As we get deeper into astronomical winter, the pattern does look to turn stormier, but it also does not look severely cold. Still, there will probably be some opportunities for winter wx, esp N of the Merritt Pkwy.
Currently: High pressure over the Appalachians is in control of our wx today. There is still a bit of a breeze, esp in E CT, from slowly departing low pressure over Nova Scotia.
Tonight: I went very close to guidance on temps, and actually a degree warmer here and there. Clouds increase, winds shift to the S. So w/weak warm air advection and overcast skies, temps don't drop fast. A warm front approaches and should have a band of light snow with it. Temps are cold enough everywhere for snow to fall and stick, but the problem is moisture content. There may only be enough moisture to kick out a couple hundredths of liquid equivalent. Therefore, any accums should be limited to a coating to less than a half inch. As such, a snow map will not be needed for this event. For low temps, I have mid to upper 20s for the state.
Tomorrow: I went below guidance on temps, as guidance appears to offer too much sun. We'll prob be slow clearing out the morning clouds and as soon as they do, clouds from the next wave increase. Don't forget, we have the lowest sun angle of the yr right now, so clouds don't break that easily. Highs should generally be in the upper 30s.
Christmas Eve night and Christmas Day: Two waves will affect the area- the first centered on Christmas Eve night and Christmas morning, and the second centered on Christmas later in the afternoon and evening. There could be a few hour break in between, which could complicate temps even more, but we'll largely stay cloudy. I have likely POPS for the entire state, except the far E, where I have high-chance (50%) POPs Christmas morning, increasing to likely 70% later in the day. The first wave may shred out and not do much at all in E CT. I did not try to time any breaks. The atmospheric column aloft is warm enough for all rain from both systems. However, sheltered valleys in NW CT and NE CT may start as freezing rain Christmas Eve (Fri) night before transitioning to regular liquid rain. Those areas will need to watch temps very closely. The worst chances look to be in the NW valleys, as they'll also coincide w/better precp coverage. I went significantly below guidance on temps, as guidance tries to allow for some sun midday, which I sincerely doubt will happen. Highs generally near 40, except 40-45 in urban areas.
Long Term (Sun and beyond): Lots of waves to track in the long term, but cold air will be marginal at best. First, for Sunday, not a bad day, but it will be windy. There is modest cold air advection, and I think we're mostly cloudy, not mostly sunny as the NBM wishes, so I knocked off several degrees from temps. Even so, it's still widespread low 40s. Winds could gust to 35-40 MPH as drier air moves in.
Monday: A weak wave approaches, but largely falls apart before reaching the state. In deference to the fact that the wave does exist and that some models do bring measurable, I have 30 POPs in for only W CT. Precipitation type, if any, should be mainly snow, but due to warm surface temps and light precip, no accums are expected. Even if this wave exercises its max potential on the area, nobody would see more than 1/2" of snow. I went a few deg below temp guidance, due to some of the NBM members showing sun. I can't see that happening even if the precip totally dissipates. I did not go as low on temps as I might have, however, since we do have warm air advection and precip would be scattered at best. Look for highs in the upper 30s.
Tuesday: i went a shade under temp guidance, since skies will generally be mostly cloudy. It could be another one of those days where we have trouble scattering out the clouds before new clouds arrive. Even so, temps still get to 40-45 statewide.
Wednesday: Gloomy day. I don't really see any cold air damming or any sign of cold enough air, even for diurnal freezing rain, even in the coldest spots. However, even a slight cooling could result in some patchy freezing rain, so the chance is not zero. For now, I have only rain in the fcst. Most rain will be light, but there could be steady, moderate rain in the morning. By midday, forcing shuts off, so steady rain could end. However, with low level moisture still available, drizzle is possible. Being this far out, the most logical fcst is to just call for rain. I went quite a bit below temp guidance. Although this does not look like a freezing rain scenario, it also doesn't look like a scenario where a warm front just blasts through, since this is not a strong system. Therefore, I expect more of a cold rain, with temps basically hovering near 40, maybe a few deg warmer in urban areas.
Thursday: Yet another wave in the train moves thru. We could clear out in the morning for an hour or two, but I just find it hard to believe we get much sun any given day during this low sun angle time of yr. W/the air mass even warmer than that of Wed, if I didn't put any frozen in on Wed, I certainly won't on Thu. More chance to likely POPs for mainly light rain. For continuity, I went pretty close to guidance, as I see warmer air slowly moving and an eroding low level cold. So temps a deg or two warmer than those of Wed.
Longer Range: Storms and cold shots may both get stronger, according to today's long range guidance. But at least for now, for snow geese out there, they never really coincide. So you'll get a storm that tracks up to the west and brings rain, then it gets cold, then repeat cycle. But it's still relatively early in winter and things can change.
I don't know if I really want to post storm graphics today, since nearly every day will offer a chance of measurable (but generally light) precip. So I am going to post a map of the pattern and discuss it instead.
The map below actually shows an odd pattern- one that doesn't happen too much. You have a fairly strong -NAO that actually connects with a weak SE ridge. That almost never happens, but the reason it can happen is because of the deep trough out west, or a very neg PNA. So in essence, what happens here is, temps are cooler than they'd be ordinarily with a SE ridge, but not nearly cold enough for sustained wintry wx. In addition, storms tend to weaken as they approach the dual ridges. As this evolves around New Years, you could probably see a stronger ridge connection over the east, with the trough over the west weakening and migrating a bit east and the ridge over Greenland also weakening. That would promote stronger, warm storms, and also stronger cold shots between storms. It is possible that as we hit mid-January, the pattern eventually flattens out into one that would transport more cold air nationwide and not necessarily favor huge storms, but at least favor light to moderate events, and perhaps a bit better wintry pattern overall. But that is a LONG way from happening yet!
