C-19 Chat Post – June 20 2021

DAYS 1-5 (JUNE 19-23)

A warm front has nearly completed its journey across the region as of the time of this blog writing, and only a few lingering showers associated with it are traversing southeastern New England early this morning, soon to exit, leaving the vast majority of the day free of any shower threat. This is a slightly different forecast than previously, which had a shower and storm threat this afternoon, but right now it looks like the air will be stable enough to prevent more than a brief pop-up shower/storm in isolated locations, and that the energy for showers and storms won’t really arrive until tonight, with a cold front that decided to hang back to the west before moving through. And by then, we’ll have lost a lot of daytime heating, leaving other atmospheric dynamics responsible for triggering and maintaining showers and storms, and the best of that may be passing across far southern portions of the region. What does that mean? It means that the shower and thunderstorm threat will most likely occur during the evening hours and the greatest chance of heaviest activity will be toward the South Coast, but we’ll have to monitor all areas, just to be sure. So if you have outdoor plans this afternoon, you can relax a little but still keep an eye out, and if you have outdoor plans this evening, be a little bit more aware. Still, I think most people get away with nothing more than a passing shower first thing today and again sometime this evening, and many see nothing at all. Any early clouds exit first thing Sunday as the cold front moves offshore, leaving us with a very warm day as there is not much cool air behind that front, but fairly comfortable air as the dew points which peak in the lower 60s today fall back to the upper 50s for Sunday. But don’t get “comfortable” (pun intended) because humidity is set to increase Monday and Tuesday. The higher dew point air will be re-introduced to the region as a warm front quietly passes through the region early Monday. The trend regarding that Gulf of Mexico low pressure area by guidance has been to either keep it as a compact low passing just south of New England or to dissipate it and have some of its moisture become involved with an approaching cold front. Guidance has also been split on the timing of that cold front, for example one model bringing it through on the earlier side Tuesday while another holds it back until later. The timing of that front with respect to daytime heating will have implications on how significant our shower and thunderstorm threat will be that day provided the Gulf low does not have direct impact and make it more of an overcast day anyway. So there are still some questions to answer regarding the forecast for Tuesday for our region. Regardless of those details, the cold front will be offshore and a pleasant polar air mass will arrive by Wednesday of next week.

TODAY: Partly sunny. Early to mid morning isolated showers eastern areas. Slight chance of a brief isolated shower or thunderstorm this afternoon. Highs 83-90, cooler Cape Cod. Dew point lower 60s. Wind W 5-15 MPH.

TONIGHT: Mostly cloudy. Scattered showers and isolated thunderstorms, greatest chance of thunderstorms may be closer to the South Coast region. Patches of fog forming. Lows 60-67. Dew point near 60. Wind W up to 10 MPH.

SUNDAY: Early clouds eastern areas, then sunny. Highs 81-88, cooler Cape Cod. Dew point upper 50s. Wind NW 5-15 MPH.

SUNDAY NIGHT: Clear evening. Partly cloudy overnight. Lows 61-68. Dew point upper 50s. Wind variable up to 10 MPH.

MONDAY: Early-day and late-day clouds with sunshine dominant between. Highs 85-92, cooler South Coast. Dew point rising through 60s. Wind SW 5-15 MPH.

MONDAY NIGHT: Variably cloudy. A shower or thunderstorm possible especially northwest of Boston in the evening. Lows 68-75. Dew point upper 60s. Wind SW to variable up to 10 MPH.

TUESDAY: Variably cloudy. Showers and thunderstorms likely. Highs 80-87, cooler Cape Cod. Dew point near 70. Wind variable 5-15 MPH.

TUESDAY NIGHT: Clearing. Lows 60-67. Dew point falling through 60s to 50s. Wind NW 5-15 MPH.

WEDNESDAY: Sun and passing clouds. Highs 75-82. Dew point falling to 40s. Wind NW 5-15 MPH.

DAYS 6-10 (JUNE 24-28)

Canadian high pressure brings fair weather and low humidity to start, then the high shifts offshore during the period with an increase in humidity and eventually shower and thunderstorm chances, especially June 26-28.

