Returning Humidity Raises Shower and Thunderstorm Chances Again

LKS_NBCU_POP_N0_NEWENG (3) LKS_NBCU_POP_N0_NEWENG (3) LKS_NBCU_POP_N0_NEWENG (3)Remarkably pleasant air remains in place regionwide for New England Wednesday as a small but distinct bubble of high pressure – a fair weather cell – remains parked over the region for one more day.  Warmth and humidity aren’t far away with much of the Eastern U.S. still very much in that classic summer air, so our reprieve will expire soon, but for one more day we enjoy dew point temperatures in the 50s with the only sign of nearby humidity seen in the high-altitude clouds that ride overhead and dim our sunshine at times.  Even with dry, comfortable air, most communities rise into the 80s – lower 80s near the coast before a gentle sea breeze eases temperatures into the 70s by evening, and middle 80s inland.  Clouds will gradually increase overnight Wednesday night as a storm center near James Bay, Canada, winds up and draws a warm front into New England, promoting a south wind that will increase humidity over the South Coast overnight, delivering pockets of clouds and fog to the South Coast by Thursday morning.  Clouds should outnumber sunny breaks for most of New England Thursday with scattered showers developing from west to east across New England, morning to midday, respectively, then continuing to develop in scattered clusters through the afternoon and into the evening as steadily increasing humidity results in embedded thunderstorms.  Although not a clear signal as of this Wednesday morning forecast, there are signs a few of these storms could become strong Thursday evening around Central New England, from Northern MA to Central NH – something we’ll monitor in the coming day.  Although humidity remains high on Friday with more clouds than sun, showers will likely be limited for much of the day without much in the way of a trigger to fire them up, at least until the heating of the afternoon and approach of a cold front late in the day that will lead to some scattered showers and thunder later Friday before another change in air to a pleasant round of summer warmth with fair sky for both weekend days.  Next week, our exclusive First Alert 10-day forecast shows a return of heat with temperatures either side of 90° on many if not all days and while humidity may be slow to build, it will – with high humidity likely to be back in place for the middle and end of the week.

As Heat and Humidity Reach a First Peak Thursday, Some Severe Storms Expected

LKS_SEVERE_OUTLOOK_BOSDMA LKS_SEVERE_OUTLOOK_BOSDMA LKS_SEVERE_OUTLOOK_BOSDMA LKS_SEVERE_OUTLOOK_BOSDMAHeat and humidity reach one peak Thursday, with another expected Sunday – each of the days sporting temperatures into the 90s with dew point temperatures measuring the amount of moisture in the air reaching oppressive values in the 70s, boosting heat index values to around 100°.  In addition, Thursday brings a severe thunderstorm threat during the afternoon and evening from northwest to southeast across New England, though areas south and east of a line from Boston to Providence will probably wait until evening before any storms arise.  The heat isn’t a new story, but does reach a new impact on the body Thursday, reaching dangerous levels for some, making hydration, breaks in outdoor activity and respites in air conditioned places all the more important.  Heat index is often referred to as “feels like temperature,” measuring impact on the body, and represents the body’s decreased ability to cool in hot and humid conditions.  Our bodies are able to cool by sweating, but more specifically, when sweat evaporates the body cools.  With abundant humidity, sweat doesn’t readily evaporate off the body and therefore isn’t as effective at cooling, meaning, under normal humidity conditions, the temperature “might as well be” the heat index value.  From an atmospheric perspective, the abundant heat and humidity provides ample fuel for thunderstorms to erupt as an energetic disturbance aloft couples with a surface cold front to focus storm development from northwest to southeast during the afternoon and evening.  Incoming dry air aloft will couple with increasing elevated wind to promote swaths of damaging wind gusts in Thursday thunderstorms, prompting severe thunderstorm warnings – be ready to seek shelter if storms threaten your community. Keep in mind lightning doesn’t prompt a severe thunderstorm warning like wind and hail do, so remembering “when thunder roars, go indoors,” helps to keep folks safe from regular, non-severe thunderstorms.  Scattered storms will slowly wane overnight Thursday night and less humid air arrives for Friday and Saturday but the heat continues.  Although storms won’t be commonplace Friday and Saturday, isolated storms certainly are possible just about anywhere in New England in the intense heat.  An increasing south wind Sunday will bring a return of oppressive humidity, heat index values around or over 100° and perhaps some scattered afternoon or evening thunder.  More widespread showers and thunder are expected Monday as a cold front “breaks” the heat – we use that term cautiously as temperatures will still reach 85 to 90 degrees for daily highs most of next week in the exclusive First Alert 10-day forecast!

