Extended Forecast

NBC10/NECN First Alert July Monthly Forecast Bodes Very Well for New England

LKN_30_DAY_FORECAST_TEMP (1) LKN_30_DAY_FORECAST_TEMP (1)On this first weekday of the month, our NBC10 Boston & NECN First Alert Weather Team delivers our monthly forecast for July – and it looks very promising.  Coming off a June that was wetter than normal and very close to average temperature (just slightly warmer than normal), the big question is whether we can dry out for July, and the answer from our meteorology team is yes.

 

The cool pool of air that lingered over the Central United States in June was well predicted by our First Alert Team, and disturbances riding around the periphery of that cool air sparked thunderstorms and rain storms where warm and cool air collided, and that included New England, where someplace like Boston saw nearly an inch and a half more rain than normal for June, totaling just over five inches for the month.  Not all of New England saw the same result, though – in fact, Worcester and Hartford were one to two inches below normal for the month, while much of Northern New England was significantly wetter than usual.  July features the Central U.S. cool pool migrating slowly west as a large dome of heat builds over the Southeastern United States, driving hotter than normal conditions through Atlanta and probably all the way into Washington D.C.  Thunderstorm outbreaks are expected to develop on the northern edge of the building heat – the reasoning for our team’s prediction of near normal precipitation from the Appalachian Mountains into the Mid-Atlantic States.  Here at home, however, it looks like we’ll remain just north of that very active thunderstorm zone, at least overall this month.  What this means for New England is likely near-normal temperatures (though, if we are to lean in one direction or another, we’d likely be leaning warmer-than-normal given how far away the cool pool is and how close the Southeast and Mid-Atlantic heat is), and below normal precipitation, overall.

LKN_30_DAY_FORECAST_PRECIP (1) LKN_30_DAY_FORECAST_PRECIP (1)With July presenting New England’s warmest average temperatures of the year, this bodes well for many days with highs in the 80s and the tendency for drier-than-normal weather for the month means, on the balance, vacation weeks and outdoor plans will meet with contentment from the weather.  Of course, there is one very important point we’re making as a team of meteorologists: even a drier-than-normal July certainly doesn’t mean we avoid summertime thunderstorms, and the reality is, if the storms hit your outdoor plans, it can be a drier-than-normal month, but that didn’t help your event!  We know how important those details are, which is why we continue to pour so much energy into making sure our daily, exclusive First Alert 10-day forecast is as accurate as it can be, so you can plan your weddings, parties, vacation days and workouts with confidence.


June Monthly Forecast - Near Normal Conditions, Overall, in New England

LKN_30_DAY_FORECAST_TEMP LKN_30_DAY_FORECAST_TEMP LKN_30_DAY_FORECAST_TEMP LKN_30_DAY_FORECAST_TEMPYou can see the video forecast including my monthly outlook here.  It’s the first weekday of the month, which means our NBC10 Boston First Alert Weather Team issued our latest monthly forecast for the month of June live in our broadcasts.  The overview of the June weather pattern nationally will feature, of course, expected warming as a nation with the jet stream winds aloft – the fast river of air, high in the sky, that steers storms and separates cool air to the north from warm to the south – slowly rising north to a position near the northern tier of the United States by mid-month.  These jet stream winds will likely stay active in June, however, meaning multiple energetic disturbances will dig into the nation’s midsection for the first half of the month, continuing the recent pattern of wet weather in the Central United States with an active thunderstorm and severe weather pattern, then will likely continue to thrust episodes of thunderstorms across the Northern United States for the second half of the month as the typical summer ridge – a dome of increasingly hot high pressure and fair weather – begins setting up across the Southern Plains and South-Central U.S.  Of course, before that hot ridge sets up, the multiple disturbances with associated thunderstorms and incursions of cool air behind them will likely suppress temperatures below normal in the Rockies, Plains and Ohio Valley, but recurring surges of warmth ahead of each disturbance will drive temperatures up along the Eastern Seaboard preceding each disturbance, likely enough to push the Southeast and Mid-Atlantic warmer than normal, while New England sees enough oscillation of warmth ahead of each disturbance and cool air behind them to keep temperatures close to normal.  Although it’s quite possible the Mid-Atlantic states see drier than normal conditions with scattered thunderstorms the predominant driver of rainfall this month, New England is more likely to find broader shields of rain developing on the north and east side of disturbances ejecting from the Central U.S., adding a broader rainfall pattern to the thunderstorm activity and bumping monthly rainfall closer to normal.  Of course, you can already see the forecast through June 10th in our exclusive, First Alert 10-day forecast and we’ll continue to help you see farther than any other media outlet in Boston with this 10-day forecast.