DAYS 11-15 (JUNE 29 – JULY 3)

A bit more west-to-east flow with overall drier but seasonably warm weather, and one or two disturbances to bring a shower or t-storm risk.

C-19 Chat Post – June 19 2021

DAYS 1-5 (JUNE 18-22)

The high pressure area that gave us nice weather during the last couple days will continue to treat us today, but its center has shifted to the Middle Atlantic States and this will turn the wind southwesterly here, warming us up with most places (except the South Coast) getting into the 80s for highs under the June sun, which is just a couple days away from reaching its pinnacle in our sky. The summer solstice will occur at 11:31 p.m. Sunday night, June 20, at the very end of the weekend. But what about the weather over the weekend? Well, while the sun does shine today you’ll notice an increase in high cloudiness at times, and by the end of the day the sun, at least in parts of the region, may be setting behind a deck of thicker clouds. This is the signal of a warm front approaching the region from low pressure moving into southeastern Canada. As that low treks along, it will first drag that warm front across New England overnight and early Saturday morning, with lots of clouds and some scattered areas of showers, and possibly a thunderstorm in a few locations. We’ll bust into the warm and more humid air on the other side of that front during Saturday morning, and any time during the day and into at least early Saturday night, until a cold front passes through, we can see some isolated to scattered showers and thunderstorms. It definitely won’t rain everywhere and where it does rain it definitely won’t rain a great percentage of the time, but if you have outdoor plans keep an eye on the sky (or a reliable radar app) and have a plan should a shower or storm visit your location. Once the front clears the region, while Sunday will be nearly as warm as Saturday, it will be less humid as a drier air mass moves in, but for a short stay. The high pressure area that delivers that brief drying air will slide offshore by Monday and the humidity, along with some heat, will come right back. And there is still a question to answer regarding Tuesday, but it’s day 5 in the forecast so we have time. That question: Do the remains of tropical low pressure in the Gulf of Mexico make it all the way to New England to add some heavy rainfall to the mix ahead of an approaching cold front on Tuesday? Still not sure. The guidance has trended a bit south and some of it a bet less emphatic with this feature the last 24 hours so we’ll see where it goes with this today. It’s likely to be a very small feature in relation to many lows we track, so it won’t be easy to pin it down either way. We at least get the threat of showers/storms at some point that day from the approaching / passing front, details dependent on frontal timing, with the wildcard of whether or not that low has any impact on the situation that day well, so for now, day 5’s wording will be general with fine-tuning to come in future updates…

TODAY: Sun followed by clouds. Highs 80-87, cooler South Coast. Dew point middle 50s. Wind SW 5-15 MPH.

TONIGHT: Mostly cloudy. Isolated to scattered showers and a slight chance of a thunderstorm overnight. Lows 60-67. Dew point upper 50s. Wind SW up to 10 MPH.

SATURDAY: Variably cloudy. Isolated to scattered showers early morning. Isolated to scattered showers and thunderstorms during the afternoon. Highs 83-90. Dew point rising to upper 60s. Wind SW 5-15 MPH, higher gusts.

SATURDAY NIGHT: Variably cloudy with scattered showers/thunderstorms evening. Clearing but patchy fog forming at lower elevations overnight. Lows 58-65. Dew point falling to upper 50s. Wind W 5-15 MPH.

SUNDAY: Mostly sunny. Highs 81-88, cooler Cape Cod. Dew point upper 50s. Wind W 5-15 MPH.

SUNDAY NIGHT: Mostly clear. Lows 61-68. Dew point upper 50s. Wind SW under 10 MPH.

MONDAY: Partly cloudy. Isolated afternoon showers or thunderstorms possible mainly interior locations then a chance of showers evening-night. Highs 85-92, cooler South Coast. Dew point rising through 60s. Wind SW 5-15 MPH.

MONDAY NIGHT: Variably cloudy. A shower or thunderstorm possible. Lows 68-75. Dew point upper 60s. Wind SW to variable up to 10 MPH.