Heat Wave Extends Into Weekend, Strong Storm Potential To Rise

LKS_BOARD_ALERT (3)As our New England heat wave continues unfolding and still looks to be a six day stretch of 90°+ daytime high temperatures for some communities, there are subtleties in the forecast each day that will prove impactful.  Wednesday’s wind is lighter than Tuesday, which means we may see a weak afternoon sea breeze developing and for this reason the immediate coast including the City of Boston may fall a degree or two shy of Tuesday’s highs in the middle 90s, but still should surpass 90° before the sea breeze kicks in.  Humidity is elevated but not outrageous with dew point temperatures in the middle 60s, though that will change Thursday as humidity increases on a southerly wind.  In the interim, New England’s sky will remain mostly sunny, but that doesn’t mean storm-free – one thunderstorm rumbled through Western MA early Wednesday morning after developing Tuesday night over Lake Ontario near the Canada border, there simply was no reason for it to weaken given the ample warmth and moderate humidity.  Similarly, while storms Wednesday will be isolated, anything that does develop will do so in a hot air with cooler air aloft, which is a great recipe for a storm to strengthen, so the phrase “when thunder roars, go indoors” applies with New Englanders encouraged to keep an eye to the western and northwestern sky.  Thursday’s thunderstorm chance appears mostly focused in the afternoon and evening for Northern/Western New England and Central/Southern New England, respectively, as a weak cold front crosses New England and triggers those storms.  The increased humidity Thursday would aid in making any of those storms capable of packing a punch with wind and hail, in addition to lightning, but outside of any storms the humidity’s widespread impact will be to drive up the heat index, making highs in the 90s feel like either side of 100°.  Although most of this hot stretch doesn’t qualify as dangerous, Thursday afternoon’s heat will, making hydration and breaks to avoid overexertion important.  Humidity is expected to lower noticeably Friday for all but the South Coast, but it won’t be dry enough to squash an isolated thunderstorm chance, which still will exist through the day, with a similar day expected Saturday before humidity spikes again Sunday and another round of more organized storms are possible late in the day.  Interestingly, even with this extended heat, our First Alert Team is not predicting any record high temperatures at this point – this week of July historically is our warmest week of the year, on average, and that means we’ve seen some hot July days, with records ranging from 99° to 103° depending on the day.  One possible warm record that may be set would be Friday or Saturday overnight low temperature, but that’s not a lock, and if our forecast high temperature continues to climb for Sunday or Monday – currently predicted to be 94° and 89°, respectively – we’d push close to the records of 98 (from 1933) and 96 (from 1882), respectively.  While the deepest of the heat should break heading into next week, our First Alert 10-day forecast still shows temperatures of 85 to 90 degrees most of the week!

Why the Ocean Water Is So Cold at the North Shore and Cape Ann, Massachusetts, So Far This July