Checking-in on the Winter Forecast: No big changes and northern snow hopes should live on

In this post:

  • Explanation of El Nino impact on winter's start
  • Check-in on our winter forecast, issued in October
  • Update and details on what to expect for the rest of the snow season in New England

Back in October, our NECN Weather Team released our Winter Preview half-hour weather special, and I shared expectation for the winter - a warmer than normal winter that would be somewhat wetter than normal, meaning messy events for Southern New England with mixed precipitation, and the hope for a bounty of snow in the North Country as long as the warm air wasn't so overwhelming that it reached so far north.  Here's an update...

First, that forecast wasn't hard, and I acknowledged that in October - that doesn't mean it was destined to be right, it just meant that in a strong El Nino winter, the expectation of warmer-than-normal conditions is second-nature.  The prediction of a wetter-than-normal winter (more precipitation than normal, be it as rain or snow) was a bit more of a toss-up, as El Nino winters vary in their precipitation to New England, but the expectation of a subtropical availability of moisture in the Eastern United States drove the idea of bumping precipitation above normal.

As the winter as just started to unfold, but November proved warm and dry and December is featuring a remarkable lack of cold air throughout the Continental United States, I've been hearing from many asking about whether snow lovers - particularly winter enthusiasts - should plan on a lackluster winter.  My answer:  Not at all, yet.  In fact, if my expectation proves true, there still will be plenty of snow to come in Northern New England, particularly, and especially in middle to late January through February.  My thinking is this:  there does not appear to be any reason to change the expectation for warmer than normal conditions, and subtropical contribution to an active Eastern U.S. storm track still seems likely, finding support from some of the seasonal models as well as the aforementioned tendency for such a pattern to evolve in a strong El Nino year.  Furthermore, observations show El Nino may have peaked and is slowly weakening - couple this with our normal descent into the coldest time of the year, and the picture begins to change.

First, the guidance - which has been consistent and strong on indications of how the rest of this snow season will turn out - a composite of January/February/March.  Below is the latest output from the National Oceanic and Atmospheric Administration's Climate Forecast System:

Temperature anomaly forecast (showing areas forecast to be warmer-than-normal in red, colder-than-normal in blue):

Fb1

Precipitation anomaly forecast (showing areas forecast to be wetter-than-normal in green, drier-than-normal in orange):

Fb2

Though these climate guidance products cannot and should not be taken verbatim in any extended forecast (and sometimes are grossly incorrect!), there are times the signals are overwhelming and the message is one that, even if exhibiting inherent error, still is clear - in this case, warmer than normal weather for the rest of the winter seems quite likely.  The precipitation signal is a bit more tenuous, as there is a fairly tight transition from above to below normal precipitation in the January through March timeframe, but this pattern nearly exactly matches the East Coast precipitation forecast laid out in our October forecast for the winter - here is that winter forecast map issued in mid-October - nearly an exact match to the recent computer guidance.  This doesn't mean the forecast is right, but it certainly does add a nice confidence to the forecast, and make me think we still have the best forecast we could possibly have:

Our October forecast for this winter still holds:

WX_SPECIAL_EL_NINO_2015-16

So...putting this all together, this is what I think we're left with:

  • Warmer-than-normal temperatures will continue to reign, regionwide, in New England and the Northeast.
  • The transition to more wintry precipitation in the weeks ahead will take place gradually, with each storm bringing a snow line somewhat farther south in the coming weeks.  In many years, we can make the transition by getting a solid shot of cold and then everyone, north and south, alike, snows on the backside of the cold - that doesn't seem likely this year.
  • As New England enters the coldest time of the year, even a warmer-than-normal regime can produce healthy snow in New England's Ski and Snowmobile Country
  • Much of Southern New England - especially far Southern New England into the Mid-Atlantic - very likely ends up with below-normal snowfall this winter
  • Many of the winter weather events for Southern and Central New England will likely feature bursts of snow on the front-end of storm, changing to sleet, freezing rain and rain as storms progress - these bursts often can produce a quick 4"-8" of snow before changing over, and closer to a foot in Northern New England
  • Ski Country will make up for some lost snow in likely "upslope snow" events as storms depart but leave behind sufficient moisture for northwest and west winds to produce enhanced snow on northwest and west facing mountain slopes.

We'll see how close to accurate this ends up, but that's my best guess based upon how the season has evolved.  In other words - those who make a living on snow in Northern New England should most definitely not give up the ship yet!

Matt


February 2015 Monthly Forecast: Cold air rules the East, snow blitz to ease

Each month, on the first weekday of the month, I air my monthly forecast for the upcoming weather pattern.  This week was so busy with active weather, that it finally made air today and, admittedly, in a short month, airing it on the 6th is like cheating, but...so many have asked for it in the last day or two, and I've had it prepared, so it seemed pertinent.  Besides, with a 6-day cheating period in a 28 day month, you can really give me heck if it doesn't work out!!

For those of you who follow my forecasts closely, you may remember at the start of our winter special back in December, I referred to a messy December, then a cold and relatively dry January leading into a snowy February as a transition to an early spring.  So far, so good, but confidence is rarely more than moderate in monthly forecasting, and rarely more than low in seasonal forecasting, so humility is always essential when constructing these.  That said, I think February is fairly clear-cut - after our recent "snow-blitz" that started at January's end and continues through early February comes to an end, it will be immediately followed by a huge dump of cold air directly from the North Pole that will charge into New England in the mid-month period.  This air will be exceptionally cold, challenging the coldest of the season for New England, and occurring in response to a southward shift in the jet stream winds aloft.  Remember that the jet stream winds are the fast river of air, high in the sky, that steer our storm systems and separate cold air to the north from milder air to the south.  So...with the jet stream dipping far south, cold air will also spread deep into the Southeast, but the storm track also should deviate. More on the storm track below, but here's the expectation for temperature, which reflects not only the deep jet stream trough in the east, but also the offsetting "ridge" - or bump - in the jet stream over the Western half of the nation, which will allow for building warmth.  That's the warmth that I think could end up our warmer-than-normal March, but we shouldn't get ahead of ourselves!

February 2015 Temperature Forecast:

30_DAY_FORECAST_TEMPS
 

As for precipitation, the "amplification" of the jet stream - a building ridge in the west and a digging trough in the east, should have some major implications - 1) The early-month feed of moisture with heavy rain into the Pacific Northwest will taper somewhat mid to late month, though by then, above normal precipitation for the month will already have been recorded there; 2) Dry conditions will likely take over for much of the Central and Western United States as the storm track (jet stream) shifts north; 3) Frequent incursions of Gulf of Mexico moisture will cross Florida and the deep Southeast; 4) The Northeast should end up cold...and drier than we've been...for much of mid to late month as the jet stream trough axis looks to set up just a bit too far east for more big storm development, which is the reason I'm expecting a break in the recent snow-blitz for mid-month, and I'm not convinced there'll be another blitz to get through on the other side.  It's really important for me to make the distinction between precipitation and snowfall - Boston, for example, is already above normal snowfall for February as of this posting!  But that's melted down to only .88" of liquid equivalent, and with the normal value for the month just over 3" of melted precipitation, it's that value I look for as "precipitation" - clearly, snowfall is a lock above normal for most of New England.

