Good afternoon from Southern Connecticut Weather​

It’s the end of October, and the forecast for the week ahead isn’t terribly exciting (or difficult), so I want to depart from the typical format today.

Snow! Much of interior Connecticut saw its first measurable snow event on October 27th. Thanks to Carole K (above) and Sean M (below) for sharing their photos! 

We’re deep into fall now, much of the region is past peak with foliage, and after I personally saw snowflakes in Upstate New York last Saturday, and most saw snowflakes in Connecticut earlier this week, the desire for winter to get here already has undoubtably been ratcheted up for some. A word of caution however. It’s still fall. Although it can be more wintry than preceding months, November isn’t terribly wintry in the whole scheme of things usually. November is a transition month in Connecticut, and I expect it to be no different this year. 

In weather, we often use the term “step-down” to describe the transition from one season to another. Late fall is a time where you can see the battle between two seasons become an all out war. You can have wild variations between hot and cold, a more muted battle that brings periods of warm and cool, or one season dominate the landscape. 

This November, I don’t see either dominating, at least in the first half of the month. I think that overall, we’re looking at a typical gradual step-down toward winter in Connecticut, with short and frequent oscillations between warm and cool early in the month, a transitional period that leans more directly toward below normal temperatures in the middle, and a more deliberate move toward colder than normal conditions in the last week to ten days of the month. I think that the long range ensembles, which are currently hinting at a push toward colder conditions by the middle of the month, may end up being a bit too fast with a quick change to consistent winter-like conditions.

November Normals
The best way to set expectations and illustrate what a typical November means in Connecticut is to present the data:

The average November snowfall in Hartford is 2.0”.
The record November (monthly) snowfall in Hartford is 15.6” in 1938. 

​The average November snowfall in Bridgeport is 0.7”.
​The record November (monthly) snowfall in Bridgeport is 8.4” in 2012.

So what do we see with the data? The step-down really begins to steepen after the first third of the month. If you dive deeper into the data, that’s when we’re most likely to see minor measurable snowfall events, if at all. A well timed event is certainly possible, especially for interior locations where temperatures at or below freezing become typical by the last third of the month, but those are impossible to forecast this far out.

One other thing that needs to be mentioned—even with our first minor winter weather event in the books, an October snow event itself does not portend a cold and snowy winter. The pattern in October is the pattern in October, and we usually get a better sense of what early winter can bring with looking at the hemispheric pattern and ENSO (El Nino/La Nina/Neutral state) in early to mid November. We’re just now getting in the range of acceptability with regard to looking ahead to winter. That said, we’re currently working on our winter forecast, and we expect it to be ready in the next week or two. Stay tuned!

Your Week Ahead
As I said at the start of the discussion—nothing terribly exciting this week. Today, we see another chance of rain (as an aside, I’ve been heartened by the uptick in rain events the last few weeks), followed by a period of below normal temperatures Monday and Tuesday, followed by a big warmth push Wednesday-Thursday with another rain chance, followed by a cool weekend.

Recent visible satellite image of New England. Note the area of cloudiness and disturbed weather out west. That's our rainmaker today. 

Today has started out nice, but our chance of rain begins in just a few hours as an area of low pressure advances from the west and slides to our south this afternoon and tonight. I expect rain to begin overspreading the state between 3-7pm, with heavier rain possible during the early evening hours. Rain should exit the state entirely shortly after midnight. It doesn’t look to be a big rain event, but we’ll take every drop we can get. 

Short range model depiction of the coming rain event. It’s an umbrella afternoon and evening for sure. 

Monday/Tuesday 
Monday and Tuesday look to be colder than normal days, as high pressure approaches from the west and brings cooler and drier air. We’re not talking about temperatures as cold as earlier this week—when many locations didn’t reach 40(!) but upper 40s to low 50s at the shore is still a bit chilly for this time of year—especially in a regime that has been warmer than normal overall the last few months. If you’re trick or treating Monday night, bundle up the kids! I expect the temperatures to drop fairly quickly with high pressure bringing ideal radiational cooling conditions. 

I don’t often do this, but above are the high resolution NAM temperatures from 2pm to 11pm on Monday. Temps may be in the 30s, especially in inland areas by 11pm. Tuesday looks a touch warmer but still (slightly) below normal.
​ 
Wednesday/Thursday
By Wednesday, the “heat” is on again, as the area of high pressure brings more of a westerly flow. Wednesday looks to be above normal, but Thursday looks to bring the biggest departure from normal, perhaps with temperatures in the 70s in spots? That’s impressive for early November. As a cold front approaches on Thursday, we see another chance for showers.

