Incredible Weekend Weather Comes Courtesy of Large High Pressure

FRONTS_D2The much-advertised beautiful weekend weather has arrived!  Sunshine and mild temperatures will stay in New England through Monday as a large dome of high pressure crests overhead.  High pressure is the term often given to areas of fair weather, because the center of the fair weather cell boasts the highest barometric air pressure in the vicinity.  A high barometer reading comes from increased pressure put on the ground from the molecules in the atmosphere overhead – which are sinking at the center of a high pressure dome.  Sinking air not only increases the pressure on the ground, but also is the opposite of how clouds and precipitation are made – those both require rising air that cools upon ascent, causing condensation that forms the clouds.  So…sinking air means no healthy cloud growth and dry weather – hence, our forecast for the weekend.  The next chance of rain won’t come until this high pressure cell moves far enough away, which will likely be either Monday night or Tuesday.  Until then, a light prevailing wind will allow for sea breezes to develop each afternoon Friday through Sunday, meaning high temperatures may briefly rise into the 70s at the coast each day, then likely cool during the afternoon as the sea breeze intensifies, while inland locales will rise to and even beyond 80 degrees.  It appears a southerly wind may increase enough on Monday to offset the sea breeze, meaning 80 degree temperatures may end up all the way to the coast.  Tuesday’s increased chance of showers and thunder comes with a weakening storm center likely to break into pieces and perhaps give us a dry Wednesday before another piece of energy arrives Thursday into Friday.  From this early view, it looks like that disturbance may move quickly enough to be out by next weekend for good weather on Father’s Day weekend.

High Pressure Locks in an Incredible Weekend for New England

LKN_FRONTS_BOSDMA (3)A sluggish cold front is slowly settling south across the six-state region today and while the front represents the leading edge to drier, comfortable air and delightful weather, the shifting wind from southwest to northwest marking the leading edge of the front is teaming with cold air high in the sky to produce several puffy clouds.  Some of the building clouds Thursday midday and afternoon will yield a few new showers, downpours and thunderstorms, though most of that will be confined to communities near and south of the MA Turnpike, where the most humidity lingers.  By late evening, even Southeast MA and Cape Cod will be done with any showers, though the flow of new, drier air will stall just a bit and this could allow for some patchy fog in far Southern New England the first part of the night…then an increasing wind will usher in the new air and sweep away most areas of fog.  Friday through Sunday look spectacular: dry air, plentiful sunshine, a light wind and mild temperatures.  This time of the year, when the land heats up the ocean is still cool and a sea breeze develops – this weekend will be no exception.  The expected sea breeze is why we’re forecasting highs in the 70s each day at the beaches before dropping during the afternoon, but 80s inland.  The next chance of showers and thunderstorms doesn’t return to New England until Tuesday, with a series of disturbances elevating the chance of showers through midweek, but already looking – at least from this early vantage point – like the weather should improve in time for next weekend.  Here’s hoping!

Chance of Showers to Grow Wednesday and Thursday

LKN_NBCU_POP_D1_NEWENG (2) LKN_NBCU_POP_D1_NEWENG (2)Another epic day has unfolded for New England with sunshine, a busy westerly wind that is holding off any sea breeze from forming and dry air.  With high temperatures around 70, this is about as pleasant of a day as we find in New England.  Well to our west, a series of disturbances are traversing the leading edge to deeper warmth and humidity, and this new air colliding with our existing dry air will eventually spell increasing clouds and showers.  In fact, the first showers will develop in the Green Mountains of Vermont shortly after supper time Tuesday evening, then expand east and southeast during the overnight, bringing scattered showers to most of the six-state region from midnight onward, excepting perhaps Southern CT, RI and Cape Cod.  Wednesday dawns with light rain and fog in Northern New England and clouds, patchy fog with a few showers farther south as a surface warm front, marked by a shifting wind and increase in both temperature and humidity, draws near.  By late Wednesday afternoon, there is question as to the exact placement of the warm front, but our First Alert Weather Team believes it should be somewhere near or north of the MA Turnpike, meaning temperatures will climb through the 70s and near 80 near and south of the Pike, but have trouble breaking much beyond the 60s to near 70 from Northern MA points north, at least until Wednesday evening.  Thursday looks humid with heaviest rain and thunder in the morning, then drier air starts returning to New England, limiting but not totally eliminating the chance of a returning scattered storm Thursday afternoon, then further reducing the chance of showers Friday until, at last, new air will be completely in place for the weekend, delivering incredibly pleasant air much like we started the workweek with…though likely turning even warmer Sunday, at least away from the coast.

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.

