DAYS 1-5 (MAY 22-26)

Summer preview, day 2, today, with high pressure off to the south and a warm southwesterly air flow in place (South Coast / Cape Cod cooler as usual). Today we see more sun than yesterday, and late-day showers and thunderstorms that develop to the north and west will do so further upstream and not make their way into southern NH and northern MA as they did last evening – even more significant than I had expected them to. Thursday, a cold front moves into the region, but slowly enough that we get another 80-degree plus day for much of the region. But that warmth does add fuel for the storms that while may not be widespread, can be heavy in some areas, along with the slight potential for isolated severe storms – wind damage primary threat / hail secondary threat. Any activity moves out in the evening, but the front responsible for them will be a little sluggish, and a follow up low pressure wave can cause another swath of showers especially for the South Coast region sometime during the first 12 hours of Friday. Some guidance has this occurring further south and Friday completely dry. This is a possibility as well. Final fine-tune on next blog. Either way, drier air arrives Friday and for the start of the Memorial Day Weekend on Saturday, with temperatures closer to seasonable, though still a little above normal. When we get to Sunday, a weak disturbance from the west may trigger a few showers, but otherwise that day looks mostly fair. Plenty of time to focus in on that potential as we get closer to it.

TODAY: Early clouds exit Cape Cod. Fog / stratus patches southwestern NH, north central MA, and eastern CT vanish by mid morning. Plenty of sun. Evening cloud patches arrive from the west. Highs ranging from 58-65 Cape Cod / Islands / immediate South Coast to 85-92 I-95 belt westward, with a sharp gradient between. Wind SW increasing to 10-20 MPH.

TONIGHT: Partly cloudy. Lows 55-62. Wind SW 5-15 MPH.

THURSDAY: Variably cloudy. Scattered showers and thunderstorms, primarily in the afternoon, with some strong to locally severe storms possible. Highs 80-87 except cooler South Coast / Cape Cod. Wind SW 5-15 MPH but locally variable, stronger, and potentially damaging winds in any storms.

THURSDAY NIGHT: Clouds linger. Chance of showers mainly South Coast. Lows 55-62. Wind shifting to NW 5-15 MPH.

FRIDAY: Clouds and a rain chance South Coast early, otherwise a sun/cloud mix. Highs 66-73. Wind NW 5-15 MPH.

FRIDAY NIGHT: Clearing. Lows 48-55, coolest interior valleys. Wind NW up to 10 MPH.

SATURDAY: Sunny to partly cloudy. Highs 66-73. Wind W 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Lows 50-57. Wind SW up to 10 MPH.

SUNDAY: Partly to mostly cloudy. Chance of a shower. Highs 68-75. Wind SW 5-15 MPH.

DAYS 6-10 (MAY 27-31)

Memorial Day (May 27) watch for low pressure to approach with a chance of showers before the end of the day. Additional showers and potential thunderstorms May 28 as a trough / cold front move across the region. Generally fair weather with high pressure in control May 29-31 based on current medium range expectations.

DAYS 11-15 (JUNE 1-5)

Weak upper low trends to hang around Great Lakes / Northeast with a couple disturbances bringing shower chances and variable temperatures with no extremes.

DAYS 1-5 (MAY 21-25)

A summer preview takes place the next couple days with high pressure off to our south and and upper level high pressure ridge on the East Coast. This allows Boston to hit 80 for the first time this season (average first date May 4, so behind that by quite a bit), likely today, definitely tomorrow. A prevailing southwesterly wind flow will be, of course, a cooling influence for the South Coast and Cape Cod. Other than fog patches and low clouds in some areas for a while this morning, and a repeat of this tonight / early tomorrow morning, the weather will be generally fair regionwide both days. One other potential exception is with a disturbance moving into northern New England from the west this evening with showers and thunderstorms, a couple of these can migrate as far south as southern NH, so keep an eye out for that. Wednesday’s shower and thunderstorm activity with an approaching cold front should stay well to the west and north of our region. That cold front does move across the region on Thursday. Trends have been a little faster and weaker for the front, so while there is a chance of the development of some showers and thunderstorms that day, they may be earlier and less widespread, with the main focus / trigger having gone by before prime heating time. Will keep an eye on that. A later arrival and efficient heating ahead of the front would increase the potential for heavier showers and stronger thunderstorms. Still eyeing the potential for a follow up low to bring at least a chance of rain for a portion of Friday. As we get into the start of the Memorial Day Weekend on Saturday, we will be in a west southwesterly air flow with a weak upper trough in the region. This will be why I can’t make Saturday’s forecast “sunny”, but I’m also thinking it won’t be that bad. With a disturbance maybe moving in quickly from the west I’m going to add the chance of a shower, but don’t cancel any plans now.

TODAY: Areas of low clouds / fog into mid morning otherwise filtered sun with variable high clouds, then more abundant sun during the afternoon before other clouds arrive from the west later in the day. The slight chance of an evening shower or thunderstorm across portions of southern NH. Highs range widely from near 60 Cape Cod to 80-87 I-95 belt westward. Wind SW 5-15 MPH.

TONIGHT: Variably cloudy. Areas of fog overnight. Lows 53-60. Wind SW diminishing to under 10 MPH.

WEDNESDAY: Fog / low cloud areas early, otherwise mostly sunny. Highs range from near 65 Cape Cod / South Coast to 83-90 I-95 westward. Wind SW increasing to 10-20 MPH.

WEDNESDAY NIGHT: Partly cloudy. Lows 55-62. Wind SW 5-15 MPH.

THURSDAY: Variably cloudy. Chance of showers and thunderstorms. Highs 75-82, cooler South Coast. Wind SW 5-15 MPH shifting to W.