Euro depiction of 850mb temperatures and flow over the course of the week. I post less for the temperatures aloft and more to illustrate the overall seesaw pattern during the week. By the weekend, we’re looking at a return to cooler conditions. 

Friday/Saturday
With the front through our region, it looks like we’re back to normal to slightly below normal temperatures with dry conditions. However, I’m a touch intrigued by the GFS, which has hinted at a possible clipper type system diving down from Canada in the Saturday timeframe. With cold air around, it’s something to watch to see if we can squeeze out another minor rain or mixed precipitation event. We shall see…

The dailies:
Sunday: Sunny early with increasing clouds and rain by mid-late afternoon. Rain may be heavy at times. Highs in the upper 60s to low 70s. Chance of rain 100%. 

Monday: Rain ending shortly after midnight. Sunny and much cooler. Highs in the mid to upper 40s inland with highs in the low 50s near the shore. Nighttime lows in the low to mid 30s. 

Tuesday: Sunny and dry. Highs in the mid to upper 50s. 

Wednesday: Sunny and warmer. Highs in the low to mid 60s. 

Thursday: Increasing clouds with a chance of rain by late in the day. Highs in the upper 60s to low 70s. Chance of rain 50%. 

Friday: Sunny and colder. Highs in the low to mid 50s. 

Saturday: Increasing clouds with a slight chance of rain or snow showers. Highs in the low to mid 40s. Chance of precipitation 10%. 

Thanks for reading! Be sure to like us on Facebook and follow us on Twitter @SouthernCTWX. Have a great week and Happy Halloween! 

-DB

Disc: I want to point out that this is not going to be a major winter weather event, but it is the first one of the season, and it is fairly impressive being so early in the year.  Just a good time to practice those winter driving skills if you will be out driving in it.

Currently:  Sprawling high pressure from VA to Central Quebec is responsible for the cool air across the area.  Low pressure organizing from Texas to the Quad Cities will be our next weather maker.

Tonight: Temperatures will be a little tricky tonight, since low temperatures will depend on how quickly it gets cloudy and how much radiational cooling occurs.  For now, the thinking is clouds will spread in from Southwest to Northeast as the night goes on.  All in all, this should result in low temperatures ranging from the mid 20s to the mid 30s.

Tomorrow: Another interesting aspect of this storm is timing the arrival of precipitation.  With these types of systems, it' s always a race between when the air can saturate enough to allow precipitation to fall and how fast the overrunning precipitation can arrive, which usually does come in faster than models suggest.  In addition, if it begins precipitating heavy enough into the dry air, evaporational cooling can temporary cool the air.  Although temporary, this can have an effect on precipitation type, mainly talking about rain vs. freezing rain.  As far as sleet and snow go, that is more determined by upper level temperatures, which wouldn't change based on what's going on at the surface.  Going by a model consensus, most places in the state will see precipitation develop too late to have anything substantial in terms of accumulating snow.  The best chance for any accumulations would be in the NW hills, and even there, the accumulations would probably be only on the order of 1-2".  Right now, I am thinking that precipitation arrives during the second half of the morning rush hour in the SW, to just after lunch in the NE.  There could be some freezing rain in the sheltered valley locations if it starts early enough.  A lot of this may have to be watched right up to the last minute.  Rain should then fall pretty much all day, not ending until midnight in the SW and a few hours later than that in the NE.  Rainfall amounts should be around one inch on average, which is good, because we need the rain.  Most of the state is in a moderate to severe drought.  As far as temperatures, they will be chilly, given the cool start, clouds, and precipitation.  High temperatures should be around 50 degrees throughout the state, though some of those high temperatures may not occur until late at night.

Tomorrow Night and Friday... Tomorrow night was pretty much already covered above. Rain tapers off from midnight in the SW to a few hours later in the NE.  Temperatures probably don't drop too much tomorrow night.  As mentioned, high temperatures will probably occur towards midnight,  After the rain ends and the cold front goes through, temperatures will begin to fall.  Low temperatures will likely be in the 40s throughout the state.

Longer Term- the weekend and beyond: The weekend's weather will be largely determined by the position of a back door type cold front.  Basically, with these fronts, when they are south of you, it's cool, often with drizzle and fog, and when they are north of you, it gets warmer and sunny.  When the front is near overhead, you can get periods of rain.  In addition, back door cold fronts are very difficult to forecast.  Right now, I will use a model consensus to determine the position of the front over the weekend, since that's the best tool we have at this juncture.  However, these back door cold fronts have generally ended up south of where models have them at this range. 

