What a day of weather it was. After the winter weather of yesterday and early this morning cleared out, bringing a general 2-3 inches to the shore line, and 3-6 inches to the rest of the state, things got windy, and I mean really windy. There was even a 72 mph wind gust recorded just over the border at Westchester Airport (HPN), with various reports of wind gusts between 40 and 60 mph, with the brunt of the damage being done in Fairfield county, with widespread power outages across the state. Combine the gusty winds with blowing snow and chilly temperatures, and it was not a pleasant day to be outside. About the only silver lining of today was the clouds breaking and the sun coming out in most places. Temperatures were in the low to mid 30s for the most part statewide. Currently, we have temperatures across the state ranging from the mid and upper 20s at the shore to the low and mid 20s inland. Temps will be allowed to radiate much lower under clear skies with a stout snowpack. I'm expecting low temperatures to be in the mid teens inland, to the upper teens and low 20s at the shore. These temperatures are expected to persist through the early morning hours, so make sure to bundle up as you head out, and make sure the kids are bundled up as they head to the bus stop. Fortunately winds will slack off greatly by this time period.
Good evening from Southern Connecticut Weather!
What a day of weather it was. After the winter weather of yesterday and early this morning cleared out, bringing a general 2-3 inches to the shore line, and 3-6 inches to the rest of the state, things got windy, and I mean really windy. There was even a 72 mph wind gust recorded just over the border at Westchester Airport (HPN), with various reports of wind gusts between 40 and 60 mph, with the brunt of the damage being done in Fairfield county, with widespread power outages across the state. Combine the gusty winds with blowing snow and chilly temperatures, and it was not a pleasant day to be outside. About the only silver lining of today was the clouds breaking and the sun coming out in most places. Temperatures were in the low to mid 30s for the most part statewide. Currently, we have temperatures across the state ranging from the mid and upper 20s at the shore to the low and mid 20s inland. Temps will be allowed to radiate much lower under clear skies with a stout snowpack. I'm expecting low temperatures to be in the mid teens inland, to the upper teens and low 20s at the shore. These temperatures are expected to persist through the early morning hours, so make sure to bundle up as you head out, and make sure the kids are bundled up as they head to the bus stop. Fortunately winds will slack off greatly by this time period.
For your Tuesday, I am expecting a tranquil, sunny day with temperatures slightly below average, with highs ranging from the low and mid 30s inland to the mid and upper 30s at the shore. Heading out Tuesday morning, be on the lookout for patches of black ice, as melted snow from the night before will refreeze on Monday night leaving slick spots on the secondary roads. Heading through Tuesday, skies remain mostly clear, but temperatures don't look to be as cold as Monday night with upper 20s at the shore to low and mid 20s inland. You will notice that temperatures really don't drop very much from the highs on Tuesday, and that is because of a system moving in from the south raising "heights" and temperatures, which is the perfect segue in discussing the potential mid to late week event.
Wednesday, again looks to start off with fair weather, but some clouds look to filter in as we head through the morning. The setup we have currently has a northern system, or shortwave, moving in from Canada, with a southern system moving in from the southwest. Now if timing were perfect, these two systems would combine with each other off the mid-Atlantic coast with the north system transferring its energy to the southern system. What that would mean for us? One heck of a system, most likely yet another significant snow maker to the state. In this case, it looks like the pattern will be a little too progressive with the northern shortwave moving into the area too quick, delaying the phase until the southern shortwave was too far east to give the state any more than a glancing blow. Most models show this, with the GGEM (Canadian model) showing the phase furthest west of the models. We are watching this one very closely, but at this time, I think snow lovers will disappointed. Currently it looks like the state will get off with some snow showers at the most, later on Wednesday afternoon through Thursday morning. Temperatures for Wednesday look to be 32-35 degrees for highs with temps dipping back into the 20s at night, and this is highly dependent on whether we get actually get a storm on Wednesday night into Thursday. What I do see is that regardless of whether the storm materializes, temperatures will be again be cold from Thursday through Saturday.