THURSDAY NIGHT: Clouds linger. Lows 50-57. Wind NW 5-15 MPH.

FRIDAY: Cloudy. Chance of rain. Highs 58-65. Wind NE 5-15 MPH.

FRIDAY NIGHT: Clearing. Lows 48-55. Wind N up to 10 MPH.

SATURDAY: Variably cloudy. Chance of a shower. Highs 63-70. Wind W 5-15 MPH.

DAYS 6-10 (MAY 26-30)

Leaning fair May 26 then unsettled May 27 (Memorial Day) as another disturbance arrives from the west. Additional unsettled weather May 28 before a drying trend. Temperatures slightly variable but overall close to normal.

DAYS 11-15 (MAY 31 – JUNE 4)

Weak upper low trends to hang around Great Lakes / Northeast with a couple disturbances bringing shower chances and variable temperatures with no extremes.

DAYS 1-5 (MAY 20-24)

This work week’s weather pattern will be quite different from the one we saw last week. Today, high pressure builds to our south and will strengthen there into midweek, while an upper level ridge builds along the East Coast. The transition today may seem a bit slow to get started as the region starts the day blanketed by clouds along with some patches of fog, but improvement will come as the clouds begin to erode, though they may hang on longest over Cape Cod. Tuesday and Wednesday will present the feel of early summer away from this ocean influence, and sunshine will be abundant both days. Tuesday and/or Wednesday you may notice some cloudiness in the western and northwestern sky later in the day, and this will be the result of upstream showers and thunderstorms generated by the sun’s heating and some instability closer to a frontal boundary moving into and through the Great Lakes region. We won’t hear from that front until Thursday when it moves into and across New England, bringing the chance of showers and thunderstorms. It’s a bit early to call how widespread and heavy these may be, so check updates over the next few days as I fine-tune this part of the forecast. Friday’s forecast is a bit of a question mark. The pattern reminds me of one that leaves Thursday’s cold front just to our south and allows a wave of low pressure to ripple along it. This may result in the chance of some rainfall on that day. If it doesn’t materialize and the front chugs further offshore and high pressure is strong enough, all bets are off on the rain chance and Friday is fair and pleasant. I am leaning toward the wet forecast right now, but don’t be surprised if this changes…

TODAY: Fog patches until mid morning, otherwise a sun/cloud mix, with clouds most dominant over Cape Cod. Highs 55-60 Islands / Cape Cod, 60-65 South Coast and immediate eastern coastal areas, 65-70 I-95 belt, 70-75 west of I-95 belt. Wind variable up to 10 MPH becoming SE.

TONIGHT: Clear. Lows 51-58. Wind SE to S under 10 MPH.

TUESDAY: Sunshine dominates, but some clouds arrives from the west late. Highs range widely from near 60 Cape Cod to 80-87 I-95 belt westward. Wind SW 5-15 MPH.

TUESDAY NIGHT: Partly cloudy evening, then clear. Lows 52-59. Wind SW 5-15 MPH.

WEDNESDAY: Sunny until late day when a few clouds return from the west. Highs range from near 65 Cape Cod / South Coast to 83-90 I-95 westward. Wind SW 10-20 MPH.

WEDNESDAY NIGHT: Partly cloudy. Lows 55-62. Wind SW 5-15 MPH.

THURSDAY: Variably cloudy. Chance of showers and thunderstorms. Highs 68-75, cooler South Coast. Wind SW 10-20 MPH.

THURSDAY NIGHT: Clouds linger. Lows 50-57. Wind NW 5-15 MPH.

FRIDAY: Cloudy. Chance of rain. Highs 58-65. Wind NE 5-15 MPH.

DAYS 6-10 (MAY 25-29)

Outlook is for fair weather 2/3 of the Memorial Day Weekend with the next shower threat potentially on May 27, but may hold off until the day after. Fair weather returns end of period. More seasonable temperatures but somewhat variable.

DAYS 11-15 (MAY 30 – JUNE 3)

Last couple days of May look fair, early part of June maybe a shower threat. Temperatures variable, but close to normal overall with no major extremes.

COMMENTARY

Horrible forecast yesterday. No excuse, but the reason for me (and according to NWS discussion, others as well), extremely poor performance by short range guidance in picking up conditions that produce more widespread and persistent rainfall than they were indicating. A forecaster from NWS Boston noted that even the “best performing” piece of guidance was inadequate and far under-forecast the scope of the rainfall. Ouch. I gave a couple of forecasts to people for outdoor events that were less than accurate, to put it nicely, though the events worked out fairly well anyway. Still, not a good feeling when that happens! But, we move forward…

DAYS 1-5 (MAY 19-23)

Since the synoptic conditions haven’t changed all that much today from yesterday, today’s short term forecast is a little less optimistic than I indicated just 24 hours ago. No I don’t think we’re in for a repeat of the rainfall, but an overcast morning with drizzle patches and areas of fog may only improve very slightly, and I can’t rule out pop up showers at any time, as low pressure sits to the south and a fresh feed of Atlantic moisture remains in place. Finally, this begins its exit this evening as high pressure starts to shift in from the southwest and overtake our weather. While some lingering cloudiness is likely to be around Monday, expect a much nicer day overall with fair weather and it turning considerably warmer than the weekend was. This trend will continue for Tuesday and Wednesday as high pressure sits just to our south and puts us in a warm southwesterly air flow. This will give us a preview of summertime with many areas going over 80 for high temps. This, of course, will be a lot harder to achieve closer to the South Coast and over Cape Cod where a southwest wind is a direct ocean wind and the cooler water will have a significant modifying influence. Thursday, the temperature forecast will depend on the speed of an incoming cold front, which will bring the chance of showers and thunderstorms, along with associated cloudiness. Details TBD.

