East of Ipswich Bay and the Stellwagen Bank Marine Sanctuary Marine Forecast
|Rest Of Tonight...W Winds 5 To 10 Kt. Seas 2 To 3 Ft. A Chance Of Showers.|
|Wed...Ne Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. Patchy Fog. A Chance Of Showers. Vsby 1 To 3 Nm.|
|Wed Night...Se Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
|Thu...S Winds 15 To 20 Kt, Becoming Se 20 To 25 Kt In The Afternoon. Gusts Up To 30 Kt. Seas 4 To 7 Ft. Patchy Fog. Showers. Vsby 1 Nm Or Less.|
|Thu Night...W Winds 20 To 25 Kt With Gusts Up To 40 Kt. Seas 5 To 8 Ft. A Chance Of Showers. Vsby 1 To 3 Nm.|
|Fri And Fri Night...W Winds 20 To 25 Kt With Gusts Up To 30 Kt. Seas 4 To 7 Ft.|
|Sat...W Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 3 To 5 Ft.|
|Sat Night And Sun...W Winds 10 To 15 Kt, Becoming Sw. Gusts Up To 20 Kt. Seas 2 To 4 Ft.|
|Sun Night...S Winds 15 To 20 Kt. Seas 3 To 5 Ft. Showers Likely. Seas Are Reported As Significant Wave Height, Which Is The Average Of The Highest Third Of The Waves. Individual Wave Heights May Be More Than Twice The Significant Wave Height.|
Area Forecast Discussion|
National Weather Service Boston/Norton MA
404am EDT Wednesday April 8 2020
Weak area of low pressure tracking over or just south of New England will spread a period of rain across the region this morning. As the low departs a drying trend develops this afternoon along with a few breaks of sunshine late in the day. Another system moves in Thursday, bringing more rain and scattered thunderstorms. Scattered showers are possible Thursday night through Friday. Drier weather for this weekend before our next wet weather system early next week.
Near Term - Until 6pm This Evening
330am update ... Today ... Mid level warm front and associated surface wave moving across or just south of the region this morning. Given NW flow aloft deep layer moisture and instability will struggle to advect northeast. Therefore lowest probability of precipitation and least qpf will be across northeast MA. In addition convection currently over southeast PA into NJ appears to be precluding deep layer moisture and instability from advecting northeast. Furthermore, leftover dry air (Dew pts in the 30s) from Tuesday initially eroding leading edge of precipitation as it attempts to enter eastern MA during the predawn hours. Thus leaning toward the lower qpf guidance. 00z HREF probability matched mean seems reasonable with greatest qpf from western MA into CT, RI and southeast MA including Cape Cod and Islands where up to 0.25 inches of qpf is possible. Meanwhile over Essex county of northeast MA only a few hundreds is likely.
Progressive NW flow aloft will result in a short duration period of rain with drying trend for the afternoon. Back edge of precipitation shield currently from Utica NY to Lake George area. Low level winds become light northeast this afternoon behind departing frontal wave. Typically this would keep low clouds lock in across the region. However given low level dry air currently over the region with dew pts in the 30s, lower clouds will be confined to western MA/CT into RI and southeast MA this morning. Thus partial clearing will advect from north-northeast to southwest this afternoon and especially late in the day when some breaks of sunshine are possible. Models have been trending milder with each run. As a result will follow these trends with highs today in the low to mid 50s, upper 50s possible Hartford to Springfield. Not as warm as the past two days but very close to normal. Coolest temps along the immediate eastern MA coastline including Boston given the northeast winds, limiting highs here to the upper 40s.
Short Term - 6pm This Evening Through 6pm Thursday
Tonight ... Weak short wave ridging provides the region with dry weather and seasonable temperatures. Given light winds and dew pts 35-40 (at or above the average nighttime lows), risk for patchy fog especially along the coast where highest dew pts will be observed.
Thursday ... Closed low just north of the Great Lakes into southern Ontario ejects a very strong short wave into New England during the afternoon. Very strong jet dynamics with this system that induces 979 mb triple pt/secondary over northeast MA around 21z Thu. Strong cyclonic curvature to the mid/upper level flow coupled with PWAT (Precipitable Water) plume of 1+ inches and steep mid level lapse rates suggest a good bet for elevated convection and brief heavy showers. In fact could be a fine line of low top convection. Key for surface based convection will be how far north does warm sector track before triple pt low pinches off warm sector from advecting northward. Some of the high res guidance hint at warm sector briefly advecting into RI and eastern MA with surface temps and dew pts climbing into the 50s! Some of the guidance has trended farther north-northeast with triple pt/secondary low. This would result in warm sector surging farther north increasing the threat of strong to severe storms. Storm Prediction Center Day 2 forecast has also trended northward with marginal risk now into NYC area. Will just have to watch how this evolves. As of now SB instability appears to be lacking.
