Good evening from Southern Connecticut Weather. 

What a weekend! After a snow event in the Hills, we saw a nice weekend, complete with sunny conditions and highs today that were near 60. 

The week ahead looks nice, with what may be an extended period of dry weather. By the weekend, shower chances will increase, but we'll also see the chance of warmer weather increase. 

Above, an image showing precipitation departures over the last few months. Although we've been wet, to my surprise it hasn't been overwhelmingly so. 

Monday-Wednesday
The first half of the week looks good, but it's cooler than normal. A cold front will pass through the region tonight into Monday. Passage should be dry, but we can't rule out a few isolated showers. That said, things should clear by tomorrow afternoon, bringing sunny and breezy conditions. Tuesday looks seasonably chilly, with highs in the lower 40s for most and breezy conditions. Wednesday should be a touch warmer, but still slightly below normal. Mornings will be chilly, so bundle up! 

Thursday-Friday
The latter half of the work week looks better, as we begin a warming trend. Conditions should be dry, but we will watch for shower potential as another area of disturbed weather may be in the area. For now, I am leaving shower probabilities out of the forecast. 

The Weekend
There are lingering shower chances for the weekend as well, but currently they look low. Should the disturbed weather maintain distance, the weekend looks wonderful, with highs in the 60s inland and slightly cooler along the shoreline. We'll keep watch, but overall it looks like the week ahead will be nice and dry weather wise. 

The Dailies
Monday: Cloudy early with decreasing clouds during the afternoon. Highs in the mid to upper 40s. Chance of showers 10%. 

Tuesday: Mostly sunny and breezy. Highs in the upper 30s to low 40s. 

Wednesday: Mostly sunny and cool. Highs in the low to mid 40s. 

Thursday: Partly cloudy and slightly warmer. Highs in the upper 40s to low 50s. 

Friday: Partly cloudy. Highs in the low to mid 50s.  

Saturday: Partly cloudy. Highs in the upper 50s (shore) to mid 60s (inland). 

Sunday: Partly cloudy. Highs in the upper 50s (shore) to low 60s (inland). 

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Thank you for reading SCW. 

-DB​

  The large storm that affected the Rocky Mountain and High Plains states will not affect our region with such force.  We will get some affects from the storm, in the form of some rain tomorrow, but nothing like anything that happened across the Western portions of the country.

Currently: The storm that produced all the bad weather out west is currently over the Missouri Valley.  High pressure that has given us decent weather is now off of Cape Cod.  Sea breezes have been stronger than guidance has modeled yesterday and today.  That is going to be something we need to consider, as long as high pressure systems exit to the northeast, rather than southeast, especially.

Tonight: Guidance is in excellent agreement.  When guidance is in such excellent agreement that close in, there generally isn't much of a reason to go against it, and I can't find a compelling reason to do so.  Lows should generally be in the mid 40s statewide, with increasing clouds tonight,  Some light showers may approach the far SW zones by dawn.  A few places along the south coast could be cooler, in the low 40s.

Tomorrow: A "showers" forecast is probably the best way to go, given that this resembles a later season cold front more than anything else.  We won't have the severe weather that could be associated with summertime cold fronts, due to the colder temperatures and March sun angle, however.  Right now, it appears that showers are possible at any time.  However, in general, days like tomorrow generally work out something like scattered showers in the morning.  Showers end and the sun comes out.  Then we destabilize and get a more solid line of rain with the cold front.  There won't be any thunderstorms tomorrow, as CAPE is very low.  But there should be a more solid line of showers later in the day.  As for temperatures, I will go under guidance for tomorrow's temperatures by 2-4 degrees, as models tend to overestimate warming in these situations early in the season, and guidance has already trended cooler.  Also, paying attention to the sea breezes like we've had the last two days, will go with low 50s along the south coast and mid to upper 50s in the interior.