TODAY: Cloudy. Areas of drizzle/fog. Chance of a shower. Highs 56-63, coolest coast. Wind E to SE 5-15 MPH.

TONIGHT: Breaking clouds. Patchy fog. Lows 49-56. Wind SE to S up to 10 MPH.

MONDAY: Variably cloudy South Coast to MA South Shore / more sun elsewhere. Highs 62-69 South Coast to MA South Shore, 70-77 elsewhere. Wind S to SW 5-15 MPH.

MONDAY NIGHT: Partly cloudy. Lows 51-58. Wind S to SW up to 10 MPH.

TUESDAY: Sunny. Highs ranging from near 60 Cape Cod to 81-88 Merrimack Valley, interior MA, southern NH. Wind SW 5-15 MPH.

TUESDAY NIGHT: Clear. Lows 52-59. Wind SW 5-15 MPH.

WEDNESDAY: Sunny. Highs ranging from near 60 Cape Cod to 81-88 Merrimack Valley, east central to central MA, southern NH. Wind SW 10-20 MPH.

WEDNESDAY NIGHT: Partly cloudy. Lows 53-60. Wind SW 5-15 MPH.

THURSDAY: Variably cloudy. Chance of showers and thunderstorms. Highs 68-75, cooler South Coast. Wind SW 10-20 MPH.

DAYS 6-10 (MAY 24-28)

Models may not yet see what turns out to be a rain threat from passing low pressure on May 24, followed by fair weather to at least start and get into the Memorial Day Weekend, with the potential for the next shower threat around Memorial Day itself, unless a slower pattern holds it off til the end of the period. Will monitor the trends. Temps will be typically spring variable.

DAYS 11-15 (MAY 29 – JUNE 2)

Last few days of May look fair, early part of June maybe a shower threat. Progressive pattern – variable temperatures not straying too extremely.

DAYS 1-5 (MAY 18-22)

A little weather toll booth stop today – a day that I thought would remain dry just a couple days ago, but for most places won’t be 100% dry after all. That said, we’re not looking at a Saturday wash-out either, just some scattered showers and patches of drizzle as low pressure offshore sends some moisture back our way via the Atlantic. This threat will last into tonight and even the very early portion of Sunday before it’s gone again, but there will also be plenty of precipitation-free time during this as well. It’ll remain on the cool side with the air flow off the Atlantic this weekend. The first few days of the upcoming week we will see a transition to fair, warmer weather as high pressure becomes established to our south and the next frontal boundary stays well to the west and north of our region.

TODAY: Cloudy. Patchy drizzle / isolated to scattered showers. Highs 56-63, coolest coast. Wind E 5-15 MPH.

TONIGHT: Cloudy. Patchy drizzle / chance of a shower. Lows 48-55. Wind E to SE 5-15 MPH.

SUNDAY: Mostly cloudy to partly sunny. A shower or patch of drizzle early. Highs 60-67, coolest coast. Wind SE 5-15 MPH.

SUNDAY NIGHT: Partly cloudy. Lows 51-58. Wind S up to 10 MPH.

MONDAY: Variably cloudy South Coast to MA South Shore / more sun elsewhere. Highs 62-69 South Coast to MA South Shore, 70-77 elsewhere. Wind S to SW 5-15 MPH.

MONDAY NIGHT: Partly cloudy. Lows 51-58. Wind S to SW up to 10 MPH.

TUESDAY: Sunny. Highs 78-85 except 70-77 South Coast / Cape Cod. Wind SW 5-15 MPH.

TUESDAY NIGHT: Clear. Lows 52-59. Wind SW 5-15 MPH.

WEDNESDAY: Sunny. High s78-85 except 70-77 South Coast / Cape Cod. Wind SW 10-20 MPH.

DAYS 6-10 (MAY 23-27)

Not high confidence on any details, but the general idea is that a cold front brings a shower or thunderstorm chance May 23, a follow up low pressure area brings a chance of rain May 24, then fair weather follows for the first couple days of the Memorial Day Weekend (May 25-26) before a trough brings a shower threat sometime on Memorial Day itself (May 27).

DAYS 11-15 (MAY 28 – JUNE 1)

Unsettled weather early period, then a progressive pattern brings drier weather back, but watch for another front with shower / t-storm chance later in the period.

DAYS 1-5 (MAY 17-21)

We’ll remain in a general easterly air flow off the Atlantic through the weekend, with varying amounts of clouds dominating over clearer sky, but very little threat of wet weather. It is only sometime tonight and into Saturday morning that some moisture from the east can result in areas of drizzle and/or a few showers. Much of the time from today through Sunday will be free of any precipitation threat. It will be on the cooler side though, especially the closer to the coast you are. This weather pattern comes about as we see a block with high pressure to the north and low pressure to the south. But the pattern breaks down early next week and high pressure moves over us on Monday, then south of us on Tuesday. This is when we see fair weather and a warming trend.

TODAY: Clouds dominate / intervals of sun. Highs 58-65, coolest near coast. Wind E up to 10 MPH.

TONIGHT: Mostly cloudy. Periods of drizzle and possibly a shower, especially eastern MA and NH Seacoast. Lows 47-54. Wind E up to 10 MPH.

SATURDAY: Mostly cloudy with patchy drizzle and maybe a shower in the morning. Clouds break for sun at times during the afternoon. Highs 60-67, coolest coastal areas. Wind E to SE up to 10 MPH.

SATURDAY NIGHT: Variably cloudy. Lows 49-56. Wind SE up to 10 MPH.

SUNDAY: Variably cloudy. Highs 60-67, coolest coast. Wind SE up to 10 MPH.

SUNDAY NIGHT: Partly cloudy. Lows 51-58. Wind S up to 10 MPH.