For the Thursday through Saturday period, Thursday is quite dependant if there is a storm or not, but I'm leaning toward cloudy early with clearing later in the day and dropping temperatures. Highs on Thursday look to be in the mid to upper 30s and falling throughout the day. By Thursday night, under clear skies, temperatures will drop back through the 20s at the shore and into the teens inland, so pretty cold night shaping up. Skies look to remain clear for Friday and Saturday with high temperatures in the 30s statewide, dropping back into the low to mid teens at night with 20s at the shore. If you're looking for a 'warm up' look no further than Sunday. Sunday looks to start off fair with chilly temperatures statewide, but look to rebound into the upper 30s and 40s statewide, for the start of an extended mild period. Looking for the potential of some rain showers on Sunday afternoon, but otherwise dry.
At a glance, winter looks to be put on hold for a while after this weekend. Most teleconnections like the PNA, NAO, AO and EPA do not look favorable for snow for at least the next 2 weeks. I'm watching for a mega ridge to build over most of the country, promoting mild temperatures, and storm tracks well into the Great Lakes through the end of the month. This is not to say there will be periodical 1 to 2 day cool downs through this period, but it looks as though warmth will rule the day. I wouldn't even rule out a few days in this period getting into the 60s, especially when the area is being affected by a storm tracking through the Great Lakes. Look for our indepth 2 week forecast sometime this week.
Have a great rest of your night! As always, thank you for reading this discussion and continuing to make Southern Connecticut Weather your trusted source for all things Connecticut weather.- TW
Good afternoon from Southern Connecticut Weather! Well, we've made it through 2 of 3 short term winter events. A general coating to 2 inches fell across the great state of Connecticut from late last night through early this morning. Some on the shoreline are saying, "What snow?" but as is standard operating procedure with "clipper" systems, the bulk of the snow trended north. For the rest of today we’re looking at a brief break in the overcast in most places before clouds filter back in later this evening. Temperatures around the state will range from the mid to upper 30s inland, with low to mid 40s at the shore. As we head through this evening temps will drop back into the low 30s at the shore and mid 20s inland. Clouds should begin to filter back in later this evening, toward midnight, with some snow filtering into the state by dawn, and then the forecast gets a bit tricky. Between early Sunday morning and early Monday morning, the state will be impacted, yet again, by an area of disturbed weather which will bring frozen precipitation to all corners of the state. In most spots this doesn't look to produce as much as the storm system on Thursday, but will still provide more of the white stuff to Connecticut. The type of storm we are dealing with is called an "SWFE" or southwest flow event. In Connecticut, these don't usually provide much in the way of snow outside of elevated areas, especially in the northeast hills, but for this system it looks as though the Litchfield hills will get into action as well. Thus dual "Jackpot" zones are illustrated on the map. On the models we have a bit of battle with the GFS standing on its own on the warm side, making things in Connecticut more wet than white. While other models such as the GGEM, NAM, RGEM, and Euro more on the cold side bringing 8-12 inches to much of northern Connecticut, especially the hills in both the eastern and western portions of the state. The GFS is the warm outlier and I will basically toss it due to my thinking that the temperature profile is wrong, while the Euro is the colder and snowier model, which I will take more with a grain of salt in the thinking that it is overdoing QPF. As far as temperatures and winds, uniformly models are really keying in on gusty winds ranging from blowing out of the east and northeast during the day on Sunday, to very gusty winds on the backside of the storm from out of the northwest promoting cooling. From everything I've seen, I'd expect wind gusts to approach 30 mph during the day on Sunday with winds ramping up later Sunday night and continuing through most of Monday. With these east winds and a storm system approaching from the south and west, temps will gradually rise at all levels of the atmosphere we head through Sunday. Inland locations will stay between 30 and 33 degrees at the surface, with temps on the shore rising into the mid to upper 30s, thus promoting a more rainy solution in these locations. At this time the difference between 8 inches and a foot of snow in the northeast and northwest hills is temperatures and snow to liquid ratios. Right now I'm thinking around 8 to 1 snow to liquid ratios at the shore, with 10 to 1 ratios inland, any slight fluctuations down in temperatures at the mid levels could mean ratios inland could be as high as 15 to 1, but generally I'm thinking in the aforementioned ratios of 10 to 1. What all the models do show is a drop off in snow as you head toward the Connecticut River Valley, as is the case with