TUESDAY: Variably cloudy. Showers and thunderstorms likely. Highs 80-87, cooler Cape Cod. Dew point near 70. Wind variable 5-15 MPH.

DAYS 6-10 (JUNE 23-27)

High pressure from Canada moves in via the Great Lakes with fair, mild, dry weather early in this period, then the high slides to and eventually off the Mid Atlantic Coast with increased warmth and humidity, and eventually some shower and thunderstorm opportunities, later in the period.

DAYS 11-15 (JUNE 28 – JULY 2)

Northward displacement of the jet stream becomes more pronounced during these days with early summer warmth, somewhat higher humidity at times, and a few opportunities for showers and thunderstorms with passing disturbances.

C-19 Chat Post – June 18 2021

DAYS 1-5 (JUNE 17-21)

An area of high pressure will control our weather through Friday with low humidity and a warming trend as the high center moves from the Great Lakes / Ohio Valley region today to the Middle Atlantic States by Friday. After that, the high moves offshore and low pressure tracking across southeastern Canada will first push its warm front through our region early Saturday morning when clouds increase and a possible round of showers may occur. Then we get into the warm sector between the warm front and approaching cold front with a shot of higher humidity, setting up the chance of showers and thunderstorms – a potential we’ll have to watch for stronger storms. Once that cold front moves by the region we’ll be set-up for a still warm but drier day on Sunday. At this time of year it’s not unusual at all for a “cold front” to be followed by air that’s pretty much the same temperature as what was ahead of it, but lower dew points. The air mass was originally cooler, but has been modified by a combination of the land it was moving over and a high sun angle, as well as more regionally by down sloping which warms air as it dries it out. So often you’ll hear the term “cold front” in a discussion, because that’s what it is by definition, but it doesn’t always bring significant colder or cooler air. In this case, it may be just a few degrees cooler Sunday in any given location than it is the day before, but it will be significantly less humid. But that won’t last, because the humidity and a bit more heat come right back on Monday. For now, I am keeping Monday’s forecast mostly dry with just isolated pop-up showers and storms possible later in the day, then a mention of showers arriving at night, but at day 5 this is already lower confidence and is further complicated by uncertainty regarding the approach of low pressure that originated in the Gulf of Mexico – not a large system, but one carrying a lot of moisture…

TODAY: Sunny to partly cloudy. Highs 76-83. Dew point near 50. Wind W 5-15 MPH.

TONIGHT: Mostly clear. Fog patches in lower elevations. Lows 52-59. Dew point lower 50s. Wind W under 10 MPH.

FRIDAY: Mostly sunny. Highs 80-87, cooler South Coast. Dew point middle 50s. Wind SW 5-15 MPH.

FRIDAY NIGHT: Mostly clear evening. Increasing clouds overnight with a risk of a passing shower near dawn. Areas of ground fog interior lower elevations. Lows 60-67. Dew point near 60. Wind SW up to 10 MPH.

SATURDAY: Partly sunny. Chance of showers and thunderstorms in the afternoon. Highs 83-90. Dew point middle to upper 60s. Wind SW 10-20 MPH.

SATURDAY NIGHT: Clearing. Lows 60-67. Dew point falling to 50s. Wind W 5-15 MPH.

SUNDAY: Mostly sunny. Highs 81-88, cooler Cape Cod. Dew point 50s. Wind W 5-15 MPH.

SUNDAY NIGHT: Mostly clear. Lows 61-68. Dew point upper 50s. Wind SW under 10 MPH.

MONDAY: Partly cloudy. Isolated afternoon showers or thunderstorms possible mainly interior locations then a chance of showers evening-night. Highs 85-92. Dew point rising through 60s. Wind SW 5-15 MPH.

DAYS 6-10 (JUNE 22-26)

Uncertainty for June 22 – a cold front approaches and we are warm and humid. There will be a chance for showers and thunderstorms at least with the approach of the front. The wildcard is whether or not the aforementioned Gulf of Mexico low adds heavier rainfall to the mix. This system has trended slightly less impressive and a bit further south on recent guidance but it will be something to keep a close eye on over the coming days. Regardless, mild/dry weather is expected behind the front for June 23 as high pressure builds in from the Great Lakes region. After this, the weather looks seasonably warm and mainly dry but we may need to watch another low pressure area or frontal system for wet weather toward the end of the period.