Fantastic Air Taking Hold of New England...Scattered Thunder for the North Country

BLOG1Unadulterated blue sky at last returned to all of New England but the Cape and Eastern Maine Monday morning, and while it marks a couple of days of fantastic weather sporting sunshine and mild days for most, there will be some subtle but important exceptions.  The first exception comes Monday afternoon, as a cold and energetic upper level disturbance responsible for a tornado in Ottawa over the weekend and a pocket of snow in Quebec Monday morning drops south and sparks scattered thunderstorms in the North Country of New England.  Thanks to the cold air aloft, these scattered storms will have the potential for not only cloud-to-ground lightning, but also hailstones and perhaps a few pockets of strong wind gusts from Northern VT to The Great Woods of NH to the Mountains of ME.  Elsewhere, a steady breeze from the west will stave off a sea breeze, meaning beaches and interior, alike, will see high temperatures either side of 70 degrees Monday afternoon.  Monday night, not only will scattered storms dissipate in the north, but skies will clear and the wind won’t quit, but it will ease, allowing temperatures to drop in our dry air, bottoming out in the 40s for most of us, with some 30s in sheltered valleys…likely only to produce frost in the far northern reaches of New England, but sure to make a chilly night for one and all.  A quick rebound Tuesday will come with continued sunshine, though by Tuesday evening clouds will increase and some sprinkles late Tuesday evening should become scattered overnight showers, marking the leading edge to warmer, more humid air trying to nose back into New England.  We’re unsure how far north the warmth will spread Wednesday but believe at least Southern New England should be able to break into the 70s or near 80…very unlikely in Northern New England. Thursday would likely continue the warmth but also continue an elevated chance of showers and thunder before another shot of delightful air, akin to the start of this week, arrives in time for next weekend in our exclusive First Alert 10-day forecast.

Mild Air Persists This Weekend, Showers/Storms Gradually Expand

LKN_NBCU_POP_D0_NEWENG (2) LKN_NBCU_POP_D0_NEWENG (2) LKN_NBCU_POP_D0_NEWENG (2)Mild air has, at last, returned to New England and while showers and storms enter the forecast for some and not others, the relatively mild temperatures will persist.  Someplace like Boston is coming off a stretch where 82 of 83 consecutive hours were spent with cloudy or mostly cloudy skies, so the return of sun is much anticipated and appreciated.  Nonetheless, the combination of lingering moisture in the air plus a energetic disturbance aloft will result in building puffy, cumulus clouds Friday afternoon, with some of the puffy clouds growing large enough for a shower anywhere between the MA Turnpike corridor, New London, CT, and the Cape Cod Canal between 2 PM and 7 PM, melting away from sundown onward.  Patchy fog is possible in Southern New England Friday night, particularly near the South Coast, and some fog with low-altitude clouds may need to burn off Saturday morning before another splendid day unfolds.  By late Saturday, enough warmth will build ahead of an incoming disturbance aloft for a few showers and thunderstorms to fire up in the mountains of Northern and Western New England, and we’ll watch the Berkshires, in particular, for possible slow-moving storms capable of localized flooding if they cross the New York State line Saturday evening.  Sunday brings an elevated chance of showers and thunder for most of us, with the potential for localized flash flooding under slow-moving storms expanding into the mountainous terrain of Vermont and Western New Hampshire, and a propensity for afternoon showers and thunder in Central and Eastern New England…though the Cape is likely to stay dry with variable clouds both weekend days.  Even as cooler air arrives early next week in our exclusive First Alert 10-day forecast, temperatures will still reach the 60s to around 70 for daytime highs, before warmth likely rebuilds across New England by the middle and end of the week, making the next 10 days warmer than normal for the six-state region.

On the Cusp of an Incredible Friday...and a Mild Spring Weekend

BLOG1One more disturbance will cross New England before notably drier air moves in for a splendid Friday.  The incoming disturbance is far enough away that Thursday will be dry for nearly the entire day with the exception of the Crown of Maine, where some afternoon showers crop up and may even grow into a strong thunderstorm.  Elsewhere, clouds rule but some breaks of sun from time to time will at least team with a southerly wind to bump temperatures to near or around 70 degrees.  The next incoming disturbance brings the leading edge of showers from about 7 to 9 PM Thursday evening, west to east, respectively, lasting through the night and departing around 3 AM, after generally depositing a quarter to a half inch of rain on Southern New England, but there may be significant variability more and less around more focused bands of rain that develop.  Nonetheless, Friday brings a surge of fresh air that will bring sunshine, highs in the 70s and a fresh breeze in the morning that diminishes later in the day.  Dry air should hold on through most of Saturday before the next disturbance approaches New England by late Saturday and Saturday evening…but the weather pattern will be changed by that point: while the jet stream winds aloft that steer atmospheric disturbances will still be nearby, meaning those disturbances still impact us, the amount of available moisture will be less, meaning fewer and more scattered showers and storms.  The decreased propensity for storms will certainly be on display Saturday, as the chance of showers grows only in the mountains at first during the afternoon, likely taking until evening to build for the rest of New England.  Moisture increases in the atmosphere Sunday, making the setup more favorable for showers and thunder to develop and probably meaning those showers will develop as soon as the morning in Northern New England, and from late morning onward elsewhere, especially away from the immediate coast.  Temperatures should top out in the 70s both weekend days, then drop only slightly to near-normal values early next week before rebounding closer to 80 by the end of the week in our exclusive First Alert 10-day forecast.

