Disc: Examining models this afternoon yields no end in sight to the assault of winter events every couple days across the NE CONUS.
Currently: High pressure has moved into the lower Hudson Valley and pushed low pressure off the coast of NC. This has taken the light snow that affected the S coast this morning out to sea with it.
Tonight: Will go several degrees below NBM guidance with clear skies, fresh snowcover in some areas, and deep "old" snowcover everywhere. Perfect radiative night. Look for lows of 5 to 10 above!
Tomorrow: Variable clouds and cold. Guidance looks OK, so temps accepted. Highs should be in the upper 20s.
Tomorrow night/Sat: Clouds increase during the day Sat ahead of our next sys. Otherwise, cold, but dry. With increasing clouds and still plenty of snowpack. I went a couple degrees under NBM guidance. Once again, highs should be in the upper 20s.
Long Term: The parade of events every two days or so will continue. As such, the focus for events in the long term is going to be Sunday, Tuesday, and then right at the end (or just beyond the end) of our fcst period. Every one of these events will present an opportunity for wintry wx. Sun will probably be the weakest (but not zero impact), the other two are poised to have significant pcpn.
Sunday's event begins during the morning for most of the state, but may hold off until later Sun evening or even early Mon morning for NE CT. Although pcpn should be light during this time frame, it could take the form of snow, but more likely become mainly sleet and freezing rain. I do not need to tell most of my readers that you do not need a lot of ice to cause problems. So even though Sunday's event is probably light in terms of overall pcpn amounts, it is not zero impact. There is a small chance this event does not happen at all, as there are still some ENS members showing very little or no pcpn. However, the chance of pcpn occurring has definitely increased since yesterday as the GFS has begun to come aboard and more ENS are on board than yesterday. Either way, pcpn pulls out before midday Mon. Since models have run warm during storms, and have become even worse lately, I took 5 degrees or so off temp guidance for Sunday. For Monday, I only took a couple deg off, since the pcpn winds down in the morning. This should keep high temps in the 20-25 deg range on Sunday, and near 30 on Mon. It's possible that the I 91 corridor could go above freezing very briefly on Mon if the sun comes out at all.
The next sys bears down on Tue. Models have come into better agreement that the p-typ for this event will be entirely frozen. Most of the guidance, except for the Canadian model, have a substantial event. The GFS model is all snow for almost all of the state, with some sleet mixing in at times along the S coast. The Canadian model, although a smaller event, is all snow. The ECMWF model starts as snow and then changes to ice, with significant ice for the S coast, after moderate to significant snow accums, then significant snow for the Central-N CT, followed by a glaze of ice. It's possible everyone changes back to snow before ending. Since this event has trended quite a bit colder on all guidance, I am leaning toward a snowier solution, although ice would not surprise me, esp along the S coast. It will be very cold. NBM temps were not even considered at all for this pkg, with modeled gridded data preferred. High temps should only be in the low 20s, so whatever falls will stick and be frozen!
Wed will be a calm day between systems. I'll cut off a few deg from NBM temps, assuming they'll be even more new snowcover, but this is still a bit uncertain as of now. This yields highs right around the freezing mark.
By Thursday, yet another sys will be moving into the area. The "Big 3" computer models all agree on major icing potential with this one, with the GFS being the warmest and driving the low well to our west. All models also suggest a possible changeover to snow at the end, with Arctic air moving in. It should be noted that even the GFS model, which is well west/warmer than other guidance, and has a bias of being too warm in storms, is still a significant icing before any changeover to plain rain. And even IF that scenario played out, we'd flash freeze pretty quickly at the end of the storm, with cold air rushing in. Needless to say, high temps on Thu are very tricky, and highly dependent on storm track. For now, I shaved 3-5 deg off guidance, out of an abundance of caution. Highs should be 30-35.
The long range looks to remain cold, but perhaps a bit less stormy. We can't really keep having a big storm every couple days, can we?
Now let's take a graphical look at some systems slated to affect the area. Here is the Canadian model, valid Sunday morning. Look at the icy mess across CT! North of I 84, according to this model, it started as snow. It is plain ice for the rest of the state.