Currently: High pressure over the Appalachians is in control of our wx today. There is still a bit of a breeze, esp in E CT, from slowly departing low pressure over Nova Scotia.
Tonight: I went very close to guidance on temps, and actually a degree warmer here and there. Clouds increase, winds shift to the S. So w/weak warm air advection and overcast skies, temps don't drop fast. A warm front approaches and should have a band of light snow with it. Temps are cold enough everywhere for snow to fall and stick, but the problem is moisture content. There may only be enough moisture to kick out a couple hundredths of liquid equivalent. Therefore, any accums should be limited to a coating to less than a half inch. As such, a snow map will not be needed for this event. For low temps, I have mid to upper 20s for the state.
Tomorrow: I went below guidance on temps, as guidance appears to offer too much sun. We'll prob be slow clearing out the morning clouds and as soon as they do, clouds from the next wave increase. Don't forget, we have the lowest sun angle of the yr right now, so clouds don't break that easily. Highs should generally be in the upper 30s.
Christmas Eve night and Christmas Day: Two waves will affect the area- the first centered on Christmas Eve night and Christmas morning, and the second centered on Christmas later in the afternoon and evening. There could be a few hour break in between, which could complicate temps even more, but we'll largely stay cloudy. I have likely POPS for the entire state, except the far E, where I have high-chance (50%) POPs Christmas morning, increasing to likely 70% later in the day. The first wave may shred out and not do much at all in E CT. I did not try to time any breaks. The atmospheric column aloft is warm enough for all rain from both systems. However, sheltered valleys in NW CT and NE CT may start as freezing rain Christmas Eve (Fri) night before transitioning to regular liquid rain. Those areas will need to watch temps very closely. The worst chances look to be in the NW valleys, as they'll also coincide w/better precp coverage. I went significantly below guidance on temps, as guidance tries to allow for some sun midday, which I sincerely doubt will happen. Highs generally near 40, except 40-45 in urban areas.
Long Term (Sun and beyond): Lots of waves to track in the long term, but cold air will be marginal at best. First, for Sunday, not a bad day, but it will be windy. There is modest cold air advection, and I think we're mostly cloudy, not mostly sunny as the NBM wishes, so I knocked off several degrees from temps. Even so, it's still widespread low 40s. Winds could gust to 35-40 MPH as drier air moves in.
Monday: A weak wave approaches, but largely falls apart before reaching the state. In deference to the fact that the wave does exist and that some models do bring measurable, I have 30 POPs in for only W CT. Precipitation type, if any, should be mainly snow, but due to warm surface temps and light precip, no accums are expected. Even if this wave exercises its max potential on the area, nobody would see more than 1/2" of snow. I went a few deg below temp guidance, due to some of the NBM members showing sun. I can't see that happening even if the precip totally dissipates. I did not go as low on temps as I might have, however, since we do have warm air advection and precip would be scattered at best. Look for highs in the upper 30s.
Tuesday: i went a shade under temp guidance, since skies will generally be mostly cloudy. It could be another one of those days where we have trouble scattering out the clouds before new clouds arrive. Even so, temps still get to 40-45 statewide.
Wednesday: Gloomy day. I don't really see any cold air damming or any sign of cold enough air, even for diurnal freezing rain, even in the coldest spots. However, even a slight cooling could result in some patchy freezing rain, so the chance is not zero. For now, I have only rain in the fcst. Most rain will be light, but there could be steady, moderate rain in the morning. By midday, forcing shuts off, so steady rain could end. However, with low level moisture still available, drizzle is possible. Being this far out, the most logical fcst is to just call for rain. I went quite a bit below temp guidance. Although this does not look like a freezing rain scenario, it also doesn't look like a scenario where a warm front just blasts through, since this is not a strong system. Therefore, I expect more of a cold rain, with temps basically hovering near 40, maybe a few deg warmer in urban areas.
Thursday: Yet another wave in the train moves thru. We could clear out in the morning for an hour or two, but I just find it hard to believe we get much sun any given day during this low sun angle time of yr. W/the air mass even warmer than that of Wed, if I didn't put any frozen in on Wed, I certainly won't on Thu. More chance to likely POPs for mainly light rain. For continuity, I went pretty close to guidance, as I see warmer air slowly moving and an eroding low level cold. So temps a deg or two warmer than those of Wed.
Longer Range: Storms and cold shots may both get stronger, according to today's long range guidance. But at least for now, for snow geese out there, they never really coincide. So you'll get a storm that tracks up to the west and brings rain, then it gets cold, then repeat cycle. But it's still relatively early in winter and things can change.
I don't know if I really want to post storm graphics today, since nearly every day will offer a chance of measurable (but generally light) precip. So I am going to post a map of the pattern and discuss it instead.
The map below actually shows an odd pattern- one that doesn't happen too much. You have a fairly strong -NAO that actually connects with a weak SE ridge. That almost never happens, but the reason it can happen is because of the deep trough out west, or a very neg PNA. So in essence, what happens here is, temps are cooler than they'd be ordinarily with a SE ridge, but not nearly cold enough for sustained wintry wx. In addition, storms tend to weaken as they approach the dual ridges. As this evolves around New Years, you could probably see a stronger ridge connection over the east, with the trough over the west weakening and migrating a bit east and the ridge over Greenland also weakening. That would promote stronger, warm storms, and also stronger cold shots between storms. It is possible that as we hit mid-January, the pattern eventually flattens out into one that would transport more cold air nationwide and not necessarily favor huge storms, but at least favor light to moderate events, and perhaps a bit better wintry pattern overall. But that is a LONG way from happening yet!
Anyway, that's all for now! Have a Merry Christmas and Happy Holidays from SCTWX! See you next week!
-GP!
-GP!
