Merry Christmas from Southern Connecticut Weather!
Unfortunately, for virtually all of the continental US, 2023 will not bring a White Christmas. In fact, the lack of snow cover so far this season is notable. For whatever reason, December has been a difficult month to produce consistent wintry conditions. The final week of December so far looks no different, with most of the week much warmer than normal.
However, change is on the way.
Let's dive in.
Unfortunately, for virtually all of the continental US, 2023 will not bring a White Christmas. In fact, the lack of snow cover so far this season is notable. For whatever reason, December has been a difficult month to produce consistent wintry conditions. The final week of December so far looks no different, with most of the week much warmer than normal.
However, change is on the way.
Let's dive in.
Above: the European Ensemble showing the 500mb pattern from today through the start of January. Note how the ridging over the east that's bringing us the warm Christmas fades as ridging begins to develop in the west and importantly, near Alaska toward the end of the run. This is a medium range change that is increasingly likely, giving confidence in a major pattern change to start January.
Christmas Day
Today is going to be warmer than normal but quiet. It's a foggy start out there with drizzle in spots, and that will give way to a cloudy day. Not much to discuss here as highs will near 50. At least there are no travel issues. It's a small section of the country waking up to a White Christmas, as shown by the snow depth map below. Most see nothing and even those with some snow are seeing very little.
Christmas Day
Today is going to be warmer than normal but quiet. It's a foggy start out there with drizzle in spots, and that will give way to a cloudy day. Not much to discuss here as highs will near 50. At least there are no travel issues. It's a small section of the country waking up to a White Christmas, as shown by the snow depth map below. Most see nothing and even those with some snow are seeing very little.
Tuesday
Boxing Day looks fine on the guidance, but the predominant state this week will be cloudy. Again, we're warmer than normal with highs in the upper 40s to low 50s!
Wednesday-Thursday
It's the middle of the week where I have the highest confidence we get unsettled. This is an increasingly high confidence forecast. A meandering system over the Midwest will finally make its way to the east coast Wednesday. The day looks mostly quiet, but showers will be possible through the day. Once again, we will be warmer than normal with highs in the 50s. By evening, we will see a secondary low develop off the coast bringing more widespread rain into Thursday.
This is nothing like the big storm we had last week. In this case, we're just looking at a steady rain late Wednesday into early Thursday afternoon. The rainfall doesn't look heavy but it will add to our very wet December. Highs Thursday look to be in the upper 40s to low 50s again. That may be our last 50 degree day for a bit.
Boxing Day looks fine on the guidance, but the predominant state this week will be cloudy. Again, we're warmer than normal with highs in the upper 40s to low 50s!
Wednesday-Thursday
It's the middle of the week where I have the highest confidence we get unsettled. This is an increasingly high confidence forecast. A meandering system over the Midwest will finally make its way to the east coast Wednesday. The day looks mostly quiet, but showers will be possible through the day. Once again, we will be warmer than normal with highs in the 50s. By evening, we will see a secondary low develop off the coast bringing more widespread rain into Thursday.
This is nothing like the big storm we had last week. In this case, we're just looking at a steady rain late Wednesday into early Thursday afternoon. The rainfall doesn't look heavy but it will add to our very wet December. Highs Thursday look to be in the upper 40s to low 50s again. That may be our last 50 degree day for a bit.
Above: the 06z GFS depiction of the midweek system. It's weak, fast moving, and keeps most of the rain centered Wednesday evening into early Thursday.
Below: the 00z Euro depiction of the midweek system is quite similar, but a touch stronger with the surface low. Overall, it's a nuisance event more than anything. No significant flooding or wind issues are expected.
Below: the 00z Euro depiction of the midweek system is quite similar, but a touch stronger with the surface low. Overall, it's a nuisance event more than anything. No significant flooding or wind issues are expected.
Friday-Sunday
The very end of the forecast period is a little tricky. While our main storm departs, there's a signal that some upper level energy will linger. What does that mean? Colder air will begin filtering in on Friday and as the upper level energy cycles through the region it may produce some more unsettled weather. This could come in the form of rain showers Friday and Saturday, or, it could bring a little snow if we get some offshore development. The Euro last night tried to show this scenario but it seems unlikely for now. The GFS has played around with it too, and the ensemble signal has been a touch stronger than operational models. It's worth watching, but not worrying about.
New Year's Eve looks quiet and seasonable.
The very end of the forecast period is a little tricky. While our main storm departs, there's a signal that some upper level energy will linger. What does that mean? Colder air will begin filtering in on Friday and as the upper level energy cycles through the region it may produce some more unsettled weather. This could come in the form of rain showers Friday and Saturday, or, it could bring a little snow if we get some offshore development. The Euro last night tried to show this scenario but it seems unlikely for now. The GFS has played around with it too, and the ensemble signal has been a touch stronger than operational models. It's worth watching, but not worrying about.
New Year's Eve looks quiet and seasonable.
The Dailies
Christmas: Foggy start with patchy drizzle, giving way to mostly cloudy skies. Highs in the upper 40s to low 50s.
Tuesday: Mostly cloudy and warm. Highs in the upper 40s to low 50s.
Wednesday: Mostly cloudy with scattered showers early, becoming steadier rain Wednesday night. Highs in the low 50s. Chance of rain 80%.
Thursday: Mostly cloudy with rain. Highs in the low 50s. Chance of rain 90%.
Friday: Partly cloudy and colder. Highs in the low to mid 40s.
Saturday: Mostly cloudy with a chance of rain and/or snow showers. Highs in the low 40s. Chance of precipitation 30%.