Based on the above, I'll have the back door cold front to the north of the state on Saturday, with some peaks of sun and temperatures getting into the 60 to 65 degree range.  I'll then show the back door front moving through later on Saturday, with a quick shower, and then cooler temperatures, in the mid 50s, for most places, on Sunday.

Looking beyond the weekend, Monday should stay in the same general air mass as Sunday, with similar conditions expected.  As ridging moves in, expect temperatures to be 5 to 7 degrees warmer on Tuesday and Wednesday.  With ridging overhead, do not expect any precipitation until beyond the long term- maybe around the end of next week, and that brings us into the...

Long Range: As we head into the first week of November, it appears the overall hemispheric pattern begins to truly shift into one that would feature more frequent intrusions of cold air, and perhaps east coast storminess.  While it may still be too early to start talking about widespread snow threats, for those of us who like winter weather, it may be a good thing that we're starting to see this pattern shift, as the first or second week of November us generally when you want to see the pattern to start lining up favorably.

That's all for the "textual" portion of this discussion.  Now let's take a look graphically at the system slated to affect the state tomorrow.   Generally, I'll just focus on rainfall amounts.  This is the GFS model, although other models have been wetter, in general, but not by a tremendous amount.  You can also see that precipitation is very uniform throughout the state, and a nice, soaking rainfall for the state.
​

That's all for now! Have a great rest of your week!

​-GP!

Good evening from Southern Connecticut Weather!
​
Let’s get right down to business. After a strong system which impacted the state this weekend with rain, wind, and some snowflakes in the higher elevations of northwest Connecticut, things are turning chilly and quiet for the next few days. In the meantime, we’re starting to watch our first potential (minor) winter weather event for Thursday and a potential moderate to heavy rain event on Friday. 
​
Tuesday/Wednesday
Tomorrow is a clear day with gusty conditions as we see strong northwest flow working in chilly conditions. Maximum temperatures are likely to be around ten degrees below normal, which is around 60 degrees in Hartford this time of year! 

Tuesday night is also breezy, but temperatures are expected to reach the upper 20s in the cold spots and lower 30s elsewhere away from the shore. A Freeze Watch will be in effect tomorrow night into Wednesday morning in Tolland County and all four southern Connecticut counties. This is where the growing season hasn’t ended yet, but the entire state outside of the shore will likely see temperatures cold enough to end the growing season…again in spots.

Wednesday looks similar to Tuesday, with high temperatures well below normal along with sunny and breezy conditions. By Wednesday night, the stage is set for cold air to remain in place in the upper levels, as an area of low pressure approaches. 

Thursday
From Thursday on, we see a more active period in the weather department, but Thursday in particular is our period of interest. Below you’ll see why. 

Note the extended period of below freezing temperatures above the surface. Now, that doesn’t tell the whole story, as we need to see the entire column above ground to have below freezing temperatures to really support a winter weather event, but at least so far, we’ve seen a fairly consistent signal for a cold enough column for mixed precipitation for some spots early Thursday before a changeover to rain. 

Simply put, we’re looking at an early season southwest flow event (SWFE), where you get an area of low pressure passing to our west or north that brings southwesterly flow aloft that overruns colder air, bringing wintry precipitation on the front end before (often) changing over. 

Much of the guidance has shown a period of mixed precipitation and snow for northern and western Connecticut, especially in Litchfield County. But tossing models aside, there are some red flags that make this a lower confidence forecast and minor event at this time. 

Even though we’re not terribly far out, there’s uncertainty that exists with regard to temperatures both at the surface, which would impact whether there would be any accumulation, and temperatures in the column just above the surface, which could be warm enough to make this a very brief period of wintry precipitation or a less widespread extent of wintry precip. Remember that this isn’t even close to our peak climatology period for wintry precipitation—that means a lot more generally has to go right for anything meaningful to fall, because it’s just less common for cold enough air to be in place.

That said, these events sometimes have cold air that is harder to scour out, especially in the valleys, so that’s something we’ll be watching closely. 

Above is a 12z GFS image showing the potential for wintry precipitation in northwest Connecticut verbatim. Take with a grain of salt...this is just a crude visualization of the potential of cold air hanging on a bit longer in spots. 

