Brief Nor’ Easter Update

We have a strange Nor’ Easter set-up that will dominate the weather this week across the region.  We first outlined this threat 6 days ago on Twitter (@SWCTWeather), mentioning the likelihood that one of our three main weather models which did not have the storm was wrong, and that the two that did show it were accurate.  As we can see now, this was the correct call, as a closer upper level low will move just east of us after stacking with a surface low pressure system offshore and pulling that low pressure system further west and closer to the coast, bringing with it rainy and windy conditions for all of New Haven, Fairfield, and Westchester county.  This post will look to just briefly break down the expected impacts that can be felt on a day-by-day basis with this very slow-moving storm.

Tuesday: We already start seeing the first signs of a forming Nor’ Easter across the region.  Look for cloudy skies in the morning with scattered showers and drizzle in the afternoon.  It will be moderately humid with temperatures generally getting into the mid 60s across the region.  We don’t expect any real accumulating rainfall, just generally cloudy skies with scattered showers in the afternoon as the low pressure system starts to begin to get organized.  Even into the night nothing more than drizzle or the occasional scattered shower are expected.

Wednesday: Cloudy skies generally in the morning with scattered showers and drizzle again throughout the day.  The low pressure center will continue to get more organized offshore throughout this time, but throughout the day should not be producing much rainfall across the area.  Through the evening it is unlikely we have accumulated even more than a tenth or maybe a quarter of an inch of rainfall.  It will be gloomy, and by the afternoon and especially evening we will see winds begin to pick up  a little bit so that gusts are noticeable (maybe 20 mph or so) but still not much significant.  It is overnight, though, that the real impacts may begin to be felt across the region.  As the low pressure center forms offshore and then retrogrades back to the west closer into us, there will be multiple pockets of very heavy rain (half an inch per hour for multiple hours and the like) that will move across the entire region.  Weather modeling guidance has the first move through Wednesday night moving from east to west, so first hitting New Haven county, then Fairfield, and then Westchester, ending early Thursday morning.  Temperatures in the mid 50s during the day on Wednesday will drop into the 40s during the rain Wednesday night as northerly winds take over and the Nor’ Easter continues to strengthen, hitting their peak.  With the storm not strengthening too rapidly, though, winds should not bring with them many impacts other than occasional gusts in the 20-30 mph range Wednesday night before they die down on Thursday.

Thursday: Impacts will reach their peak overnight Wednesday night into Thursday, with heavy rain remaining around the region during the day on Thursday.  At this time, however, most weather model guidance shows that the heaviest, potentially flooding rain all remain to the north of the region in northern Connecticut and up further into New England, meaning we should be spared the worst.  Still, we could get stuck in another heavy plume of retrograding moisture (retrograding meaning moving east to west here) during the morning.  If current modeling is correct, though, we should see the rain die down in the afternoon so that we are looking at only scattered showers and drizzle later in the afternoon and into the evening as winds almost entirely die down.  With any winds and the overall flow coming from the north due to the Nor’ Easter orientation, temperatures across the entire region will struggle to get out of the 40s, maybe hitting 50 in isolated locations.  Overnight, temperatures will stay in the upper 40s as the flow subsides and scattered showers and drizzle move on out.

Friday: By Friday morning, the storm system will be pulling away, and any lingering showers will be gone by afternoon.  There should be clearing before evening, with a chance of sun and temperatures hitting 60 degrees before the day is over.  Overnight, temperatures will then drop back into the mid to upper 40s, but the storm will be on its way out and actually pave the way for a decent weekend with partly cloudy skies and temperatures in the upper 50s to lower 60s across the entire region.

Impact Summary:  Rainfall of a little over an inch.  We expect around 1-1.5+ (more north, less south) inches in New Haven county, with .75-1.25+ inches in Fairfield County (again, more north and less south and east, with some pockets of heavier rain possible), and as little as .66-1 inch across Westchester County, as the heavier rain is focused further north and east than that part of New York State.  Wind gusts up to 30 mph are possible, but again no serious impacts there are expected.  Few other impacts are expected than prolonged cold and gloominess and some isolated flash flooding possibilities Wednesday night into early Thursday as the heavier rain pockets move onshore.  River flooding will also be a possibility as much heavier rain gets focused even further north.