DAYS 11-15 (JUNE 27 – JULY 1)

Seasonal northward displacement of the jet stream becomes more pronounced during these days with early summer warmth, somewhat higher humidity at times, and a few opportunities for showers and thunderstorms with passing disturbances.

C-19 Chat Post – June 17 2021

DAYS 1-5 (JUNE 16-20)

Our weather will be dominated by a west-to-east flow in upper levels, or a zonal flow, as we head down spring’s home stretch to the summer solstice, which occurs late evening of June 20. High pressure will bring fair and seasonable weather today and Thursday, with some pop up clouds each day as the sun heats the air which rises into lingering colder air aloft. Then we warm up both surface and aloft on Friday as high pressure slides south of New England to off the East Coast. Our only risk of unsettled weather during this 5-day period comes on Saturday as a warm front sneaks in with maybe a pre-dawn or early morning shower, then a cold front approaches with a shower and thunderstorm threat during the afternoon hours. High pressure moves toward the region via the Great Lakes bringing fair and pleasant weather back to the region for Sunday.

TODAY: Sun and passing clouds. Highs 74-81, but turning cooler some coastal areas. Dew point near 50. Wind NW up to 10 MPH but possible coastal sea breezes.

TONIGHT: Mostly clear. Lows 52-59. Dew point upper 40s. Wind NW to variable under 10 MPH.

THURSDAY: Partly sunny. Highs 75-82, coolest coastal areas. Dew point near 50. Wind variable to W up to 10 MPH but coastal sea breezes possible.

THURSDAY NIGHT: Clearing. Lows 55-62. Dew point lower 50s. Wind variable to S up to 10 MPH.

FRIDAY: Mostly sunny. Highs 80-87, cooler South Coast. Dew point middle 50s. Wind S 5-15 MPH.

FRIDAY NIGHT: Mostly clear evening. Increasing clouds overnight with a risk of a passing shower near dawn. Areas of ground fog interior lower elevations. Lows 60-67. Dew point near 60. Wind SW up to 10 MPH.

SATURDAY: Partly sunny. Chance of showers and thunderstorms in the afternoon. Highs 81-88. Dew point middle to upper 60s. Wind SW 10-20 MPH.

SATURDAY NIGHT: Clearing. Lows 60-67. Dew point falling to 50s. Wind W 5-15 MPH.

SUNDAY: Mostly sunny. Highs 78-85. Dew point in 50s. Wind W 5-15 MPH.

DAYS 6-10 (JUNE 21-25)

A west to east flow pattern will continue. Look for a low pressure area bringing a warm front toward the region later June 21 with clouds and possible showers, and a cold front to bring showers and thunderstorms June 22. Mostly fair weather is expected thereafter but may have to watch for one wave of low pressure with possible showers about June 24.

DAYS 11-15 (JUNE 26-30)

Overall west-to-east flow pattern is expected to continue but slowly weaken with a northward lifting of the jet stream. This is a warm pattern with limited opportunities for showers and thunderstorms.

C-19 Chat Post – June 16 2021

DAYS 1-5 (JUNE 15-19)

Unsettled weather will continue today as additional showers form in the area as a result of humid air, an upper level low pressure trough, and a surface cold front moving slowly through the region. While most times it won’t be raining in any given location, any location may see passing showers and downpours, even some thunder remains a possibility too. Once the front gets by the region it will dry out this evening and tonight. High pressure builds in for Wednesday and Thursday but above there will still be a couple upper level disturbances which bring colder air in aloft and help initiate diurnal cloud development. This is expected both of those days, especially Thursday with the coldest pocket of air will be passing by above. Surface high pressure slides offshore Friday when it warms up nicely, and this continues into Saturday but may be interrupted by showers and thunderstorms as a cold front moves into the region from west to east…

TODAY: Mostly cloudy through mid afternoon with episodic showers and a chance of thunderstorms. Partly sunny late afternoon on but still with the possibility of additional passing showers and perhaps a thunderstorm. Highs 71-78. Dew point lower to middle 60s. Wind S up to 10 MPH.