Track is also an important consideration, and the 18z GFS didn’t inspire much confidence in what the eventual track will be with a downright weird surface track with a high in place to the northeast. The 12z euro was more bullish, with accumulation in much of northern Connecticut verbatim, but, I don’t think this is a situation to buy exactly what any model is selling. It’s always best to take all the various runs with a grain of salt and blend the possibilities, but it’s even more prudent here. With regard to track I'll be watching closely if we see a southern trend of both the surface and mid level center. 

This is something we’ll continue to watch and hone in on as we get closer, but right now, I lean toward the northern sections of Litchfield County being most likely to get a minor accumulation with much of northern and western Connecticut seeing a rain/sleet/snow mix Thursday morning with no accumulation before a transition to all rain by later in the morning in most spots and early afternoon in Litchfield County at the elevation spots. 

With a strong area of high pressure in place, I wouldn't be surprised to see a late trend toward colder conditions Thursday morning. That is something to watch closely. For those tracking, be wary of GFS surface temps.  

Friday
The rest of Thursday and much of Friday look wet, as this deepening area of low pressure rolls its way through our region. In fact, this looks like it may be a very nice widespread rain producer, helping areas that have endured drought conditions this year. Right now, I’m thinking of total accumulations between .75-1.5 inches of rain. Not bad! 

Saturday
By midday to late Saturday, we’re back at it again as another system likely passes to our north and brings rain showers to the state. This doesn’t look as potent as the preceding system, but it should provide more precip to the state.
 
Sunday/Monday
Things quiet down by Sunday and Monday, and I currently anticipate fair conditions. There looks to be a spit on how cool we get, but I expect this period of colder than normal temperatures to remain for the forecast period.

The dailies
Tuesday: Sunny, cold, and windy. Highs in the upper 40s to low 50s. Nighttime temperatures in the upper 20s to low 30s inland, with lows in the mid 30s at the shore. 

Wednesday: Sunny, cold, and breezy. Highs in the upper 40s to low 50s. Nighttime lows in the upper 20s to low 30s away from the shore. 

Thursday: SCW period of interest. Mixed precipitation early in northern and western Connecticut, especially the northwest hills, with rain elsewhere. Rain everywhere by afternoon. Highs in the low to mid 40s. 

Friday: Rain. Highs in the low to mid 50s. Chance of rain 70%. 

Saturday: Cloudy with a chance of rain. Highs in the mid to upper 50s. Chance of rain 40%. 

Sunday: Sunny. Highs in the upper 50s. 

Monday: Sunny and seasonably cool. Highs in the low 50s.

Thanks for reading! This is something we'll be watching closely and we'll be sure to keep you updated as we track the first potential widespread wintry event this season.

Remember that a forecast is a dynamic thing. Thoughts one day may not be thoughts the next. We're working with the best data we have, when on social media, always look for the confidence levels of forecasters and take model runs with grain of salt. Please like, share, and ask questions both on Facebook and Twitter @SouthernCTWX. 

-DB

​Good evening to you from Southern Connecticut Weather!
 
After the past few days have produced record highs across the state, the mercury is about to take a plunge heading into next week. However, before we get there, we’ve got a storm system to deal with for tomorrow into Saturday that will bring a chance of rain and strong winds to the state.
 
Friday-Saturday
 
A large area of low pressure is moving north to our west, however, instead of cutting into the Great Lakes and placing us in the warm sector, it will transfer to a secondary low off the coastline, which will generate a deformation band to it’s west as it passes just to our east. Both the primary and the secondary will bring rain, however, between the two lows, there will be a dryslot area that will see little to no rain. Here’s a panel of the GFS that shows the two jackpot area well; all guidance is in general agreement on the layout. You can see the primary low hanging on on the western flank, while the new secondary is forming on the eastern edge.

​Eventually the primary dies and the secondary becomes the dominant low, winding up essentially due north of us. However, by that time, the deformation rains associated with the low may be too far north to bring heavy rain to the area. This GFS panel shows that, with the heaviest rains winding up in northern New York and Vermont. We still see some rain, but it is lighter and more scattered.

​What determines how much rain we end up seeing will be the track of the initial primary low and resulting placement of the dryslot. Guidance is split between the transfer taking place to our west and the dryslot ending up over New Jersey and PA vs. the transfer taking place right over us and putting the state in the dryslot. As the trend has been for a slight shift to the east over the past several runs, I am inclined to lean a bit drier than the model consensus. I still expect to see a moderate to heavy rainfall across the state, with totals between half an inch and an inch statewide. We could see some higher amounts in the eastern portion of the state depending on where the band of rain sets up, but I’m not confident enough in that to call for higher totals.
 
