A very good Tuesday evening to you from Southern Connecticut Weather!
We’ve been enjoying some Indian summer like weather the last few days, with highs passing the 60 degree mark and skies being mostly sunny. If you’ve been enjoying what we’ve been seeing recently, you’ve got one more day of it coming up tomorrow, before we head into a colder pattern for the end of the week into next weekend and beyond. There’s also a couple of chances for precipitation in the forecast, and we all know what happens when you have cold temps and precipitation J Still a lot of uncertainty as to how the individual events play out, but we’ll go through the models and have a look. Without further ado, here’s the daily discussion.
Models are in good agreement on tomorrow being the warmest day of the period, with highs in the low to mid 60s and mostly cloudy skies expected. We might see some showers from a system that passes well to our north(As shown in the image below from the GGEM model) (If you recall, we discussed this briefly a few discussions ago as a low probability for a snow chance, but likely passing to the north. The likelies won out here), but otherwise, mostly cloudy through the day, perhaps with a brief glimpse of sunshine at times. Chance of precipitation is 50%.
We’ve been enjoying some Indian summer like weather the last few days, with highs passing the 60 degree mark and skies being mostly sunny. If you’ve been enjoying what we’ve been seeing recently, you’ve got one more day of it coming up tomorrow, before we head into a colder pattern for the end of the week into next weekend and beyond. There’s also a couple of chances for precipitation in the forecast, and we all know what happens when you have cold temps and precipitation J Still a lot of uncertainty as to how the individual events play out, but we’ll go through the models and have a look. Without further ado, here’s the daily discussion.
Models are in good agreement on tomorrow being the warmest day of the period, with highs in the low to mid 60s and mostly cloudy skies expected. We might see some showers from a system that passes well to our north(As shown in the image below from the GGEM model) (If you recall, we discussed this briefly a few discussions ago as a low probability for a snow chance, but likely passing to the north. The likelies won out here), but otherwise, mostly cloudy through the day, perhaps with a brief glimpse of sunshine at times. Chance of precipitation is 50%.
A cold front swings through overnight tomorrow night, leading to much cooler temps on Thursday with highs in the mid to upper 40s, around 5 degrees or so below normal. Mostly sunny skies are expected. Up to this point, forecast is essentially a blend of guidance, which is in strong agreement so far.
The first of two major deviations in guidance comes late Thursday night into early Friday morning as a wave of overrunning moisture comes in ahead of a weak northern stream wave. The limiting ingredient here that keeps this from becoming a significant event is the lack of low level moisture, which as a result, keeps QPF relatively low. Models are split on how to handle this event, however.
The 12z GGEM is the strongest of the guidance, actually turning the wave into a weak coastal low and as a result bringing the most precipitation to the area of the models. Total QPF is a quarter to a third of an inch, but because of the stronger wave and earlier timing, it would start as rain for all outside of possibly the far NW hills before changing to a mix and finally snow as the low pulls away and colder air filters in overnight. This setup would still produce the most meaningful accumulations of the models, but would at best be a 50/50 split between snow and rain in the interior and mostly rain on the coastline, leading to a coating or so on the shoreline and maybe an inch of snow in the interior early Friday morning. The gallery below shows the GGEM precipitation types at 1 AM Friday morning, the total precipitation as rain, and the total precipitation as snow. Remember that 1 mm = .04 liquid equivalent = ~.4” of snow.
The first of two major deviations in guidance comes late Thursday night into early Friday morning as a wave of overrunning moisture comes in ahead of a weak northern stream wave. The limiting ingredient here that keeps this from becoming a significant event is the lack of low level moisture, which as a result, keeps QPF relatively low. Models are split on how to handle this event, however.
The 12z GGEM is the strongest of the guidance, actually turning the wave into a weak coastal low and as a result bringing the most precipitation to the area of the models. Total QPF is a quarter to a third of an inch, but because of the stronger wave and earlier timing, it would start as rain for all outside of possibly the far NW hills before changing to a mix and finally snow as the low pulls away and colder air filters in overnight. This setup would still produce the most meaningful accumulations of the models, but would at best be a 50/50 split between snow and rain in the interior and mostly rain on the coastline, leading to a coating or so on the shoreline and maybe an inch of snow in the interior early Friday morning. The gallery below shows the GGEM precipitation types at 1 AM Friday morning, the total precipitation as rain, and the total precipitation as snow. Remember that 1 mm = .04 liquid equivalent = ~.4” of snow.