most storms. Being in an area with a lack of elevation near a body of water really does not help, especially with this storm, so you may see 8-10 inches of snow in a place like Suffield or East Granby but head east toward the Connecticut River a few miles and have 4-6 inches. All a function of downsloping winds, which promotes warmer temps and drier conditions, many of you in the valley know all about "screw zones" due to this feature. As we navigate down the map, you will see a familiar sight for those who have lived on the shore for a while, the least amount of snow is expected to fall there, and most of that 1-3 inches will fall with the warm air advection snows on Sunday morning. Basically, this will be a storm where the low pressure area is too close to the coast for sub-freezing temps to stay in place. As shortwave system moves in, winds will gradually turn from being out of the north, to being out of the northeast, and finally out of the east, promoting warming of all levels of the atmosphere from the 500 level all the way to the surface, but before that, there is some cold air to be displaced, thus accumulating WAA snows to start the event in southern Connecticut. I think all places outside of the northeast and northwest hills change to a period of rain. During the evening on Sunday, and when the storm has really wound up well to the east of us, winds will really pick up and will begin to swing more out of the west and northwest, promoting cooling, therefore I expect any places that have changed to rain to change back to a quick burst of snow and sleet with minimal extra accumulations. Gradual clearing is expected by very early Monday, but strong, gusty northwest winds stick with us during the day on Monday making for a blustery and cold day. Wind gusts could approach 50 mph. To recap...
- Clouds thicken late Saturday night, snow moves into the state by early Sunday morning - 1-3 inches of snow at the shore before changing to rain late Sunday morning/ Early Sunday afternoon - 3-6 inches of snow in central CT and northern CT outside of the hills before a change to rain Sunday PM - 5-10 inches in the northeast and northwest hills, expected to be mostly snow, some sleet and rain could mix in Sunday PM -Everyone is expected to change back to snow later on Sunday night, with the chance for an extra inch or 2 of accumulation before precipitation tapers off early on Monday - Gusty winds will become an issue as we head through the day on Sunday, and especially so during the day on Monday when winds could gust up to and over 45 mph Thank you for taking your time to read our storm discussion, we really appreciate it! Have a great rest of your day and feel free to ask questions on our Facebook and Twitter pages. Stay tuned for all the latest as we keep you informed, before, during and after the storm.- TW
Good evening from Southern Connecticut Weather.
First, I want to take a moment to say THANK YOU to all of those who liked, shared, asked questions, and decided to follow SCW during and after the Blizzard of 2017. It was and always will be an honor to serve you and give you the information you need to make informed decisions. Now, to business. When I wrote my two week outlook at the start of the month, I mentioned that week two could be more active but I had no idea which direction things would go. For those snow starved nutmeggers, what a turnaround!
Connecticut is set to see more snow overnight tonight, but in this discussion, I am focusing on the potential for another major storm to impact much of Connecticut by the latter half of the weekend. The setup for this one is more complicated, and many factors are yet to be resolved.
What we know right now:
Our first call reflects the fact that I think northern Connecticut is able to hang onto snow the longest, with colder temperatures from the surface and into the column above. The greatest confidence in a significant event is there. In the second zone, there is a battle between warmer solutions and colder ones, but the consensus thus far is for a moderate to significant snow event with mixing as well. Along southern Connecticut, we have our lowest zone, as the area goes from snow to mix to rain on most guidance.
Technical Discussion
This ain’t going to be an easy one to forecast. Unlike the last setup, where things were straight forward in the larger scheme of things, we’re talking about a lot of moving pieces here. I want to break it down piece by piece. We get an area of low pressure that forms to the west of the region. It is a very weak low at first overall, but as it gets closer it begins to strengthen, especially in the upper levels.
Note here, on the latest run of the GFS, how temperatures in advance of the low are marginal in the 850mb layer. This is a signal for problems with precipitation type, as there isn’t a really good cold air mass in place. Ahead of the low, precipitation breaks out. This is warm air advecting into the region and overrunning colder air at the surface. The result is precipitation...snow.
By Sunday afternoon, the GFS has snow falling in much of Connecticut. Note the mix and rain in southern Connecticut though. Temperatures matter. The faster the low develops and the further south the low goes the better in terms of getting a longer duration of snow.