MONDAY: Partly cloudy. Highs 68-75, cooler South Coast. Wind S 5-15 MPH.

MONDAY NIGHT: Partly cloudy. Lows 51-58. Wind S to SW up to 10 MPH.

TUESDAY: Mostly sunny. Highs 75-82, cooler South Coast. Wind SW 5-15 MPH.

DAYS 6-10 (MAY 22-26)

Above normal temperatures middle of next week followed by a cool-down. Unsettled weather chances go up in the May 23-24 window followed by improvement heading into the Memorial Day Weekend later in the period.

DAYS 11-15 (MAY 27-31)

Drier with warming weather early period, unsettled mid period, cooler late period as we have more west to east progression of the pattern.

DAYS 1-5 (MAY 16-20)

Low pressure to the south brings wet weather through midday today, then a drying trend begins as the low starts to pull away and drier air arrives from the north. A blocking pattern then puts high pressure north of our region but close enough to keep the weather dry from Friday through Monday with a generally cooling easterly air flow, starting to transition to a warming trend by early next week as the high center slips southeastward. After today’s heavier overcast, we’ll see varying amounts of clouds Friday through the weekend as additional unsettled weather is held at bay not too far away to our south and west, but by Monday the sun should increase.

TODAY: Cloudy. Rain and drizzle around through early afternoon, then ending from north to south. Highs 55-62, coolest coast. Wind E 5-15 MPH.

TONIGHT: Mostly cloudy. Lows 45-52. Wind E up to 10 MPH.

FRIDAY: Mostly cloudy. Highs 58-65, coolest coast. Wind SE up to 10 MPH.

FRIDAY NIGHT: Partly cloudy. Lows 46-53. Wind variable under 10 MPH.

SATURDAY: Partly sunny. Highs 60-67, coolest coast. Wind SE up to 10 MPH.

SATURDAY NIGHT: Variably cloudy. Lows 49-56. Wind SE up to 10 MPH.

SUNDAY: Variably cloudy. Highs 60-67, coolest coast. Wind SE up to 10 MPH.

SUNDAY NIGHT: Partly cloudy. Lows 51-58. Wind S up to 10 MPH.

MONDAY: Partly cloudy. Highs 68-75, cooler South Coast. Wind S 5-15 MPH.

DAYS 6-10 (MAY 21-25)

Blocking high pressure holds early in the period with fair, warmer weather (cooler some coastal areas), then a bout of unsettled weather around mid period then a cool-down as fair weather returns at the end of the period, based on current expecting timing.

DAYS 11-15 (MAY 26-30)

Drier with warming weather early period, unsettled mid period, cooler late period as we have more west to east progression of the pattern.

DAYS 1-5 (MAY 15-19)

Frontal boundary to north, low pressure to south. These players result in a kind of disorganized unsettled weather day. Patchy rain is around, more to the west, this morning and should diminish with time, but can’t rule out a few stray showers wandering northward in a southerly air flow today. Tonight, low pressure to our south gets closer and the wind turns more easterly. This is when that low’s rain shield works northward into the region, only to start getting eaten away at and pushed back to the south by blocking high pressure to the north during Thursday. This period of time will show a cool-down with a broad scale onshore flow more established. The weather for Friday and the weekend depends on the magnitude of the block and the ability of high pressure to keep additional moisture at bay. Today, I continue to lean to the drier forecast, similar to that of yesterday. But this is not a super high confidence forecast, so monitor updates.

TODAY: Mostly cloudy. Patchy rain morning. Isolated showers afternoon. Highs 60-67 South Coast, 68-75 elsewhere. Wind S 5-15 MPH.

TONIGHT: Cloudy. Rain returns, especially South Coast to I-90 belt. Lows 50-57. Wind SE 5-15 MPH.

THURSDAY: Mostly cloudy. Rain most likely in the morning I-90 belt southward, then diminishing. Highs 57-64, coolest coast. Wind E 5-15 MPH.

THURSDAY NIGHT: Mostly cloudy. Lows 45-52. Wind E up to 10 MPH.

FRIDAY: Mostly cloudy. Highs 58-65, coolest coast. Wind SE up to 10 MPH.

FRIDAY NIGHT: Partly cloudy. Lows 46-53. Wind variable under 10 MPH.

SATURDAY: Partly sunny. Highs 60-67, coolest coast. Wind SE up to 10 MPH.

SATURDAY NIGHT: Variably cloudy. Lows 49-56. Wind SE up to 10 MPH.

SUNDAY: Variably cloudy. Highs 60-67, coolest coast. Wind SE up to 10 MPH.

DAYS 6-10 (MAY 20-24)

Fair, milder weather early to mid period. Shower chance increases later in the period with a cooling trend.

DAYS 11-15 (MAY 25-29)

Improving conditions, cooler start then warming trend.

DAYS 1-5 (MAY 14-18)

A spring blocking pattern is going to create better weather than we might have otherwise during the next 5 days. Now don’t get the idea that we have 5 straight top-ten days ahead. We don’t. And we’ll see a variety of weather. Follow along to gain and understanding of how I think this will play out…

A bit of an atmospheric chess game will work out mostly in our favor, keeping the weather on the drier side more often than not in the days ahead. First, a warm front is passing by first thing this morning, having produced lot of clouds and a few scattered showers overnight. But today, we’ll have a late spring feel in much of the region, even a little preview of summer, as the temperature surges well into the 70s to around 80 for highs, away from the cooling influence of a southwest wind off the Atlantic which will prevent much of the South Coast from even reaching 70. A cold front will be approaching the region tonight, but the short range guidance has been steadily trending this feature weaker and slower and I believe this will be the case. The front never really truly moves through the region at all. We get more clouds tonight and a few showers may wander into the region into the early part of Wednesday, favoring northern portions of the WHW forecast area, and then that should be about it for that front for us as it pretty much washes out. Our cool-down will result from low pressure forming and moving out south of our region later Wednesday through Thursday, turning our wind more easterly off the Atlantic. But the blocking in place wants to force this system further south, another trend I’ve been following over several days on medium range guidance, now pretty much confirmed by short range guidance. So the forecast for this feature is for some rain to occur near the South Coast Wednesday night and part of Thursday, but the majority of the region to miss out on the rain from it. This low sits off to our southeast then on Friday and Saturday, far enough way to keep rain away, but close enough to exert influence on the next approaching low, slowing it down and keeping it further south and west, hence a now mainly dry forecast for both Friday and Saturday. This part of the forecast, of course, is lower confidence than the next couple days, so check updates going forward.