Next, we turn to the GFS model. The GFS is much weaker with the wave than the GGEM is, but it also comes later than the GGEM brings it. As a result, the entire state would see a round of light snow early Friday morning except for perhaps the immediate shoreline would start off as rain before flipping to snow. Total QPF is only around .05” though, with the heaviest on the shoreline closer to the low, so any accumulations would be limited, probably a dusting to a coating for most and maybe up to a few tenths of an inch in southern areas. The gallery below is the same three images as the GGEM, but for the GFS.
Next, we turn to the ECMWF. The EURO was originally the model that first sniffed this event out and continued to show it when no other guidance supported it. Of course, nothing is ever easy in meteorology, and when the other models came onboard last night, the EURO promptly lost the idea of snow on Friday and now has nothing but cold air, with perhaps a few scattered flurries or snow showers. We can’t share the same maps as the other models because the EURO is a paid service and is copyrighted, but we can show you the positon of the low pressure at 72 hours(7 AM Friday) as well as the air temps at 850 mb, showing that the EURO is well SE of the other guidance and is also quite chilly due to no energy being around. Those two images in the gallery below.
In terms of the other guidance, the NAM model supports the EURO, while the SREFS are sort of all over the map, with some of the members being closer to the GGEM like solution and some of them being closer to the EURO solution. Below are the two plumes from the 21 SERF members for BDR and BDL, showing a mean of around .2” for BDR and a little under .5” for BDL. Looking at the SREFS, 14/21 members have at least some accumulating snow for BDL, while 11/21 have at least some accumulating snow for BDR. Those are probably fairly realistic probabilities at this point. There is a distinct cluster of 6/21 members that have close to 1” at BDL on the SREFS, lending the GGEM solution some support, so we’ll note that as well.
It’s also worth noting that the NAVGEM model, which is usually quite weak and progressive(So much so that we don’t use it in operational forecasting for the most part) looks a lot like the GGEM, lending some support to that solution.
Insofar as a forecast goes, taking a blend of all guidance gives us a chance of some snow showers/ light snow inland on Friday morning with light rain transitioning to light snow/snow showers on the coastline. Looking at guidance, I don’t see any major red flags as to why either camp should be trusted more than the other at the time except for the NAVGEM supporting the wetter camp, so we’ll add a little more weight to that. As a result, we’ll go with a 60/40 blend of the GGEM/GFS combo and the EURO, which gives us a chance of light snow/SHSN inland Friday morning and a chance of light rain transitioning to light snow/snow showers on the coastline. We’ll go with a 60% chance of precipitation for right now considering our blend. As far as accumulations go, the worst case scenario as shown by the GGEM would bring around an inch of snow inland, but it is somewhat of an outlier with that right now, and so we’ll stick closer to the consensus and go with a dusting to a coating on the shoreline, with possibly up to a half an inch or so inland. Keep in mind that we only have 60% chance of precipitation, so it’s still a 4 in 10 shot that we see nothing.
So, to summarize, light snow/rain possible Thursday night into Friday morning, accumulations up to a half an inch possible inland with dusting/coating possible on the coastline, chance of precipitation is 60%.
Behind this event, our first taste of winter cold is expected for Friday, with highs struggling to crack 40 across the state, around 15 degrees below normal, and a solid freeze expected for all Friday night. Skies cloudy in the morning clearing to sunny for the afternoon. Here’s images for the high and low for Friday from the 18z GFS.