LKS_OCEAN_TEMPERATURESOne of the most common weather questions I’ve been receiving lately comes from residents along the North Shore and Cape Ann: why is the ocean water still so cold?  It’s not your imagination – ocean water temperatures from Boston Harbor points north have been exceptionally cold this summer, after a fairly typical start to the warmer water season in the spring.  As of this writing on July 19, the water temperature at Wells Beach, Maine, is 63° but Portsmouth is only 59° and the ocean water is similarly at or below 60° all the way into Boston Harbor!  Believe it or not, Portsmouth averages 60° water this time of the year, but Boston Harbor should be running either side of 67°, which is why North Shore and Cape Ann residents are especially sensitive to the cold water this late in the season. The cooling ocean water really became noticeable after the first week of July as two phenomenon occurred back-to-back to send water temperatures spiraling.  First, a feed of colder water sliding south down the Maine coast surged along the Cape Ann shoreline and entered Boston Harbor from the north.  Interestingly, ocean currents helped the water miles offshore recover fairly quickly over the last two weeks, but closer to shore, not only was a cooler pocket of water trapped, but a new phenomenon took hold: upwelling.  Upwelling is a common occurrence for any coastal community near the open ocean – when the wind blows from off the land, usually a northwest, west or southwest wind in New England, that wind pushes the skim of relatively shallow, milder ocean water out to sea.  The void left behind near the shoreline has to be replaced, so new water rises up from deeper, colder ocean levels to replace it, causing a drop in water temperature near the shoreline.  This July has been exceptional because right after we saw the push of a cold pool of water from the northeast, a steady supply of warm air has come surging into New England, arriving on a southwest and west wind.  Even when cold fronts come through and break the warmth, the wind still blows from the northwest.  All of this means the surface skin of ocean water keeps getting blown away and upwelling continues repeatedly along the coast.  If the wind relaxes, or sea breezes set up for a few days, this would allow much milder water sitting miles offshore to blow back into our beaches…that change in wind just hasn’t happened yet.  As you might expect, there are many New England coastal locales who benefit from warmer water in a pattern like this: the South Coast!  From New Haven, Connecticut, all the way to the South Coast of Cape Cod, water temperatures in the middle 70s are running 1-3° warmer than normal, as the shallow, mild water over Long Island Sound, Block Island Sound and both Vineyard and Nantucket Sounds is blown into the shoreline by the persistent wind.  Chances are good that when the weather pattern allows for a relaxed wind and sea breezes develop – or if we get a few days of an easterly wind – you’ll see those North Shore and Boston Harbor water temperatures rebound fairly quickly.  We’ll keep an eye out for those changes and keep you posted in our weather broadcasts on-air and online on NBC10 Boston, NECN and Telemundo New England’s First Alert Team.

Pleasant Air Fades Only Briefly to Warmth on Friday

LKS_FCST_HIGHS_D0_NEWENG (14) LKS_FCST_HIGHS_D0_NEWENG (14) LKS_FCST_HIGHS_D0_NEWENG (14) LKS_FCST_HIGHS_D0_NEWENG (14) LKS_FCST_HIGHS_D0_NEWENG (14) LKS_FCST_HIGHS_D0_NEWENG (14)Pleasant and comfortable air is entrenched regionwide in New England Thursday, but that doesn’t stop the puffy, cumulus clouds from developing.  In addition to making a picturesque blend with sun at times and blotting out the sun at others, some of these fair weather clouds grow large and heavy enough to drop a few stray sprinkles Thursday midday and afternoon across interior New England.  Nonetheless, the comfortable air will remain in place Thursday evening and night under variable clouds ahead of a meaningful shift in wind direction Friday.  After a south-southeast wind Thursday and Thursday evening, a southwest wind takes over Friday which does two things: 1) It transports warmer air into New England and, 2) It diminishes the cooling impact of the ocean for all by south-facing coastal locales.  The result will be a return to daytime high temperatures well into the 80s and building humidity, particularly in Southern New England and especially in the afternoon.  There are two possible triggers for showers and thunder Friday, but they don’t line up for a widespread and significant event, instead coming through separately.  In the late morning through early afternoon, a weak disturbance aloft ripples overhead at the jet stream level, prompting clouds to build and some isolated or widely scattered showers to develop.  By late afternoon to evening, the cold front at ground level swings from north to south across New England, meaning new widely scattered to scattered showers and thunderstorms are a possibility until the front clears off the New England coast Friday evening, opening the door to yet another fresh installment of dry and pleasant air that will last through the weekend.  Thousands of feet above our heads, the change in air actually may take several hours longer, which is why some clouds will probably linger over most of Southern New England Friday night and near the South Coast including the Cape and Islands Saturday morning, but even those clouds should press south by Saturday afternoon, affording sunshine regionwide that will last through Sunday, Monday and into Tuesday.  An onshore wind from the northeast and east both weekend days will mean high temperatures in the 70s at the coast and just over 80° inland, but a wind shift to blow from the south and southwest Monday into Wednesday will mean more widespread warmth well into the 80s and even 90s for some, with gradually increasing humidity, particularly noticeable Tuesday and Wednesday, priming the atmosphere for an increased chance of thunderstorms.  As the next cold front and upper level disturbance approach simultaneously at midweek, thunder will become more likely in Northern New England Tuesday, then for most of New England Wednesday and Thursday, with a chance of scattered showers or thunder lingering into next weekend.