Tomorrow Night/Sat: After the cold front clears the region, the weather will turn much nicer.  The NAM and GFS guidance sets are far apart for Saturday's temperatures.  Given the fact that we will have fairly strong cold air advection and wind gusts into the 30s at times, I've opted to go close to the NAM guidance, and call for highs to range from the mid 40s in the NW hills, to the upper 40s most elsewhere.  A few readings near or just above 50 may be possible in the usual warmest spots.

Long Term: There are two systems of concern in the long term.  The first system is Monday.  A weak Alberta Clipper system should pass well to our south, taking most of its precipitation with it.  However, there is a chance that some of the precipitation associated with it reaches the state, especially along the south coast.  Thermal profiles do support snow.  However, it is highly likely that if any precipitation does make it this far north with that system that it would be very light.  The majority of precipitation associated with this system will also fall during the day.  Very light snow, with temperatures a bit above freezing does not tend to accumulate in the third week of March.  Therefore, I am not expecting any accumulations with this. 

The next system that could affect the state is slated to affect us around Thursday.  There are a myriad of solutions still on the table with this, as can be expected this far out.  Right now, thermal profiles do support some type of frozen precipitation with this.  However, once again, being so far out and being this late in the season, it would take the perfect setup and heavy snow falling to get any kind of decent accumulations, especially if temperatures were marginal and it fell during the day.  If the coastal storm system can organize and produce heavy, banded precipitation, then and only then can we start talking about potential accumulations from that storm.

Now for temperatures in the long term... I stayed close to guidance throughout the long term, except went 5 to 7 degrees colder than guidance for Thursday, with the possibility of a stronger storm.  Expect high temperatures to range 40-45 on Sunday, mid 40s statewide on Monday,  40-45 on Tuesday, around or just below 50 on Wednesday, and 40-45 on Thursday.

The long range does not look too uncommon for this time of year, seeing the usual war between winter trying to hang on and spring coming.  There will be warm periods and cold periods, and an overall stormier than average pattern.  However, a lot of guidance hints that troughiness will dominate across the east with transient ridges in between.  If you combine this with the sea breeze pattern setting up, it is hard to get too excited about any warm-ups of extended duration.

Now, let's take a look at some of the systems that are slated to affect the area in the coming days in a graphical format.  First, let's take a look at the cold frontal passage tomorrow afternoon.  This map shows the classic "cold frontal shape" of rainfall along and ahead of the cold front.  That's a shape we'll see more frequently as we get into the warmer season.

Next, we'll take a look at the Alberta Clipper system that is slated to affect the state on Monday.  Please note, I am showing the GFS' version.  However, most models are further south than the GFS, and 80% of my forecast is not using the GFS for this system.  We can note that this system is extremely weak.  (1020 MB is not even really classifiable as a low).  I doubt precipitation extends back as far north as the GFS shows it if that strength is true.  Models tend to spread light precipitation further away from the low center than reality.

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Anyway, that's all for now! Have a great week and I'll see you next time!

​-GP!

It certainly has felt more like winter in the past week than it has felt for most of the winter- frequent snowfalls, snow on the ground over most of the area, and a real chill in the air! We've had the cold air most of the winter, but we really haven't had all that much snow.  

Currently: A very weak cold front is located near the Delaware River.  An attendant weak Alberta Clipper low was over upstate NY.  This combination is producing some flurries and even light snow showers across the area now.  These will tend to diminish with the loss of daytime heating and instability once the sun sets.

Tonight: Since the flurries and snow showers will tend to diminish after sunset, there's no point including them in the forecast.  Skies should gradually clear after dark and winds should diminish, as well.  This should set the stage for a good radiational cooling night.  Therefore, I'll go with the coolest guidance.  Lows should range from the mid single digits in the NW hills and coolest sheltered valleys to the upper teens in urban centers and along the south coast.

Tomorrow: Temperatures tomorrow should be fairly uniform.  This is because the warmer, southern areas, should see more clouds than the northern areas, which should serve to balance out temperatures.  Highs should be in the mid 30s statewide.  Clouds will tend to increase during the day, especially along southern areas.

