DAYS 1-5 (MAY 21-25)

Today we are going to get an example of how a little mesoscale feature, not forecast that far in advance by guidance, can impact the weather fairly significantly – in this case, delaying sunshine and heat by several hours and as a result impacting the sensible weather for the entire day. Only 2 1/2 days ago a meso-scale batch of showers and thunderstorms originated in the Colorado area and has since made its way steadily eastward, passing across far southern New England (mostly just offshore) late last night. The departure of this feature, which produced showers as far north as the MA/NH border and a few heavier showers and thunderstorms closer to the South Coast (with big t-storms offshore), has left us with a delayed warm frontal passage, only across about 1/2 the region as of sunrise, and lots of cloudiness, dampness, and even areas of fog. As the hotter air mass works its way in from the west and southwest, we will see an erosion and departure of this cloudiness and eventually the light and variable wind, even from the north and northeast in some areas, will become more southwesterly. Some East Coast beaches may never fully realize the southwesterly breeze until sometime tonight though, and that will keep temperatures down there, as well as along the South Coast where a southwesterly wind is already coming off cooler water anyway. So we don’t just blast into the heat today – it will be a slow process, especially the further east or nearer the coast one lives, where the 90 degree temperatures may have only existed in a forecast heard in the last few days. Once we get to tomorrow though, we’re in it. Full southwesterly air flow everywhere, and only where that wind comes off water will there be a modifying influence, so there will be parts of southern New England that stay below 90 again, but this should come as no surprise in late May, when our surrounding waters are cold enough to pain the ankles of those who venture in too quickly. (And speaking of, if you do beach it, beware of that chilly water and limit your immersion. It is dangerous if you try to swim in water that’s too cold.) We’ll be watching the approach of a cold front later Sunday, which will generate some strong to severe thunderstorms west and north of the WHW forecast area, but the timing of that front appears too late to bring the heavy duty stuff into our region, only remnant showers and embedded weakening storms Sunday evening and night. Ironically, the best instability in our atmosphere occurs today, but most of the atmosphere doesn’t cooperate and storms will never be realized. Tomorrow, however, we may see a couple isolated cells pop up ahead of any cold frontal activity – air mass storms in the heat of the day. Though most will not see that. Regardless, the cold front that arrives Sunday night puts an end to our brief early-season heat, and we’re right back to near seasonable air for Monday. We’ll have at least partial but not maybe complete clearing, as the frontal boundary will be a bit sluggish on departure, and a few rain showers may skirt the South Coast region because of that. But for the most part, Monday will be a rain-free day with much lower humidity than we’ll have Sunday. Tuesday’s and Wednesday’s weather will be governed by high pressure, the center of which will be north of our region Tuesday, which will be a fairly cool and breezy day. The center of the high slips a bit south and weakens by Wednesday, which will still have a broad scale onshore flow, but more southeasterly, and less brisk. Just don’t let this weekend’s burst of heat make you think summer is here to stay. It’s still very much springtime here in southeastern New England…

TODAY: Through mid morning – clouds and areas of fog, even patchy drizzle especially near the coast. Midday – decreasing clouds from west to east. Remainder of day – sunny. Increasingly humid – dew point rising into 60s. Highs 75-82 Cape Cod / South Coast, 82-89 just inland from South Coast as well as immediate East Coast, 89-96 inland, hottest over interior valleys. Wind variable under 10 MPH becoming SW 5-15 MPH from west to east.

TONIGHT: Clear except patchy ground fog. Lows 63-70. Humid – dew point lower to middle 60s. Wind SW up to 10 MPH.

SUNDAY: Sunny to partly cloudy. Slight chance of isolated afternoon thunderstorms. Highs 75-82 Cape Cod / South Coast, 83-90 just inland from South Coast and portions of immediate North Shore & South Shore, 91-98 elsewhere with hottest interior valleys. Wind SW 5-15 MPH but some localized weak sea breezes on eastern shores.

SUNDAY NIGHT: Variably cloudy. Chance of showers and thunderstorms. Patchy fog. Lows 65-72. Humid – dew point 60s. Wind SW 5-15 MPH, higher gusts.

MONDAY: Sun/cloud mix. Passing showers possible South Coast / Cape Cod. Highs 75-82. Less humid. Wind W-NW 5-15 MPH.

MONDAY NIGHT: Clearing. Lows 50-57. Wind N 5-15 MPH.

TUESDAY: Mostly sunny. Highs 64-71, coolest coast. Wind NE 10-20 MPH.

TUESDAY NIGHT: Clear. Lows 49-56. Wind E up to 10 MPH.

