10:08AM

It’s time for the heat again, starting today in some areas and in pretty much all areas Monday through Thursday, hanging on in many Friday, before easing slightly next weekend. That’s a capsule of the coming week plus. A full discussion will follow later with The Week Ahead post but for now here is an updated forecast for southeastern New England…

TODAY: Mostly sunny to partly cloudy. Isolated thunderstorms possible especially late afternoon or early evening but most areas rain-free. Humidity rising. Highs in the 80s, may hold in the 70s some immediate coastal areas and may approach 90 interior valleys. Wind variable 5-15 MPH.

TONIGHT: Partly cloudy to mostly clear. A few patches of fog. Muggy. Lows 65-70. Wind light variable.

MONDAY: Mostly sunny to partly cloudy. Slight chance of isolated thunderstorms late day. Highs around 90, cooler some beaches. Wind variable to NW 5-15 MPH.

TUESDAY THROUGH THURSDAY: Mostly sunny to partly cloudy each with a risk of a few isolated thunderstorms mainly late afternoons and early evenings. Lows 64-74, warmest urban areas. Highs 84-94, coolest some coastal areas with most areas 90+.

FRIDAY: Partly sunny. Thunderstorms late. Low 70. High 90.

SATURDAY: Partly cloudy. Showers early. Low 66. High 88.

5:41PM

A cold front is lazily drifting across southeastern New England and won’t even clear Cape Cod before stalling and washing out during the next couple days. The lingering boundary will help initiate some shower activity, but the best chance for this will be Friday as a disturbance also crosses the region. Activity should diminish though is still possible during the weekend.

A repeat of the retrograding ridge pattern (high pressure moving westward from the western Atlantic) will bring a return to hot weather for much of next week.

Updated forecast for southeastern New England (eastern MA, southern NH, and RI)…

THIS EVENING (THROUGH SUNSET): Filtered sunshine most areas, but some heavier clouds and isolated to scattered showers and possible thunderstorms (especially Metro West and Merrimack Valley). Temperatures ranging from near 70 coast to near 80 inland, but cooler in areas that showers occur. Wind S to SW in eastern areas, NW to N further to the west, 5-15 MPH.

OVERNIGHT: Mostly cloudy. Lows in the 60s. Wind N up to 10 MPH except variable in coastal areas.

FRIDAY: Mostly cloudy. Episodes of showers, especially late morning and afternoon. Slight chance of a thunderstorm. Highs in the 70s, coolest coast. Wind NE to E 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Patchy fog. Chance of showers. Lows in the 60s. Wind light SE.

SATURDAY: Mostly cloudy to partly sunny, except more sun possible north and west of Boston in the afternoon. Chance of showers and possibly a thunderstorm, favoring areas from the Mass Pike southward. Highs middle 70s to middle 80s, coolest coastal areas. Wind SE to S 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Patchy fog. Lows in the 60s. Wind S 5-15 MPH.

SUNDAY: Partly sunny. Isolated showers and thunderstorms especially south of Boston. Highs in the 80s. Wind S 10-20 MPH.

MONDAY-THURSDAY: Partly cloudy. Isolated thunderstorms possible each afternoon. Lows 65-75. Highs 85-95, coolest South Coast and Cape Cod.

11:48PM

If you regularly look at the computer models, you’ll know right away which one I am leaning toward. With a warm front moving through the region today, a cold front sliding into the region then slowing down just offshore Thursday and Friday, and a probable cut off low pressure area forming over the region early in the weekend, it looks like an unsettled time continuing for southeastern New England during the next several days. Optimistically, better weather should be expected by late in the weekend or more likely early next week as a ridge of high pressure in the western Atlantic starts to build westward into the Northeast, much like what happened last week, resulting in the heat. Before that, expect several period of showers and thunderstorms.

Updated forecast for southeastern New England…

OVERNIGHT: Mostly cloudy. Areas of fog Cape Cod, Islands, southeastern and east coastal MA. Lows in the 60s. Wind light E to SE.

WEDNESDAY: Mostly cloudy morning with patchy rain moving south to north across the region. Variably cloudy afternoon with a stray shower or thunderstorm possible interior MA and south central NH. Highs 70s coast, 80s inland. Wind SE shifting to S increasing to 10-20 MPH.

WEDNESDAY NIGHT: Mostly cloudy. Showers and thunderstorms moving in from west to east but weakening as they cross the region. Lows 65-70. Wind SW 5-15 MPH.

THURSDAY: Variably cloudy. Scattered showers and thunderstorms. Highs 75-85, coolest South Coast, warmest interior MA and NH. Wind variable 5-15 MPH.

FRIDAY: Mostly cloudy. Showers and possibly a thunderstorm in the morning becoming less numerous in the afternoon. Low 66. High 74.

SATURDAY: Mostly cloudy. Scattered showers. Low 62. High 75.

SUNDAY: Partly cloudy. Isolated showers. Low 64. High 82.

MONDAY: Sunny. Low 65. High 88.

TUESDAY: Sunny. Low 68. High 92.