Independence Day Delight!

LKS_1PART_SKY_FENWAY (3) LKS_1PART_SKY_FENWAY (3) LKS_1PART_SKY_FENWAY (3) LKS_1PART_SKY_FENWAY (3) LKS_1PART_SKY_FENWAY (3)Delightful, picture-perfect weather has unfolded regionwide in New England on this Independence Day!  A large dome of “high pressure” – sinking air that is the opposite of what’s needed for cloud development – has delivered dry air for a bright and pleasant summer day.  The only exception to our dry Fourth may be during the evening in the Crown of Maine – far northern Maine – where an energetic disturbance aloft may touch off an evening shower or thunderstorm.  Otherwise, after temperatures topping out in the middle 80s for many and lower 80s at the coast where a sea breeze kicks up for the midday and afternoon, Monday evening fireworks will explode under perfect weather: a partly cloudy sky with any clouds high in altitude, great visibility, temperatures in the 60s to around 70 and just enough light breeze to keep firework smoke moving so the displays will be seen and enjoyed.  The rest of the night will bring increasing clouds and temperatures dropping to the 50s north and lower 60s south ahead of an approaching disturbance aloft that will be working with limited moisture but should be able to wring out a shower or two Tuesday morning in Central New England with Tuesday morning to midday showers more likely in the North Country.  Farther south, rain is unlikely for most of Tuesday but a veil of high-altitude clouds will dim the sun through the day and eventually lower and thicken during the afternoon, leading to increasing showers Tuesday evening and night into Wednesday.  Wednesday’s precise forecast details hinge on the exact timing of a “backdoor cold front” – a cold front approaching from the opposite direction from most cold fronts, arriving from the northeast – as this shift in wind will bring sharply cooler air and start squashing out any scattered showers.  At this point, our First Alert Team expects the cold front to arrive late Wednesday morning after an early high temperature in the 80s, cooling through the afternoon.  Cool and dry air is expected Thursday – though even cool air this time of the year can mean high temperatures in the 70s – and one more approaching disturbance Friday may touch off a few late day showers or storms before delivering yet another shot of cooler-than-normal and dry air for the weekend.  The early call for next week in our exclusive First Alert 10-day forecast is a return of deeper warmth and humidity gradually during the first half of the week, culminating in midweek storms as a cold front approaches.

Independence Day Weekend Brings Classic Summer Weather to New England

LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1) LKS_LIFESTYLE_BEACH (1)With the Independence Day holiday weekend upon us, most New Englanders not only are prepared for heat, but expect it – this year won’t disappoint.  Friday’s high temperatures in the middle 90s for some don’t reach dangerous levels dangerous, particularly with limited humidity much of the day keeping any potential for heat index (elevated “feels like” temperatures) in check, but certainly those with outdoor plans can be impacted by the heat, with hydration and sunscreen two big essentials.  The breeze will increase from the southwest Friday midday and afternoon with the arrival of a weak warm front – the leading edge to increasing humidity – and not only will New Englanders feel the humidity steadily rising during the afternoon and evening, but an isolated thunderstorm or two may develop on the leading edge to that more humid air, particularly from Southern to Central New England between 2pm and 6pm Friday evening.  Thereafter, clouds will gradually fill in overnight Friday night with a muggy and mild night, then showers, downpours and thunder will arrive in scattered form from west to east after midnight, toward dawn.  Saturday likely will dawn with at least some pockets of showers, downpours and thunder, and while the entirety of the day won’t rain, much of the Southern half of New England will see recurring showers, downpours and thunder from time to time over the course of the day, morning until early evening.  Northern New England improves dramatically after lunch Saturday as new, drier air arrives, with the leading edge of that new air – a cold front – triggering the final round of downpours and thunder when it arrives to Southern New England from mid-afternoon in Southern NH and Northern MA to early evening at the South Coast.  With the passage of the cold front later Saturday, the door opens to a brand new air that will not only lower the risk of showers and thunder substantially for July 3rd and 4th, but will also provide lots of comfort and terrific weather for fireworks on both nights with evening temperatures in the 70s and dry weather expected.  Next week is a classic early July week in our exclusive First Alert 10-day forecast, with scattered storms on some afternoons – particularly Tuesday, Friday and Saturday – and high temperatures either side of 80.