Breezy conditions will develop in the warm sector late Thu morning into Thu afternoon with south winds 10-15 mph gusting up to 25-35 mph at times, then abrupartly shifts to the west late in the day with the FROPA.
Long Term - Thursday Night Through Tuesday
Highlights... * Gusty winds, light rain, and high elevation snow on Friday with a few rumbles of thunder possible
* Potential for minor coastal flooding through early Friday around high tide across the east and south coasts of MA and RI. See the Tides and Coastal Flooding section below for more details.
* Temperatures running near to below normal through Saturday, then a warm up Sunday- Tuesday
* Rain and gusty winds return Monday
Details... Thursday night and Friday... By late Thursday evening/early overnight hours the cold front will have exited offshore ushering in a drier airmass and leaving clearing skies in its wake. Strong jet dynamics remain, now out of the W/NW. This brings mid level Cold Air Advection and steepening lapse rates, helping to mix down a strong 40-50 kt 850 mb LLJ. The strongest winds should remain aloft during the overnight hours, but with diurnal heating on Friday and the cold pool(a region of relatively cold air) aloft the boundary layer should mix very well all the way up to at least 750 mb. This will allow for widespread very strong wind gusts to mix down, potentially necessitating a Wind Advisory or even a High Wind Warning; 40-50 mph gusts are likely.
Even though the surface low will be well to our north, the upper low lingers overhead keeping cyclonic flow in place with wraparound moisture and the strong LLJ. This will mean scattered rain showers, especially during the day. This as diurnal heating of the surface together with the cold pool(a region of relatively cold air) aloft contribute to some surface based instability which could bring about a thunderstorms or two as well.
Saturday and Sunday... Nice weekend in store, though Sunday looks to be the nicer of the two days (warmer with less wind). A ridge of high pressure begins to move overhead early Saturday, and this means the pressure gradient will be slowly relaxing, so winds likely remain breezy on Saturday before calming Saturday night and Sunday. Temperatures remain in the low 50s on Saturday under NW flow on the downstream side of the ridge. By Sunday though, the ridge axis approaches and SW return flow warms us up into the upper 50s. Low temperatures on Sunday morning were trended toward the colder MOS guidance to account for likely radiational cooling under clear skies and light winds...into the upper 20s and low 30s.
Monday and Tuesday... The mild temperatures continue on Monday and Tuesday. However, it comes with the return of widespread rain. A deep mid level trough and surface low will bring rain and gusty winds around Monday, with another potentially wet disturbance right on its heels.
Today ... weak surface low tracks south of New England this morning then eastward to Georges Bank this afternoon. Morning rain gives way to a drying trend in the afternoon. Light SSW winds become NE this afternoon.
Tonight ... Weak high pressure over the waters provides dry quiet weather.
Thursday ... strong cold front sweeps across the water late Thu with widespread showers and embedded thunder likely. Strong SSW winds ahead of the front abrupartly shifts to the WNW and remains strong and gusty.
Outlook /Thursday Night through Sunday/... Thursday Night: Moderate risk for gale force winds with gusts up to 40 kt. Rough seas up to 11 ft. Slight chance of rain showers.
Friday: Moderate risk for gale force winds with gusts up to 40 kt. Rough seas up to 12 ft. Slight chance of rain showers, isolated thunderstorms.
Friday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas.
Saturday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas.
Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft.
Sunday: Winds less than 25 kt.
Tides / Coastal Flooding
Next 4 tides (Midday and midnight today and Thursday) are astronomically high and run the risk of minor coastal flooding/inundation. Midday today and then midnight tonight main risk is eastern MA and again tonight given light onshore flow. Then tomorrow with southerly surface winds risk shifts to the south coast of MA/RI.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...Coastal Flood Advisory from 8am this morning to 8am EDT Friday for MAZ019-022. Coastal Flood Advisory from 8pm this evening to 8am EDT Friday for MAZ015-016. Coastal Flood Advisory until 8am EDT Friday for MAZ007. RI...Coastal Flood Advisory from 8pm this evening to 8am EDT Friday for RIZ002-004>007. MARINE...Gale Watch from Thursday afternoon through Friday evening for ANZ232-250-254-255. Gale Watch from late Thursday night through Friday evening for ANZ233>235-237-256. Gale Watch from Thursday afternoon through Friday afternoon for ANZ231-251.