As the low continues its slide east, the upper level lows explode. For the second time in a few days, we’re looking at a low to experience bombogenesis, a very fast intensification that happens sometimes as lows take advantage of favorable upper level and surface conditions. These upper level lows, at 500 and 700mb respectively, cause the development of a surface low on Sunday. This low pulls in cold air, changing many back to snow before precipitation shuts off Monday morning.
If it happened sooner, cold air would rush in faster, resulting in a faster changeover. If that happened we would be talking about an even bigger event. The GFS shows bombing, but the Euro is more explosive.
That’s incredible. Probably even more impressive than our most recent storm. The Ukmet (fondly known as the Ukie to me) has a similar solution.
Ukie showing the pressure of this low going from 999mb to 970 in 12 hours. Incredible.
With a split in the guidance, it’s best to blend and look at the overall setup. Right now, I lean toward a more impactful event for more people--especially in north and central Connecticut. Very slight shifts in the track of the low and the temperatures at and just above the surface will make the difference in how impactful this becomes. The last thing, which shouldn’t be ignored, is wind. With rapid intensification of this low, by Sunday night and Monday we may see very strong wind gusts. Some of the guidance show the strongest winds after precipitation falls. We’ll have to watch closely to make sure that is the case. Currently, I think snow breaks out in Connecticut early on Sunday, with snow becoming more widespread and heavy by Sunday afternoon. Depending on the track and rate of strengthening by the low, the rain/mix/snow line will creep north during the day and evening hours before changing back to snow for most as the storm passes to our south and east. Overall, this is one to watch. This could be a moderate to high impact event across much of Connecticut. Current odds—remember that this will change. I went to low odds to blizzard with the last storm!
As always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts! All you have to do is click one of the buttons at the top of the page!
Thank you for reading SCW! -DB
Good evening to you from Southern Connecticut Weather!
What a day for weather in Connecticut! One of the most intense snowstorms in years passed through the state today, bringing widespread snowfall rates of 2-3” per hour statewide. We also saw what was arguably the most widespread thundersnow outbreak I've seen in my seven years forecasting, which at least for me, was the highlight of the storm! Snow totals ranged from 10-18” across the state, with the heaviest numbers in the I91 corridor where the band stalled out as the storm pivoted, allowing a bit of extra time under the heavy rates. We’ll do a more widespread post-mortem when we have a break in the action to catch our breath, but for now, I’m very happy with this forecast. We started with 6-12” on Tuesday night and slowly upped amounts as the magnitude of the system continued to increase, and our final call of 12-20”(10-16” SE) will verify nicely in most areas. One could make an argument that sticking with 10-16” from last night would have been just as good and eliminated the need for a mid-storm upgrade, but we wanted to highlight the intensity that we were seeing on radar this morning and the possibility for some isolated spots to close in on 20”. In this business, we’ll take this one as a well-earned success. Thank you to everyone who sent us snow totals and pictures today – keep an eye out for new cover photos on our Facebook and Twitter pages soon! Friday-Saturday Here’s our forecast snowmap for tomorrow evening into Saturday morning.
First off, I am expecting a slow commute tomorrow morning due to poor visibility and potentially slippery roads, especially on the secondary roads, so leave some extra time in the AM just in case. Lots of school closings and delays coming in already as well.
Moving past this system, the main attraction in the short range is a clipper system that will bring a light snowfall to the state tomorrow evening into Saturday. A shortwave drops southeast from Alberta and scoots under us before weakly redeveloping off the coastline. This system will be relatively weak, and so snow amounts will be limited, but a quick couple of inches appear likely. Model consensus is in good agreement on this event – clippers tend to be well modeled, and this one has been very consistent since early this week. Snow should start late tomorrow evening and wrap up by early Saturday morning. A minor event, but keep it in mind if you’ve got plans Friday evening or early Saturday. Given the above, have gone ahead and issued a map for 1-3” statewide, with locally 4” possible if a quick period of moderate snow develops in northern areas. Here’s a look at the clipper on the NAM and GFS. Otherwise, the main story for the short range will be the cold; highs tomorrow are expected to only be in the low to mid 20s. Temps will rebound into the low 40s on Saturday. Sunday-Monday Another potentially significant storm could impact the state during this time period. This will be an overrunning type event to start with, with low pressure coming out of the Ohio Valley and moving eastward into the area. Guidance then splits on what happens next. Both the Euro and GFS redevelop the storm, but the GFS keeps it relatively weak while the Euro and UKMET develop strong lows off the coastline. In the former scenario, precipitation over the state would be relatively weak, with mainly rain south and a wintry mix in the interior, while in the latter scenario, dynamics will result in some front end snow flipping to heavy rain flipping to heavy snow for the interior, with significant accumulations possible. Coastal areas would see some front end snow to heavy rain, and possibly some back end snow as well. Timing would be from Sunday afternoon through Monday morning. Here is a look at the Euro and GFS surface placements for 7 AM Monday. Similar placements, but the Euro is much stronger!