So that’s a day-by-day overview of the upcoming Nor’ Easter for the region.  As confidence is quite high with the storm, there doesn’t seem to be as much need here for a technical discussion.  A reminder that on November 1st we will be launching both consistent free blog posts and forecast updates here on the free site alongside a Premium site, where for a low competitive monthly fee you can view additional forecasting content, technical discussions of weather models and the winter climate, and even see some potential investment analysis we provide of temperature anomaly forecasts across the nation impacting commodity pricing.  Free blogs like this will continue to be provided through the winter, though maybe not quite as in-depth, but the subscription site will be more hyper-local, breaking the weather down by county, focusing on storms further out, and offering additional sidebar content.  We look forward to the roll-out of all of this additional content for those interested, and we also look forward to continuing to offer the high-quality free forecasting that has allowed SWCTWeather to become so well known over the last few years.

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Official 2014-2015 Winter Forecast Summary

This is the summary of the SWCTWeather official forecast for the winter. This basic summary is just meant to give a first glimpse into expected conditions of the winter, with the actual details provided in the Premium Winter Forecast, on sale now.  The winter forecast is created through a number of statistical forecasts, indicators, and correlations, stemming primarily from climatological factors such as pacific ocean temperatures, stratospheric winds, and the like. We combine these weaker correlations to attempt to find an overall view of the most probable winter conditions. Of course, with any number of variables in every season, it is impossible to predict with complete accuracy any scenario. Using climate variables, we can essentially find what is more likely every winter season, and come to some broad conclusions regarding individual variables. We then combine these broader conclusions with different random observations throughout the historical data sets we use to find the general trends published.

This year, we are publishing a slightly modified version of the winter forecast: we are giving a probability of different various snowfall amounts and temperature differentials based on our observed trends. We will list the latest official forecast here, and then give an explanation as to what drove some of the forecast. However, since this is just the basic summary, we will just provide a general overview of our thoughts, and the in-depth technical analysis is available for the half-off price of $24.99.

SNOWFALL

Less than 10 inches of snow: 15%

Less than 20 inches of snow: 35%

Less than 30 inches of snow: 65%

Less than 40 inches of snow: 80%

Less than 50 inches of snow: 90%

More than 50 inches of snow: 10%

TEMPERATURE

Temperatures more than 1 degree above average November-March: 50%

Temperatures within 1 degree of average November-March: 30%

Temperatures more than 1 degree below average November-March: 20%

These forecasts are based off of a base of Bridgeport, CT. The surrounding area will likely see more snow as Bridgeport will often report slightly less snow due to the urban heating effect, and inland areas of Westchester, Fairfield, and New Haven counties historically see significantly more snow as the cold low level air gets locked in longer. With an average of around 28 inches of snow per season, the going forecast is for a winter with less than average snowfall and above average temperatures not just for Bridgeport but for the entire forecast region.

A number of different indicators were taken into play when creating this forecast, and for those that enjoy the snow and the cold (often those most involved in predicting the weather) forecasts such as these are normally not taken too well. Meteorologists use any number of indicators for a forecast; the main ones used here were ENSO (El Nino/La Nina and Pacific Ocean temperatures) along with the QBO (stratospheric winds) and other climate and longer-run indicators.

It is important to note that there are multiple historical winters that exhibit strong similarities to the upcoming one. The strongest analog was the winter of 1968-1969, with almost exactly the same ENSO conditions and formation as we are observing now. Sadly QBO data is not widely available from that time frame to access. That winter season saw average snowfall with slightly below average temperatures. The second strongest analog was the winter of 2012-2013; this winter has a very similar QBO set-up and is one possible ENSO track. As most remember, that winter had above average snowfall alongside slightly above average temperatures.

Some central technical assumptions for the winter were a weak El Nino (DJF ENSO value around .6 or .7), which is essentially in line with the daily updates from the Climate Prediction Center. Similarly, a negative QBO value will dominate the winter; this combination will help drive a slightly above average PNA value although the NAO and AO will oscillate.

When going through the weighted snowfall forecast, a base of 21.5 inches of snow was found for Bridgeport; approximately 23% below seasonal snowfall. It is expected that there will be a period in time that is snowy this winter; historically speaking there will be a time frame with a positive PNA and a negative NAO that is conducive for snowfall.  In the premium forecast, we detail when it is most likely this cold and snowy time frame is this winter.  Most storms in patterns like this tend to be smaller rather than larger, with a week or two with a couple small snow events moving through. However, the one thing that is worth watching out for, which occurred in 2012-2013, is that the lack of major storms can prime the pattern, via warmer ocean temperatures, etc. for an extreme snow storm. This does not occur very often, but a couple analogs did indicate the potential for significantly above average snowfall. It will be important through the winter to continue to monitor the potential for larger snow events, especially later in the winter, as it is far from impossible.  Again, in the premium forecast we detail what the odds of this happening are, how much snowfall would occur in such a scenario, and when it has happened in the past other than this one year.