7:39AM

We became a meso-scale weather lab experiment on Monday as cool outflow air from thunderstorms exiting Maine into the Atlantic pushed southward as a back-door frontal boundary and moved into southern NH and much of eastern MA, popping some showers and thunderstorms in the process. This boundary cooled coastal areas off from around 80 to near 70, 60s in some cases, while areas well southwest of Boston remained very warm. This boundary which has now cooled off most of the region and even notched-down the humidity (though it is still technically humid) will hang around the region and fall apart today, being only a minor focus for development of showers. We’ll have to wait for another boundary, a warm front, to push through the region early Wednesday, with showers and thunderstorms, introducing very muggy air back to the region from mid into late week. Additional showers/storms are expected Thursday-Friday as a cold front moves into the region from the west and slows down. Its too early to tell how soon this will get out of here, but there is optimism for at least part of the weekend being better.

Updated forecast for southeastern New England…

TODAY: Mostly cloudy to partly sunny. Isolated showers. Highs 70 coast to 80 far inland. Wind light E becoming variable.

TONIGHT: Mostly cloudy. Patchy fog. Showers mainly south and west of Boston late. Lows in the 60s. Wind light variable to SE.

WEDNESDAY: Variably cloudy. Episodes of showers and thunderstorms. Highs upper 70s to middle 80s. Wind S to SW 10-20 MPH.

THURSDAY: Showers and thunderstorms likely. Low 66. High 85.

FRIDAY: Showers and thunderstorms possible. Low 68. High 82.

SATURDAY & SUNDAY: Isolated showers and thunderstorms. Lows 60-68. Highs 78-88.

MONDAY: Sunny. Low 66. High 88.

9:36PM

The heatwave that impacted parts of the region from as early as Wednesday through Sunday is done, but the humid pattern is not going anywhere during the coming week. Though a weak trough will dominate, this trough sits between a ridge to the west and a rebuilding ridge in the western Atlantic, and with no real push of dry air available from Canada, the humidity level will remain rather high right through the next 7 days. It won’t be as hot because of the lack of ridging and limited sunshine through at least the end of the work week. By sometime next weekend, another retrogression or westward movement of high pressure from the Atlantic may heat the region up again. Some signs point to another potential heatwave resulting but not until sometime the following week. We’ll also be eyeing an early-season system in the tropics for development and eventual track.

In the mean time, the updated forecast for southeastern New England goes something like this…

OVERNIGHT: Variably cloudy. Patchy fog valley and swampy areas. Humid. Lows in the 60s to lower 70s, warmest in urban centers. Wind light variable.

MONDAY: Variably cloudy. Showers and thunderstorms developing mid to late afternoon. Humid. Highs 80-85 except 70s South Coast. Wind S to SW 10-15 MPH, higher gusts.

MONDAY NIGHT: Mostly cloudy. Showers and thunderstorms likely early then diminishing. Patchy fog redeveloping. Muggy. Wind light SW to W.

TUESDAY: Partly sunny. Slight chance of afternoon showers or thunderstorms. Humid. Highs upper 70s to middle 80s. Wind W 5-15 MPH.

WEDNESDAY: Partly sunny. Scattered showers/thunderstorms. Low 66. High 84.

THURSDAY: Variably cloudy. Scattered showers/thunderstorms. Low 67. High 83.

FRIDAY: Mostly cloudy. Scattered showers/thunderstorms. Low 68. High 81.

SATURDAY: Variably cloudy. Scattered showers/thunderstorms. Low 66. High 83.

SUNDAY: Partly cloudy. Low 67. High 88.

11:44AM

The high pressure ridge that pushed most of the storms back to the west of the WHW forecast area of southern NH, eastern MA, and RI, will start to flatten this weekend, still keeping us in the ongoing heatwave, but allowing a slightly greater risk that a few showers and storms could get into the area. The ridge will weaken and retrograde further to the west during the coming week, as a new ridge re-builds in the western Atlantic. This will leave our area in a weak area of troughing that will bring increase shower and thunderstorm activity, less heat (80s instead of 90s), but continued humidity.

Updated forecast for southeastern New England…

TODAY: Partly cloudy. Isolated late day thunderstorms. Highs 92-97 except 80s to around 90  South Coast, Cape Cod, and Islands. Wind W 10-20 MPH.

TONIGHT: Partly cloudy. Isolated showers or thunderstorms early. Lows upper 60s to middle 70s. Wind W 5-15 MPH.

SUNDAY: Partly sunny. Scattered afternoon thunderstorms. Highs 90-95 except 80s South Coast, Cape Cod, and Islands. Wind W to SW 10-20 MPH.

MONDAY THROUGH FRIDAY: Daily episodes of scattered showers and thunderstorms. Lows 65-72. Highs in the 80s.

7:31AM

Happy Birthday USA!

This is just a carry-forward of yesterday’s forecast, getting rid of old info. Discussion on previous entry is the same. Have a safe and happy 4th of July everyone!

TODAY – INDEPENDENCE DAY: Partly cloudy. Slight chance of isolated afternoon to early evening thunderstorms north and west of  Boston. Humid. Highs from around 80 South Coast to around 90 elsewhere. Wind SW 5-15 MPH.