TODAY: Lots of clouds early, then mostly sunny to partly cloudy. Highs ranging from near 60 Cape Cod to around 80 from Metro Boston west and north. Wind SW 5-15 MPH.

TONIGHT: Partly cloudy early, then mostly cloudy with isolated to scattered showers late evening and overnight. Lows 54-61. Wind SW 5-15 MPH, higher gusts possible.

WEDNESDAY: Mostly cloudy. A few showers possible in the morning favoring areas north of I-90. A bit of rain possible near the South Coast late in the day. Highs 60-67 South Coast, 68-75 elsewhere. Wind S 5-15 MPH.

WEDNESDAY NIGHT: Cloudy. Chance of rain near the South Coast. Lows 48-55. Wind SE 5-15 MPH.

THURSDAY: Mostly cloudy to partly sunny. Chance of rain near the South Coast early. Highs 58-65, coolest coast. Wind E 5-15 MPH.

THURSDAY NIGHT: Partly cloudy. Lows 45-52. Wind E up to 10 MPH.

FRIDAY: Variably cloudy. Highs 58-65, coolest coast. Wind SE up to 10 MPH.

FRIDAY NIGHT: Partly cloudy. Lows 46-53. Wind variable under 10 MPH.

SATURDAY: Partly sunny. Highs 60-67, coolest coast. Wind SE up to 10 MPH.

DAYS 6-10 (MAY 19-23)

Fair, milder weather early to mid period. Shower chance increases later in the period as an evolving zonal flow allows a trough and front to move in from the west.

DAYS 11-15 (MAY 24-28)

Early-period unsettled weather potential, then improvement following. Temperatures start cooler, then moderate.

DAYS 1-5 (MAY 13-17)

Like last week, we have a warm-up to start the week off today and Tuesday. Today we moderate over yesterday quite nicely as we’ve lost the clouds and will turn the wind around to southwest with high pressure to our south. Tonight, a warm front will cross the region with clouds and maybe a few showers – much of the region probably staying dry or just seeing brief rain. Tuesday warms even more over today behind the front, with more sunshine and a slight up-tick in the humidity that those sensitive to it may notice. A cold front approaches at night, but most of the energy for its showers will stay to the north, with just perhaps a few wandering into the region overnight and early Wednesday as the front moves in and washes out. While this is happening, low pressure organizes to our south. The trend on this from guidance has been for it to occur further and further south, to the point where the primary rain threat from the low is confined to the South Coast. It looks like that at this point and my hints of a mostly cloudy but largely rain-free forecast for Wednesday as discussed on yesterday’s blog are carried over and solidified today. There’s a little uncertainty on medium range guidance for late week with a few different scenarios depicted, but the one I am leaning toward carries the surface low out to sea Thursday while an upper level disturbance brings a sun/cloud mix and maybe a shower. And Friday, another trough approaches from the west with an increase in clouds. Further refinement of this later-week outlook will take place on the next update.

TODAY: Cloud patches early to mid morning in some locations, otherwise a fair amount of sun then some additional clouds arriving later in the day. Highs 56-63 South Coast and Cape Cod, 63-70 elsewhere. Wind SW 5-15 MPH.

TONIGHT: Mostly cloudy. A passing shower possible. Lows 50-57. Wind SW 5-15 MPH.

TUESDAY: Partly to mostly sunny. Highs 65-72 South Coast, 73-80 elsewhere. Wind SW 5-15 MPH.

TUESDAY NIGHT: Partly cloudy early, then mostly cloudy with scattered showers late evening and overnight. Lows 54-61. Wind variable 5-15 MPH.

WEDNESDAY: Mostly cloudy. A few showers possible in the morning favoring areas north of I-90. A bit of rain possible near the South Coast. Highs 58-65, coolest coast. Wind variable to SE 5-15 MPH.

WEDNESDAY NIGHT: Variably cloudy. Lows 45-52. Wind N 5-15 MPH.

THURSDAY: Partly sunny. A possible shower. Highs 56-63. Wind NE 5-15 MPH.

THURSDAY NIGHT: Partly cloudy. Lows 45-52. Wind N up to 10 MPH becoming variable.

FRIDAY: Increasing clouds. Highs 58-65, coolest South Coast. Wind variable to S up to 10 MPH.

DAYS 6-10 (MAY 18-22)

My outlook continues to largely ignore medium range guidance in anticipation of some errors, so after an early unsettled start for the weekend of May 18-19 it should improve with a milder finish than it starts out. Fair weather early next week, maybe unsettled by middle of next week with milder weather.

DAYS 11-15 (MAY 23-27)

Upper level low pressure may bring cooler and somewhat unsettled weather early to mid period – details TBD. Improvement may follow for Memorial Day Weekend which is May 25-27. Low confidence based on how far in the future this is, so follow updates.