A Few Showers With Splashes of Sun...the Weekend Warmth Unfolds

LKS_FCST_HIGHS_D0_NEWENG (11) LKS_FCST_HIGHS_D0_NEWENG (11) LKS_FCST_HIGHS_D0_NEWENG (11) LKS_FCST_HIGHS_D0_NEWENG (11) LKS_FCST_HIGHS_D0_NEWENG (11) LKS_FCST_HIGHS_D0_NEWENG (11) LKS_FCST_HIGHS_D0_NEWENG (11) LKS_FCST_HIGHS_D0_NEWENG (11)New England remains in a repetitive weather pattern for the last half of the week, with overnight and morning stretches of clouds and fog breaking for a blend of sun and clouds with isolated to widely scattered sprinkles and light showers popping up during the middays and afternoons as temperatures rebound into the 70s.  This pattern holds through Friday, when, yet again, pockets of clouds will start the day but sun will emerge and some inland communities will touch 80° by afternoon.  The pattern of scattered sprinkles and showers will end Saturday, as a stubborn and large storm center that’s been stalled southeast of New England nudges east and allows a change in 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.  With the change in the jet stream will come a sea change of air – new, warm, humid air arrives Saturday with high temperatures boosted into the 80s regionwide with some inland communities touching 90 in the afternoon as a sea breeze kicks up at the coast after our beaches reach the 80s.  Sunday looks similar, with a continued increase in humidity but no sufficient trigger for thunderstorms in most of New England, except in the mountains of Northern New England where an isolated Sunday afternoon storm may pop up from “differential heating” – a difference in temperature from mountaintop to valley that can serve to initiate isolated storms.  Monday brings a more widespread storm instigator: a cold front crossing New England from northwest to southeast that will be slow enough for most of the six-state region to experience another very warm and humid day, but prompting a number of showers, downpours and thunderstorms.  Behind the cold front, less humid and cooler air sets up for Tuesday, when an early shower can’t be ruled out but the trend should be toward drying and fair weather through the middle and end of next week, when heat and humidity will start a return to New England.  The start of the July Fourth holiday weekend is on the 10-day forecast and right now our First Alert Team expects the weekend to start with temperatures in the 80s, humidity and a chance of thunderstorms, but we’ll continue to roll out the rest of the holiday weekend in the two days ahead.

Drought Rolls On As Rain To Lack Organization in Days Ahead, Weekend Warmth on Track