Currently: High pressure has moved into the lower Hudson Valley and pushed low pressure off the coast of NC. This has taken the light snow that affected the S coast this morning out to sea with it.
Tonight: Will go several degrees below NBM guidance with clear skies, fresh snowcover in some areas, and deep "old" snowcover everywhere. Perfect radiative night. Look for lows of 5 to 10 above!
Tomorrow: Variable clouds and cold. Guidance looks OK, so temps accepted. Highs should be in the upper 20s.
Tomorrow night/Sat: Clouds increase during the day Sat ahead of our next sys. Otherwise, cold, but dry. With increasing clouds and still plenty of snowpack. I went a couple degrees under NBM guidance. Once again, highs should be in the upper 20s.
Long Term: The parade of events every two days or so will continue. As such, the focus for events in the long term is going to be Sunday, Tuesday, and then right at the end (or just beyond the end) of our fcst period. Every one of these events will present an opportunity for wintry wx. Sun will probably be the weakest (but not zero impact), the other two are poised to have significant pcpn.
Sunday's event begins during the morning for most of the state, but may hold off until later Sun evening or even early Mon morning for NE CT. Although pcpn should be light during this time frame, it could take the form of snow, but more likely become mainly sleet and freezing rain. I do not need to tell most of my readers that you do not need a lot of ice to cause problems. So even though Sunday's event is probably light in terms of overall pcpn amounts, it is not zero impact. There is a small chance this event does not happen at all, as there are still some ENS members showing very little or no pcpn. However, the chance of pcpn occurring has definitely increased since yesterday as the GFS has begun to come aboard and more ENS are on board than yesterday. Either way, pcpn pulls out before midday Mon. Since models have run warm during storms, and have become even worse lately, I took 5 degrees or so off temp guidance for Sunday. For Monday, I only took a couple deg off, since the pcpn winds down in the morning. This should keep high temps in the 20-25 deg range on Sunday, and near 30 on Mon. It's possible that the I 91 corridor could go above freezing very briefly on Mon if the sun comes out at all.
The next sys bears down on Tue. Models have come into better agreement that the p-typ for this event will be entirely frozen. Most of the guidance, except for the Canadian model, have a substantial event. The GFS model is all snow for almost all of the state, with some sleet mixing in at times along the S coast. The Canadian model, although a smaller event, is all snow. The ECMWF model starts as snow and then changes to ice, with significant ice for the S coast, after moderate to significant snow accums, then significant snow for the Central-N CT, followed by a glaze of ice. It's possible everyone changes back to snow before ending. Since this event has trended quite a bit colder on all guidance, I am leaning toward a snowier solution, although ice would not surprise me, esp along the S coast. It will be very cold. NBM temps were not even considered at all for this pkg, with modeled gridded data preferred. High temps should only be in the low 20s, so whatever falls will stick and be frozen!
Wed will be a calm day between systems. I'll cut off a few deg from NBM temps, assuming they'll be even more new snowcover, but this is still a bit uncertain as of now. This yields highs right around the freezing mark.
By Thursday, yet another sys will be moving into the area. The "Big 3" computer models all agree on major icing potential with this one, with the GFS being the warmest and driving the low well to our west. All models also suggest a possible changeover to snow at the end, with Arctic air moving in. It should be noted that even the GFS model, which is well west/warmer than other guidance, and has a bias of being too warm in storms, is still a significant icing before any changeover to plain rain. And even IF that scenario played out, we'd flash freeze pretty quickly at the end of the storm, with cold air rushing in. Needless to say, high temps on Thu are very tricky, and highly dependent on storm track. For now, I shaved 3-5 deg off guidance, out of an abundance of caution. Highs should be 30-35.
The long range looks to remain cold, but perhaps a bit less stormy. We can't really keep having a big storm every couple days, can we?
Now let's take a graphical look at some systems slated to affect the area. Here is the Canadian model, valid Sunday morning. Look at the icy mess across CT! North of I 84, according to this model, it started as snow. It is plain ice for the rest of the state.
Now, let's look at the GFS valid Tue morning. There is a classic "banana high" setup to hold in the cold air. The storm track will ultimately determine whether we get a lot of snow, ice, or both.
That's all for now, I'll see you next time!
-GP!
-GP!