DAYS 1-5 (MAY 12-16)

An upper level low crosses there region today with a weak surface low passing to the south. By evening, it’s already moving out to the east. Instability and sun fuel will be limited today so I only expect a few pop up showers later in the day, mainly to the north of Boston, while anything with the low to the south passes well offshore. Monday, high pressure slides off the Mid Atlantic coast and we see milder weather. A warm front scoots through the region Monday night and may produce a few showers. As a result, Tuesday’s a warmer day with dry conditions during the day as an approaching cold front stays far enough to the north and west. This front finally brings showers to the region that night as it moves into and across the region. Medium range guidance has been advertising a slowing down of this front and a wave of low pressure bringing more rain for Wednesday, but recent trends are this taking place further and further south, and based on some recent happenings with models in relation to the overall pattern, I’m going to lean cloudy but not too wet for Wednesday, with more notable improvement for Thursday with drier air arriving. However that day we may have to watch for a pop up shower as we’ll have solar heating and cold air aloft.

TODAY: Partial sun, especially eastern areas through mid morning, otherwise clouds dominate, but sun breaks may return later in the day favoring northern and western areas. A pop up shower possible this afternoon, favoring southwestern NH and northern MA. Highs 57-64, coolest along the coast. Wind variable to SE up to 10 MPH.

TONIGHT: Clouds decrease. Lows 46-53. Wind variable to W up to 10 MPH.

MONDAY: Sun/cloud mix. Highs 56-63 South Coast and Cape Cod, 63-70 elsewhere. Wind SW 5-15 MPH.

MONDAY NIGHT: Mostly cloudy. A passing shower possible. Lows 50-57. Wind SW 5-15 MPH.

TUESDAY: Partly sunny. Highs 68-75 except cooler South Coast / Cape Cod. Wind SW 10-20 MPH.

TUESDAY NIGHT: Partly cloudy early, then mostly cloudy with showers likely. Lows 54-61. Wind variable 5-15 MPH.

WEDNESDAY: Mostly cloudy. Showers possible, favoring areas south of I-90. Highs 58-65. Wind variable 5-15 MPH.

WEDNESDAY NIGHT: Variably cloudy. Lows 45-52. Wind N 5-15 MPH.

THURSDAY: Partly sunny. A possible shower. Highs 56-63. Wind NE 5-15 MPH.

DAYS 6-10 (MAY 17-21)

My outlook here largely ignores medium range guidance in anticipation of some errors that have been pretty consistent, so I lean toward a return to unsettled weather for a brief period May 17, improvement for the May 18-19 weekend which carries into early the following week along with a warm-up.

DAYS 11-15 (MAY 22-26)

This period should feature upper level low pressure returning to dominate the pattern with a cool-down and some occasionally unsettled weather.

COMMENTARY

If you did not get to see last night’s display of the aurora borealis which was widespread across not only New England, but a good portion of the North America, including as far south as Alabama and Georgia, seek out photos online. I witnessed it myself and am in awe at how magnificent it was. I’d seen the display before, in a barely-visible state near the horizon a few times, but never close to this magnitude. Am I ever glad my sky forecast was wrong for most of the region. 🙂

DAYS 1-5 (MAY 11-15)

A large scale northeasterly flow continues today and the dry air that allowed the northern lights to be seen last night will help much of the region start the day with sun today, but a little more moisture coming from the Atlantic will help clouds to pop up and move in from the northeast, and a few of these can produce showers, though they will be isolated in nature, and most of the region will have another rain-free day. Upper level low pressure drifts into the region Sunday but the surface reflection of low pressure is rather weak and will move south of our area. At most, a few showers will work into the region Sunday afternoon but I’m not expecting very widespread coverage, making it possible that the entire weekend is rain-free for many areas. This feature exits Monday and that day, as well as Tuesday, will feature a warm up with a southwesterly air flow as an area of high pressure scoots to our south. A frontal boundary approaches later Tuesday, but I feel its associated showers will wait until sometime that night to move in. The front and a wave of low pressure likely combine for an unsettled day on Wednesday.

TODAY: Sun/cloud mix. Chance of a shower but most areas remain rain-free. Highs 57-64. Wind NE 5-15 MPH.

TONIGHT: Variably cloudy. Lows 45-52. Wind N to NE up to 10 MPH.

SUNDAY: Mostly cloudy. Chance of showers, mainly late in the afternoon. Highs 57-64. Wind NE to variable up to 10 MPH.

SUNDAY NIGHT: Mostly cloudy. Chance of showers. Lows 48-55. Wind variable up to 10 MPH.

MONDAY: Variably cloudy. Highs 56-63 South Coast and Cape Cod, 63-70 elsewhere. Wind SW 5-15 MPH.

MONDAY NIGHT: Variably cloudy. Lows 50-57. Wind SW 5-15 MPH.

TUESDAY: Partly sunny. Highs 68-75 except cooler South Coast / Cape Cod. Wind SW 10-20 MPH.

TUESDAY NIGHT: Partly to mostly cloudy. Chance of showers. Lows 55-62. Wind variable 5-15 MPH.

WEDNESDAY: Mostly cloudy. Showers likely. Highs 58-65. Wind variable 5-15 MPH.

DAYS 6-10 (MAY 16-20)

Best chance of unsettled weather mid period. Overall pattern features a cool-down early in the period, then a warm-up later in the period.

DAYS 11-15 (MAY 21-25)

Mild and fair to start, then a cooling trend with mid to late period unsettled weather possible.