TONIGHT: Partly cloudy. Patchy ground fog forming. Lows 52-59. Dew point lower 50s. Wind NW up to 10 MPH.

WEDNESDAY: Partly cloudy. Highs 74-81 but may turn cooler in some coastal areas. Dew point upper 40s. Wind NW up to 10 MPH but possible coastal sea breezes.

WEDNESDAY NIGHT: Mostly clear. Lows 52-59. Dew point upper 40s. Wind NW to variable under 10 MPH.

THURSDAY: Partly sunny. Highs 75-82, coolest coastal areas. Dew point lower 50s. Wind variable to NW up to 10 MPH but coastal sea breezes possible.

THURSDAY NIGHT: Clearing. Lows 55-62. Dew point lower 50s. Wind variable to S up to 10 MPH.

FRIDAY: Mostly sunny. Highs 80-87, cooler South Coast. Dew point upper 50s to lower 60s. Wind S 5-15 MPH.

FRIDAY NIGHT: Mostly clear. A few areas of ground fog interior lower elevations. Lows 60-67. Dew point lower 60s. Wind SW up to 10 MPH.

SATURDAY: Partly sunny. Chance of showers and thunderstorms in the afternoon. Highs 81-88. Dew point middle to upper 60s. Wind SW 10-20 MPH.

DAYS 6-10 (JUNE 20-24)

West-to-east “zonal” flow will be the weather pattern as we reach the summer solstice on June 20 and for the early days of summer 2021. However this flow does carry disturbances in it, and one such with a warm front / cold front combo with low pressure passing to the north will bring some unsettled weather at some point later June 21 into June 22 based on current timing, and another wet weather system may make a run at the region at the end of the period.

DAYS 11-15 (JUNE 25-29)

Overall west-to-east flow pattern is expected to continue but slowly weakening with a northward lifting of the jet stream. This is a warm pattern with limited opportunities for showers and thunderstorms.

C-19 Chat Post – June 15 2021

DAYS 1-5 (JUNE 14-18)

Today and Tuesday will be the unsettled days of the “work week” as a couple of frontal systems traverse the region underneath a low pressure trough. This will result in several opportunities for showers and thunderstorms. Wednesday and Thursday, high pressure will build in from the west with fair and seasonable weather, but some lingering troughiness and chilly air above will trigger diurnal cloud development each of those days with the sun’s heating. Right now, leaving showers out of the forecast. Friday, that high pressure area will slide offshore and we’ll warm up nicely.

TODAY: Most sunshine early to mid morning in eastern areas otherwise mostly cloudy with episodic showers and embedded thunderstorms. Highs 68-75. Dew point near 60. Wind S 5-15 MPH, gusts around 20 MPH.

TONIGHT: Variably cloudy with showers likely and a chance of thunderstorms evening. Partly cloudy with patches of fog forming overnight. Lows 58-65. Dew point upper 50s. Wind W up to 10 MPH.

TUESDAY: Variably cloudy. Episodes of showers and thunderstorms especially through mid afternoon. Highs 71-78. Dew point lower 60s. Wind W 5-15 MPH.

TUESDAY NIGHT: Partly cloudy. Patchy ground fog forming. Lows 51-58. Dew point lower 50s. Wind W under 10 MPH.

WEDNESDAY: Partly sunny. Highs 74-81 but may turn cooler in some coastal areas. Dew point upper 40s. Wind NW up to 10 MPH but possible coastal sea breezes.

WEDNESDAY NIGHT: Mostly clear. Lows 52-59. Dew point upper 40s. Wind NW to variable under 10 MPH.

THURSDAY: Partly cloudy. Highs 75-82, coolest coastal areas. Dew pinte lower 50s. Wind variable to NW up to 10 MPH but coastal sea breezes possible.