Insofar as a forecast goes, taking a blend of all guidance gives us a chance of some snow showers/ light snow inland on Friday morning with light rain transitioning to light snow/snow showers on the coastline. Looking at guidance, I don’t see any major red flags as to why either camp should be trusted more than the other at the time except for the NAVGEM supporting the wetter camp, so we’ll add a little more weight to that. As a result, we’ll go with a 60/40 blend of the GGEM/GFS combo and the EURO, which gives us a chance of light snow/SHSN inland Friday morning and a chance of light rain transitioning to light snow/snow showers on the coastline. We’ll go with a 60% chance of precipitation for right now considering our blend. As far as accumulations go, the worst case scenario as shown by the GGEM would bring around an inch of snow inland, but it is somewhat of an outlier with that right now, and so we’ll stick closer to the consensus and go with a dusting to a coating on the shoreline, with possibly up to a half an inch or so inland. Keep in mind that we only have 60% chance of precipitation, so it’s still a 4 in 10 shot that we see nothing.
So, to summarize, light snow/rain possible Thursday night into Friday morning, accumulations up to a half an inch possible inland with dusting/coating possible on the coastline, chance of precipitation is 60%.
Behind this event, our first taste of winter cold is expected for Friday, with highs struggling to crack 40 across the state, around 15 degrees below normal, and a solid freeze expected for all Friday night. Skies cloudy in the morning clearing to sunny for the afternoon. Here’s images for the high and low for Friday from the 18z GFS.
Saturday looks almost identical to Friday, with mostly sunny skies and temps again 15 degrees or so below normal with highs around 40. Strong model consensus for Saturday so took a blend of all guidance. Sunday is similar, perhaps a bit warmer, with some clouds building in ahead of the next event.
The forecast gets more interesting again towards the end of the period. All guidance is in agreement on a wave of energy forming in the gulf late in the weekend and moving up the coastline towards us to start next week, but what path that energy takes and therefore the end result is very different. To show this, the gallery below shows the low placements on the GFS, GGEM and EURO models for 7 AM Monday morning.
The forecast gets more interesting again towards the end of the period. All guidance is in agreement on a wave of energy forming in the gulf late in the weekend and moving up the coastline towards us to start next week, but what path that energy takes and therefore the end result is very different. To show this, the gallery below shows the low placements on the GFS, GGEM and EURO models for 7 AM Monday morning.
The GGEM cuts the low into the lakes, while the EURO and GFS both bring it up the coastline, with the GFS being quicker and weaker with the low, already having it NE of us by the timeframe shown. The weaker nature allows for the cold air to stay locked in place longer, and as a result, bring a snow event to the area, potentially with decent accumulations for interior areas. The EURO, on the other hand, is stronger and closer to the coast, and also slower, coming during the daytime, which means it would bring warm air into the area and bring us a nice cold rain. The Parallel GFS(not shown), an upgraded version of the GFS which is currently in beta testing, looks similar to the current GFS in having a weaker more disorganized low, but is slower with it, bringing it in later next Monday into Tuesday, which would result in a snow event for many. Models are flipping around by the run with this system and ensemble guidance is all over the map, so not going to go into any more detail with this one except suggest the possibility of a storm impacting us late in the weekend into early next week, with perhaps some wintry weather being possible depending on how the low tracks. Highest probability of wintry weather would be in NW areas. It’s a thread the needle setup if we’re looking for snow though, so odds are likely towards the rain side of things relative to snow, but worth mentioning and keeping an eye on. Confidence is medium in the likelihood of a system during that timeframe and low on details/precipitation type.
Colder weather looks to continue behind this potential event through next week before signs of a relaxation begin to appear in the very long range.
All in all, generally chilly weather expected for the period, with tomorrow being the exception, and two different possibilities for us to see our first flakes lie in the models. As always, questions are welcomed and encouraged, use the comments below or leave us a comment on the FB post. We’ll update again tomorrow evening on Friday mornings event, and potentially issue a snowmap if the odds for snow are still in our favor. Until then though, if you enjoyed the discussion, share it with your friends on Facebook, and have a wonderful rest of your evening!
-SA
Colder weather looks to continue behind this potential event through next week before signs of a relaxation begin to appear in the very long range.
All in all, generally chilly weather expected for the period, with tomorrow being the exception, and two different possibilities for us to see our first flakes lie in the models. As always, questions are welcomed and encouraged, use the comments below or leave us a comment on the FB post. We’ll update again tomorrow evening on Friday mornings event, and potentially issue a snowmap if the odds for snow are still in our favor. Until then though, if you enjoyed the discussion, share it with your friends on Facebook, and have a wonderful rest of your evening!
-SA