WEDNESDAY: Mostly sunny. Highs 67-74, coolest coast. Wind NE 5-15 MPH.

DAYS 6-10 (MAY 26-30)

High pressure slips to the south and our air flow turns more southerly May 26 with some more cloudiness, then add in the chance of showers for May 27 as a disturbance and frontal system move through from west to east. Based on current timing, Memorial Day Weekend May 28-30 looks dry with high pressure in control, along with seasonably to slightly warmer than normal temperatures.

DAYS 11-15 (MAY 31 – JUNE 4)

End May / early June looking like weak zonal flow pattern with minor disturbances. Overall regime is seasonable temperatures and drier than average weather.

C-19 Chat Post – 5-21-2022

DAYS 1-5 (MAY 20-24)

A slow-moving warm front is still traversing our region, as evident by the surface wind, very light but from the east and southeast in the Boston area to southern NH and from the southwest in areas to the south, as well as a pretty extensive blanket of stratus clouds across all coastal areas and even inland for some distance in southern NH and northeastern MA as well. It basically takes the entirety of today for this front to push its way through our area. The high May sun will work on the stratus which should break up in most locations it sits as of the time of this writing. So all in all it’s not to be a bad day, other than contending with some low cloudiness in some areas. Tonight, as the warmer air becomes more established, we’ll have to eye the remains of a mesoscale convective system from the west, as it may bring a batch of at least showers and potentially heavier thunderstorms to parts of southern New England. Short range guidance indicates this favors areas near and south of I-90, but these things are fickle and can be very poorly forecast by short range guidance at times, so tracking it closely will be necessary. I don’t think this is going to be a cause of concern regarding severe weather, but it’s always worth watching just in case. And then the heat is on for the weekend. Things come together at upper levels and at the surface to deliver a 2-day hot spell where many areas will see 90+ for high temps. It’s important to note this will NOT be a heatwave, as you need 3 or more consecutive days of 90+ for that. And this is going to break by Monday. But before that, we’re hot. The usual areas along the South Coast and some East Coast beaches will be cooler though. If you go to the beach, remember that the water temperatures remain very chilly at this time of year (barely to 50 East Coast beaches, and just into the 50s South Coast beaches). You lose body heat rapidly in the water, so be wise about immersion and length of time in there if you decide to brave the chilly water. Humidity will be on the increase this weekend, but we’re starting low, and it will never really get overly oppressive, although the combination of the moderate humidity and early-season heat will make it feel quite uncomfortable for those sensitive to it. A bit of atmospheric irony: There are some conditions that would help initiate explosive thunderstorm development on Saturday, but too many limiting factors including no triggers and a big old cap, so we’re not going to have any storms around at all that day. Sunday, the “perfect” conditions are lost a bit, but so are some of the limitations, so we may see a few isolated air mass storms pop up, but more organized activity will wait until a cold front enters and crosses the region. But the timing of this front is so late that we probably experience a much weakened version of what was stronger to our north and west, and this will come through Sunday night and early Monday. So while Monday may start a bit unsettled, it will be a much cooler day with dry weather returning – temperatures about 20 degrees lower than Sunday, and much lower dew point air moving in after a somewhat humid start. I’m a little nervous about that front not getting that far to the south and a wave of low pressure that may keep it cloudier for more of Monday, and even threatening some showers, but for now staying optimistic with a sun/cloud blend and drier air – just know that my Monday outlook is lower confidence. High pressure to the north will turn the wind northeast by Tuesday and while I expect fair weather, it should be rather cool, especially in comparison to what we had just gone through over the weekend.

TODAY: Mostly cloudy start coastal areas as well as southeastern NH and northeastern MA followed by a sun/cloud mix trending sunnier these areas while other areas that start with sunshine keep it with just a few clouds. Highs 68-75 coast, 75-82 inland. Wind E shifting to S up to 10 MPH eastern MA and southern NH, S-SW up to 10 MPH elsewhere.

TONIGHT: Clouds return. Showers and possible thunderstorms favoring areas near and south of I-90 from west to east late evening / overnight. Patchy fog forming especially behind any shower activity. Lows 58-65. Wind S-SW 5-15 MPH but brief stronger gusts can occur near any thunderstorms.

SATURDAY: Areas of low clouds and patchy fog to start, then turning sunny. Highs 90–97 except 83-90 East Coast beaches and just inland from South Coast, 76-83 South Coast / Cape Cod. Becoming more humid – dew point rising to 60s. Wind SW 5-10 MPH but weak sea breezes possible eastern shores.

SATURDAY NIGHT: Mostly clear. Patchy ground fog. Lows 63-70. Humid – dew point 60s. Wind SW 5-15 MPH.