Tomorrow Night/Sat: The main focus around this time period will be a warm frontal system.  Right now, the models keep all precipitation later Friday (snow) to the south of the state and the trend has been for a weaker system.  Therefore, at this time, although clouds will be introduced into the forecast for much o the state, I will keep any mention of precipitation out of the forecast.  The best chance for any very light snow to make it into the region would be along the south coast.  I will call for a chance of snow showers there Friday night, but all measurable precipitation should remain well south of the state.  I think skies should be slower to clear than most models have for Saturday.  In addition, there are two other factors going against rapid warming on Saturday.  First, warm fronts struggle to come north this time of year.  Secondly, the ground is snow covered.   Therefore, I'll go a couple degrees below all guidance for temperatures on Saturday, and call for highs in the low 40s statewide (again northern areas will have more sun earlier, thus balancing out temperatures).

Long Term: Sun-Thu: The main highlights of the long term period are two storms that will track to our west, one at the start of the long term period and the second at the end of the long term period, with near normal weather for this time of year in between.

The first system should affect the state from the predawn hours to the late afternoon hours on Sunday, except lingering until later Sunday evening east of I 91.  A burst of snow is possible, with a couple inches accumulation before it changes to rain pretty much everywhere except the SE coast,   The good news with this system is it appears there will be no concerns about freezing rain, as the 0C 850 temperature (which we use for snow or sleet) actually rises above freezing AFTER the surface warms.  This is more of a "normal" atmosphere, and not one really supportive of freezing rain.  So we should go straight from snow to rain with this one, and everyone should change to rain, because the low pressure system is passing to the west of the area, and any high pressure to the north moves out early in the storm.  As is typical with this type of storm at this time of year, models are trending colder with the high temperatures on Sunday, as surface warm fronts do have trouble making it through this time of year.   Therefore, I'll try to capture the trend and go a little under guidance for highs, and call for low 40s for most of the state- perhaps a bit warmer along the SE coast, although even there it could be tricky with a flow off the cool Long Island Sound.  It could turn out even cooler than I am predicting, but I don't want to go too cool with a low passing to our west.

Monday through Wednesday should feature generally fair weather with temperatures somewhere around normal.  Guidance looks a bit too warm, especially on Monday.   Even so, high temperatures should generally be in the mid 40s.  Tuesday should be the coolest day of the period, when temperatures could be a few degrees cooler.

The next storm system to affect the area is slated for Thursday into Friday.  Since this storm is way at the end of our forecast period, I did not put much time into the exact details.  However, it is tracking to our west, with what appears to be even less high pressure in place to start than Sunday's event.  Therefore, I would be very surprised if anyone in the state got any frozen precipitation from that system.

In the long range, a blocky pattern looks to set up, at least for a while.  That generally translates to below to much below normal temperatures and above normal precipitation.   I would not be surprised if we have not yet seen the last snowfall of the season.  Odds obviously favor interior sections this time of year, but anyone can still get snow, as we saw just last year!

Now, here is a look at a couple of systems of concern for this week for the area.  First, this is the warm front slated to move through tomorrow night.  As mentioned, any precipitation with it would be snow.  But aside from a brief flurry or snow shower along the south coast, all measurable precipitation should remain south of the state.

​

The next map we'll look at is Sunday's system.  With the system passing to the west of the state, precipitation will ultimately become all rain.  However, there is a high pressure system to our northeast and enough cold air in place that most of the state, possibly sans the far SE coast, should be able to see a quick inch or two of snow before the snow changes to rain.

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That's all for now, everyone enjoy your week!

-GP!

Good evening from SCW!

Most of the energy on this discussion will be spent on tomorrow evening into Monday morning's snowstorm, as this is obviously the highlight of the forecast.

Highlights: Significant snow for at least part of the state later tomorrow until early Monday.   Bitter cold to follow the storm for most of the week. The next storm system is slated to affect the region at the end of the week.