30_DAY_FORECAST_PRECIP

Where could the forecast go wrong?  With regard to temperature, there's not a lot of room for error, given the significant mid-month arctic blast, unless we get some unforeseen big warmth at the end of the month, but even that will likely be insufficient to offset colder than normal temperatures.  The precipitation forecast is definitely a bit more tenuous, and very well could end up above normal if additional precipitation events occur on the backside of the mid-month cold.  That is, right now I'm expecting the jet stream pattern to remain sufficiently amplified that, even as cold air eases toward month's end, new snow would not be enough to push us significantly above the normal precipitation amounts for the month - though a reminder that doesn't mean normal snowfall...we've already bested that.

Hopefully, if all goes as planned, I'll be here advising of a warmer-than-normal March, but again...that's just a tease...I won't lose that humility and overstep my bounds yet!

Matt


December in New England likely to be messy...much of the country warmer-than-normal

At the start of November, I shared my expectation of a cold November here with you.  At the time, the Climate Prediction Center was forecasting a month of above normal temperatures from the Great Lakes to New England, and I mentioned how much respect I have for our nation's center of expert monthly and seasonal forecasters, but that a jet stream trough seemed likely to hold strong, so there was decreased confidence in the forecast, but I truly favored a colder solution.

For the month of December, agreement has returned to the forecast, and for good reason.  A large "trough," or dip, in the jet stream is forecast to dig through Alaska and the Gulf of Alaska in December, and this will force a downstream "ridge," or bump, in the jetstream to develop over the Western and Central United States.  These troughs and ridges are crucial to the forecast, as the jet stream is a fast river of air, tens of thousands of feet in altitude, that acts as a river of air: steering storm systems near it, and separating cold air to the north from warm to the south.  When the jet stream rises north, warm air moves north with it.  So...a developing large ridge in the United States implies increasing warmth in most of December.  In this image, below, note the overall "anomaly" - or difference from normal - for average atmospheric temperature through the middle of December - note the large pool of colder-than-normal air near Alaska (blue and purple), associated with the trough, and warmer-than-normal air building in the Lower 48 and Canada.

1

Of course, the forecast isnt' quite that simple.  A strong dome of surface high pressure is forecast to remain persistent in Eastern Canada and will include the Northeast U.S. for at least the first half of the month, and this often means cold air will continue pouring from Canada into the Northeast, and specifically, New England.  So...while the temperature of a deep layer of the sky may be rising (warming aloft), the surface temperatures - what most of us care about - will likely lag behind.  That's why you see temperatures at or even slightly below normal in the 10-day forecast issued today, taking us through December 10.  The principle I suggest will dominate here, however, is that if we can't recharge new cold into the the Eastern Canada high sufficiently, we will eventually see the cold erode even from here in New England.  It's for this reason I kept the North Country of New England just barely out of the warmer-than-normal regime, but allowed the rest of New England to warm.  Of course, it's really important to remember that "normal" for New England in December is an average high of 39 and low of 24, so even an above-normal forecast is still wintry.

My December Temperature Forecast:

30_DAY_FORECAST_TEMPS

Northeast-zoom of My December Temperature Forecast:

30_DAY_FORECAST_TEMPS_ZOOM

There are two regions that will be active for storms this month.  The first region will be a continuation of moisture-loaded storms slamming the West Coast, where mudslides already have become a problem in recent days, and the weather shows no sign of relenting in the coming weeks.  The second region will be from Texas through the Tennessee and Lower Ohio Valley, as subtropical disturbances occasionally interact with stronger northern stream energetic impulses to develop plumes of moisture that will impact New England.  The likely result is a month of somewhat above-normal precipitation for Southern and pehaps Central New England, and near-normal precipitation in Northern New England:

My December Precipitation Forecast:

30_DAY_FORECAST_PRECIP

Combining these ideas actually matches very well the forecast you'd expect in a weak El Nino pattern, which lends further support.  An above normal temperature and precipitation regime in Southern New England is likely to mean multiple mixed precipitation events of snow changing to sleet and rain, while Northern New England, deeper in the cold air, has a better chance of seeing a more appreciable build in snowpack.