TONIGHT: Partly cloudy. Muggy. Lows upper 60s to lower 70s. Wind SW up to 10 MPH.

FRIDAY: Mostly sunny. Humid. Highs upper 80s to lower 90s, cooler South Coast. Wind SW to W 5-15 MPH.

SATURDAY & SUNDAY: Isolated PM thunderstorms. Lows 65-75. Highs 85-95.

MONDAY & TUESDAY: Scattered PM thunderstorms. Lows 65-75. Highs 85-95.

9:21AM

The outline from a few days ago is basically the same. Retrogression of high pressure from the western Atlantic will continue and eventually merge with high pressure from over the southern USA to form a large flat ridge of  high pressure, creating a hot weather pattern that will last well into next week. A little house-cleaning details are being taken care of today before this really gets underway. The back-door cold front that cooled off and in some cases fogged up parts of southern NH and eastern MA is heading back northeastward as a warm front and that cooler maritime air will be a distant memory in a short time. The thunderstorm threat is also diminishing, though we cannot rule out pop up storms from time to time in this pattern. For the next few days, the most likely place to see them would be across interior MA and southern NH in the late afternoon to early evening. Plan on mainly rain-free, very warm to hot, humid conditions. The most cloud cover will probably exist today, as the high pressure ridge continues to push the tropical moisture belt that had been over the region back to the west.

Updated forecast for southeastern New  England (southern NH, eastern MA, and RI)…

THIS AFTERNOON: Variably cloudy. Isolated showers and thunderstorms. Highs upper 70s South Coast to 80s elsewhere. Humid. Wind SW 10-15 MPH, gusting 20-25 MPH.

TONIGHT: Partly cloudy. Muggy. Lows in the 60s. Wind SW 5-15 MPH.

THURSDAY – INDEPENDENCE DAY: Partly cloudy. Slight chance of isolated afternoon to early evening thunderstorms north and west of  Boston. Humid. Highs from around 80 South Coast to around 90 elsewhere. Wind SW 5-15 MPH.

THURSDAY NIGHT: Partly cloudy. Muggy. Lows upper 60s to lower 70s. Wind SW up to 10 MPH.

FRIDAY: Mostly sunny. Humid. Highs upper 80s to lower 90s, cooler South Coast. Wind SW to W 5-15 MPH.

SATURDAY & SUNDAY: Isolated PM thunderstorms. Lows 65-75. Highs 85-95.

MONDAY & TUESDAY: Scattered PM thunderstorms. Lows 65-75. Highs 85-95.

12:51AM

Before I update the coming weather, a quick look back at the surprise “severe weather outbreak” of Monday. I put it in quotes, because it was not a severe outbreak in the classic sense. What these storms were made of was low level wind sheer. The storm tops were not very high. They were not typical storms, producing large hail and widespread damaging winds. Lightning was sparse at best. These storms were more like what you might see in a land-falling tropical storm, producing relatively weak spin ups (very brief and weak tornadoes), still capable of producing damage, however.

The set-up that caused this will still exist today (Tuesday), and though storms and showers may be a little less numerous overall, we will still have to watch for the possibility of isolated flooding downpours and isolated tornadoes and/or micro bursts in rapidly-developing tropical showers and storms. A very warm and humid tropical air flow will provide plenty of fuel for this.

As we have been discussing, the retrogression (westward movement) of the ridge of high pressure in the western Atlantic Ocean is underway and will continue through this week. After today, it means a decrease in thunderstorm activity, coverage-wise, though the threat will still exist at times, mainly in isolated form. It also means an increase in heat, and a continuation of humidity. This will include the Independence Day holiday and through the extended weekend following it. Anybody with outdoor plans should take precautions to stay protected from the sun, stay hydrated, and watch for any thunderstorms that develop or move into the region.

Updated forecast for southeastern New England (RI, eastern MA, southern NH)…

TODAY: Mostly cloudy with scattered to numerous showers and embedded thunderstorms. Isolated storms may produce damaging wind and local flash flooding. Very humid. Highs middle 70s South Coast to 80-85 interior areas. Wind SW 10-20 MPH.

TONIGHT: Mostly cloudy. Areas of fog. Lingering showers becoming isolated then ending. Very humid. Lows middle 60s to 70. Wind SW 5-15 MPH.

WEDNESDAY: Mostly cloudy with patchy fog early, then partly sunny. Isolated to scattered thunderstorms during the afternoon. Humid. Highs upper 70s to middle 80s. Wind SW 5-15 MPH.

THURSDAY – INDEPENDENCE DAY: Partly cloudy. Isolated thunderstorms mainly late day and early evening favoring far northern MA and southern NH. Low 70. High 87.

FRIDAY: Partly cloudy. Isolated late-day thunderstorms. Low 70. High 90.

SATURDAY: Mostly sunny. Isolated late-day thunderstorms. Low 71. High 91.

SUNDAY: Mostly sunny. Isolated late-day thunderstorms. Low 70. High 90.

MONDAY: Sunny. Low 69. High 88.