Southwestern New England On-Guard for Strong Storms Wednesday Evening

BLOG1Clouds and cool air are holding firm for New England – particularly closer to the coast – and even where splashes of sun emerge today, temperatures will be hard-pressed to surpass 70 degrees.  Nonetheless, another energetic disturbance caught in the jet stream winds aloft – the fast river of air, high in the sky, that steers storm systems – will move quickly from the Great Lakes to the Northeast and Mid-Atlantic, spawning another round of showers, downpours and thunder Wednesday evening.  Severe weather Wednesday evening will be focused mostly in Pennsylvania, New York and New Jersey southward to Washington D.C., but Connecticut is close enough to the action we may see a few severe storms in the Constitution State.  In fact, lower atmospheric winds in Connecticut are favorable for rotating storms, so if the storms can grow strong enough, either straight-line or tornado winds are possible, though the risk is not as high as neighbors to the south. Farther north, the Springfield-Worcester-Boston corridor will see showers developing between 5 PM and 6:30 PM, respectively, ramping up over the course of the evening, but not making it into the northern half of New England as anything more than a couple of showers.  After midnight into early Thursday morning, patchy fog and drizzle will linger, much like it did Wednesday early morning, then lift for mostly cloudy skies but a mostly dry day.  The next quick-moving disturbance arrives Thursday evening and night, once again sparking showers, downpours and thunder across particularly Southern New England as it moves through.  A bona fide break in the action sets in Friday: sunshine, a fresh breeze of new air and mild temperatures for a pleasantly perfect end to a somewhat drab week of weather.  This weekend, we’ve had to increase the chance of showers Saturday afternoon, as a new disturbance looks to move quickly enough to be into New England by the second half of the day, and Sunday continues to look like a day of scattered showers and thunder at any given time.  Next week looks mild from this early vantage point, with high temperatures possibly climbing above 80 degrees by the end of the week in our exclusive First Alert 10-day forecast.

Pattern of Frequent Disturbances for a Few Days

BLOG1Although the disturbance responsible for Memorial Day tornadoes near Dayton, Ohio, dove southeast to the Mid-Atlantic, a related piece of atmospheric energy is moving due east into New England.  The result has been increased clouds, followed by sprinkles…to showers…to rain as Tuesday wears on, even with some thunder in CT, RI and Southeast MA Tuesday evening.  In fact, while severe thunderstorms are most likely in New York, Pennsylvania and New Jersey Tuesday evening, a few of these storms may keep enough strength into Southwest Connecticut to produce localized damage briefly Tuesday evening.  Rain departs Tuesday night, though patchy drizzle and coastal fog will linger into Wednesday morning. After the patchy drizzle early, most of Wednesday should be dry albeit mostly cloudy and, as a result, cool.  In an active weather pattern with the jet stream winds – the fast river of air aloft that steers disturbances – flowing near to New England, each disturbance that moves overhead will raise the chance of showers.  One disturbance brings some showers and thunder Wednesday evening and night, and another brings the same Thursday evening and night, and we’ll watch both for the potential of embedded strong thunderstorms.  Drier air takes hold Friday and Saturday, ensuring sunshine and a great start to the weekend with highs in the 70s ahead of our next disturbance, slated to bring showers and thunder Sunday, though the timing is still to-be-determined, which will be important in understanding just how much of an impact on outdoor plans the showers will have.  Next week our spring stretch will continue, with temperatures near or perhaps slightly above normal.

Mild Memorial Day Air to Disappear by Tuesday

BLOG1Memorial Day remembrances in New England found sunshine and pleasant air, though an upper level atmospheric disturbance diving southeast from Canada may deliver a few isolated showers or a downpour to a very few, select communities in Eastern New England Monday evening as clouds build in response to the passing disturbance.  Just as evening clouds dissipate, new clouds will arrive from the west, ahead of a stronger disturbance responsible for severe thunderstorms and possible tornadoes near Chicago this evening.  Although thunder is a possibility in Southern New England later Tuesday, severe weather will be quite unlikely when the storm center arrives here…first entering as showers by midday Tuesday, then ramping up to a rain for the afternoon into the night, but the limiting factor to thunderstorm strength will be cool air – lots of it.  Highs Tuesday are unlikely to break out of the 50s for many communities and Wednesday, though drier with morning drizzle and an afternoon shower, isn’t likely to be warmer than the lower to middle 60s.  All the while, warmth will be squarely in place and building further north from the Mid-Atlantic states, which may lead to renewed showers or thunder overnight Wednesday night, and again Thursday afternoon as temperatures rise back into the 70s Thursday…and we should see the return of great weather for Friday, Saturday and most of Sunday ahead of the next increased chance of showers and thunder later Sunday into Monday in our exclusive First Alert 10-day forecast.