Montauk NY to Marthas Vineyard out 20 NM South of Block Island Marine Forecast
|Rest Of Tonight...W Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 4 Ft.|
|Sun...Nw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 5 Ft.|
|Sun Night...Nw Winds 5 To 10 Kt With Gusts Up To 20 Kt, Becoming N 10 To 15 Kt After Midnight. Seas 2 To 4 Ft.|
|Mon...Nw Winds 5 To 10 Kt, Becoming Sw 10 To 15 Kt With Gusts Up To 20 Kt In The Afternoon. Seas 2 To 4 Ft.|
|Mon Night...W Winds 10 To 15 Kt, Becoming Nw 5 To 10 Kt After Midnight. Seas 2 To 4 Ft.|
|Tue...Sw Winds 5 To 10 Kt. Seas 3 To 4 Ft.|
|Tue Night...Sw Winds Around 10 Kt. Seas Around 4 Ft. A Chance Of Showers.|
|Wed And Wed Night...Sw Winds 5 To 10 Kt. Seas 4 To 7 Ft. A Chance Of Showers.|
|Thu And Thu Night...W Winds 5 To 10 Kt, Increasing To 10 To 15 Kt. Seas 5 To 7 Ft. 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
318am EDT Sunday May 31 2020
High pressure from the Midwest builds into New England today bringing dry weather. A weak disturbance slides down from Canada for Monday causing a period of clouds and isolated showers. Cooler, drier weather then prevails through Monday night. Unsettled midweek with warming temperatures and chances for showers Tuesday through Thursday. Best chances for rain with even a risk for thunder on Wednesday. Gradual warming trend to temperatures for the workweek, then trending cooler for the weekend.
Near Term - Until 6pm This Evening
Patchy clouds early, but otherwise a sunny day with scattered afternoon cumulus. Cold advection aloft will translate to cooler temperatures than yesterday. The mixed layer is forecast to reach to 775 mb this afternoon, supporting max surface temperatures in the mid 60s to around 70. This mixing will also tap slightly stronger winds aloft and allowing northwest gusts around 20 mph.
Short Term - 6pm This Evening Through 6pm Monday
Upper trough and cold pool(a region of relatively cold air) dig over New England tonight. The torugh moves off across the Gulf of Maine on Monday, while the cold pool(a region of relatively cold air) remains overhead through the day.
Tonight... High pressure weakens the pressure gradiant, bringing light winds tonight. With dew points in the 30s, expect min temps in the upper 30s to mid 40, except around 50 on the Cape/Islands.
Monday... Midwest high pressure gets the region off to a sunny start. But sunshine and heating will combine with the cold temps aloft and a moist layer between 850-mb and 775-mb to produce diurnal clouds and possibly a few (light) diurnal showers. As noted by the previous forecaster, cold temps aloft may support a non-zero chance of graupel. Mixing again reaches 775 mb, where temperatures would support max surface temps in the 60s.
Long Term - Monday Night Through Saturday
Highlights... * Dry, cool evening Monday night.
* Generally unsettled Tuesday through Thursday, but big uncertainty on timing. Couldn't discount showers any time, though somewhat better chances (even embedded with thunder) on Wednesday.
* Warming trend to temperatures through the workweek, then a cooldown for the weekend.
Overall Pattern... Mid-level pattern across CONUS looks fairly amplified but also quite blocky with slow-evolving and slow-translating large-scale features. The pronounced upper trough set to take shape over New England late tonight into Monday trudges into the northern Atlantic early in the period, only to then retrograde toward the Canadian Maritimes as a closed low Tuesday night into midweek. This retrogression is in response to large mid-level ridging forecast over the north-central Atlantic Ocean, with associated somewhat cooler conditions underneath the closed low. In the center of the U.S., a building heat ridge which also features conditionally-unstable air will be prominent. Sets the stage for a fast belt of WNW flow aloft across the Great Lakes into Southern New England, separating these two air masses. Periodic pieces of shortwave trough energy, some of which could be of remnant-convective origin from forecast activity in the northern Plains area, to traverse across our area around the southern fringe of the Canadian Maritimes closed low. By the weekend, cyclonic flow/troughing amplifies with cooler conditions and limited prospects for showers.
Given the above, the confidence in the precip/Wx forecast and more specifically the timing of higher Probability of Precipitation is quite low. This results in a rather generic/broad- brushed Probability of Precipitation forecast for mid to late week. Better confidence exists on temperatures, with our area generally remaining northeast/cooler side of the summerlike heat-humidity dome over the Ohio Valley, Appalachians, mid-Atlantic area.
Details... Monday Night:
Surface ridge axis shifts east late Monday night and allows initial NW winds to back to the WSW. Should be a generally quiet night with the 850 mb warm front still well to our west. Cool but comfortable lows Monday night in the mid 40s to lower 50s.
Tuesday into Thursday:
This is really where uncertainty on the PoP/Wx forecast begins to rise significantly due to variance in the details and timing of shortwave energy rippling southeast from the upper Midwest/Great Lakes region. Really couldn't discount a threat of showers at any point in this period and have kept slight to Chance Probability of Precipitation going. There is some loose consistency in showing somewhat better chances for rains at least the second half of Wednesday into Wednesday night, with some elevated instability (Showalter indices near 0 to -1 from slightly better than moist-adiabatic 850-500 mb lapse rates) supporting a risk for thunder over our western and southwestern counties. Less of a chance, though still slight chance for showers on Thursday. Probability of Precipitation will need fine tuning once there's better clarity on upper- disturbance timing/track.
General warming trend to temperatures with highs initially in the lower to mid 70s Tuesday, then rising into the upper 70s to mid 80s for Wednesday and Thursday. Humidity levels start to rise back upward, though not oppressive with dewpoints in the upper 50s to lower 60s. Lows Tuesday night in the 50s, and into the lower to mid 60s for Wednesday and Thursday nights.
Friday Into The Weekend
Given uncertainty in the mid to late week period, mainly strayed close to a guidance blend for this period especially for PoPs. Though temps on Friday look to be the warmest of the workweek, a cooldown looks to be in the offing Saturday into Sunday as another upper trough digs into New England. Associated much cooler 850 mb temperatures (in the lower to mid single digit Celsius range) translate to cooler than normal temps.
Seas linger near 5 feet on the outer waters today, while the remaining waters are below 5 feet. Seas then trend below 5 feet all waters tonight and Monday. Winds will be less than 25 kt through the period. Small Craft Advisory on the southern outer waters remains in effect this morning, and on the southeast outer waters through this afternoon.
Outlook /Monday Night through Thursday/... Monday Night: Winds less than 25 kt. Slight chance of rain showers.
Tuesday: Winds less than 25 kt.
Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers.
Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers.
Wednesday Night: Winds less than 25 kt. Local rough seas. Rain showers likely, isolated thunderstorms.
Thursday: Winds less than 25 kt. Local rough seas. Slight chance of rain showers.
Expecting dry and gusty conditions across southern New England Today. Winds will be out of the northwest across the region with speeds of 10-15 mph, with gusts of 20-25 mph...strongest this morning. This will couple with minimum relative humidities of 25 to 35 percent across much of the interior. Coastal locations will see minimum relative humidities of 30 to 50 percent.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
Small Craft Advisory until 5pm EDT this afternoon for ANZ254- 255. Small Craft Advisory until 10am EDT this morning for ANZ256.