SUNDAY: Mostly sunny. Only a slight chance isolated afternoon thunderstorms. Highs 91-98, hottest interior valleys, but 84-91 East Coast beaches and just inland from South Coast, and 77-84 South Coast / Cape Cod. Humid – dew point middle to upper 60s. Wind SW 5-15 MPH, but local weak sea breezes eastern shores.

SUNDAY NIGHT: Variably cloudy. Chance of showers and thunderstorms. Patchy fog. Lows 65-72. Humid – dew point 60s. Wind SW 5-15 MPH, higher gusts.

MONDAY: Sun/cloud mix. Chance of a shower early. Highs 75-82. Less humid. Wind W-NW 5-15 MPH.

MONDAY NIGHT: Clearing. Lows 50-57. Wind N 5-15 MPH.

TUESDAY: Mostly sunny. Highs 60-67, coolest coast. Wind NE 10-20 MPH.

DAYS 6-10 (MAY 25-29)

Cool start, fair weather holds May 25 with high pressure to the north. Warmer air attempts a come-back with some unsettled weather possible May 26-27. Drier and warmer weather possible by later in the period which includes the start of Memorial Day Weekend.

DAYS 11-15 (MAY 30 – JUNE 3)

Overall pattern dry, zonal flow, but brief wet weather threats with air mass changes. Temperatures variable, averaging near to slightly above normal.

C-19 Chat Post – 5-20-2022

DAYS 1-5 (MAY 19-23)

Big weather changes will take place over the next few days from a cool and damp day today to the full feel of mid summer for the weekend before we break the 2-day hot spell by Monday. How do we get from here to there? Today, a warm front will approach from the southwest with a cool air mass in place, overrunning taking place and producing some rainfall, especially this morning and midday. The front won’t really pass by us at all today so we’ll keep the clouds around even after the rain exits, but there is the chance of another shower later in the day or early this evening as another quick-moving disturbance moves by at upper levels. While we work drier air into the region at mid and upper levels we’ll clear out by early Friday, but that day while warmer won’t introduce us to the summer heat quite yet, as the actual frontal boundary will take its time and won’t really get by the region until sometime at night, at which time one more disturbance may bring a renegade batch of showers or even thunderstorms to the region. After that, the heat is on for the weekend, and with high pressure centered to the south of our area supplying it, the humidity levels will also increase. With a lot of outdoor activities that go on at this time of year on weekends, anybody planning on being outside for any length of time will have to prepare for it with the use of sun screen and especially staying hydrated! We’ve talked about a cold front putting an end to the short-lived hot spell, and that will happen, but the front’s timing looks late enough for Sunday to be a fully hot day and a shower/thunderstorm threat holding off til evening or even sometime at night to early Monday, before we bring in a drier and cooler air mass for the start of next week.

TODAY: Cloudy through midday with periods of rain. Mostly cloudy thereafter with just a chance of a passing shower. Highs 57-64. Wind SE-S 5-15 MPH, higher gusts in the afternoon.

TONIGHT: Mostly cloudy. A passing shower possible early. Patchy fog overnight. Lows 50-57. Wind SE-S 5-15 MPH.

FRIDAY: Early clouds and possible patchy fog, then mostly sunny. Highs 68-75 coast, 75-82 inland. Wind S-SE 5-15 MPH.

FRIDAY NIGHT: Mostly clear. Lows 58-65. Wind S-SW 5-15 MPH.

SATURDAY: Mostly sunny. Highs 88-95 except 80-87 some eastern beaches and near the South Coast except 73-80 immediate South Coast and Cape Cod. More humid – dew point rising into 60s. Wind SW 5-15 MPH.

SATURDAY NIGHT: Mostly clear. Patchy ground fog. Lows 63-70. Humid – dew point 60s. Wind SW 5-15 MPH.

SUNDAY: Mostly sunny. Highs 90-97, cooler shoreline especially South Coast. Humid – dew point upper 60s. Wind SW 5-15 MPH, higher gusts.

SUNDAY NIGHT: Variably cloudy. Chance of showers and thunderstorms. Patchy fog. Lows 65-72. Humid – dew point 60s. Wind SW 5-15 MPH, higher gusts.

MONDAY: Sun/cloud mix. Chance of a shower early. Highs 75-82. Less humid. Wind W-NW 5-15 MPH.

DAYS 6-10 (MAY 24-28)

This 5-day period will be a little more unsettled as the frontal boundary that goes by will be nearby and we’ll have some disturbances moving along it and a bit of a battle between warm to hot weather to our south and Canadian coolness.