New Year's Eve: Partly cloudy and seasonable. Highs in the upper 30s to low 40s.
The Coming Pattern Change
With apologies to the winter haters out there, it wouldn't be Christmas without providing some hope--focused on the winter lovers among us.
I don't need the next seven days to play out to know that much of the winter forecast for December will be wrong. We predicted December being 1-2 degrees above normal and we are poised to have another blowtorch December. We predicted below normal snow but at least half of normal, and it's quite possible we get shutout in the snow department. We'll probably be close to right about rainfall.
The most important thing in that December forecast, however, had nothing to do with December at all.
From our Winter Forecast:
"It's important to remember El Nino climatology. A Nino in itself isn't bad for a normal winter. Normally you have a warmer and less wintry December, followed by a transition to colder and more wintry conditions in the second half of January and through February and sometimes even early March. This is what we call a "backloaded winter" and that's the expectation here.
This year, we think the El Nino is balanced out by a favorable December teleconnection pattern. Even if December ends up less snowy than normal, the expectation is that after January 15, we see a return of favorable conditions for colder and snowy periods. There is a huge difference between this pattern on December 10 and January 10.
The thing to watch is not snow in December, but rather 1) whether the mild period materializes in mid-December/how strong it is, and 2) what the end of December upper level pattern becomes. If it is a transition earlier to more wintry conditions, that is a likely signal of an active and wintry 2024."
The last days of 2023 will have a lot of folks thinking that a repeat of the horrific 2022-23 season is upon us, but I am here to say this season does not look anything like last year.
The mild period arrived in a big way, but it does not look persistent
Yes, December will be a blowtorch. It will bring another snowless Christmas. But the overall pattern, where an anomalously strong Pacific jet filled the continental US and importantly, Canada, with warm air does not look to persist. In fact, that pattern is going to start to break down this week.
Christmas: Foggy start with patchy drizzle, giving way to mostly cloudy skies. Highs in the upper 40s to low 50s.
Tuesday: Mostly cloudy and warm. Highs in the upper 40s to low 50s.
Wednesday: Mostly cloudy with scattered showers early, becoming steadier rain Wednesday night. Highs in the low 50s. Chance of rain 80%.
Thursday: Mostly cloudy with rain. Highs in the low 50s. Chance of rain 90%.
Friday: Partly cloudy and colder. Highs in the low to mid 40s.
Saturday: Mostly cloudy with a chance of rain and/or snow showers. Highs in the low 40s. Chance of precipitation 30%.
New Year's Eve: Partly cloudy and seasonable. Highs in the upper 30s to low 40s.
The Coming Pattern Change
With apologies to the winter haters out there, it wouldn't be Christmas without providing some hope--focused on the winter lovers among us.
I don't need the next seven days to play out to know that much of the winter forecast for December will be wrong. We predicted December being 1-2 degrees above normal and we are poised to have another blowtorch December. We predicted below normal snow but at least half of normal, and it's quite possible we get shutout in the snow department. We'll probably be close to right about rainfall.
The most important thing in that December forecast, however, had nothing to do with December at all.
From our Winter Forecast:
"It's important to remember El Nino climatology. A Nino in itself isn't bad for a normal winter. Normally you have a warmer and less wintry December, followed by a transition to colder and more wintry conditions in the second half of January and through February and sometimes even early March. This is what we call a "backloaded winter" and that's the expectation here.
This year, we think the El Nino is balanced out by a favorable December teleconnection pattern. Even if December ends up less snowy than normal, the expectation is that after January 15, we see a return of favorable conditions for colder and snowy periods. There is a huge difference between this pattern on December 10 and January 10.
The thing to watch is not snow in December, but rather 1) whether the mild period materializes in mid-December/how strong it is, and 2) what the end of December upper level pattern becomes. If it is a transition earlier to more wintry conditions, that is a likely signal of an active and wintry 2024."
The last days of 2023 will have a lot of folks thinking that a repeat of the horrific 2022-23 season is upon us, but I am here to say this season does not look anything like last year.
The mild period arrived in a big way, but it does not look persistent
Yes, December will be a blowtorch. It will bring another snowless Christmas. But the overall pattern, where an anomalously strong Pacific jet filled the continental US and importantly, Canada, with warm air does not look to persist. In fact, that pattern is going to start to break down this week.
Above is the European Ensemble, showing a 5 day average or 500mb heights over our part of the hemisphere. The key to follow here is the ridging (upward moving lines) and heights (red shading). Look at how it transitions from the east to the west over into January. That's a strong signal for breaking the continuous Pacific jet and allowing for some cold loading into Canada. That's our source region for cold.
This will take time but it's likely to happen. Let's look at the same view a little lower in the atmosphere, with an average of 850mb temperatures. It's an absolute furnace relative to normal in Canada, but watch how the warmth is cutoff and erodes over Canada and the US in January. We don't need (and probably don't want) massive cold departures if you're looking for snow. This signal tells me that the window for wintry events will open soon.
This will take time but it's likely to happen. Let's look at the same view a little lower in the atmosphere, with an average of 850mb temperatures. It's an absolute furnace relative to normal in Canada, but watch how the warmth is cutoff and erodes over Canada and the US in January. We don't need (and probably don't want) massive cold departures if you're looking for snow. This signal tells me that the window for wintry events will open soon.
Finally, how does that translate to the surface? Note Canada again. While 850mb temperatures return to near normal, that translates (roughly) to temperatures near 0 degrees F in our cold source location. With an El Nino supplying an active storm track, we should have chances. Will every storm be an all snow bomb? No, that's unlikely even in the best of winters, but it tells us that the window, which was closed most of December, is opening up.