Finally, just statistically speaking, with the past two winters in Bridgeport having seen over 50 inches of snow, there is no time in recorded meteorological history there (since 1949) that there were two winters in a row where that happened. Having a third is even less likely (as we explain in the premium forecast, there is a reasoning for such logic). Typically, snowfall oscillates with the QBO, which changes every year or two and can prevent back-to-back exceptionally severe winters. Due to “Nemo” in 2012-2013, that wasn’t the case; it’s more likely now that we revert back to the mean. This pattern may help us reach slightly elevated snowfall levels and get close to average even in an atmospheric pattern that is not all that favorable; the forecast basically gives us around a 35% chance of achieving average snowfall across the region. While completely possible, the current thinking is that it is more likely that we just fall short.

There are plenty more data points and analysis, but we had promised a basic summary of the winter forecast, and as soon the data analysis was completed we wanted to publish the preliminary findings here. We have published all of the additional details in the 40-page premium winter forecast available to the right. Please stay tuned as the publishing of the winter forecast traditionally signifies consistent site updates and storm coverage through the Fall season.  An update to the premium forecast will come in early November.

Additionally, we are pleased to announce that we will be launching a premium subscription service tentatively on November 1st. For a reasonable monthly or yearly fee, we will provide additional meteorological services beyond what we have historically served in the past, along with additional impact forecasts. We will be posting polls to sign up and receive email updates when the service becomes available and goes live, as we are also looking to gauge interest in the advanced weather services. Free services will still of course be offered through the winter here as well, but the premium website is a chance to receive more regularly updated content that goes more in depth with all of the storms. More information will be available on this in the coming weeks.

Thank you for reading our 2014-2015 winter forecast overview and we look forward to serving you through the coming season.

Revamping For Fall, Winter 2014-2015, And Beyond: Organizational News

Welcome back to Southwestern Connecticut Weather, where we are pleased to announce a number of new additions as we prepare for the upcoming fall and winter season.  This post will simply be organizational about all new services that we will now be offering, and this will begin the official forecasting season for 2014-2015.  We are expecting to publish continuous updates on upcoming weather and climatological updates from here on out through the winter.  The first of such updates will either come later today or tomorrow regarding a brief warm up, some thunderstorms, and a few other weather patterns through the next 10 days.

The first major announcement is that we will be officially expanding our services to both Westchester and New Haven Counties.  Previously forecasts were made primarily for Fairfield County and then extrapolated to surrounding counties, but we are happy to announce that we plan on furthering the services in Westchester and New Haven Counties so that we will publish forecasts specifically detailing expected conditions across them.  We will still publish general forecasts regarding model analysis, storm track, etc. outside of 72 hours for most storms, but inside of that we will begin to break down exact snowfall amounts across the three counties, detailing regions of potentially higher snowfall and taking into account regional microclimate.  Snow day and delay forecasts will now also be officially forecast for Westchester and New Haven Counties, with each region being even further broken down into inland and coastal.  For various storms, forecasts may go town-by-town; specific details are still pending.  Regardless, we hope to offer the same quality of coverage to both Westchester and New Haven that we currently do across all of Fairfield County.

The next major update we are pleased to announce are the additional services and forecasting packages.  For any major event that you may have coming up, or for any trip you may be taking, we offer competitive rates for custom forecasts so that you can always be ahead of any storm and prepare accordingly.  Packages vary from a basic forecasting package, which gives you custom forecasts 7 days out and detailed regional forecasts up to 15 days out, to premium forecasting packages, which can offer forecasts and data for up to 30 days out, providing updates every day or every other day along the way.  If traveling, we offer a trip package where we forecast the weather for your flight both leaving and returning daily up to seven days in advance, giving you recommendations on when you should attempt to reschedule, what times would be best to do that, and what the odds are any flight you are taking gets delayed or canceled.  We are also offering individualized forecasts, our cheapest offering, where if you do not want a full package complete with anywhere from 7-30 days of updates you can get one forecast tailored specifically to any location of an upcoming event.  Our goal is to make weather as local as possible; every single mile can affect temperature, wind direction, and outdoor conditions, and for any special occasion we want to ensure you are prepared for all scenarios.