DAYS 1-5 (MAY 10-14)

The battle between moisture and dry air continues in our region for a few days. An area of low pressure passing south of New England this morning is starting the South Coast with a period of steady rain, with a little light rain further northwest from eastern CT to above the western reaches of the WHW forecast area in MA (CT Valley). All of this will be suppressed south while it slides east as dry air wins the battle by late morning, and the heavier overcast that sits over the region may thin out at times today. So while not as nice as yesterday turned out, we’re not facing a regionwide washout either. Another low pressure area passes by tonight and early Saturday, and this one brings some rain to the region from the South Coast to the MA South Shore, but much of that occurring prior to and right around sunrise, before that one makes an exit and dry air prevails for the most part. While there will be some breaks in the clouds to be seen Saturday, one difference from today is a slightly more unstable atmosphere can help trigger a few pop up showers, mainly in southern NH and northeastern MA, mainly during the midday hours. These should be spotty and not last long in any one area, and most of the region stays rain-free. Upper level low pressure moves into the region on Sunday and a weak surface low passes by to the south (again), and this day will turn out mainly cloudy with scattered showers around the region, but again not a widespread soaker. Early next week, this upper low has departed and we find ourselves in a warmer southwesterly flow with high pressure to our south and a frontal boundary slowly approaching in a ripply fashion from the northwest. While some episodic clouds from the frontal boundary will find their way into our region, we will otherwise see fair and mild weather, with of course a cooling influence where a southwest wind comes off ocean, especially along the South Coast. There’s some uncertainty as to whether or not the frontal boundary will be close enough by later Tuesday to bring a shower chance, so with low confidence it appears in this update today.

TODAY: Overcast morning including rain South Coast into mid morning. Mostly cloudy midday-afternoon. Highs 55-62, coolest eastern coastal areas. Wind NE-E 5-15 MPH.

TONIGHT: Mostly cloudy evening. Cloudy overnight with periods of rain South Coast to MA South Shore. Lows 46-53. Wind E-NE 5-15 MPH.

SATURDAY: Early-day rain potential for South Coast / Cape Cod, and patchy drizzle possible eastern coastal locations, otherwise clouds break for partial sun. A pop up shower possible especially midday hours favoring southern NH and northeastern MA. Highs 57-64. Wind NE to N 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Lows 45-52. Wind N to NE up to 10 MPH.

SUNDAY: Mostly cloudy. Chance of showers, mainly late in the afternoon. Highs 57-64. Wind NE to variable up to 10 MPH.

SUNDAY NIGHT: Mostly cloudy. Chance of showers. Lows 48-55. Wind variable up to 10 MPH.

MONDAY: Variably cloudy. Highs 56-63 South Coast and Cape Cod, 63-70 elsewhere. Wind SW 5-15 MPH.

MONDAY NIGHT: Variably cloudy. Lows 50-57. Wind SW 5-15 MPH.

TUESDAY: Variably cloudy. Afternoon showers possible mainly western areas. Highs 68-75 except cooler South Coast / Cape Cod. Wind SW 10-20 MPH.

DAYS 6-10 (MAY 15-19)

Cooling trend in general. Hard to time specific unsettled weather threats but a couple of them exist, probably very early period and again mid to late period.

DAYS 11-15 (MAY 20-24)

General best idea of pattern points to fair, milder weather to start this period then a return to somewhat unsettled weather later in the period with a cooling trend.

DAYS 1-5 (MAY 9-13)

Forecasts always present challenges in the longer term as it’s naturally more difficult to predict the air flow through the atmosphere and its impact on a given region the further out from “now” you get. Sometimes those challenges are realized in a much shorter term. Such was the case yesterday. Yes, the forecast was “right” in terms of a warm front causing one swath of showers and embedded thunder earlier in the day and then an approaching cold front setting off showers and thunderstorms later. The hail potential was definitely realized in the storms with many reports of it across portions of southern New England. What was a bit of a surprise was the coverage of the second round of activity, and the persistence of it. I was definitely lead a bit astray by buying too much into shorter range guidance that had the activity, but less widespread and of a shorter duration. But now that show is over, and we have some other forecast adjustments to make. You might recall several days ago I indicated some hope for Thursday in a longer stretch of unsettled weather starting Wednesday, then abandoned the idea based on more pessimistic looking guidance. Well, once again, should have stuck with the other idea. High pressure indeed noses its way in enough to give us a fairly decent day today. While we won’t have wall to wall sun, there is a good mix of sun and clouds across the region to start the day, with some high clouds streaming in from the west above patchy lower level stratocumulus clouds drifting north to south. This north-to-south motion is indicative of that drier air flow at the surface, and the difficulty of the higher clouds from the west to overspread and thicken during the day today indicate somewhat drier air above us too. It is tonight, finally, when a wave of low pressure approaches New England from the southwest, and the surface wind turns more northeasterly, that we’ll see clouds collect in a more concentrated fashion. A few of the lower clouds around during the day can build up just enough to produce a few rain showers mainly over southern NH and the northern half of MA, but these will be rather isolated. From late evening tonight to the very early hours of Friday morning, we can see an area of rain from the low pressure area to our southwest moving into the region, only to be obliterated by a renewed push of drier air. While I expect cloud cover to be more dominant on Friday than it will be today, the rain chance will likely be held at bay again after that initial push, for most of the day and into the evening. Finally, the low pressure area makes its closest pass Friday night and first thing Saturday morning as it slides east northeast, to our south. This is when a little more wet weather can occur, but most of it looks like it will be toward the South Coast, especially Cape Cod, while much of the rest of the region may be spared or just see brief light rainfall. Behind that, a shift of wind to the north will dry the region out again, and breaks in the clouds allow partial sun for Saturday, which is definitely a more optimistic outlook than I was carrying before. Does this means the entire weekend is saved? Probably not, because it still looks like another upper low and associated surface trough will drift eastward into the region on Sunday when I cannot rule out some showers, but some guidance does keep the region mainly dry for much of the day, so the potential definitely exists to salvage much of the weekend rain-free. Monday’s weather looks ok as upper level low pressure starts out nearby then shifts to the east, with a sun/cloud mix and maybe a pop up shower.