I'm a big believer that it's extremely important not to take these forecasts literally - that is, a tendency for warmer-than-normal surely does not mean cold outbreaks will be exempt.  Similarly, a tendency for mixed precipitation events doesn't mean you can't burst six inches of snow on the front side of a warm air surge, or that you can't squeeze out an all-snow event if a storm coincides with an occasional blast of deep cold.  What this does tell us, though, is that - if my estimation is correct - we are not going to see prolonged blasts of bitter, artcic cold in December, but we'll have plenty of opportunity for stormy weather of varying precipitation type, which is why I'm expecting a "messy" December, overall.

I'll keep you posted along the way.

Matt


November monthly forecast: Colder than normal and a chance to build a mountain snowpack

On Monday, the first weekday morning of the new month, I aired my monthly forecast as I usually do on my NECN morning weathercasts.  In my estimation, a trough in the jet stream should carve out across the Eastern United States by this upcoming weekend, and define the prevailing weather pattern for the first two to three weeks of the month.  Given the cold air bottling up in Canada, this should drive the Great Lakes and Northeast significantly below normal for the first half of the month, and given the depth of the cold, 1) I'm not sure the pattern will relent entirely, and 2) Temperatures will go enough below normal that a recovery to above normal for the month, overall, would be hard to achieve.

As for precipitation, such a pattern would not only allow some Pacific moisture to be brought into the Westerlies, but also would bring a propensity for coastal storm development, and is the reason I've placed much of the Northeast coast in above-normal precipitation.  All of this, together, argues for a deepening of the snowpack in the Northern Mountains over the coming two weeks, and quite possibly, over the month as a whole.

Below, you'll find my temperature and precipitation forecast for the month of November 2014.  Below those, the official Climate Prediction Center forecast from NOAA, which is quite a bit different.

My November 2014 Temperature Forecast:

30_DAY_FORECAST_ZOOM_ACTIVE

My November 2014 Precipitation Forecast:

30_DAY_FORECAST_PRECIP

Below, I'm including the Climate Prediction Center's forecast of temperature and precipitation for November, which is markedly different.  I include these because they are the nation's leading government seasonal forecasting experts, and I think it's important to humbly introduce that there clearly is not "high confidence" in my forecast, when the official government forecast is so different.  Why the difference?  My guess would be their forecast is heavily based upon a longer-term climate forecast model, while mine is predominantly on weather pattern interpretation based upon the next 2-3 week timeframe.

CPC Temperature and Precipitation Forecast for November 2014:

1

2


Prolonged chilly, wet weather quite likely next week for much of the Northeast

Who doesn't like a three or four day nor'easter, right?  Every once in awhile, fall in the Northeast U.S. certainly can feature intense atmospheric energy digging into the Eastern Seaboard, prompting storm development along the coast, and slowing or stalling.  That setup appears to be in the cards next week, and with New England and much of the Northeast on the north side of both the upper level energy and the resultant surface storm, a deep onshore flow of wind through the atmosphere is likely to be the result.  This far out, there surely are still questions of exactly where the storm develops and stalls, but we can get an idea of the general pattern and impact by examining this forecast product, below - atmospheric moisture and the weather pattern at about 12,000 feet in altitude are indicated on the left (700mb relative humidity and heights), with the surface forecast of barometric pressure, surface wind and forecast surface temperature on the right (MSLP, surface wind & temp), both valid at midday next Wednesday.  Notice the huge swath of moisture, indicated in green on the left image, and check out the midday temperatures on the right - only in the 40s and lower 50s for many!  If this thing sticks around for a few days, it'll be a raw, damp stretch from later Tuesday through Friday of next week.

1


8 to 14 Day Forecast: Mild pattern continues May 7 to 13 in New England, rain showers likely to return

For more, I invite you to follow me on Twitter, my weather Facebook page, my non-weather Facebook Page, and, of course, check in at my Weather Analysis Page and NECN Weather Team Blog for new posts.