Additionally, we are offering institutional weather consultation services for private businesses or other organizations that could benefit from storm alerts.  Currently, we are offering a FREE trial of our institutional weather consultation services for any town or school administrator; through January 1st anyone who were to sign up for this service would get briefing packages daily or every other day up to a week before any potential winter storm with detailed hyperlocal information on how best to prepare.  We have already received strong interest, and encourage all interested to spread their word to local town and school administrators to get a free service and then determine by January 1st if the service is something they would be interested in; our pricing will always remain some of the most competitive in the industry.  Additionally, we have already partnered with local libraries regarding similar services, and hope to continue spreading our services to others in the region to ensure safe travel and preparations for all storms across the region.  Should anyone have questions or interest in any of these services, they are asked to email site operator and chief meteorologist Jacob Meisel at jacob.meisel@gmail.com.  As a limited time offer, any institution or organization that signs up for the consultation services by October 1st will receive a detailed version of our full winter forecast; only the brief press release and summary is ever made public.

Finally, we are tentatively working on developing a premium portion of SWCT/NY Weather.  More on this will be coming in future updates through the upcoming months, but the goal here is that new, engaging content will be available through a premium subscription for our services.  This will ensure that our services remain top-notch while also becoming increasingly hyperlocal; our goal is to develop storm impact forecasts and school cancellation/delay forecasts that are not only the most accurate but also the most local, allowing all visitors to easily see content crafted for their local towns and cities.  Our promise to you, though, is that this free site at swctweather.com will remain here through it all, as will the twitter account at @SWCTWeather, which will continue to provide daily weather information as well as live coverage of all major storms that impact Southwestern Connecticut and Westchester, NY.

Those are some of the largest changes coming to SWCT/NY Weather through the coming season, and we hope they will allow our weather forecasting to become even more applicable, relevant, and updated so that all residents are kept ahead of any impending major weather events.  Our goal is to slowly transition this site into a year-round weather resource for any and all residents of the three highlighted counties, as well as any surrounding regions, where we will continue to offer the quality of forecasting exhibited over the last few years.  We will continue to update you about any changes, and will also begin issuing daily forecasts as well.  We still aim to have the preliminary winter forecast issued by September 5th, though we admit it may be slightly delayed by all of the new services and products we have been preparing for the coming winter.  From here on out though, you can expect occasional blog updates alongside constant twitter and 5-day forecast updates.

We hope you are as excited as we are for the upcoming changes here at SWCT/NY Weather, and we look forward to serving you as best we can!

Fondly,
Jacob Meisel
Chief Meteorologist and Owner, SWCT/NY Weather

The Coming 7-10 Days: Two Storm Threats, Spring Arriving

As expected, the winter season appears to be winding down, and my forecast last week of the snow events being over from here on out looks accurate on long range models.  There’s a chance some snow/sleet could mix in at the onset of a storm moving in Thursday night, but with temperatures above freezing for the entire region no significant impacts are expected.  This post I’m going to run through the two main storm threats I am watching, one Thursday night into Saturday morning and another Monday night into Tuesday of next week; each one will bring some minor impacts but I am not expecting anything major.  I am watching the latter of the two for potential impacts slightly larger than the one later this week, but neither one should be cause for much concern.  Overall, the weather is relatively tranquil now as we transition from our winter-weather pattern into a more spring-like pattern of severe potential.  There’s always the chance of large, strong Nor’ Easters this time of year, but I don’t see too many of those on the horizon.  Monday night into Tuesday could try and come close to that, but I’ll discuss that more in a little.

Tomorrow should be a relatively nice day, with temperatures approaching 60 and clouds increasing throughout the day.  However, temperatures drop quickly overnight into the low 40s and upper 30s overnight as overrunning precipitation approaches the area.  Some weather models are more defined with heavier precipitation, but both agree that enough cold air will be pooled in front of the overrunning precipitation that some sleet/snow could begin inland at the onset for an hour or so before we go to all rain.  Most weather models have the heaviest rain between 4 AM and 8 AM, though again there is some variance.  Then during the day on Friday light precipitation and drizzle will continue as a very strong inversion sets up; temperatures at the surface will generally be in the 30s but aloft at 850mb (around 5,000 feet) temperatures will approach 10 degrees Celsius.  Though this warm air occlusion can be common, it occurring to this magnitude at this time of year is rare.  In fact, surface temperatures may not even reach the seasonal LOW temperature for this time of year in areas.  Either way, temperatures should remain just on the higher side of freezing, so I don’t expect we deal with any freezing issues on Friday into Friday night as light precipitation continues.  I’ll keep an eye on future surface temperatures runs, but right now I just expected stagnant air and potential air quality issues with light rain/drizzle throughout the day Friday into Friday night.  Any precipitation then winds down into the day on Saturday with total rainfall amounts anywhere from .2-.5 inches varying across the region.  A large variance, but this is a small-scale event so exactly where heavier precipitation sets up tomorrow night will determine what part of that range we reach.  Regardless, even high-end estimates are low enough that there are no flood risks or real impacts from this storm other than cold weather and nuisance rain on Friday.