Currently: The storm system that brought snow to the region this morning is now exiting stage right east of Nantucket.  A new storm is organizing over the Southern Plains. That storm is our next snowstorm.

Tonight: Will go a bit below most of the guidance for low temperatures tonight, due to fresh, but not super deep snowpack.  In general, look for low temperatures from the low 20s in the outlying areas to around 30 in the metropolitan centers and the south coast.

Tomorrow: Clouds increase from SW to NE rapidly during the day.  Snow should arrive within a few hours of dinner time. The snow could very briefly start as rain, depending on how warm we get during the day, especially along the south coast and in urban centers.  High temperatures should range within a few degrees of 40, perhaps warmer along the south coast.

Now for the storm... Here’s our forecast snowmap.

In general, we are expecting 4 to 8 inches of snow across the majority of the state, with slightly lesser numbers in the NW hills.  Now, as with any storm, these numbers are not set in stone. The forecast numbers are based mostly around the 12Z NAM, which is a good compromise between the ECMWF and GFS.  A slightly stronger storm, like the NAM or even stronger RGEM shows would produce higher snowfall numbers, especially in some areas. So while we have 4-8" on our map, it is possible that some areas may get more than that.  For two reasons, we have opted not to go so high. First, we do not have confidence in higher numbers being widespread, and secondly, those numbers could set up in banding anywhere across the region. A stronger storm would also raise numbers in the NW Hills more.  Now, a track further south like the GFS would probably keep similar numbers along the south coast, but lower numbers even further across the NW hills. A further north and west track would result in more snow for the NW hills, but introduce mixing issues along the south coast.

Here’s a look at the RGEM, NAM and GFS for late tomorrow evening as well as the total simulated snow amounts from each model (not perfect, but a good visual). Notice the track differences and the resulting impacts to snow totals.

As far as potential mixing, right now the general feeling is that this is an all or mostly snow event for most of the state.  However, a change to sleet is possible for a while along the SE coast. So all in all, the numbers we have posted are the best consensus for now, but changes are still possible tomorrow. Depending on how things track, some possible changes include increasing (or decreasing) snow totals in the NW portion of the state (current 3-6” zone) and lowering totals due to mixing in the far SE (that would likely correspond with an increase in the NW). We’ll take a look at the overnight guidance in the morning and Tim will have the final call by around lunchtime.

Temperatures will not be super cold during the storm and will likely rise into the lower 40s during the day on Monday.  Therefore, some melting during the day. Temperatures Monday night will fall rapidly into the teens, allowing any standing water and slush to refreeze.  Although we do have a long time during the day on Monday between when the snow stops and when temperatures drop, there is already snow on the ground from this morning's snow.  When you add that to the snow that falls tomorrow night, there will be a lot of water in the ground. This will not all melt or dry in one day. So the final hazard from this storm will likely be refreezing of standing water and slush on surfaces and patchy black ice.  

Beyond that, the week looks very cold.  Each morning should have lows in the teens, with maybe even a few single digits possible in the normally colder spots on Wednesday and Thursday mornings,   On those two days, highs will struggle to get out of the 20s! There could also be some snow showers Tuesday and Wednesday afternoons. The shortwave for Tuesday night has trended a bit more potent in the latest model runs and could deposit a quick coating to an inch in the NW hills.  It won't take much moisture to get a coating of snow in that air mass, given how cold it will be! In addition, winds will gust to 30-40 MPH at times, producing wind chills well below zero! It certainly will not feel like March!

The next storm system will approach the area later Friday into Saturday.  Given the fact that we have a significant storm slated to affect the area tomorrow, I did not pay much attention to this storm yet.  However, a cursory glance looks like this storm will probably be more like the ones we had back in February, where there are a lot of mixing issues, especially near the coast.  However, it is a really long way out and six days earlier, the projected track of this morning's storm was only 1000 miles different than what verified. I'm not saying that that storm will be that much different, but I am giving an example of how much can change in six days.