8_TO_14_DAY_PRECIPAfter a remarkably dry stretch, I'm expecting showers to return to the forecast in this forecast pattern, more typical of spring in New England.  Having said that, confidence is somewhat low that the forecast of near normal precipitation will verify, as it hinges upon a more significant precipitation producer developing late in the period.  The forecast period begins with a decaying omega block, giving way to a somewhat more progressive pattern, though height falls (atmospheric cooling) will be slow to occur at the start of the period, and may limit total precipitation, even as some rain showers return to the forecast.  Late in the period, the baroclinic zone located west of New England for several days may migrate into the region, focusing at least one wave of low pressure to develop along it.

8_TO_14_DAY_TEMPSAs for temperature, slow height falls means slow cooling as New England remains on the "warm side" of the jet stream, and - especially given mild air in the first half of the forecast period - I expect above normal temperatures to rule.


NECN Weather Team announces pioneering nightly 10-Day Forecast for New England television

For more, I invite you to follow me on Twitter, my weather Facebook page, my non-weather Facebook Page, and, of course, check in at my Weather Analysis Page and NECN Weather Team Blog for new posts.

10DAY_ACTIVE

Announced in our special weather program on Monday, April 22, "Project Weather: Spring," I'll now be offering an exclusive, nightly TEN DAY forecast on New England's Only News at 9 PM, Monday through Friday nights in our NECN weather broadcast.  I'm excited to offer this forecast for the first time in New England weather, including the Boston television viewing area, and I hope the new extended forecast will help everyone at home to better plan ahead.

Some of you have undoutbedly seen my 8 to 14 day forecast on Monday night's News at 9 on NECN - that "Week Two" forecast has featured the overall weather pattern for the long-range, and has been a regular Monday night feature for nearly a year.  This new venture into nightly ten day forecasting has grown from that Week Two forecast, and the overwhelming strong, positive response garnered from offering that extended prediction.  Of course, we're all aware that a ten day forecast should be viewed as guidance, not gospel - there will be changes needed, just like there always have been to forecasts.

Just how accurate can you expect the ten day forecast to be?  If you watch NECN often, or read my online posts, you know that one of the big things I look at regularly is "predictability" - that is, how much agreement on a particular forecast solution is there?  Sometimes, we see excellent predictability from far in advance - I've made plenty of forecasts from two weeks out that have verified.  Then again, sometimes we see very low predictability on a given day or weather event, and this can sometimes remain very low, even as we near the day, which is why there are days in New England weather that may be as much as ten or, very rarely, even fifteen degrees off our forecast for the next day!  The key to finding the right length of forecast period is to examine average error of the forecast, rather than the exceptionally good or bad forecasts.

Back in the 1970s, a three day forecast saw a 6 to 6.5 degree error.  Today, the error at Day 3 is closer to 3.5 degrees.  The five day forecast has seen a similar improvement, with Day 5 verifying at about a 7 to 8 degree error when it began in the 1970s, and now closer to 4.5 to 5 degree error.  Seven day forecasts are more recent, and therefore haven't seen such a substantial improvement, but since the 1990s have gone from a 6.5 degree error to a 5.5 degree error.  In the summer months, our NECN Weather Team has verified closer to 4.5 degrees as an average error at Day 7.

So...what do we expect for Day 10?  I expect an error of approximately 6.5 to 7 degrees is a reasonable estimate, though I hope reality will be even better.  Regardless, that's the equivalent of what the three day forecast, five day forecast, and seven day forecast all saw when they first debuted - in other words, the time has come to make this advancement.  It seems reasonable that if we can give you the forecast temperature to within 6 or 7 degrees, on average, at ten days out, this is guidance (not gospel!) that you can use to help plan.  Deep summer heat or a cool down en route?  Should we put in the air conditioner?  Make an order for heating oil?  These are the types of questions I believe you should have guidance to answer from ten days out.

I know I speak not only for myself, but for our NECN Weather Team, when I express our excitement to lead the way in New England weather forecasting - pioneering in the television industry for our area, but also doing so responsibly and after an in-depth evaluation to ensure we'll continue bringing you the same, high-quality forecasts you've become accustomed to from our team.

All My Best,

Matt