It’s worth pointing out that the 18z GFS (what is shown here) trended fairly significantly towards the Euro; the 12z GFS didn’t strengthen the low until it was well past our latitude and thus negated our area from any significant impact. I want to see another couple of cycles of consistency from the Euro before becoming more confident in a significant event, but the potential is definitely there. The Euro also had rock solid consensus from it’s ensembles on a major event, which is always something to look for (one of the first red flags for todays event was that the ensembles were consistently wetter than the operational models, suggesting that the operational models were underdoing liquid. As we saw over the past 36 hours of trends and in today’s event, that suggestion proved to be correct). So for now, we will keep an eye on the trends, and will have much more on this system in the near future if it appears as if it will pose a threat to the area. If needed, a first call map would be issued on Saturday.
Tuesday-Thursday Below normal and active pattern looks to continue into the middle of next week, with another clipper system showing up on guidance for midweek. This one, at least according to the Euro and GFS, could have a bit more upside as the low develops sooner, but way too early to look at details on that right now. Will paint in low chance pops for snow in the dailies and allow future forecasters to elaborate in more detail. The Dailies Friday: Partly sunny, then clouds building later with a slight chance of snow showers. Then snow in the evening and overnight. Highs in the low to mid 20s. Chance of snow is 40% before 8 PM and 80% 8 PM – 6 AM. Saturday: A slight chance of snow showers, otherwise, mostly cloudy, with highs in the low 40s. Chance of snow is 40%. Sunday: Mostly cloudy with a chance of rain or snow later in the day. Highs in the mid 30s. Chance of precipitation is 60%. Monday: Mostly cloudy with a chance of snow. Highs in the low to mid 30s. Chance of precipitation is 50%. Tuesday: Mostly sunny, with highs in the mid to upper 30s. Wednesday: A chance of snow, otherwise, partly cloudy, with highs in the mid 30s. Chance of precipitation is 30%. We’ve got an action packed period of weather coming up, so make sure to stay right here with Southern Connecticut Weather for the best source of hype free weather info out there. To all our new readers from this storm, welcome to the SCW family, and to all our loyal readers, thank you for continuing to trust us as your source for Connecticut weather! -SA
Good evening to you from SCW!
Summary We are gearing up for the largest snowstorm to hit the state since February of 2015, and the system has only continued to look more impressive throughout the day. While it will be a quick hitter, the snowfall rates will be extremely impressive, and combined with high snow ratios it will pack a significant punch. As such, we have upgraded snow totals by 4” across the board for the entire state, making the new forecast 10-16” statewide. Snow will begin in the pre-dawn hours across the state and taper off west to east over the course of the afternoon. While most snow will be gone by the evening commute, roads will be snowpacked and uncleaned, making the PM commute almost as much of a mess as the AM commute will be. Snowfall rates of 2”+ per hour are expected, with some locations likely seeing periods of over 3” per hour in the heaviest bands. Travel will be difficult to impossible across the state tomorrow, and I expect virtually every school district in the state to close (many already have). If you don’t absolutely have to go out tomorrow, stay home and enjoy the snow. Here’s the latest forecast snowmap:
Models and Trends
As mentioned earlier, the general trend in the guidance today has been to strengthen the surface low and bring it further west. This results in more precipitation making its way onshore and a general increase in QPF across the region. The GFS and the Euro are now in good agreement on a widespread ~1” of QPF statewide, a fairly significant increase from previous runs where the 1” amounts were limited to the areas that got under the best banding. This trend makes sense to me; as the storm has become stronger and better defined, it has allowed for more inflow to come in off the water and for more moisture to be drawn into the system. The signals for good snow growth and excellent frontogenesis is also there, making this a very dynamic system in the mid to upper levels. All of these factors should result in heavier bands of snow and stronger precipitation overall as the general circulation of the system becomes well defined. We have seen this trend on pretty much all guidance today, and I am reasonably confident that it is legitimate. As such, I am comfortable going towards the higher end of guidance for this forecast. Here’s a look at low placement and total QPF from the 6z and 18z GFS from today. Notice the jump NW in the surface low and the corresponding increase in QPF.