Clearing comes into the weekend with high temperatures in the mid 50s and low temperatures in the mid 30s or so.  Then we start tracking the next storm system that will move through Monday into Tuesday.  Like during winter, weather models generally agree on the overall pattern but can diverge on the specifics, but the agreement here seems fairly strong, hence why I’m going to go a little more in depth with this storm system.  During Sunday night into Monday a storm system will move out of the Gulf of Mexico and progress over Ohio and then into Canada.  This has been a fairly significant trend to the west, which is good as it may help spare Southwestern Connecticut the worst of the winds with the storm system.  Generally, when strengthening low pressure centers move just west of the area, we deal with strong southerly flow that results in stronger surface winds due to relatively less friction over the Long Island Sound (especially in convection, where strong downward motion can mix down very strong winds aloft).  Some models even indicate a very weak secondary low pressure center trying to form near the area as the storm moves through, again limiting winds.  In terms of real conditions, the end result of this should be a period of heavy rain Monday night and maybe some briefly gusty winds as the precipitation shield on the southeastern flank of this low pressure center moves through.  Again, no serious impacts, but any strengthening low pressure center moving there just bears a little watching to make sure there are no more serious impacts than a period of rain, so stay tuned in case anything changes there.

The bad news for Spring and Summer lovers is that after that low pressure center moves through it will be strong enough to usher in a brief period of (relatively) very cold air.  We’re not talking teens or anything here, but areas are likely to get below freezing as temperatures aloft at the 5,000 foot level could get below 10 degrees celsius.  A very strong April sun angle will help warm things up during the day, but Wednesday night could be quite chilly as radiative cooling takes over.  Wednesday and Wednesday night maybe into Thursday will thus be unseasonable chilly, but warm air looks to flood back into the region a little more Thursday night into Friday, so we should return closer to average temperatures very late next week.

That’s a brief summary of the weather over the next 10 days or so.  Nothing too impactful expected, but two periods of unsettled weather could potentially disrupt some outdoor plans, along with a cold shot late that could throw us back to thinking it is February or March.  I’ll continue watching all future weather disruptions across the region, so make sure to keep it here for the latest!  As always, the 5-day forecast will be updated daily, and we will soon be revising the “Winter Storm Update” to make it more relevant for the spring weather we are about to see.  SWCTweather will be here throughout the Spring and Summer when bad weather threatens the region, so make sure to stay tuned!

Colder Surface Temperatures: 30% Delayed Opening Monday

We have been tracking a strong storm system that has moved into the area and stalled over the last few days.  As it slowly tracks to the east, we are noticing models trending colder at the surface, and a result is that tonight all of Southwestern Connecticut is expected to drop below freezing after a sizable amount of rain.  This could mean some icy patches on roadways, and with light precipitation potentially continuing through the night, some sleet/freezing rain could pop up.

Precipitation may not even wind down until 8 or 9 AM tomorrow, and though it will remain quite light, it could be freezing rain and sleet lightly tonight.  I had been tracking this potential, but a combination of it being a low-end chance and a lot of school-work has prevented much constant updating.  Regardless, we are continuing to update and monitor this tonight as colder air works into the area, and we will be up at 5 AM to report on any school delays should some crop up.  Again, delays are not exactly expected, as some weather models have surface temperatures remaining above freezing or have conditions that are bearable as long as roads are properly treated, but icy patches on some roadways may be enough to delay some school districts tomorrow, especially inland.  Precipitation is in a lull now across Southwestern Connecticut, but expect it to pick up off and on again throughout the night before the storm entirely moves out.  If necessary, I’ll have another update tonight at 11 PM, so be sure to check back in then for another update as the cold air marches east.