DAYS 11-15 (MAY 29 – JUNE 2)

Overall pattern dry, zonal flow, but brief wet weather threats with air mass changes. Temperatures variable, averaging near to slightly above normal.

C-19 Chat Post – 5-19-2022

DAYS 1-5 (MAY 18-22)

High pressure builds toward the region today with dry, bright, breezy weather. The high moves right across our area this evening when we’ll finally have lost the breeze and clouds start to move in ahead of an approaching warm front. This front will take its time moving through the region on Thursday, so expect a generally cloudy day, but most of the rain with the warm front will be on the light side and occur in the morning. Friday warms up behind this front, and then with stronger high pressure offshore and a cold front hanging off to the northwest we will have a taste of summer Saturday into Sunday before that front swings through at some point on Sunday, with a shower and thunderstorm threat, breaking the brief hot spell by the end of the weekend.

TODAY: Mostly sunny. Highs 66-73. Wind NW 5-15 MPH, few higher gusts.

TONIGHT: Clouding up. Chance of light rain overnight. Lows 51-58. Wind variable up to 10 MPH.

THURSDAY: Cloudy through midday with periods of rain. Mostly cloudy thereafter. Highs 57-64. Wind SE-S 5-15 MPH, higher gusts in the afternoon.

THURSDAY NIGHT: Partly cloudy. Lows 55-62. Wind SW up to 10 MPH.

FRIDAY: Mostly sunny. Highs 75-82. Wind SW 5-15 MPH.

FRIDAY NIGHT: Mostly clear. Lows 55-62. Wind SW 5-15 MPH.

SATURDAY: Partly cloudy. Highs 85-92, cooler South Coast. Wind SW 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Lows 63-70. Wind SW 5-15 MPH.

SUNDAY: Partly sunny. Chance of showers and thunderstorms, mostly in the afternoon. Highs 85-92. Wind SW 10-20 MPH.

DAYS 6-10 (MAY 23-27)

A shot of cooler/dry air May 23. Wave of low pressure brings a chance of rain May 24. Variable weather with a boundary nearby, in and out of clouds with a few shower threats May 25-27.

DAYS 11-15 (MAY 28 – JUNE 1)

Overall pattern dry, zonal flow, but brief wet weather threats with air mass changes. Temperatures variable, averaging near to slightly above normal.

C-19 Chat Post – 5-18-2022

DAYS 1-5 (MAY 17-21)

Today we’ll be in the zone between low pressure to the northeast and high pressure approaching from the west. The air will be cooler drier than yesterday and the breeze will be active. Upper level low pressure crossing the region brings cold air aloft and will initiate diurnal cloud development. A few of these clouds may grow enough to produce a shower, favoring areas in southern NH and adjacent northern MA sometime this afternoon. High pressure brings dry weather Wednesday with diminishing wind. Systems are moving more quickly now and a warm front will cross the region Thursday with cloudiness, but right now it appears the rain threat will be minor and limited mostly to the morning hours. We warm up late week with another preview of summer heat arriving by the weekend as high pressure builds along the Atlantic Seaboard.

TODAY: Sunny start then a sun/cloud mix. Slight chance of an afternoon shower favoring northern MA and southern NH. Highs 70-77. Wind W 10-20 MPH, gusts as high as 30 MPH.

TONIGHT: Clearing. Lows 50-57. Wind W diminishing to 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 66-73. Wind NW 5-15 MPH, few higher gusts.

WEDNESDAY NIGHT: Clouding up. Chance of light rain overnight. Lows 51-58. Wind variable up to 10 MPH.

THURSDAY: Cloudy with a chance of light rain early, then mostly cloudy to partly sunny. Highs 65-72. Wind SE to S up to 10 MPH.

THURSDAY NIGHT: Partly cloudy. Lows 55-62. Wind SW up to 10 MPH.

FRIDAY: Mostly sunny. Highs 75-82. Wind SW 5-15 MPH.

FRIDAY NIGHT: Mostly clear. Lows 55-62. Wind SW 5-15 MPH.

SATURDAY: Mostly sunny. Highs 85-92, cooler South Coast. Wind SW 5-15 MPH.

DAYS 6-10 (MAY 22-26)

Another preview of summer heat ends with a cold front and shower/t-storm threat on May 22. Cooling to more seasonable or even slightly cooler than normal after that. Watching for a low pressure wave with rain threat around May 24 – moving faster than current medium range guidance shows.

DAYS 11-15 (MAY 27-31)

Overall pattern dry, zonal flow, but brief wet weather threats with air mass changes. Temperatures variable, averaging near to slightly above normal.

C-19 Chat Post – 5-17-2022