Although some showers fell in the Western half of New England Wednesday morning, Eastern New England started with clouds for many and sun near the coast. With an onshore wind, it’s a bit usual to have the driest air near the coast, but a slow-moving, large upper atmosphere storm center swirling southeast of New England has captured some dry air and carried it west into New England, caught in the counter-clockwise flow of air around the storm.  As a result, clouds will persist in Western New England Wednesday but will give way to increasing sun in Eastern New England, with a few showers in the morning diminishing for the afternoon, but an onshore wind meaning high temperatures only around 70 near the coast and 70-75° - cooler than recent days – inland.  Variable clouds Wednesday night into Thursday will mean while a few showers crop up from time to time, particularly toward midday and afternoon, no organized slug of rain is expected to develop.  Limited organization to rain has really been the trend of the forecast over the last couple of days – from days out, it looked like the storm southeast of New England would throw at least one or two slugs of rain over New England for the end of the week, but as the storm positions itself and pulls in chunks of drier air, the forecast undoubtedly has taken on a tone of occasional showers instead.  This time of the year, with the strongest sun angle, that also makes a difference on temperature – if you can get breaks of sun to emerge, temperatures can easily nudge into the 70s.  Deep heat has been building in the nation’s midsection while New England has stayed cooler thanks to the nearby storm inducing a northerly wind flow through a deep layer of the sky, but as the storm finally shifts east, the window will open for a warmer, southwest wind into New England that will carry both heat and humidity into the Northeast US this weekend.  High temperatures both weekend days should climb at least into the 80s, with 90s likely for some inland while sea breezes may kick up each afternoon along the coast.  Right now, any chance for thunderstorms looks limited until a slow-moving cold front arrives Monday with showers and thunder, likely to squash the humidity for a few days heading into the middle of next week but not carrying much cool air, with seasonable temperatures lasting through next week and deeper summer warmth attempting a comeback by week’s end.

U.S. Open Forecast in Focus: Chances for Showers and Thunder

LKS_LIFESTYLE_GOLFThe U.S. Open has arrived to New England with all eyes of the golf world on The Country Club in Brookline, Massachusetts!  June in New England always begs the question of whether the weather will cooperate with outdoor plans, and this weekend is no exception.  The simple answer: for the most part the weather will cooperate.  The forecast actually runs a higher risk of inaccuracy than usual heading into the Thursday and Friday timeframe to kick off the tournament play – thunderstorms the last few days where our weather is coming from in the Great Lakes, Midwest and Upper Ohio Valley have been fickle for forecasters, erupting hours ahead of schedule for some, and missing locations by a wide margin for others.  The reason for this decrease in predictability to our west has hinged on the trigger for thunderstorm development: disturbances aloft interacting with a steady flow of increasingly warm and humid air on the northern periphery of a large dome of hot weather across the heart of the Lower 48.  Thursday and Friday, New Enlgand will find ourselves on that northern fringe, meaning our chance of showers and thunder increases overall, but now we need to answer the question of which disturbances will trigger showers and thunder, and we’ll hope for better reliability than has been observed to our west!  The first opportunity for showers expands from Western New England Wednesday evening and night to Central and Eastern New England Thursday morning, including Brookline and The Country Club with a chance of showers the first half of Thursday.  Likely to lack the energy needed for thunderstorm development, these showers should be relatively light and scattered in nature, coming to a close before lunch and leaving behind an afternoon of sun breaking through clouds and temperatures in the 70s.  Thursday afternoon, thunderstorms will develop in Upstate New York and migrate east Thursday night at the same time deeper humidity is building into New England – a great combination to keep downpours and thunderstorms going, meaning the chance of overnight Thursday night storms is elevated for most of Southern New England, but the timing is such that most of the storms should be gone by early Friday morning.  Nonetheless, the job of delivering humidity to The Country Club will be complete, meaning Friday brings steamy humidity with temperatures nearing 90 degrees on the golf course before an approaching cold front results in towering clouds Friday afternoon that will develop into scattered downpours, then thunderheads, Friday middle to late afternoon into evening.  As with any thunderstorm event, the exact placement will be critical, but there’s no question the chance of thunder is elevated later in the day.  The approaching cold front will swing through the Boston area Friday night, bringing a return to comfortable air for the weekend, which means Saturday and Sunday’s forecast looks great for golf, overall – highs in the 70s and lower humidity.  The only trick to the weekend setup is the jet stream level energy – high in the sky, several thousand feet above our heads – will still be left overhead and this will encourage building, puffy, fair weather “cumulus” clouds Saturday afternoon that very well may yield a few scattered light showers – a 20-30% chance of these over the Country Club, via our exclusive NBC Forecast System.  Any Saturday afternoon showers would be scattered and unlikely to have a significant or prolonged impact on golf, and by Sunday the shower chance drops further as the energy aloft moves away from New England and pleasant air continues.