TODAY: Sun/cloud mix. A possible shower favoring southern NH and northern MA late afternoon. Highs 57-64. Wind NW 5-15 MPH, higher gusts.

TONIGHT: Mostly cloudy. Chance of light rain favoring central MA, eastern CT, and RI late evening / overnight. Lows 46-53. Wind NE 5-15 MPH.

FRIDAY: Mostly cloudy. Potential for early-day rain favoring the South Coast. Highs 55-62, coolest coast. Wind E 5-15 MPH.

FRIDAY NIGHT: Cloudy. Rain returns to areas mainly near and south of I-90. Patchy drizzle possible elsewhere, especially eastern coastal locations. Lows 46-53. Wind NE 5-15 MPH.

SATURDAY: Early-day rain potential for South Coast / Cape Cod, and patchy drizzle possible eastern coastal locations, otherwise clouds break for partial sun with a chance of an afternoon pop-up shower. Highs 57-64. Wind NE to N 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Lows 45-52. Wind N to NE up to 10 MPH.

SUNDAY: Mostly cloudy. Chance of showers, mainly late in the afternoon. Highs 57-64. Wind NE to variable up to 10 MPH.

SUNDAY NIGHT: Mostly cloudy. Chance of showers. Lows 48-55. Wind variable up to 10 MPH.

MONDAY: Variably cloudy. Chance of a shower. Highs 58-65. Wind variable 5-15 MPH.

DAYS 6-10 (MAY 14-18)

Early period milder and fair weather expected with a short-lived southwesterly flow as high pressure shifts offshore and a frontal boundary sits to the north and west. After this, a cooling trend and occasionally unsettled with some wet weather episodes middle to latter part of next week. More precise timing and details TBD of course.

DAYS 11-15 (MAY 19-23)

Medium range trends point to fair, cool then milder weather to start this period then a return to somewhat unsettled weather later in the period.

DAYS 1-5 (MAY 8-12)

A “dynamic duo” impacts today’s weather across the WHW forecast area. First up, a warm front with good instability moves in quick fashion from west to east across the region this morning and midday with the early sun you saw if you were up being lost behind thickening clouds, followed by areas of showers with potential embedded thunder in some locations. Behind this a break comes with some thinning and breaking of the clouds. Then the second member of the duo comes along from the west northwest from mid afternoon to early evening – this a cold front that will set off scattered showers and isolated thunderstorms, possibly a cluster or two a little more organized. Any of these heavier cells have the potential produce hail of up to 1 inch in diameter and a lower probability of a damaging wind gust, so while the chances are low that any one location sees this, keep an eye to the sky (and the radar) as we move through the afternoon. This exits early evening, possibly with rainbows in showers’ wakes in locations where it occurs before sunset as some partial clearing can occur right behind them. Another swath of clouds will slide across the region later this evening as the air flow shifts to northerly, but this will be followed by some additional partial clearing overnight into early Thursday as an area of drier air arrives. This means a little bit of sunshine can be seen to start the day Thursday, before clouds thicken up ahead of the next low pressure area. This will the first in a series of 2 or 3 low pressure waves that travel just south of our region through early Saturday, resulting in a much cooler and unsettled stretch of weather. It won’t rain all the time, but all in all it will be pretty dreary and chilly with a regionwide northeasterly to easterly air flow. This finally starts to back to the north during Saturday as low pressure pulls away, but upper level low pressure in the region will keep the clouds locked in and still the chance of a passing shower or patch of drizzle. So, it’ll clear out Sunday, right? Not so fast. Just as our system departs, another will be on its heels via the Ohio Valley, and will move across the region during Sunday which now looks like a slightly milder but still unsettled day. Sorry!

TODAY: Early sun east, thicker clouds from west quickly with showers and possibly a thunderstorm west to east across the area mid through late morning. Thinning / breaking clouds with partial sun possible first half of afternoon then heavier clouds move through again with scattered to broken showers and isolated thunderstorms, possibly containing hail and gusty wind. Highs 58-65, coolest coast. Wind SE up to 10 MPH morning, S-SW 5-15 MPH afternoon, shifting to WSW late-day. Winds can be variable and over 20 MPH with brief strong gusts around any heavier showers/storms.

TONIGHT: Early-evening showers South Coast / Cape Cod, otherwise variably cloudy. Lows 46-51. Wind N 5-15 MPH.

THURSDAY: Partial sun morning, then cloudy. Periodic rain by late-day. Highs 52-59, coolest coast. Wind N shifting to E 5-15 MPH.

THURSDAY NIGHT: Overcast. Periodic rain and drizzle. Areas of fog forming. Lows 46-53. Wind E to NE 5-15 MPH.

FRIDAY: Cloudy. Periodic rain and drizzle, especially through midday. Patchy fog early. Highs 48-55, coolest coast. Wind NE 5-15 MPH.

FRIDAY NIGHT: Cloudy. Chance of drizzle and possibly a shower. Lows 45-52. Wind NE 5-15 MPH.

SATURDAY: Mostly cloudy. Patchy drizzle and possible showers. Highs 50-57, coolest coast. Wind NE to N 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Chance of drizzle. Lows 43-50. Wind N to NE up to 10 MPH.

SUNDAY: Mostly cloudy. Chance of drizzle and showers. Highs 55-62. Wind NE up to 10 MPH.

DAYS 6-10 (MAY 13-17)

Improving weather early next week – drier & milder – as upper level low pressure moves away and high pressure moves in. This will be followed by another cooling trend as the next upper level trough and a couple disturbances associated with it bring more clouds and some wet weather chances mid to late next week.

DAYS 11-15 (MAY 18-22)

Cool, drier weather early period, then a warming trend. Unsettled weather may return by the end of the period.