THURSDAY NIGHT: Clearing. Lows 55-62. Dew point lower 50s. Wind variable to S up to 10 MPH.

FRIDAY: Partly sunny. Highs 80-87, cooler South Coast. Dew point upper 50s to lower 60s. Wind S 5-15 MPH.

DAYS 6-10 (JUNE 19-23)

West-to-east flow dominates the pattern. A cold frontal passage brings a shower and thunderstorm chance June 19 and the next warm front / cold front combo is due later June 21 and June 22 with additional unsettled weather. The summer solstice occurs late evening of June 20.

DAYS 11-15 (JUNE 24-28)

Overall west-to-east flow pattern is expected to continue but slowly weaken. Wave of low pressure brings a rain chance early in the period then high pressure shifting offshore may bring warmer/hotter weather later in the period.

C-19 Chat Post – June 14 2021

DAYS 1-5 (JUNE 13-17)

After a wet start to Saturday, it evolved into quite the nice day as drier air arrived from north to south thanks to high pressure moving toward the region from eastern Canada. This high will be overhead to just offshore today, providing us with another nice and slightly warmer day. A warm front will approach from the west tonight, returning more cloudiness to the region and eventually some showers overnight into Monday morning before we get briefly into a warm and humid air mass behind the warm front and ahead of an approaching cold front, which will pass through Monday evening. This results in the opportunity for additional showers and thunderstorms during the day Monday into Monday evening before pushing offshore. But the front will be close by and a wave of low pressure may form on it and bring another round of showers at least to southeastern MA at some point Tuesday, while upper level low pressure crosses the entire region and also brings the chance of diurnally-driven showers that day. Finally, this conglomeration moves away and high pressure builds in with fair and seasonable weather for the middle of the coming week…

TODAY: Mostly sunny. Highs 76-83. Dew point middle 50s to near 60. Wind S 5-15 MPH.

TONIGHT: Mostly cloudy. Showers likely late evening and overnight. Areas of fog. Lows 56-63. Dew point middle to upper 50s. Wind S up to 10 MPH.

MONDAY: Variably cloudy. Showers most likely early morning. Isolated to scattered showers and thunderstorms thereafter. Highs 70-77. Dew point lower 60s. Wind SW 5-15 MPH.

MONDAY NIGHT: Variably cloudy with showers likely and a chance of thunderstorms evening. Partly cloudy with patches of fog forming overnight. Lows 52-59. Dew point falling to lower 50s. Wind W up to 10 MPH.

TUESDAY: Mostly cloudy with a period of widespread showers over southeastern MA. Sun/cloud mix elsewhere with isolated to scattered afternoon showers and possibly a thunderstorm. Highs 71-78. Dew point 50s. Wind W 5-15 MPH.

TUESDAY NIGHT: Partly cloudy. Patchy ground fog forming. Lows 51-58. Dew point lower 50s. Wind W under 10 MPH.

WEDNESDAY: Sunny to partly cloudy. Highs 74-81 but may turn cooler in some coastal areas. Dew point lower 50s. Wind NW up to 10 MPH but possible coastal sea breezes.

WEDNESDAY NIGHT: Mostly clear. Patchy ground fog in lower elevations. Lows 52-59. Dew point lower 50s. Wind NW to variable under 10 MPH.

THURSDAY: Mostly sunny. Highs 75-82, coolest coastal areas. Wind variable to NW up to 10 MPH but coastal sea breezes possible.

DAYS 6-10 (JUNE 18-22)

West-to-east flow dominates the pattern. Brief warming to a little above normal June 18-19 with a shower and thunderstorm chance June 19 with a frontal passage. Fair weather expected June 20 into June 21 but a disturbance may return more humid air and a chance of showers and thunderstorms to the region later in the period. The summer solstice occurs late evening of June 20.

DAYS 11-15 (JUNE 23-27)

The west-to-east (zonal) flow pattern should continue to start this period with a shower threat possible early in the period depending on system timing. With time we may start to transition to a warmer/hotter set-up, but this remains a low confidence outlook at this time.

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