temperatures will plummet and overnight lows should get into the 25-30 degree range. A few of the normally colder spots may make it even lower than that! Temperatures on Saturday will be about fifteen degrees colder than those of Friday- only in the low 40s. A few of the colder Northern locations may not even get out of the 30s!
The next portion of the discussion will be dedicated to the potential upcoming winter storm. So let’s start with a model rundown. The models are generally in two camps this evening, and it’s really an American vs. foreign model scenario right now. The GFS and NAM focus more energy on the first wave, although the NAM gets us a bit more snow than the GFS, since the follow-up coastal is a bit closer than on the GFS. However, the American models only really have a light to moderate snowfall.
Then there are the foreign models. The ECMWF and UKMET are VERY similar. It’s hard to tell exactly how similar, because access to the UKMET model is limited and we don’t have access to the “in-between” times. Unfortunately for forecasters, the most important time is the “in-between” time. The GGEM (Canadian) model is similar in terms of evolution to the ECMWF and UKMET, but winds up 50-100 miles west with the coastal low. The ECMWF and UKMET would result in a major snowstorm for all of CT, with over a foot of snow for the entire state if taken literally. The GGEM, being further west, warms the south coast and changes them to rain, after a moderate snowfall. Meanwhile interior portions still receive a major snowfall.
Summing this all up, it is too early to make a snowfall map. For one thing, there is still a lot of uncertainty regarding the track of the upcoming storm and the resultant impacts and snow amounts on the area. Secondly, the storm is still too far out to be able to pin down snow amounts. Even timing is uncertain. The foreign models downplay the initial Northern stream energy and give most of the energy to the costal. Thus, the snow takes longer to develop and doesn’t really get going until Sunday night. The American models emphasize the earlier, Northern stream energy more. Thus, going by those solutions, it is more of a Sunday morning and afternoon event. Therefore, with all this uncertainty still present, it is too early to issue a snow map. However, it is not too early to say that I have high confidence that the entire state will see some type of accumulating snowfall into the Sunday and Monday timeframe. Whether the state gets just light to moderate snowfall or a major winter storm remains to be seen. A snow map will be issued tomorrow, as the data (hopefully) converges on one solution and the storm evolution becomes more clear.
I didn’t focus too much energy on anything beyond this storm. However, what I did see was that a moderating trend should be expected. In fact, we could see a few very warm days a few days after the storm. There is also a signal for another blast from the Arctic toward the end of the month, and maybe, just maybe, another winter storm threat!
Now, here a few maps to visualize the pattern better.
This is the GFS depiction. Notice the coastal low is fairly weak and quite a distance offshore. Meanwhile, here is the GGEM (Canadian) solution, which is similar, but just west (and warmer) than the ECMWF solution.
Notice how much stronger and further west the surface low is. Most of the state is under heavy snow at that hour, and there are mixing issues along the immediate south coast.
Obviously, which model solution becomes correct will have a huge impact on our state's weather. That's all for now, stay tuned for adjustments and a preliminary snow map tomorrow afternoon or evening!
Please remember to like, share our discussions and follow us on Facebook and Twitter @SouthernCTWX. All you have to do is click below!
-GP
Obviously, which model solution becomes correct will have a huge impact on our state's weather. That's all for now, stay tuned for adjustments and a preliminary snow map tomorrow afternoon or evening!
Please remember to like, share our discussions and follow us on Facebook and Twitter @SouthernCTWX. All you have to do is click below!
-GP