The further long range looks to feature a gradual warming trend, since it will be mid March by then and it's almost impossible not to warm from near record early March cold! However, I do not see any signs of true spring weather on the horizon, at least yet.  And there probably will be more winter storm threats before we finally close the books on the winter of 2018-19.

I want to thank my cohorts, SA and TW, for great coordination today with putting this package together.

​-GP!

Good evening from Southern Connecticut Weather. 

Happy Fake Spring! March 1st marks the start of meteorological Spring. You wouldn't know it, with winter suddenly deciding to show up (maybe). 

This discussion will cover the coming winter storm for tomorrow. We will be back after this winter weather threat passes to discuss the other potential storm for Sunday/Monday. 

An area of low pressure is taking shape in the south, and will deepen as it moves off the coast and toward New England. There is a significant amount of uncertainty on snowfall totals, as it is unclear how organized and how close the low will track to the area. 

​Winter Weather Advisories are up statewide. 

Overall Setup
As I mentioned at the top, we have an area of low pressure that is taking shape in the south. A few days ago, this looked like a system that would miss, but has gradually come back on the guidance.

However, in recent cycles, we've see a tick back southeast, which puts our state in the highest zone of uncertainty with regard to final snow amounts. 

The progression however is pretty straight forward. We have a low that will move off the coast tonight, and will bring snow to the region during the overnight hours. Snow will be heavy at times, statewide, and while I do not expect this to be a predominantly mixed precipitation event anywhere, there is the chance for a brief period of mixing at the shore, especially if the low tracks further to the coast. Again, this is one of those rare times this winter where I think this is a virtually all snow event everywhere. 

Below: latest surface analysis of the low (1014mb over TN and NC). Note the isobars sagging south through the Mid-Atlantic. That's a signal for surface cold air being in place there and further north. Here, we don't expect mid-level lows tracking overhead, which has been the source of mixing in other storms this season.

Timing/Impact
Snow should break out from SW to NE between 1-5am. It will likely become moderate to heavy at times, and those areas that stay in the banding will see the highest totals. Snow will taper off later in the morning, and light snow is possible through the afternoon. 

Snow Accumulation: Moderate
As shown above in the map, this looks like a moderate to significant snowfall for most. The highest confidence in higher snow totals is in eastern CT, where snowfall is less dependent on storm track due to proximity to the best banding. In much of CT, we're on the line, a closer shift would bring higher end totals where a shift away from the coast could create our fourth consecutive snowfall disaster. In far NW CT, this seems like a light event. I think there will be some accumulation, but confidence in a plowable event is by far the lowest here. 

Snowfall Rates: Moderate
Snowfall rates may approach 1" an hour at times, or even higher if we get good mid-level progression as hinted at by guidance like the European model. That's a nowcast event however. Overall, moderate to heavy snow seems like a good bet for at least a short period of time. 

Below: 12z European model showing moderate snow at around 5am statewide.

Wind/Power Outages: Low
This isn't a bombing or phased low, so we are not expecting high winds or power outages with this one. The only real risk of some isolated power outages is if SE CT sees significant amounts of paste like snow that comes down heavily. 

Timing: Low
One of the key positives about this system is that it is coming during the overnight and morning hours on a Saturday. As a result, there shouldn't be a huge economic or commuting impact. 

Road Conditions: Moderate
With the potential for moderate to heavy snow, things are likely to get tricky on the roads statewide. This is especially true during the morning hours. Conditions should improve as snow tapers off, but roads will remain slick with cold air in place. 

Overall this looks like a moderate event. Unfortunately, we're dealing with a higher amount of uncertainty than usual, but we think this is a good forecast. If you're locking in the highest amount in your zone, you'll probably end up disappointed. This is a storm that's going to require real-time analysis of banding.  

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. Hit the buttons below to join.

Thank you for reading and trusting SCW. 

-DB​