As the storm exits to our north, it will tug down cold air from Canada, leading to a chilly Saturday. It will also be windy as the midlevel low moves over us, with gusts of up to 40mph possible. Further to the north, upslope snow showers will develop over the Berkshires, Greens and Adirondacks(bringing the first significant snowfall of the year there); while I don’t expect any snow of significance in Connecticut, the Litchfield hills could see some non-accumulating first flakes Saturday evening and Sunday depending on temperatures.
 
Sunday-Thursday
 
Behind the storm, much colder air moves into the area, with highs only making it to the mid 50s on Sunday and then steadily trending colder over the course of the week. The cold peaks on Thursday morning, when guidance currently sends the whole state below freezing except for the immediate coastline; that will likely end the growing season across the state for anywhere that has not frozen already.  Generally calm weather throughout the forecast period; some sort of system looks to approach towards the end of next week, but right now it’s too far out to get into it with any sort of detail. 

The Dailies
 
Friday: Showers likely, otherwise, cloudy, with highs in the upper 60s to lower 70s. Chance of precipitation is 70%.
Saturday: Showers likely in the morning, then a chance of showers, otherwise, mostly cloudy and windy, with highs in the mid to upper 50s. Chance of precipitation is 50%.
Sunday: Partly sunny and windy, with highs in the mid 50s.
Monday: Mostly sunny, with highs in the low to mid 50s.
Tuesday: Mostly sunny, with highs in the upper 40s to low 50s.
Wednesday: Mostly sunny, with highs in the upper 40s to low 50s.
Thursday: A chance of rain, otherwise, partly sunny, with highs in the upper 40s to low 50s. Chance of precipitation is 20%.
 
Have a great weekend and thank you for reading SCW!
-SA

Good evening from Southern Connecticut Weather

After a very nice Sunday, we have a potentially unsettled week ahead. For reasons explained below however, I am becoming less bullish on our chances of “interesting” weather. I lean toward us continuing the boring and dry period we’ve been in for quite some time, but at least we have something to talk about. 

Overall, we’re looking at a very impressive warmup early in the week, followed by a potentially unsettled period at the end of the week and weekend as we watch a quasi-tropical entity and area of low pressure from a deep trough. Let’s dive in.

Monday through Wednesday
Well, we’re into the second half of October, and guess what? The heat is on, again. The first half of the week will be dominated by unusually strong ridging in the south that will bring significantly warmer than normal temperatures and a fair amount of humidity for the second half of October. With higher dew points, we should also expect fog late Monday night into early Tuesday. 

Tuesday and Wednesday in particular look like torch days, as we maximize 850mb temperatures and see temps soar into the low 80s with strong ridging in the east. Temperatures will easily be 15-20 degrees above normal, quite a feat any time of the year.  

GEFS Temp anomaly for the week. Wow! Look at this fall “heat dome”! Very impressive for this time of year…though we saw absurd ridging during December of last year. 

Thursday-Friday
Although we’re still pretty warm Thursday, we’re on a downward descent with temperatures as we turn our attention to a digging trough to our west and a potential area of low pressure off of the east coast. Earlier in the week, it looked like the Atlantic low would become entrained by the cold front, bringing significant rain to New England Friday through the weekend. That has become less clear recently, with guidance keeping the Atlantic low well out to sea. It’s something to watch, but right now, I favor cloudy and unsettled conditions without a washout occurring. That's almost a shame, because we still need the rain.

The weekend
​Should my forecast hold, I expect there to be continued clouds and showers early on Saturday, but we clear by the afternoon and see a nice day Sunday. With the cold front pushing through, I expect temperatures significantly cooler, with temps struggling to reach the 60s.

GFS depiction of the unsettled weather for the latter half of the week. The guidance has jumped around quite a bit, so my forecast from Thursday on is of lower than normal confidence. 

The dailies
Monday: Mostly sunny and warmer. Highs in the low to mid 70s.
 
Tuesday: Fog early, but turning sunny and warm. Humid. Highs in the upper 70s to low 80s. 

Wednesday: Fog early, but sunny and warm. Humid. Highs in the upper 70s to low 80s. 

Thursday: Sunny early with increasing clouds. Chance of showers late. Highs in the mid to upper 70s. Chance of rain late 20%. 

Friday: Mostly cloudy with a chance of rain. Highs in the mid to upper 60s. Chance of rain 40%. 

Saturday: Mostly cloudy early with lingering rain showers. Highs in the upper 50s to low 60s. Chance of rain early 30%.

​Sunday: Sunny and seasonably cool. Highs in the mid to upper 50s. 

Thanks for reading!

-DB