The other trend that is less quantifiable, yet potentially more significant to the forecast, is the trend for the computer generated algorithms to indicate very high snow ratios across the state. Traditionally, 10:1 is the standard ratio, meaning that 1” of QPF would translate into about 10” of snow. In a scenario like this one where there will be intense lift and heavy snowfall rates, I would expect that number to be on the low side. While there is no great way to forecast ratios, there are some algorithms, such as the Kuchera and COBB methods, that take a stab at it using modeled upper air temperatures at various points in the column. In this case, those algorithms are extremely bullish, suggesting snow ratios of 18-22:1. That would mean that our 1” of QPF would translate to 18-22” of snow, making this the most significant statewide snow event since the Blizzard of February 2013 (better known as Winter Storm Nemo or the Great Blizzard of 2013). Needless to say, I don’t buy those numbers. The algorithms are often too extreme on either end of the spectrum, and I think they are going a little bit crazy with the amount of lift and the rates that are modeled. For now, I’m going with ratios around 13:1, which fits in nicely with our 10-16” forecast. However, the bust potential with this is high; should the ratios verify as they are being modeled, we will see some 20”+ totals in the state. I would say the chances of that are less than 10%, but hey, you never know.
Forecast and Timing As we said above, we have upgraded snow totals to 10-16” across the state. I do think that most reports will end up in the 10-14” range, but we decided to allow the maximum to be up to 16” to account for both any areas where banding persist and the possibility of snow totals being enhanced. While there will be some fairly strong bands and likely some subsidence zones around them, this storm should keep moving fairly quickly, and therefore most should get into the banding for a time. Therefore, totals will likely be fairly uniform across the state, with a bonus where the banding remains for an extended period of time. As far as snow rates go, they will be extremely impressive. Models are consistently spitting out areas of 2”+ per hour, and the latest NAM and GFS have fairly large areas of 3” per hour at the height of the storm. We will start out with a heavy, wet snow, but will quickly transition over to a light, fluffy snow for the majority of the event. Winds will also be an issue. While I don’t expect gusts high enough to hit blizzard criteria, it will definitely be a bit gusty, especially on the coastline. For timing, snow will move into the state during the pre-dawn hours. By daybreak, snow should be falling statewide. Heavy snow will move in from west to east over the course of the morning rush, and will persist throughout the morning. I would expect that the heaviest band of snow will generally push eastward over the course of the morning, but even areas that are only seeing lighter rates will still be seeing rates that we’d usually consider “heavy”. Snow will begin to lessen in intensity and then taper off throughout the afternoon, with most snow out of the state by dark. Some scattered snow showers may persist through the evening, especially in eastern areas. Impacts
The Bottom Line A significant snowstorm is coming. While it’s nothing we haven’t seen before, it demands respect and attention. Don’t travel if you don’t have to, use extreme caution if you do have to, and above all, get out there and enjoy it! Send us your photos and reports tomorrow – we’ll be on Facebook and Twitter all day and your reports allow us to corroborate our forecast with what’s on the radar and what’s on the ground. We’ll be up bright and early watching the radar, with the first update of the day to come by 7 AM and rapid-fire throughout the day until the last flake has left the state. Like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts! All you have to do is click one of the buttons below! We’ll be here all evening answering your questions, so ask away! Thank you for reading SCW! -SA |
Archives
November 2023
Categories
All
AuthorsSouthern Connecticut Weather is brought to you by Timothy Wrightington Jr. (TW), Spencer Aronstein(SA), Greg Petridis (GP), and Don Bell (DB). |